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The International Space Station



The International Space Station
The International Space Station is the second home of humans in Earth orbit, which is considered an engineering masterpiece.

The International Space Station

The International Space Station, or ISS for short, is a multi-piece space structure that is placed in low Earth orbit and several elite astronauts live in it for a certain period of time, during various missions. The process of building the International Space Station started in 1998 and it is said that it can be used until 2028. As its name suggests, the International Space Station is a multinational project, and the cost of its construction and development is divided among several specific countries; But according to the statistics and evidence, it can be said that Russia and America are the main contractors of the project and provide most of the expenses related to the station. Every year, some astronauts are sent to the station and return to Earth to carry out some necessary research. The existence of the International Space Station is necessary to investigate the effects of living in space on the human body; Because soon man will travel to planets like Mars.

The International Space Station

The International Space Station has been constantly being completed during its mission. The first structure of this station was launched into orbit in 1998 and the last module was installed on the station in 2011. NASA, Roscosmos (Russian space agency), Japan Space Agency, European Space Agency, and Canadian Space Agency are among the main contractors of the station and each of them has sent astronauts to the station. The budget of this station is provided internationally and the member countries are obliged to allocate a certain amount of their budget to the International Space Station every year. The cost of building the International Space Station until the moment of installation of the last module was 150 billion dollars, and for this reason, it is considered the most expensive structure of the human hand.

The International Space Station is the second home of humans in Earth orbit. People who go to the station experience zero gravity and are affected by the conditions of space. One of the reasons humans are stationed in the station is to measure the effects of space conditions on their bodies. When humans want to travel to planets like Mars, they have months to reach their destination; Therefore, during this period, they live in special conditions that will definitely have effects on their bodies. For this purpose, conducting a series of experiments in the International Space Station can reduce the risks of space travel.

The International Space Station

The International Space Station is not the first station to be built in the Earth’s orbit, and before that, stations such as Mir, Salyut, Almaz, and Skylab were also built in the Earth’s orbit; But ISS is the largest and most advanced of them and its mission duration is longer than others. This station has certain intricacies that make it an engineering masterpiece. In this article, we intend to put the International Space Station under the microscope and take a close look at all the details of the most expensive human structure.

Read More: Receiving a message from a distance of 16 million kilometers from the earth


The history of the construction and development of space stations goes back to the time of the Cold War and the height of the space competition. When the Saturn 5 rocket was being developed by America and by Dr. Werner von Braun and his group, this German engineer always had the idea of ​​building a space residence in his mind. In the same years, in order to be able to explain this idea to people in a better way, Hanzmenda created cinematic works in which space stations were depicted. These stations were circular and rotating; Because in the hypothetical case, they should have created artificial gravity with their rotation. In these movies, many people traveled to the station and started businesses there; The ships also moved towards the station like the ships that dock at the port. A similar idea was recently portrayed in the movie Elysium.

These stations were like hotels on the way, and humans could go to the moon or Mars from there. This idea was very timeless, But that was exactly what Dr. Brown had in mind. This idea is not applicable even today despite the advances, But scientists have been able to implement the original idea of ​​building a space station, and this work was done for the first time by the Soviet Union. The first space station was launched in 1971, and since then, the United States and the Soviet Union have always had a station or stations in orbit. The first station that was placed in the earth’s orbit was the Salyut space station (Салю́т), which was considered a military scientific project the Soviet Union was very sensitive about it and tried not to reveal any details about it and not to be available to the Americans.

The International Space Station

After the Salyut space station, it was the Americans’ turn to enter this field. Skylab was the first American space station in Earth orbit, which was sent into space at once by the Saturn V rocket in 1973. The Salyut station was a multiple project, the first of which was called Salyut 1, and actually, this station was a combination of the Almaz and Soyuz spacecraft systems. Almaz was a military system designed for space purposes by the Soviet Ministry of Defense, But later its usage was changed and it became a part of Salyut 1 station.

After the Soyuz 11 mission, the Soviet Union launched another space station called Salyut 2, which unfortunately was unsuccessful and did not reach Earth’s orbit. After this failed mission, the Soviet Union launched the Salyut 3, Salyut 4, and Salyut 5 space stations, and after the launch, the astronauts connected to the station with the help of the Saiz spacecraft and stayed there for a longer period of time to carry out new missions. Salyut stations were only connected to Soyuz spacecraft and it was not possible to connect them to other types of spacecraft. In September 1977, the Salyut 6 space station was launched, which had two entrances and the unmanned Progress spacecraft could also dock with it. Salyut 6 continued to work until 1982, and then it was replaced by Salyut 7, which was the last station of the Salyut project.

Salyut 7 was one of the news-making and controversial stations. This station was launched in 1982 and hosted 11 astronauts for 800 days; But in the same year, the Salyut 7 accident happened and the station was out of Soviet control. The electrical system of this station failed due to the impact of several cosmic bodies, and the station began to rotate in the earth’s orbit and the process of falling towards the earth began. The Soviet Union, which was under international pressure at the time, decided to launch two astronauts on a Soyuz spacecraft during a hasty mission to manually dock the rotating station and return it to a stable state. These two Russian astronauts managed to connect to the station and recover it, and this rescue operation is one of the most impossible missions in the history of aviation. The Salyut 7 space station later paved the way for the formation of the Mir space station project.

The International Space Station

America, unlike the Soviet Union, did not invest much in the field of space stations, and before the development of the International Space Station, Skylab was the first and only American space station. Skylab was launched in 1973, But it was damaged during the launch and 2 of its solar panels were completely fragmented and another solar panel did not open completely. These events caused Skylab to have little electrical power in the circuit and the station’s temperature regulation system did not work well. To solve this problem, the United States launched the manned spacecraft Skylab 2 so that the astronauts could repair the station. These astronaut engineers were able to successfully repair the station bring it to a stable state and stay in the station for 28 days.

Orbital workshop, weatherproof module, multiple docking station, Apollo telescope unit, and Apollo spacecraft were among the constituent parts of Skylab. The Skylab 3 and 4 missions, whose crews stayed on the station for 59 and 84 days, respectively, docked with the station after the Skylab 2 mission. Skylab was not a permanent station, and the US intended to use it solely as a space laboratory to measure the effects of flights lasting a week to a month on the human body. Skylab 3 was the last mission to dock with the station, and the Skylab space station entered the Earth’s atmosphere much earlier than expected due to rapid orbital rotation caused by collision with intense solar activity and burned up in the sky over Australia.

Another space station was the Soviet Mir station, which was launched and assembled in 1986. Mir was considered the most advanced man-made space station at that time and was operational for 10 years. The first astronauts who went to the station were the same astronauts who performed the rescue operation of Salyut 7. These people stayed at Mir station for 75 days and then returned to Earth. The Mir space station consists of parts such as the life module (bathroom and kitchen, etc.), the mediating part, the assembly part, the Quantum 1 astrophysics module, the Quantum 2 airtight and scientific module, the Crystal technological module, the Specter module, the Periroda remote sensing module, The docking module was formed by the unmanned Progress spacecraft and the Soyuz spacecraft.

The International Space Station

In 1994, Russia allowed the United States to allow American astronauts to spend some time at the Mir station to prepare for the International Space Station. Worried about the high costs of maintaining the Mir station, Roscosmos decided to partner with NASA; But the Russian government did not agree and said that it is better to abandon the station so that all the focus is on the International Space Station. Mir was a permanent space station, But the Russian government decided to direct it to the ground and destroy it. Finally, in 2001, the remnants of the Mir space station fell into the South Pacific Ocean.

According to the information we have obtained, we now know that the ISS is the ninth habitable space station in Earth orbit, It was developed after Diamond, Salyut, Skylab, and Mir, and perhaps inspired by them. The process of building the International Space Station began in 1998; But the first astronauts who stayed there were launched into space during the Expedition 1 mission on November 2, 2000. Since then, more than 17 years have passed and this is the longest presence of a space station in low Earth orbit. Before the International Space Station, the record for the longest stay of a space station in orbit was held by the Mir space station with 9 years and 357 days. The cargoes required for the International Space Station are transported to the station with the help of spacecraft such as Russia’s Soyuz and Progress, America’s Dragon and Cygnus, Japan’s H-II, and Europe’s transfer system. Before the cancellation of the space shuttle program, it was also possible to connect these shuttles to the station. The International Space Station has hosted astronauts, cosmonauts, and tourists from 17 different countries.

According to the contract signed between NASA and Russia’s Roscosmos, it was decided that the International Space Station will be a laboratory in low Earth orbit, where necessary investigations will be carried out to improve future space travel. NASA had predicted that humans will travel to Mars in the future and dangers are threatening them; Therefore, it is necessary to measure the results of being in space on the body in the International Space Station so that there are no problems for astronauts in future trips. In 2010, the US Space Flight Agency announced that the ISS had more potential and could be used for educational purposes and to share information with the public in the form of television programs.

Construction of the station

The construction of the International Space Station officially began in November 1998. Russia was the first country to produce the initial modules of the station, and all of these modules, except for the Razovet module, were robotically connected in space. The other modules of the station were launched by the American space shuttles and connected by the shuttle crew using the Canadarm2 robotic arm. By June 5, 2011, when the construction process of the station was completed, 159 pieces had been connected during 1000 hours of spacewalk, and this was considered a record. 127 spacewalks were performed by the station’s crew, and the remaining 32 were performed directly inside the shuttles and airlocks. Scientists on the ground had to constantly calculate the station’s beta angle and provide it to the astronauts so that the work went as well as possible. Beta is the angle between the orbital plane of a satellite and the solar radiation vector and shows how much energy a satellite receives during solar radiation to generate electricity. For the engineers who were building the station in space, the beta angle was of particular importance; Because it showed how many hours they were exposed to sunlight during the docking operation, and if the beta was not calculated, the shuttle could not be placed correctly on some modules during some limited hours.

The International Space Station

The first module of the International Space Station is the Zarya module (Заря́) which was launched on November 20, 1998, by the Russian Proton self-propelled rocket. Zarya was a module that could provide the necessary propulsion power to be placed in the orbit, control the height, and also provide the necessary electrical power; unfortunately, it did not have enough facilities to be used for a long-term stay. Two weeks after Zarya, the United States launched the Unity module (Unity) in the STS-88 mission with the help of the space shuttle and several crew members. The Unity module was attached to the Zaria module by astronauts who performed several hours of spacewalk. Unity had two pressure-coupled adapters, one connecting to Zaria and the other to the space shuttle. At the same time, the Mir space station was still in orbit and could host the crew.

The International Space Station was uninhabitable for two years, and the Mir station was gradually decommissioned. On July 12, 2000, Russia launched the Zvezda (Zvezda) module into space. The Roscosmos space agency had planned Zivezda to deploy its solar arrays and communications antenna before connecting to Unity and Zaria. This module itself had a command center and was autonomous, But Zaria and Unity were controlled and commanded by ground stations. Zyuzda was the most advanced module to be attached to the ISS. After connecting Zyuzda to other modules, the task of controlling the overall structure of the station was taken from Zarya and given to Zyuzda. Zivzda was a large module where there were sleeping quarters for the crew, a kitchen, carbon dioxide scrubbers, humidifiers, oxygen generators, sports equipment, radio and television connected to the mission control system, etc. Zvezda was the module that made the ISS habitable for the first time.

The first crew of the International Space Station, in the form of the Expedition 1 mission and with the help of the Russian Soyuz TM-31 spacecraft, connected to the space station in November 2000. Late on the first day of the mission, astronaut Bill Shepard of NASA and cosmonaut Sergei Krikalyov of the Russian space agency, as two members of the Expedition 1 crew, announced in a radio message that they wanted to name the station Alpha. Alpha had previously been considered for the station’s naming, But America and Russia had in mind the name ISS. Now that the two astronauts had applied, NASA and Roscosmos decided to rename the Expedition 1 mission to Alpha. Shepard believed that they should name the entire station Alpha; Because alpha is always a reminder of being first. In a speech, he announced that this is the first experience of a long-term stay in space and that we are considered the pioneers of staying in space. NASA had agreed to some extent, But Russia said that this is not true and the Mir station has been habitable before, and if the name Alpha is to be chosen, Mir should be Alpha.

For two years after this mission, the station was still expanding. In 2001, a Soyuz rocket carried the Pierce Multiplexer into space. A pier is a connecting section that has vents to connect the manned Soyuz and the unmanned Progress spacecraft and acts as a trike. The space shuttles Atlantis, Discovery, and Endor also brought the Destiny Laboratory and the Quest airlock into space to dock with the station. In addition, for the first time, the Canadarm2 robotic arm and several other parts were also attached to the body of the station. Everything was going well and according to the plan until the explosion of the space shuttle Columbia disrupted the program. In 2003, the space shuttle Columbia exploded in the sky and killed all its passengers. This incident caused a two-year hiatus in NASA’s space shuttle program. The space shuttle program was suspended until 2005 when it was finally restarted with the launch of the space shuttle Discovery.

The process of assembling the modules of the space station started again in 2006 with the launch of the shuttle Atlantis in the STS-115 mission. During this mission, NASA attached the second set of solar arrays needed by the station to the main structure. The next three NASA missions also connected other body components and the third series of solar arrays to the station, and as a result, the power generation capacity of the station was completed. After Russia and America were sure about the power supply of the station, they started the process of sending the next modules. The Harmony Node and the Columbus Laboratory (belonging to the European Space Agency) were among the modules that were attached to the body of the station and other modules. Soon after the connection of these two modules, the Japanese Space Agency announced that the first part of the Kibo laboratory was produced and ready to be sent.

In March 2009, the STS-119 mission completed the construction of the subsystems and was able to install the fourth and final group of solar arrays on the hull of the station. The second and last part of Japan’s Kibo Laboratory was connected to the station by the STS-127 shuttle mission in July 2009, and then the Poisk module (По́иск), or the small research module, was launched by Russia. In February 2010, the STS-130 mission, carried by the space shuttle Endor, attached the third node, or Tranquility, to the station, along with the Cupola observation tower. A few months later, Russia also launched one of its last modules called Razvet (Рассве́т). Russia did not carry out the launch itself, but entrusted the task of the launch to the Atlantis space shuttle and paid the cost of the launch. Earlier, the US had financed the launch of the Proton rocket that launched the Zarya module into space in 1998.

The International Space Station

On its last mission in February 2011, Discovery delivered the Leonardo Pressurization Module to the station, and in the same year, the space shuttle Endor also docked the Alpha Electromagnetic Spectrometer during mission STS-134. As of June 2011, the space station consisted of 15 pressurization modules and an integrated structure, and member states declared that all major equipment was installed on the station and that anything launched after that would be considered auxiliary equipment. Currently, 5 other modules are in the launch queue. These modules are:

  • The Nauka module (Нау́ка), which is a Russian multipurpose laboratory, connects to the Zyuzda module.
  • The European Space Agency’s robotic arm
  • Узловой module, which is a Russian spacecraft
  • NEM-1 power supply module
  • NEM-2 power supply module

The Russian Space Agency has announced that the Nauka module will most likely be launched in the last quarter of this year along with the robotic arm of the European Space Agency. After the Nauka module docks with the space station, Russia will also launch the Yuzloy module to connect to one of the Nauka module’s docking ports. When these 5 modules are connected to the station, the total weight of the station will be more than 400 tons. The net weight of the station constantly changes over time; Because newer modules are always added to the station. By September 2011, when the construction of the station was completed, its total weight was 417 tons. Of course, this is considering only the weight of the station structure itself and ignoring the weight of water tanks, gas tanks, laboratory equipment, clothes and personal belongings of astronauts, food, connected spacecraft, and other things.

The International Space Station is a third-generation modular space station. A modular structure allows the body of the station to be changed to suit different missions and new parts can be added or removed from the structure. Also, the modular structure has flexibility and its shape is not static.

The main modules of the station

As mentioned earlier, the International Space Station is made up of several different modules; But some of these modules are original and other modules are installed on top of these modules. Zaria, Unity, Zyvesda, Destiny, Quest, Pierce and Poisk, Harmony, Tranquility, Columbus, Kibo, and Coppola are among the core modules of the International Space Station currently installed on the station. There are a number of other modules that are going to be connected to the station soon, which we will also mention. In the following, we will examine each of these modules and their features.

Zaria module

Zarya, which is also known by the Russian name Заря́ meaning dawn, is the first module of the International Space Station that was launched by the Russian Space Agency (Roscosmos) and placed in orbit. The task of Zaria was to provide electricity, propulsion, and positioning of the International Space Station in the early stages of construction and production. When the other modules were launched and attached to Zaria, Zaria had no special function and is now used as a storage area. Zarya is actually a more advanced version of the Russian TKS spacecraft that was used to connect to the Salyut space station. As mentioned, Zaria means dawn; Because it was supposed to usher in a new era in spaceflight. Zaria was built by a Russian company, But the main owner of that company was the United States of America.

The International Space Station

Initially, Zaria was supposed to act as one of the modules of the Mir space station; But unfortunately, Zaria was not ready until the Mir space station was stable. Zarya has the ability to maintain a station in orbit and, due to the batteries that are placed inside its body by default, it has the ability to provide power to one or more other modules until the solar arrays are launched. Zarya weighs 19,323 kg, is 12.56 meters long and 4.11 meters wide at its widest point, and is considered a medium module in terms of size. Zarya can be connected from three different parts, one of them is located exactly in the front part, another one is in the ground part and the other one is placed in the back part. The Unity module is connected to the Zarya’s front connector with the help of a push-fit adapter. The Zyuzda module is also connected to the end of Zarya, and its ground connection valve is also connected to the Soyuz and Progress spacecraft that come to the station. Not long ago, the Razovet module was attached to the downward docking port of Zarya, and now if a spacecraft arrives at the station, it must be attached to the Razovet module first.

Zaria has two solar arrays 10.67 meters long and 3.35 meters wide and 6 nickel-cadmium batteries that can produce 3 kilowatts of electricity. Zaria has 16 external fuel tanks that can hold 5.4 tons of fuel. Zarya has 24 large thrusters, 12 small thrusters, and two large engines that were used for the station’s orbital changes. Since the Zyuzda module connected with the station, Zarya’s engines were disabled; Because with Zyuzda, Zarya engines were no longer needed. Zarya’s fuel tanks are now used as a place to store the fuel needed by Zyuzda.

On November 20, 1998, Zarya was launched by a Russian Proton rocket from the launch pad of Cosmodrome 81 in Kazakhstan to an altitude of 400 km. Zarya was originally designed to have a useful life of 15 years and be able to fly autonomously for 6 to 8 months; But due to the delay in the launch of the Zyuzda module, Zarya had to move autonomously for more than two years. At first, Zaria’s battery charging circuits had problems; But gradually these problems were solved by Russian cosmonauts.

Unity module

The Unity module, also known as Node 1, is the first American module of the International Space Station launched by NASA. Unity uses a cylindrical design and can be connected to the station and other modules from 6 separate points. Unity is 4.57 meters in diameter and 5.47 meters long and was jointly developed by NASA and Boeing at the Marshall Space Flight Center in Alabama. Unity is the first docking module of the space station, followed by Harmony and Tranquility modules.

The International Space Station

Unity was the main cargo of the space shuttle Endor, which was launched as part of the STS-88 mission. This mission was the first space shuttle mission to connect to the station. In space, before reaching the Zaria module, the rear end of the Unity module was attached to the Endor shuttle, and then they moved towards the Zaria module until they finally managed to attach the upper part of the Unity to the front section of the Zaria. Unity has 2 axial connection systems and 4 radial connection systems, and in addition to connecting to Zaria, it is connected to parts such as Destiny Lab, Z1 Integrated Structure, PMA-3 Pressure Connecting Adapter, Quest Airtight Knee, Leonardo Multipurpose Module and Raffaello Multipurpose Module Is. During the STS-120 mission, the Harmony module was also attached to the Unity side port. Tranquility and Coppola also docked with the Unity module during the STS-130 mission.

Some of the essential resources of the space station, such as fluids, life support systems, electrical systems, and data support systems, are precisely located in Unity to provide the necessary conditions for living in different parts of the station. More than 50,000 mechanical parts, 216 liquid and gas transmission lines, and 121 hidden and covered electrical cables (6 miles of cable) have been installed in the Unity node. The overall material of the module is aluminum and stainless steel.

Zvezda module

Zvezda, also known by the Russian name Звезда́ meaning star, is a Russian command and service module. Zvezda, the third module and one of the most important parts of the International Space Station, was able to provide everything needed to support life on the station after the launch. Zvezda was launched into space by a Russian Proton rocket on July 12, 2000, and connected to the Zarya module on July 26 of the same year. The Zyvezda module was built by the Russian company RKK Energia, which is one of the main contractors of the International Space Station.

The main frame of the Zyuzda structure was first built in the mid-1980s and was to be used as the core of the Mir-2 space station. In fact, for a while, this module was called Mir-2. The construction of the main part of this frame was completed in 1985 and the equipment was installed on it in October 1986. Zyuzda has a cylindrical design and is built in such a way that the crew can live and work in it. Zyuzda has a total of four connecting valves that are used to connect to other masoles. The total weight of Zyuzda is 18051 kg and it is 13.1 meters long. Solar panels are also installed on Zivzda, which are 29.7 meters long when opened.

The International Space Station

Zivzda has 14 windows, two of which have a diameter of 230 mm, and two crews sleep in the compartments. Six other windows with 230 mm diameter glass are located on the lower floor of Zyuzda and face the ground. One of the windows, which has a diameter of 410 mm, is located in the Zyuzda workshop. Other Zyuzda windows are placed in the transfer chamber and the laboratory part, respectively.

On July 26, 2000, Zyvezda successfully docked with the Zarya module, officially becoming the third module of the ISS. On September 11, 2000, the two crews of the STS-106 mission completed the final stages of connecting Zarya and Zivzda. This find was made during a spacewalk of 6 hours and 14 minutes by American astronaut Ed Lowe and Russian cosmonaut Yuri Melenchenko. They successfully connected 9 cables between Zarya and Zivzda. Zivzda was a module where there were places for the crew to sleep, a kitchen, carbon dioxide scrubbers, humidifiers, oxygen generators, sports equipment, radio and television connected to the mission control system, etc.

As Russia faced financial difficulties, it did not produce any supporting versions of Zyuzda; Therefore, the risk of launch was greatly increased. NASA decided to produce the Interim control module, which could launch this module as a backup if something went wrong during the launch. Fortunately, the launch was successful and Zyuzda did not have the slightest problem.

Destiny module

Destiny, also known as the American Laboratory, was the first American laboratory module that was attached to the space station. Dastini was connected to the Unity module by connecting valves. Destiny is NASA’s first research laboratory in Earth orbit after the destruction of the Skylab space station. The design and production of this module are under the responsibility of Boeing and the construction process of this 16-ton structure began in 1995 at the Marshall Space Flight Center. Destiny was transferred to the Kennedy Space Center in Florida in 1998; But due to interruptions in NASA’s plans and conducting a series of necessary tests, the launch was postponed until 2000. The Destiny Module was launched into space on February 7, 2001, by the Space Shuttle Atlantis as part of the STS-98 mission.

The International Space Station

On February 10, 2001, Destiny arrived at the space station and was docked with the Unity module by the Canadian of the space shuttle Atlantis. Destiny has an aluminum structure and uses a cylindrical design. This module is 8.5 meters long and 4.3 meters in diameter. The front part of Destini is connected to the Unity module and its end part is also connected to node number 2. A glass window with a diameter of 510 mm is also placed on one side of the door that has a view of the ground. Destiny’s total weight is declared as 14520 kg, which is considered average.

Quest module

The Quest airlock knee, formerly known as the airlock knee module, is the first airlock of the International Space Station. Quest is designed in such a way that astronauts can enter space directly in space and stabilize the air pressure. In this airlock, astronauts can enter in Russian and American clothes and there is no problem in this regard. Until the launch of this module in 2001 and in the form of the STS-104 mission, Russian astronauts who used their special suits had to enter the station through the Zyuzda module, and American astronauts only entered the space shuttle connected to the station. The station could enter the interior of the station.

The International Space Station

The Quest module consists of two main parts; One for keeping the spacesuits and the other for when the astronauts want to leave or enter the station. These two parts are completely isolated from each other. It was necessary to build the quest module; Because the American astronauts, who had their own spacesuits, could not enter the station through the Russian Mazul Zyuzda airlock, and it was not possible to enter from other parts either.

Pierce and Poisk modules

Пирс and По́иск are two Russian airlock modules, each of which has two different valves. Pierce was launched in August 2001 and provided a docking station for the Soyuz and Progress spacecraft. It also made it possible for Russian cosmonauts wearing Orlan-designed spacesuits to enter and exit the station. Pierce was supposed to be separated from the station by the Progress spacecraft in 2017 and fall towards the Earth to make room for the Russian Nauka laboratory; Lamel, due to the delay in the construction of the Naoka laboratory, the separation process of Pierce was also postponed until the end of 2018.

Poisk is another Russian docking module that was launched and attached to the station in 2009. Poisk was the first Russian module of the station to be launched after 2001. Poisk generally uses Pierce’s design. Pierce is connected to the lower part of the Zyuzda module, But Poisk is attached to its upper part. Poisk in Russian means search and discovery, and for this reason, it has a series of scientific tools and equipment.

Harmony module

Harmony, also known as Node 2, is the second American node of the International Space Station. This module has the ability to provide electricity and electronic data of the bus, and due to having 6 connection valves, it can be connected to different parts of the station. European Columbus module, Japanese Kibo Labs connected to Harmony Radial Valves. Harmony’s upper and lower hatches are also used to dock spacecraft arriving at the station. Dragon, Cygnus, and HTV spacecraft are typically attached to these vents. By 2011, space shuttles were also docked at the bottom of Harmony.

The International Space Station

This module was initially known as node number 2; But in March 2007, NASA named it Harmony. At that time, NASA held a name competition among 32 American states, in which 2,200 kindergartens participated, and Harmony was chosen among the proposed names. At that time, NASA presented the children with information about the space station and asked them to build a small model and choose a name for it. Harmony in the term means the center that hosts scientific works. Harmony was launched on October 23, 2007, as part of the STS-120 mission and arrived at the station 3 days later.

Tranquility module

Tranquility, also known as Node 3, was built by the European Space Agency and the Italian Space Agency. In February 2010, NASA sent this module into space with the help of a space shuttle. The task of controlling and commanding this module was assigned to NASA from the very beginning. This node has 6 connecting valves, But one of them is still inactive because the rocket it was supposed to connect to was never launched.

In this node, more necessary life support equipment is placed and there is also a water purification system. The water purification system of this node can turn the astronauts’ urine into drinking water again if needed. The crew can use the oxygen generators in this node when necessary. The connecting valves of this node are each connected to a part. The first valve is connected to the Unity module, the heart of the station, and the others are connected to the Assonardo module, the Bigelow expandable module, the pressure connection valve number 3, and the Copola module.

Columbus module

Columbus is the first European research laboratory of the space station. In this module, there is a small laboratory and facilities for biological research and fluid physics. Several special bases are placed on the outside of this module, on which equipment can be installed to provide data and electrical energy necessary for external laboratory equipment. The European Space Agency plans to expand the space station to study quantum physics and cosmology. The European Space Agency is always trying to improve the life support systems of this module and make it still usable for the next 20 years.

The International Space Station

Kibo Laboratory

Kibo is a Japanese laboratory and also the largest module of the International Space Station. Scientists use this laboratory to study space medicine, biology, earth observation, materials production in space, biotechnology, and the development of communication technologies. In this laboratory, there is equipment that can be used to grow flowers in space. In August 2011, the MAXI observatory was installed on the Kibo module. The observatory uses the orbiting orbit of the space station to take X-ray images of the entire sky. This observatory was able to observe a star being swallowed by a black hole for the first time.

The International Space Station

This module consists of 23 different sections, 10 of which are laboratory sections. This module also has an air seal for testing. Another pressurized module is attached to the top of the Kibo, which mostly serves as a compartment for additional equipment.

Copula module

The cupola is an observatory that has 7 windows and is used to observe the Earth and connect other spacecraft. The name of this module is inspired by the Italian word copola which means dome. The construction of the Coppola module was done by NASA and Boeing; But due to lack of funds, the work was stopped. Sometime later, in an agreement between NASA and the European Space Agency, this organization agreed to pay part of the cost, and thus the construction process resumed in 1998.

The International Space Station

Boeing was no longer the contractor for this project and its construction was handed over to the Italian Space Agency. This module has 7 small glass windows and a circular window with a diameter of 80 cm, which is the largest window of the space station so far.

The future of the station

As it was said at the beginning, the station is supposed to remain operational until 2028; on the other hand, NASA will probably stop cooperating with the project until 2024, and stopping NASA’s cooperation will probably mean the end of the space station. It was in 2014 that the US Congress announced that it had to decide on the International Space Station and see if it could still be funded. Finally, in the same year, Congress announced that it would retire the International Space Station in 2024 and not fund it. With these interpretations, there are only six years left in the life of the International Space Station; Only seven years, and then it is not clear what is going to happen.

NASA spends the other half of its budget on rover missions, sending humans to Mars or sending to an asteroid. If NASA is to expand its projects and enter space exploration into a new field, it will no longer be able to allocate three to four billion dollars of its annual budget to the International Space Station. Of course, this is not a decision made by NASA; Rather, Congress and especially the White House decide how much funding NASA receives.

As mentioned at the beginning, one of the ways that NASA can investigate how to send humans to other planets is to test this work on the International Space Station. This station has a microgravity environment (weightlessness of humans and other objects) and is outside the Earth’s atmosphere; This means that scientists of all sciences can conduct their own experiments on the station to observe the effects of space on everything. Also, in this station, the effects of long-term human stay in a zero-gravity environment are measured. Recently, some politicians have said whether all the funds allocated to the International Space Station were worth it or not; Unfortunately, it seems that the United States Congress does not have a very good record of supporting applied sciences.

The International Space Station

No one is saying that the International Space Station should be supported and funded forever. With the growing private sector and large companies such as SpaceX, Blue Origin, and Virgin Galactic, we hope that one day the International Space Station will be supported by the private sector. There are some companies that are interested in making equipment for use in space; These companies can pay huge sums of money just to be able to test their equipment on the International Space Station. Maybe Elon Musk will decide to add this station to his company’s subsidiary; no one knows However, in the next two years, 5 more modules will be connected to the International Space Station, which will be used for different applications; But different countries are still waiting for NASA’s green light for the station to be operational by 2028.


As mentioned at the beginning, the International Space Station is the most expensive man-made integrated structure. In 2010, it was announced that the total cost of the station is likely to be around $150 billion, of which $72.4 billion belongs to NASA. The Russian Space Agency spent $12 billion, the European Space Agency $5 billion, the Japanese Space Agency $5 billion, and the Canadian Space Agency spent $2 billion to build the station. The cost of launching each shuttle was 1.4 billion dollars, and by calculating the 36 launches and the cost of construction, it can be said that this process alone cost 50.4 billion dollars. With another calculation, we can find out that in 15 years, the daily cost of each crew member at the station was 7.5 million dollars.

Interesting Facts

  • 16 countries are members of the International Space Station project. These countries are the United States of America, Russia, Canada, Japan, Belgium, Brazil, Denmark, France, Germany, Italy, Netherlands, Norway, Spain, Sweden, Switzerland, and the United Kingdom.
  • The International Space Station orbits at a speed of approximately 8 kilometers per second, which means that the space station orbits the Earth once every 90 minutes.
  • You might think that your apartment or house has more space than the space station, But it is interesting to know that this station has a total length of 109 meters provides a lot of space for the crew and has a lot of rooms.
  • The International Space Station is the largest man-made structure in space and has a total of 1141829 cubic centimeters of internal space.
  • There are only two toilets throughout the station. The water used in these services, together with the astronauts’ urine, is re-purified and turned into drinking water.
  • Being in space does not mean being safe from computer viruses. There are 52 computers in the space station, each of which has been infected with the virus more than once. For the first time, these computers were infected with a worm designed to steal computer game passwords.
  • The International Space Station is the only place in space where you can smell the smallest things. One of the astronauts said that he felt a special smell like the ionization of metal. Such a smell is rarely felt on earth.
  • The International Space Station is the brightest object in the night sky after the Moon and Venus, and if the weather is clear, you can see the space station with the naked eye.
  • Being in space destroys bone tissue and muscles. Therefore, astronauts should exercise two hours a day to avoid any problems.
  • In total, 12.87 kilometers of cables have been used in the space station, which is more than the cables used in New York’s Central Park.
  • Astronauts eat only three meals a day and do not know if they are sitting or not while eating; Because sitting in the space makes no sense at all, and there are no special seats in the station’s kitchen.


In general, it can be said that the International Space Station is a masterpiece of human engineering in space. This station was built thanks to the great experience of Russia and America and it allocates a lot of budget annually. The existence of this station in the Earth’s orbit is very necessary; Because in the near future, humans will travel to the moon, Mars, and other planets, and they must make the necessary preparations in the space station. It is still unclear what will happen to the International Space Station and what NASA will decide about it.

With the growth of private organizations such as SpaceX, it seems that this project will be left to the private sector and NASA will focus on other sectors. However, the space station is currently the only place in space where humans can go; Because humans haven’t left Earth’s lower orbit for almost 50 years.

The International Space Station

The International Space Station owes its existence to stations such as Salyut, Almaz, Mir, and Skylab, and maybe if these stations were not built, the ISS would not have progressed to this extent. Of course, we should not forget Dr. Werner von Braun, the creator of the Southern 5 rocket; Because he proposed the idea of ​​building a space station for the first time. We are still in the early stages of space station development. The International Space Station has made significant progress over Salyut, Skylab, and Mir; But we still have a long way to go to make the big space stations and colony-centered ones a reality as written by science-fiction writers.

It seems that in the future space stations will have artificial gravity, and none of our stations currently have gravity. Another reason is that we lack the technology to actually spin a massive system like a space station, so we can’t create artificial gravity.


Fermi’s paradox; Where are the extraterrestrials?




Fermi's paradox
Fermi’s paradox refers to the contradiction between the high probability of extraterrestrial intelligence in the universe and the fact that we have no conclusive evidence for the existence of such aliens.

Fermi’s paradox; Where are the extraterrestrials?

From NASA’s efforts to scientifically study UFOs or unidentified flying objects to the unveiling of alien bodies in Mexico , these days extraterrestrial intelligence has apparently become a more serious issue for politicians, researchers and the public. Although decades have passed since the first sighting of UFOs in the skies, there is still no evidence that definitively points to their extraterrestrial origin.

We’ve also been listening to space radio signals since about the middle of the last century, maybe for a message from aliens. On the other hand, for decades we have been trying to find extraterrestrial life in its very simple form in our own cosmic neighborhood by sending various spacecraft; But we still haven’t found any sure sign of extraterrestrial life. But how can we be really alone in such a big world?

Table of Contents
  • What is Fermi’s paradox?
  • The abundance of potentially habitable worlds
  • Drake’s equation
  • Large filter
  • Possible answers to Fermi’s paradox
  • Aliens are not advanced yet
  • Life is fragile
  • Intelligent life destroys itself
  • Other answers

What is Fermi’s paradox?

Given that our solar system is very young at approximately 4.5 billion years old compared to the 13.8 billion year old universe, and that interstellar travel may have been relatively easy to achieve over this long period of time, aliens would have to Today they were meeting the earth. But as far as we know, there has been no contact between us and extraterrestrials yet. As a result, the question arises, where are the aliens?

The contradiction between the high probability of the existence of alien intelligence and the lack of evidence for the existence of such aliens is called Fermi’s paradox. This paradox takes its name from Enrico Fermi, a renowned physicist who won the Nobel Prize. Fermi apparently made the above points in 1950 during a casual lunchtime conversation.

Enrico Fermi in his laboratory
Enrico Fermi in his laboratory.

The Search for Extraterrestrial Intelligence (SETI) Institute in California explains the paradox: “Farmey found that any civilization with a moderate level of rocket technology and colonialist motives could quickly colonize the entire galaxy. Over the course of a few tens of millions of years, any star system could be dominated by an empire. Tens of millions of years may seem like a long time, But it is very short compared to the age of the galaxy (which is almost a thousand times longer).”

Fermi died in 1954; As a result, other scientists were responsible for investigating and explaining his idea. One of these people was Michael Hart, an American astrophysicist who published an article in 1975 titled ” An Explanation for the Absence of Extraterrestrials on Earth ” in the Quarterly Journal of the Royal Astronomical Society (RAS). According to some, Hart’s article is the first research that examines Fermi’s paradox; However, it is difficult to prove this claim.

Any civilization with a moderate level of rocket technology and colonialist motives could quickly colonize the entire galaxy.

Hart writes in the abstract of his paper: “We see that no intelligent beings from space currently exist on Earth.” This fact can be explained by the hypothesis that there are no other advanced civilizations in our galaxy.” More research into biochemistry, planet formation, and atmospheres is needed to determine the exact answer, he noted.

Hart argued that if intelligent aliens began their interstellar journey more than two million years ago, they likely visited Earth at some point in our planet’s history. The apparent lack of such visitations, he believes, is most likely due to the lack of intelligent aliens. However, Hart offered four other potential explanations:

  • The aliens never got here because of a physical problem that might be related to astronomy, biology, or engineering that makes space travel impossible.
  • The aliens simply chose never to come to us.
  • Advanced extraterrestrial civilizations emerged too late to reach us.
  • Aliens have visited Earth in the past, But we have not seen them.

Frank Tipler, professor of physics at Tulane University, followed Hart’s argument in a 1980 paper titled ” There Is No Extraterrestrial Intelligence.” The bulk of his paper focuses on how to obtain resources for interstellar travel. According to Tipler, interstellar travel can be achieved by having a self-replicating artificial intelligence that creates multiple copies of itself as it moves from one-star system to another.

Because evidence of such advanced intelligence has never been found on Earth, Tipler argues that we are probably the only intelligent beings in the universe. He also wrote in an article in 1980 that those who believe in extraterrestrial intelligence are similar to UFO enthusiasts; Because they both believe that “we will be saved from ourselves by miraculous interstellar intervention.”

Nowadays, extraterrestrial intelligence is a popular topic, and every year numerous articles from different research groups are published about it. The idea that advanced civilizations may exist beyond Earth has been bolstered by the current revolution in the discovery and study of exoplanets.

The abundance of potentially habitable worlds

A view of an exoplanet facing its star

The universe is incredibly vast and ancient. Data collected by various telescopes show that the observable universe is approximately 92 billion light-years across (and growing faster and faster all the time). Also, separate measurements indicate that the universe is nearly 13.82 billion years old. As a result, alien civilizations have had a lot of time to emerge and expand; But before reaching us, they probably have to cross a big cosmic gulf.

When Fermi came up with his famous idea, the only worlds known to scientists were the planets in our solar system. But in 1992, astronomers saw worlds orbiting a superdense stellar body called a pulsar, and a few years later, the first exoplanet was confirmed around a Sun-like star.

Currently, there are more than five thousand confirmed exoplanets and more are being discovered every year. The large number of alien worlds suggests that life may abound throughout the universe.

Read More: 25 surprising facts about the solar system

The large number of alien worlds suggests that life may abound throughout the universe

Now, with advanced instruments like the James Webb Space Telescope, scientists have found it possible to examine the chemical composition of the atmospheres of some nearby exoplanets. However, “adjacent” is a relative term. The nearest known exoplanet, Proxima b, is located at a distance of 4.2 light years from us, which is approximately 40 trillion kilometers.

The ultimate goal is to find out how likely it is to form rocky planets in the “habitable belt” or “habitable zone” of stars. This region is traditionally defined as the range of orbital distances where water can exist on the surface of the world. However, habitability is not just about water, other factors such as the activity of the host star and the composition of the planet’s atmosphere must also be considered. Also, due to some reasons, the habitable area is considered too simple based on the aforementioned definition. For example, icy moons in our own solar system, such as Jupiter’s Europa and Saturn’s Enceladus, lie far beyond the Sun’s habitable zone; But they may still host life in the seas below their surface.

However, it seems that there are many settlements in the world. For example, a November 2013 study using data from NASA’s Kepler space telescope found that one in five Sun-like stars has a roughly Earth-sized planet orbiting it in the habitable zone. A few months later, Kepler scientists announced the discovery of 715 new worlds. Many of these planets were confirmed using a new technique called “multiple proof” that works in part on the logic of probability. For example, objects that pass in front of their star through the telescope or exert gravitational forces on it, are more likely to be planets instead of companion stars; Because with two stars so close to each other, the whole system is likely to become unstable over time.

Artistic rendering of NASA's Kepler Space Telescope

An artist’s rendering of NASA’s Kepler Space Telescope, an exoplanet finder.

However, Sun-like stars are a minority population in our galaxy. Almost three-quarters of the stars in the Milky Way are small, dim flares known as red dwarfs. Astronomers have found several rocky worlds orbiting in the habitable zone of red dwarfs; Like Proxima B and three planets located in Trappist 1; A system that is about 39 light-years away from Earth and contains a total of seven rocky worlds.

However, it is not known how habitable the planets around red dwarfs are; Because these stars are extremely unstable especially when they are young. As a result, their stellar eruptions may quickly destroy the nascent atmospheres of their neighboring planets, making it very difficult for life to flourish. Scientists say more studies are needed to better understand these stars and the ability of life to survive around them.

Researchers are acquiring more tools to study the stars. For example, NASA’s Passing Exoplanet Mapper satellite was successfully launched in April 2018, tasked with discovering extrasolar worlds as a successor to the Kepler telescope. Also, the James Webb Space Telescope, launched in December 2021, will study biological traces in the atmospheres of alien planets, among other tasks. The European Space Agency’s PLATO (Planetary Transit and Stellar Oscillation) spacecraft is also expected to launch in 2026.

Sun-like stars are a minority population in our galaxy

Three massive ground-based observatories, including the Extremely Large Telescope, the Giant Magellan Telescope, and the 30-meter telescope, which is powerful enough to probe the atmospheres of exoplanets, are slated to begin operating by the end of this decade. On the other hand, one of the more ambitious projects known as “Bractro Starshot” wants to study Proxima b and other nearby worlds with an array of tiny laser-guided nanoprobes. If the technology development process goes well, the first such interstellar spacecraft could be launched by around 2050.

These spacecraft and probes will help scientists improve their relatively rudimentary understanding of astrobiology. For example, we still don’t know if there are life-hosting worlds in our cosmic neighborhood. Studies conducted on Earth indicate that microbes can survive in unfavorable environments; A finding that suggests microbial life may exist on Mars, Europa, Enceladus, or Saturn’s giant moon Titan. But we haven’t explored either of those worlds enough to know for sure.

Drake’s equation

Despite the explanations given, Fermi’s paradox paints a much larger picture of microbes. To resolve this paradox, we need to know not only how common life is on alien planets, but also to what extent those extraterrestrials acquire the ability or desire to communicate with other intelligent life forms or to venture among the stars.

The number of intelligent and detectable alien civilizations is estimated by the Drake equation. According to the Seti Institute, the equation is written as “N = R* • fp • ne • fl • fi • fc • L” and has the following variables:

  • N: number of Milky Way civilizations whose electromagnetic emissions can be detected.
  • R*: the rate of formation of stars suitable for the development of intelligent life (number per year).
  • fp: fraction of those stars with planetary systems.
  • ne: the number of planets in each solar system with habitable environments.
  • fl: fraction of suitable planets where life appears.
  • fi: Fraction of life-bearing planets in which intelligent life arises.
  • fc: fraction of civilizations with technologies capable of producing recognizable signs of their existence.
  • L: average length of time such civilizations produce such signs (years).

None of the values ​​of Drake’s equation are currently known with certainty; This means that it is difficult to predict the number of civilizations willing to communicate. As a result, the Fermi paradox is fertile ground for speculation, and scientists and laypeople alike have come up with hundreds of possible explanations over the years.

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Large filter

Asteroid hitting the earth

The large filter is a general idea that attempts to explain Fermi’s paradox. According to this hypothesis, intelligent interstellar life must take many critical steps to evolve, and at least one of these steps must be highly impossible. In fact, the large filter assumes that there is at least one very large barrier that virtually no species can pass to the next stage. But in order to become a truly advanced and space-faring civilization, what important obstacles must be overcome? Here are a few things:

  • A planet capable of harboring life must form in the habitable zone of a star.
  • Life must grow on that planet.
  • Life forms must be able to reproduce using molecules such as DNA or RNA.
  • Simple cells (prokaryotes) must evolve into more complex cells (eukaryotes).
  • Multicellular organisms must grow.
  • Sexual reproduction, which greatly increases genetic diversity, must occur.
  • Complex organisms capable of using tools must evolve.
  • Those beings must develop the advanced technology needed to colonize space. (This stage is roughly where humans are today.)
  • The spacefaring species must continue to colonize other worlds and star systems while avoiding their own destruction.

The assumption of the large filter is that there is at least one very large barrier that virtually no species can pass.

But which stage is the big filter? Unfortunately, no one knows. Maybe the rarity of life is actually a big filter. Maybe life is common, But most organisms do not evolve beyond unicellularity. It may be the great filter of annihilation technology that wipes out its advanced creators. It is possible that an external factor such as the impact of a stray asteroid is the cause of the destruction of life.

If we have passed the great filter, we can hope for our future. Maybe a wise man is the kind that can colonize the world. But if the big filter is still ahead, we’re probably doomed. In the next section, we mention some hypothetical explanations for Fermi’s paradox.

Possible answers to Fermi’s paradox

A very wide range of answers can be considered for Fermi’s paradox. Probably the most obvious and likely answer is that we haven’t looked hard enough for alien life, and interstellar travel is difficult. As mentioned, the first planets beyond the solar system were discovered just 30 years ago; As a result, in the field of exploring alien worlds, we are still in the most elementary stage.

We have yet to find many planets that look exactly like Earth and orbit a Sun-like star. However, even if we were to achieve such success, the distance between the star systems is too great, and travel to them would be extremely difficult. For example, the closest star system to us, Alpha Centauri, is four light years away from Earth. For comparison, the distance from Earth to Neptune is only 0.0005 light years; As a result, it takes tens of years to reach the nearest neighboring star with current technology.

Aliens are not advanced yet

In 2015, scientists analyzing data from the Hubble Space Telescope and the Kepler Space Telescope concluded that Earth was one of the first worlds in the universe to harbor life. According to the researchers, only 8 percent of all potentially habitable worlds that will emerge in the entire lifetime of the universe existed when Earth formed about 4.5 billion years ago. Consequently, this is one possible explanation for the paradox: aliens will come; But not now.

Life is fragile

Perhaps life is too fragile to last long. A 2016 study in the journal Astrobiology showed that the early part of a rocky planet’s history could be very favorable for life; This means that life may usually emerge 500 million years or more after the planet cooled and liquid water became available. Our own Earth history seems to support this conclusion. There is (controversial) evidence that life appeared on Earth about 4.1 billion years ago, and was definitely established by 3.8 billion years ago. But those good days may not last long as a result of the greenhouse effect (as happened on Venus long ago) or other climate changes.

Perhaps life is too fragile to last long

“Between initial heat pulses, freezing, unstable content changes, and out-of-control positive feedbacks, maintaining life on a rocky, wet young planet in the habitable zone is like trying to ride a wild bull,” said Aditya Chopra and Charlie Lineweaver, researchers of the 2016 study. Life often falls.” The authors add that life may be rare in the universe; not because it is difficult to start, but because it is difficult to maintain habitable environments during the first billion years.

Intelligent life destroys itself

Conditions leading to the collapse of life may occur much later. Some thinkers believe that civilizations may self-destruct shortly after they become technologically capable. Again, Earth supports this hypothesis: humanity came alarmingly close to nuclear war during the 1962 Cuban Missile Crisis. Also, we are probably destroying ourselves and many other types of terrestrial life right now through climate change caused by our own activities or the development of dangerous technologies such as artificial intelligence.

Other Answers

There are many other factors to consider. For example, Alan Stern, a planetary scientist and director of NASA’s New Horizons mission, believes that buried oceans, such as the seas of Enceladus and Europa, are likely the most common environments for life in the Milky Way. As a result, it seems unlikely that the evolved beings in such regions would achieve the necessary technology to build spacecraft. In fact, many of them may not even know that there are other worlds to explore.

Alien psychology can also be effective. For example, maybe there are many advanced alien civilizations in the world; But most of them don’t want to communicate with us or visit Earth. Perhaps Earth and its inhabitants are simply not interesting enough for aliens to waste their time on, and until humanity shows enough intelligence and competence to be accepted into the “galactic club”, it will not attract the attention of extraterrestrials.

Most intelligent aliens may tend to be silent as a general rule; Because they are worried that contact with their cosmic neighbors will lead them to slavery or death. Some researchers, including the late Stephen Hawking, have cited such possibilities with the argument that humans should not actively show their presence.

Most intelligent aliens may tend to be silent as a general rule

In addition to all the aforementioned assumptions, finding intelligent aliens in a very, very vast and ancient universe is associated with complex logistical problems. Mankind only appeared on Earth 200,000 years ago and only started listening to possible radio signals from extraterrestrials in 1960. As a result, the probability that it overlaps with a recognizable alien civilization in terms of time and place does not seem very high.

Most researchers say that there is probably no single solution to Fermi’s paradox. A combination of factors, including perhaps some of the ones discussed above, is probably responsible for the great silence that currently reigns in the world. The nature of those factors will probably be more clearly noticed relatively soon.

For example, suppose scientists find evidence of ancient or current microbial life on Mars, Europa, or any other body in our own solar system. The discovery of such creatures near the Earth, which are completely different from terrestrial life, speaks of the “Second Genesis” and definitely shows the commonness of life throughout the universe. At that point, researchers can cross off a possible explanation on the long list of explanations for Fermi’s paradox. 

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How did photographing “nothing” change astronomy?




How did photographing "nothing" change astronomy?
In deep-field photography, the empty and dark part of the sky is chosen to photograph faint galaxies in the distance. The Deep Webb Space Telescope and other telescope images from these regions are more fruitful than we imagine. So how did photographing “nothing” change astronomy?

How did photographing “nothing” change astronomy?

On July 11, the world was stunned by the release of the deepest astronomical image ever recorded by the James Webb Space Telescope ( JWST ). In the background of the galaxy cluster called SMACS 0723, whose image is from 4.6 billion years ago, thousands of galaxies of different shapes and sizes shine like brilliant diamonds in the dark universe. Some of these distant beacons were shining when the universe was only a few hundred million years old. Understanding the path of this achievement, including reaching distant cosmic islands and collecting photons that began their journey near the Big Bang, will help better understand observations of the deep field.

The origin of the first James Webb Deep Space Telescope wallpaper dates back to the early 1990s and the launch of the Hubble Space Telescope. At that time, the deep field observation project was still in its infancy. Hubble was originally designed for targeted observations, and astronomers were supposed to use this telescope to observe a specific part of the sky based on the brightness of the light source; But Hubble also had the ability to photograph the deep field, which was exactly in front of the goal of astronomers: for this type of observation, astronomers place the telescope towards a region of the sky that does not have any visible light source, and from a very long exposure time to reach the depths of the universe and They use observation of dim light sources. At that time, Hubble was the best instrument for deep-field imaging.

Read More: 25 surprising facts about the solar system

However, not everyone agreed with the observation of the deep field. In a 1990 paper in the journal Science, John Bahcal and his colleagues from the Institute for Advanced Study point out that Hubble’s deep background image does not show many more galaxies than ground-based telescopes. Bahcal is best known for his solution to the solar neutrino problem and his calculations of the distribution of stars around a supermassive black hole. He was instrumental in the development of the Hubble telescope from its original design in the 1970s to its launch. Bahkal believed that Hubble’s deep field would not reveal new populations of galaxies, but such images could provide confirmation of the morphology and size of faint galaxies and the statistics of quasars.

Hubble and James Webb Deep Wallpaper Comparison

Comparison of the first Hubble Space Telescope “deep field” image captured in 1995 (left) and the first similar image from the James Webb Space Telescope (right). Both images cover roughly the same area of ​​the sky but contain different populations of galaxies. The Webb Telescope, for example, covers more cosmic time and reveals galaxies older than the early universe.

Such expectations suppressed the need for deep-field imaging with Hubble. For this reason, the first attempt to photograph the deep field was made around the winter holidays of 1995 after the optical repair of the telescope. The telescope took 10 days of exposure time for a small part of the sky in the constellation Ursa Major. After weeks, astronomers got their Christmas present by seeing the final image known as the Deep North Field.

The number of stars in the Milky Way galaxy was very small in the target area, so the Hubble telescope looked into the depths of the universe, just like a viewer looking into a pinhole. This telescope observed nearly 3,000 faint galaxies of various shapes and sizes, some of which were 12 billion light-years away from Earth. Hubble’s mission was not only to explore space but also to study time and collect light from stars that existed billions of years ago in the early cosmic ages. The Hubble Deep wallpaper quickly became an iconic image.

But a fundamental question was raised: was the galaxy-filled region in the deep field north image normal? Or were the astronomers lucky enough to point the telescope at a point full of galaxies? In 1998, the Hubble telescope captured the southern image of the deep field. The exposure of this photo was similar to the previous one, with the difference that this time the telescope was facing the southern hemisphere of the sky, which is at the farthest possible distance from the first point. The new image proves that the universe is more galaxy-filled than previously thought, especially in the far reaches. In addition to scientific value, Hubble’s deep fields revealed a technical challenge; These images covered more than 10,000 galaxies, which was the first big data challenge for astronomers.

Hubble and James Webb telescopes

The Hubble Space Telescope as seen from the space shuttle in low Earth orbit (top) James Webb Space Telescope imaging (bottom) at a distance of more than 1.5 million kilometers from Earth.

Deep-field imaging is not limited to the visible spectrum. By the beginning of the third millennium, the universe was preparing for the first deep, energetic image from the Chandra X-ray telescope. NASA’s revolutionary telescope was launched in July 1999 and has continued to operate until today. Chandra’s deep-field south image was captured with an exposure time of approximately one-millionth of a second over a portion of the sky in the Lockman Hole, a window of hydrogen clouds and dust in the Milky Way. An image south of Chandra’s deep background revealed a strange universe: hundreds of black holes that some placed far away. Although this image was not as eye-catching as the Hubble images, it contained a lot of scientific information. This field was re-imaged by Chandra with a total exposure of seven million seconds, yielding the deepest field in the X-ray spectrum. In 2003, the Chandra Deep North Image was released, which included more than 500 X-ray sources.

With the addition of instruments such as the Advanced Mapping Camera to Hubble, the Hubble Deep Space Wallpaper was released in 2006. This historic image included thousands of galaxies, and some of them were less than a billion years old. The ultra-deep field provided unprecedented details of the formation history of galaxies; Distant galaxies appeared smaller and more irregular than closer galaxies, and this observation became a support for theories of galactic evolution.

The ultra-deep field is the deepest image that can be captured at visible wavelengths. If a galaxy is too far away, its visible light is transferred out of the visible spectrum and into the infrared spectrum; This phenomenon is the result of the cosmic redshift effect, according to which the expansion of the universe causes the length of light wavelengths to be stretched, which travel huge intergalactic distances.

With this account, the infrared camera was necessary to observe longer distances in space and time. With the addition of the near-infrared camera to the Hubble telescope, the field of far-infrared was released in 2009; This image revealed galaxies that were glowing just 600 million years after the Big Bang. A decade later in 2019, another deep field was released by NASA’s Spitz Infrared Space Telescope. Both images had fruitful results for the discovery of galaxies on a cosmic scale.

Finally, Hubble’s Frontier Fields campaign provided a new deep-field imaging capability that became the precursor to James Webb’s first deep-field image. During the observing campaign, which ended in 2017, Hubble aimed at six major galaxy clusters. According to Einstein’s theory of general relativity, mass density can bend along the path of light and thus amplify the light received from the background source with an effect called gravitational lensing; Therefore, these galaxy clusters were used as microscopes for distant observations.

In addition to galaxy-filled images, Frontier Fields images contain strange arcs of light that show enhanced or stretched images of background galaxies much farther from the cluster. These galaxies are so faint that it is not possible to directly observe them with Hubble. These images show some of the most distant galaxies and the first supernova transformed into a gravitational lens.

Almost 200 years have passed since the advent of photography. At that time, for the first time, humans were able to trap photons to record images. Today, highly sophisticated cameras on space telescopes millions of kilometers beyond the Earth push the boundaries of our knowledge of the universe and open new windows to space and time. There is a relatively short period of time between these two inventions, but both were designed with the same goal: to gain an understanding of nature by looking at what is not visible to the human eye.

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25 surprising facts about the solar system




25 surprising facts about the solar system

From the vastness of the solar system and its strange moons to the ubiquitous presence of water and organic molecules, our solar neighborhood is full of surprising facts.

25 surprising facts about the solar system

Our solar system includes the sun and everything that revolves around it; Among the eight planets that we have all been familiar with since elementary school. But the main planets, despite their diversity and charm, are only part of the wonders of our cosmic neighborhood. Planet Earth’s neighbors in space include comets, asteroids, dwarf planets, mysterious moons, and a series of phenomena so strange and alien that they are not easily explained.

Table of Contents

  • 1. The solar system is very, very large
  • 2. Even our neighborhood is very big
  • 3. Uranus orbits the Sun sideways
  • 4. Jupiter’s moon Io is full of volcanic eruptions
  • 5. Mars has a volcano that is bigger than the entire state of Hawaii
  • 6. The biggest canyon on Mars could take Earth’s Grand Canyon in one bite
  • 7. Venus is swept by super-powerful winds
  • 8. Water is everywhere
  • 9. Human spacecraft have visited all planets
  • 10. Pollutants may be transported to habitable areas
  • 11. Mercury is shrinking
  • 12. Pluto has mountains
  • 13. Pluto has a strange atmosphere
  • 14. Rings are more common than you might think
  • 15. Jupiter’s Great Red Spot is shrinking
  • 16. Most comets are detected with solar telescopes
  • 17. The ninth planet
  • 18. Neptune is very hot
  • 19. Earth’s Van Allen Belt is much stranger than expected
  • 20. What happened to Miranda?
  • 21. Saturn’s yin-yang moon
  • 22. Titan has a liquid cycle, But there is no water involved
  • 23. Organic molecules are everywhere
  • 24. Saturn has a hexagonal storm
  • 25. The atmosphere of the Sun is much hotter than the surface of the Sun

From fascinating glaciers on the dwarf planet Pluto and a deep valley the size of the United States on the Red Planet to the possibility of a giant, undiscovered world known as the ninth planet beyond Neptune, the space around Earth is full of wonders. Stay tuned to Zoomit for some of the weirdest facts about the solar system.

25 surprising facts about the solar system

1. The solar system is extremely largeOort cloud and Kuiper belt

By including the Oort cloud, our star’s realm becomes much, much larger.

NASA’s Voyager 1 spacecraft began its mission in 1977, and more than three decades later in 2012, it became the first man-made object to enter interstellar space by passing through the heliopause or heliosphere boundary. The heliopause is the region where the magnetic fields and most of the particles emitted from the sun disappear.

However, according to NASA, “If we define our solar system as the Sun and primarily everything that orbits it, Voyager 1 will continue to remain within [dominance of] the Sun until, in the next 14,000 to 28,000 years, Get out of the Everett cloud. 

2. Even our neighborhood is very big

Visualization of the placement of all the planets of the solar system between the Earth and the Moon

Did you know that all the planets in the solar system can fit between the Earth and the Moon?

Depending on how accurately you do the math and how you arrange it, all the planets in the solar system can fit between the Earth and the Moon. The distance between the Earth and the Moon varies as does the diameter of each of them. Our planet and its moon are wider at their equator; As a result, Saturn or Jupiter or both must be slightly tilted to the sides to fit between them. However, if you lined up the planets from pole to pole, they would barely fit between us and our only space companion, blocking the sky with their rings and huge gas masses.

The moon is the farthest object humans have ever traveled to, and depending on how you think about it, it’s both amazingly far and incredibly close. Eight giant planets of the solar system can fit in the space between us and the moon, and yet, the distance from the Earth to the sun is more than 390 times the distance from the Earth to the moon.

Scientists use the approximate distance from the Earth to the Sun, known as an astronomical unit, or AU, to compare distances within the solar system. Jupiter is approximately 5.2 AU from the Sun and Neptune is 30.07 AU or approximately 30 times the distance from Earth to the Sun from our star.

 3. Uranus orbits the sun sideways

Composite image of the planet Uranus and its rings

This composite image of the two hemispheres of Uranus was obtained with the adaptive optics of the Keck telescope. The north pole of the planet is at 4 o’clock.

In solar system models, Uranus usually appears as a blue ball with no special features; But this gas giant, located in the outer limits of the solar system, is very strange from a global perspective. First of all, the seventh planet of the solar system has a very extreme axial deviation of 97.77 degrees; This means that it rotates sideways and completes its orbit around the sun like a rolling ball. The most likely explanation for the planet’s unusual orientation is a catastrophic collision with another body in the distant past.

The tilt of Uranus has caused NASA to witness the most unusual seasons in the solar system on this planet. In about a quarter of each Uranian year (equivalent to 21 Earth years), the Sun shines directly on the north or south pole of the planet; This situation means that half of Uranus does not see the Sun at all for more than two Earth decades.

Scientists have been monitoring these temperate seasons on Uranus and predicting that they will witness unusual weather on this planet at the moment of the 2007 equinox. But it was seven years later that unexpected violent storms occurred in the atmosphere of Uranus, and the planet became a bigger mystery than ever. 

4. Jupitor’s moon Io is full of volcanic eruptions

The eruption of the volcano in Io from the view of the Galileo spacecraft

Io has hundreds of active volcanoes. In this image, the moment of the spectacular eruption was captured by NASA’s Galileo spacecraft as it flew over the moon.

Jupiter’s moon Io may seem like a world of surprise compared to Earth’s silent moon. This Galilean moon, which is slightly smaller than the Earth’s moon, has hundreds of volcanoes and is considered the most active moon in the solar system. Io sends masses of sulfur smoke up to 300 km into its atmosphere. According to NASA, Io’s volcanoes emit a ton of gas and particles every second into space near Jupiter.

The eruptive nature of Io is due to the enormous forces that this moon is exposed to. Trapped in Jupiter’s gravitational well and magnetic field, Io experiences constant tension and relaxation as it moves away from the planet and approaches it, gaining enough energy for volcanic activity.

Scientists are still trying to figure out how heat is distributed inside Io. However, it is difficult to predict the location of volcanoes using only scientific models. 

5. Mars has a volcano that is bigger than the entire state of Hawaii

Mount Olympus on Mars

Mount Olympus is the largest volcano discovered in the solar system.

Although Mars seems peaceful now, giant volcanoes once ruled the planet’s surface. One of these volcanoes is Mount Olympus, the largest volcano discovered in the solar system. With a width of 602 km, Olympus can be compared to the state of Arizona in America. The height of this volcano is 25 km or three times higher than Everest, the highest mountain on earth. According to NASA, Olympus is 100 times larger in volume than Mauna Loa, the largest volcano on Earth in Hawaii.

Scientists suspect that volcanoes can grow to such enormous sizes on Mars because of Mars’ weak gravity compared to Earth’s. Moreover, while the earth’s crust is constantly moving, the crust of Mars is probably stationary based on the belief of some researchers. If the surface of Mars does not move, a volcano can form in one spot for a longer period of time. 

25 surprising facts about the solar system

6. The biggest canyon on Mars could take Earth’s Grand Canyon in one bite

Mariner Valley on Mars

Mariner Canyon on Mars is more than 10 times longer than the Grand Canyon on Earth.

The huge system of Martian canyons, known as the Mariner Canyon, is 4,000 kilometers long, more than 10 times larger than the Grand Canyon on Earth. Mariner Canyon was overlooked by early Martian spacecraft that flew over other parts of the planet and was finally discovered by the Mariner 9 probe in 1971. If the Mariner Valley was located on Earth, it could stretch from the East Coast to the West Coast of America.

The lack of active plate tectonics on Mars makes it difficult to discern how Mariner Valley formed. Some scientists think that a chain of volcanoes on the other side of the planet, known as the Tharsis Plateau, which includes Mount Olympus, somehow bent the crust away from Mars. That destructive force created fissures in the crust, exposed vast amounts of groundwater to excavate the rocks, and formed glaciers that opened new routes into the canyon system. 

7. Venus is swept by super-powerful winds

Computer image of the rocky surface of the planet Venus

This artistic image shows the rocky surface of Venus and sulfuric acid clouds.

Venus is a hellish planet with a high temperature and pressure environment on its surface. The second planet in the solar system is extremely dry and hot enough to melt lead and has probably never had an environment conducive to supporting life. When the heavily protected Venus spacecraft from the Soviet Union landed on Venus in the 1970s, each lasted only a few minutes, or hours at most, before melting or shattering.

However, Earth’s infernal twin has a far stranger environment beyond its surface. Scientists have found that the winds in the upper atmosphere of Venus blow 50 times faster than the rotation of the planet. The European Venus Express spacecraft, which orbited Venus between 2006 and 2014, tracked the winds over long periods and detected periodic changes. The probe also showed that powerful winds appear to be getting stronger with time.

A study in 2020 pointed to the presence of phosphine, which is a possible sign of the decay of biological materials, in the clouds of Venus. This study initially excited some astrobiologists, But the supplementary research firmly rejected the possibility of the existence of life in the dry and windy atmosphere of Venus. 

8. Water is everywhere

Computer image of Mars with water lakes

This artistic rendering shows what Mars would look like with water lakes.

At one time, water was considered as a rare substance in space; But the truth is that water ice exists throughout the solar system and is a common constituent of comets and asteroids.

Water can be found as ice in the permanently shadowed craters of Mercury and the Moon. However, we don’t know if there is enough water to support possible human settlements in those places. Also, Mars has ice on its poles. Even smaller solar system objects, such as Enceladus, Saturn’s moon, and the dwarf planet Ceres, have ice.

NASA scientists believe that Jupiter’s moon Europa is the most likely candidate known to support extraterrestrial life; Because contrary to all expectations, liquid water is probably flowing under its cracked and frozen surface. Europa, which is much smaller than Earth, probably has a deep ocean that researchers believe contains twice as much water as all the oceans on Earth combined.

However, we know that not all ice is the same. For example, a close examination of comet 67P/Churyumov-Grasimenko by the European Space Agency’s Rosetta spacecraft revealed a different type of water ice than that found on Earth. 

9. Human spacecraft have visited all planets

Montage of Voyager 2 images of the outer planets of the solar system

The outer planets of the solar system as seen by the Voyager 2 spacecraft.

We’ve been exploring space for over 60 years and have been lucky enough to get close-up images of dozens of celestial bodies. Most importantly, we have sent spacecraft to all the planets in the solar system, including Mercury, Venus, Mars, Jupiter, Saturn, Uranus, and Neptune, as well as the two dwarf planets, Pluto and Ceres.

Most of the close flybys of the planets were made by NASA’s Voyager twins, which left Earth more than four decades ago and are still transmitting data from interstellar space to this day. Voyagers met all of them during their long journey, thanks to a rare alignment of the outer planets. 

10. Pollutants may be transported to habitable areas

Hydrothermal vents on the ocean floor

Hydrothermal vents in the ocean.

Scientists have not yet found evidence of life in other parts of the solar system; But as they learn more about the hardy microbes that inhabit Earth’s harsh environments, such as ocean-floor hydrothermal vents or frozen environments, they have more opportunities to find alien life on other planets.

Currently, the presence of microbial life on Mars is considered so probable that scientists take special precautions to clean spacecraft bound for this planet. NASA decided to crash the Galileo spacecraft into Jupiter to avoid the risk of contaminating Europa’s potentially habitable oceans. 

Read More: Will Earth one day become a wandering planet?

25 surprising facts about the solar system

11. Mercury is shrinking


Mercury, the smallest planet in our solar system, has short years, long days, and extreme temperatures.

With the exception of the dwarf planet Pluto, Mercury is currently the smallest planet in the solar system and the most dense planet after Earth. However, the innermost planet in our solar neighborhood is shrinking and becoming denser.

For many years, scientists believed that Earth was the only tectonically active planet in the solar system. But after NASA’s MESSENGER spacecraft, performing its first orbital mission on Mercury, mapped the entire planet in high resolution and took a look at its surface features, this belief changed.

In 2016, MESSENGER data revealed chasm-like features known as fault chasms. Because these fault chasms are relatively small, scientists are confident that they did not form long ago and that Mercury is still contracting, 4.5 billion years after the formation of the solar system. 

12. Pluto has mountains

Pluto's mountains as seen by the New Horizons spacecraft

In July 2015, NASA’s New Horizons spacecraft sent back impressive images of Pluto and its moons.

Pluto is a small world at the edge of the solar system; As a result, scientists thought that this dwarf planet would have a completely uniform environment full of craters. But this belief changed in 2015. That year, NASA’s New Horizons spacecraft flew past Pluto and sent back unprecedented images, forever changing the way we look at this distant object.

Among the amazing discoveries of New Horizons, there were icebergs with a height of 3,300 meters; A finding that suggests Pluto must have been geologically active at least 100 million years ago. But geological activity requires energy, and the source of this energy inside Pluto is a mystery. The Sun is too far away to generate enough heat for geological activity, and there are no large planets close enough to Pluto to cause such a gravitational disturbance. 

13. Pluto has a strange atmosphere

Pluto's atmosphere as seen by the New Horizons spacecraft

NASA’s New Horizons spacecraft took this image of Pluto from a distance of 200,000 km. Pluto’s atmosphere can be seen as a blue haze.

Pluto’s observed atmosphere disproved all predictions. The scientists observed that the dwarf planet’s unexpectedly hazy atmosphere extends up to 1,600 km and extends beyond the Earth’s atmosphere, away from the surface. When data from NASA’s New Horizons mission came in, scientists began analyzing the nebula and discovered some surprises there as well.

Scientists have found nearly 20 layers in Pluto’s atmosphere that are both colder and denser than expected. This feature affects calculations related to the rate of loss of Pluto’s nitrogen-rich atmosphere in space. The New Horizons team found that thousands of kilograms of nitrogen gas escape from the dwarf planet every hour; But Pluto somehow manages to continuously replenish the lost nitrogen. The recovery of this gas is probably done mostly through geological activities. 

14. Rings are more common than you might think


Saturn is not the only ringed object in the solar system.

Since the invention of telescopes in the 17th century, we have known about the existence of rings around Saturn; But to reveal more rings, we needed the powerful spacecraft and telescopes built in the last 50 years. We now know that all the outer planets of the solar system, including Jupiter, Saturn, Uranus, and Neptune, have ring systems.

However, the rings vary from planet to planet: Saturn’s spectacular ring, which is partly made of glowing, reflective water ice, is unmatched anywhere else. In contrast, the rings of other giants are probably made of rocky particles and dust.

Rings are also not limited to planets. For example, in 2014 astronomers discovered rings around the asteroid Chariklo. 

15. Jupiter’s Great Red Spot is shrinking

The Great Red Spot of Jupiter

Jupiter’s Great Red Spot is the largest storm in the solar system.

Besides being the largest planet in the solar system, Jupiter also hosts the largest storm in the solar neighborhood. This red storm, known as the Great Red Spot, has been observed in telescopes since the 17th century and studied with modern instruments such as NASA’s Juno probe. The spacecraft has recently provided evidence that Jupiter’s giant storm is hundreds of kilometers high and is likely fed by winds thousands of kilometers below. This storm has been a complex mystery for centuries; But in recent decades, another secret has been revealed: the Great Red Spot is shrinking.

In 2014, Jupiter’s Great Storm was only 16,500 km wide, roughly half its historical size. This diminution is monitored by professional telescopes as well as amateur astronomers. Amateurs can often take more consistent measurements of the client; Because the observation time in larger and professional telescopes is limited and is often divided between different objects. 

25 surprising facts about the solar system

16. Most comets are detected with solar telescopes

Comet Ison

Comet Ison appears from the lower right of the image and moves to the upper right. This impressive image was captured by the Horspeary Solar Observatory, and the image of the Sun in the center was obtained from NASA’s Solar Dynamics Observatory.

Comets used to be the domain of amateur astronomers who probed the sky night after night with their telescopes. Although some professional observatories also made discoveries while observing comets, the status of explorations in this field started to change with the launch of the Solar and Horseshoe Observatory (SOHO) in 1995.

Since then, SOHO has found more than 2,400 comets. This volume of comet discovery has been a very fruitful side mission for a probe that only observes the Sun. The nickname of these comets is “Sunriser” or “Solstice”. Many amateur astronomers continue to help find these objects by identifying comets in raw SOHO images. One of SOHO’s most famous observations was when it observed the collapse of the bright comet Ison in 2013. 

17. The ninth planet

Hypothetical ninth planet

A ninth planet is a hypothetical world that could explain the motion of some Kuiper belt objects.

In January 2015, California Institute of Technology (Caltech) astronomers Konstantin Batygin and Mike Brown, relying on calculations and mathematical simulations, announced that a giant planet might be hidden far beyond Neptune. Now several teams are searching for this hypothetical “ninth planet” and research shows that it is possible to discover it within the next decade.

A ninth planet, if present, could help explain the motions of some objects in the Kuiper Belt (an icy collection of objects beyond Neptune’s orbit). Brown has already discovered several large bodies in that region, in some cases rivaling Pluto in size. In fact, his discoveries were the catalyst for Pluto’s status change from a planet to a dwarf planet in 2006.

But some scientists follow another theory; That “Planet Nine” might actually be a black hole the size of Grapefruit that bends space just like a giant planet. However, another team suggests that the strange movements of the Kuiper belt’s distant inhabitants are likely the collective effect of several small objects; No undiscovered planets or black holes. 

18. Neptune is very hot

The planet Neptune from the perspective of Voyager 2

The distance of Neptune from the Sun is approximately 30 AU.

Neptune, the outermost planet in the Solar System, is 30 times farther from the Sun than Earth and receives less light and heat. However, Neptune emits much more heat than it receives and has a much more active atmosphere than its neighbor Uranus. Uranus is closer to the Sun, yet emits nearly as much heat as Neptune. Scientists still do not know the cause of this problem.

The wind on Neptune can blow up to 2400 km/h. Does this amount of energy come from the sun, the planet’s core, or gravitational contraction? Researchers are trying to find the answer to this mystery. 

19. Earth’s Van Allen Belt is much stranger than expected

Van Allen belts around the earth

Discovered in 1958, the Van Allen belts are large bands of radiation that surround the Earth and expand and contract based on the activity of the Sun.

The Earth has several magnetically trapped bands of highly energetic charged particles around it, called the Van Allen Belts in honor of their discoverer. Although we’ve known about these belts since the dawn of the space age, the Van Allen probes, launched in 2012, provided the best possible picture of them and revealed many surprises along the way.

We now know that the belts expand and contract based on the activity of the sun. Sometimes the belts are very distinct from each other, and at other times, they swell as one large unit. An additional radiation belt, beyond the two known, was discovered in 2013. Understanding these belts helps scientists make better predictions about space weather or solar storms. 

20. What happened to Miranda?

Miranda, the moon of Uranus

Uranus’ moon Miranda has one of the most diverse landscapes of any extraterrestrial object.

One of the strangest outer moons of the solar system is Miranda. This mysterious moon of Uranus was observed only once in 1986; Voyager 2 caught a glimpse of it during its tour of the solar system. Miranda hosts sharp ridges, craters, and other large discontinuities on its surface that are usually the result of volcanic activity. Tectonic activity can cause the formation of such a surface, But Miranda is too small to generate that kind of heat on her own.

Researchers believe that the gravitational pull of Uranus could have caused the necessary pressure to heat, overturn, and deform Miranda’s surface. But to be sure, we need to send another spacecraft to investigate the unseen northern hemisphere of the moon. 

25 surprising facts about the solar system

21. Saturn’s yin-yang moon

Iaptus, a moon of SaturnIaptus, a moon of Saturn

Saturn’s moon Iapetus shows drastic differences in surface brightness depending on which side it faces the Sun.

Saturn’s moon Iaptus has a very dark hemisphere that always faces the planet and a very bright hemisphere that always faces Saturn. The brightness of most asteroids, moons, and planets is relatively uniform across their surfaces; But Iaptus sometimes shines so brightly that it was observed by the Giovanni Cassini telescope in the 17th century, and then dims considerably as it spins the other way.

Current research shows that Iaptus, also known as Saturn 8, is made mostly of water ice. According to scientists’ hypothesis, when the dark side of the moon faces the sun, water ice sublimates from that area and leaves behind darker rocks. Since dark matter heats up more than bright, reflective ice, this process may have created a positive feedback loop; In this way, when the darker and warmer part of the moon loses its ice, it heats up more easily when facing the sun and accelerates the loss of ice. 

22. Titan has a liquid cycle, But there is definitely no water involved

Artistic rendering of Titan's lakes

Titan’s lakes are full of methane and ethane and possibly a layer of water.

Another strange moon of the solar system is Titan, a moon of Saturn. Titan hosts a “fluid cycle” that moves material between the atmosphere and the surface. This circulation of materials is apparently very similar to the water cycle on Earth; But Titan’s huge lakes are filled with methane and ethane, probably on top of a layer of water.

Using data from the international Cassini mission, researchers hope to uncover some of the moon’s secrets before designing a submarine that could one day explore Titan’s mysterious depths. 

23. Organic molecules are everywhere

The rough surface of comet 67P/Churyumov-Grasimenko

Organic molecules have been found in many places in the solar system, including comet 67P/Churyomov-Grasimenko. In this image, the rugged landscape of the comet’s core was captured by the Rosetta spacecraft.

Organics are complex carbon-based molecules found in living organisms, But abiotic processes can also be their creators. Although common on Earth, organic molecules can be found unexpectedly in many other places in the solar system. For example, scientists have discovered organic matter on the surface of comet 67pi. The hypothesis that organic molecules were probably brought to the surface of our planet from space to start life on Earth was strengthened by the discovery of these molecules in comet P67.

Organic matter has also been found on the surface of Mercury, Titan, Saturn’s moon (which gives it its orange color), and Mars. 

24. Saturn has a hexagonal storm

Saturn's strange hexagonal storm

Saturn’s northern hemisphere is home to a strange hexagonal storm that has been raging for decades.

Saturn’s northern hemisphere has an intense six-sided storm known as the “hexagon”. This hexagon, a towering multi-layered storm, has existed for decades, perhaps even hundreds of years.

Saturn’s strange storm was discovered in the 1980s; But until the Cassini spacecraft flew between 2004 and 2017, it was difficult to observe it. Cassini images and data showed that the hexagonal storm is 300 km high and 32 thousand km wide and consists of air moving at a speed of 320 km/h. 

25. The atmosphere of the Sun is much hotter than the surface of the Sun


The temperature of the sun is different in each layer of its atmosphere.

While the temperature of the visible surface of the sun or photosphere is 5500 degrees Celsius, the temperature of the upper atmosphere or corona (solar corona) reaches millions of degrees. This extreme temperature difference is one of the great mysteries of the star of our system.

However, NASA has several solar-observing spacecraft in its fleet of probes, and they have some hypotheses for how heat is generated in the sun. One such idea is the “heat bombs” that occur when magnetic fields align in the corona. Another hypothesis is related to the time when plasma waves move from the surface of the Sun to the corona.

With new data from the Parker probe, which has become the closest man-made object to the Sun,we are closer than ever to unlocking the secrets of the heart of the Solar System.

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