Space and time are intertwined. Light travels at a constant speed, so the images captured by telescopes like James Webb’s are actually images of the universe from millions or even billions of years ago. The higher the sensitivity and accuracy of a telescope, the more distant objects it can observe and thus display more distant times. As the most powerful telescope ever launched, the James Webb Space Telescope (JWST) is extremely sensitive. This telescope can theoretically see objects within 100 million years since the formation of the universe.

There are still many unknowns about the history of the universe, but telescopes like Webb’s can unravel these mysteries and reveal unprecedented detail.

History of the world

The entire universe was created from an ancient and vast explosion that continues to this day. This spark , called the Big Bang, happened nearly 13.8 billion years ago. The Big Bang is the best hypothesis ever proposed for the existence of the universe. Although there is still no way to directly observe the Big Bang, this theory is well established and has been confirmed by many scientists over the past few decades.

In the first moments of the universe, a fraction of a second after the Big Bang, everything was inside a singularity, which is an infinitesimally small point of space with a very strange and high density that encompasses everything. In a few moments after the birth of the universe, the world was in an era known as Planck’s age. In this era, the whole world was so small that space and time had no meaning. Then, in less than a second, the universe entered a phase known as cosmic inflation, and for a moment, it expanded greatly. The infant universe consisted of a hot soup of subatomic particles and radiation, preventing any kind of structure from forming.

The early universe was a highly viscous place filled with turbid plasma for several thousand years. This murky plasma was a mass of subatomic particles that were too hot to contract into atoms. The lack of transparency of the early world makes it impossible to see the events of that time; However, the early chapters of the universe’s history are of interest to many cosmologists because they represent a stage for the existence of everything.

Scientists believe that the early universe was filled with equal amounts of matter and antimatter, which eventually annihilated each other, leaving only a small amount of matter in the present universe. The question of why one of them was more remains a mystery and physicists are still trying to answer this question.

Eventually, the universe cooled and atoms and then strange molecules began to form. The first molecule that was formed in the world was made of only two elements, hydrogen and helium. These molecules finally made a compound called helium hydride. This chemical reaction actually created a helium compound that looks like it shouldn’t exist.

On its 300,000 birthday, the world entered an era known as the age of recombination. It was during this period that atoms began to form, although the word “recombination” is a bit of a misnomer because it was during this period that everything was combined together for the first time. As the universe cooled enough, matter began to form atoms, and the universe became transparent for the first time. This transparency allowed the light left over from the Big Bang to spread throughout the universe.

The ancient Big Bang radiation marks the edge of the visible universe and can still be observed. As the universe continues to expand, the light in it is stretched, which astronomers witness in the form of the redshift phenomenon. The older the light of an object, the more it is stretched and moves to the red side of the spectrum like infrared and finally to longer wavelengths.

The initial light of the birth of the world is the most stretched light and the human eye cannot observe it. This light can be seen in all directions today as the cosmic background radiation (CMB). As seen in the image above, some speckled areas show slight fluctuations left over from cosmic inflation. These faint background rays are the last reflections of the birth of the universe.

With the universe filled with atoms, light was finally able to move freely in open space. However, there was nothing in the universe capable of producing light. In fact, this age of the world is known as the age of cosmic darkness. In this period, the stars were not yet born and the space was full of silence and infinite darkness. The universe was in its infancy and there was nothing but dark matter with neutral helium and hydrogen, But it was in this darkness that the materials of the world gradually joined each other.

Finally, with the formation of the first stars, the world entered an era known as the Bazion, and the first stars shone. They emitted intense ultraviolet light in the dark and eventually removed the electrons from the new atoms; But even though the stars were shining for the first time in the universe, their light could not travel very far. Because the entire space was filled with a fog of hydrogen gas and blocked the light of the first stars. After some time, the starlight traveled further distances and reached us today.

According to human earth standards, any place with liquid water can be classified as habitable. As the early Earth cooled, the surprising truth was revealed that the entire universe was once at a habitable temperature. According to an article published in the International Journal of Astrophysics, this period is called the early habitable age. Based on this hypothesis, the question arises as to what exactly happened in a world where life theoretically existed everywhere. According to calculations, this cosmic age corresponds to the time when the universe was still 10 to 17 million years old.

Of course, scientists have differences in this hypothesis. According to an article in Nature that argues against this idea, life requires a hot-to-cold energy flow and cannot exist in a uniformly warm universe. Furthermore, at this early age it is not known whether the universe had stars or planets, or even oxygen to produce water. However, this hypothesis cannot be completely rejected. The first planets were probably formed in the first few billion years of the universe; So the hypothesis of an early habitable age is little more than a fascinating thought experiment.

History of the world

The first stars of the universe were formed from the virgin material left over from the Big Bang and were the cause of the formation of the first heavy elements of the universe. These stars, which lacked elements heavier than helium, are known as population 3 stars (confusingly named stellar populations in the wrong order). Since these stars were responsible for the formation of the heavy elements of the universe, they must have existed at some point in history. These objects are expected to have formed between 100 million and 250 million years after the Big Bang.

According to the models, Population 3 stars were very massive and short-lived by today’s stellar standards. The lifetime of some of these stars reached only 2 million years, which is a long time from the human point of view; But on a stellar scale, it’s like a blink of an eye. When these stars ended their lives, they likely perished in unstable binary supernova explosions, the most violent type of stellar explosion in the universe. Although no stars belonging to this group have been observed so far, perhaps this trend will change with powerful instruments such as the James Webb Space Telescope.

Blooming cosmos with stars

We live in a season of the world known as the age of star formation. This age is the beginning of the stars shining in the dark and is actually the modern age of the world, in which the cosmic matter turns into stars, planets and galaxies. According to scientists, the era of star formation began approximately one million years after the Big Bang and will continue until the universe is 100 trillion years old. Until the very distant future, the birth, life and death of stars in the universe and the fusion of hydrogen into heavier elements will continue until hydrogen disappears completely.

Although stars are actively forming in the universe, there is a wide range from newly born stars to very old stars. Stars can live for billions of years. Red dwarfs, the smallest and most populous stars in the universe, live so long that their deaths have not been recorded until now because the universe is not old enough. Astronomers have also observed very old stars in the universe, some of which date back to the earliest days of the Milky Way, between 11 and 13 billion years ago. Stars like this have been observed for most of the history of the universe.

By weight, most of Earth is made up of chemical elements heavier than helium, which are made in the cores of stars. This process is known as nucleation. During the lifetime of a star, nuclear reactions combine light elements and produce heavier elements. In this way, elements such as carbon, oxygen, silicon, sulfur and iron are formed in the hearts of stars. When stars run out of fuel, they throw the elements they made back into the universe.

Stars fill the galaxy with elements by their birth and death over billions of years. Carbon, oxygen, and nitrogen are among the most abundant elements made by smaller stars. As these stars die, their outer layers form a stellar nebula. From this example, we can refer to the Southern Ring Nebula, whose image was published by the James Webb telescope.

The life of the biggest stars also ends in a supernova explosion. These explosions not only fill galaxies with heavy elements such as iron, but their shock waves can be the basis for the birth of new stars.

The hunt for the oldest stars in the universe is one of the fascinating fields of astronomy that can help scientists understand the early days of the universe. The oldest star ever discovered is HD 140283. The star is so old that the first estimates of its age are older than the universe itself. However, this effect is an illusion caused by the uncertainty in the estimates. Therefore, measuring the age of a star is not an easy task.

According to another research in the Journal of Astronomy and Astrophysics, the age of HD 140283 was estimated to be almost the same as the age of the universe, i.e. 13.7 billion years. In other words, this star was probably born a hundred million years after the Big Bang, and thus it is one of the first generation of stars that were born in the world. This star is metal-poor, or in other words, has a small number of chemical elements heavier than helium, and thus it is placed in the category of population 2 stars. Such stars are among the oldest objects that have ever shone in the universe. Based on the ratio of chemical elements, these stars are survivors of early stars from the early days of the universe.

No one knows exactly when the first planets formed, but they seem to be able to outlive stars. The oldest known planet orbits two dead stars, one of which is a pulsar and the other a white dwarf. Both stars are stellar wrecks that have run out of fuel and have released much of their chemical material into their galaxy. The mentioned pulsar is called PSR B1620 and the planet located in its orbit is known by the nickname Methuselah. This planet, which is a kind of gas giant, is not unlike the planet Jupiter.

According to estimates, the lifespan of Methuselah reaches 12.7 billion years, but this age is not exact. There is no good way to estimate the age of planets, so this estimate is based on other stars in the Methuselah cluster. Globular clusters, such as the Methuselah host cluster, are full of stars that formed at the same time.

According to the research of Science magazine, the existence of the ancient planet Methuselah offers interesting hints about the time of formation of the oldest planets. If the estimates are correct and Methuselah is really 12.7 billion years old, we can say that the planets were formed earlier than we think. In other words, Methuselah may not be the only ancient planet in our galaxy.

When the universe was only 200 million years old, the first galaxies were formed. The discovery initially surprised astronomers because they thought galaxies formed much later. Early galaxies were not similar to today’s massive galaxies. Rather, they were shapeless clouds of irregular gas and dust. These galaxies, accompanied by a wave of star birth, eventually became the massive galaxies that fill the universe today. It seems that the Milky Way galaxy was formed approximately 13.6 billion years ago. Our galaxy was then an unrecognizable mass of stars, not unlike the present spiral.

The oldest galaxy ever discovered was formed 300 million years after the Big Bang. This galaxy is called HD1 and the James Webb telescope played an important role in determining its age. HD1, if confirmed, would be the oldest galaxy ever seen by astronomers and could offer fascinating insights into the formation of the universe’s first galaxies. The formation of galaxies is still a mysterious research field full of unanswered questions. Helping to solve these questions will be one of the main goals of the James Webb telescope.

Much of the world seems to be an empty void, But the universe has complex structures on very large scales. The universe is covered with an array of dark matter filaments that form a web-like structure. This network of dark matter, called large-scale structure, shapes the universe and causes galaxies to fall into regular patterns. The gravity of the large-scale structure causes both dark and visible matter to lie next to each other. By examining this structure, we can find signs of the youth of the world.

Deep background images, such as the James Webb Telescope image, can reveal how galaxies fit together. These structures are actually the largest visible structures or galaxy strings in the universe, held together by gravity. In addition, the structures are not random but have an order that still fascinates researchers. Galaxies and large galaxy clusters appear to be evenly spaced in the galactic strings, resembling a pearl necklace. There are still many uncertainties about large-scale structures.

Gravity pulls everything in the universe together, and the heavier the mass, the greater this attraction. Galaxies are among the heaviest objects in the universe, whose formation and evolution are still a matter of discussion and their evolution is strongly influenced by their interaction with each other.

Galaxies usually tend to form groups or clusters that come together due to gravity and start interacting when they are close to each other. The gravitational pull of galaxies leads to the creation of lethal forces. In the most dramatic examples, galaxies can collide and their merger may take billions of years.

Galactic collisions can lead to the formation of new stars; Because the change of gravitational forces causes disturbances on huge scales. Some stars are ejected into the dark intergalactic space, while others are trapped by the gravity of supermassive black holes at the center of colliding galaxies. As the galaxies merge, their spiral arms are eventually destroyed, and the two galaxies eventually become one massive elliptical galaxy. In this way, some of the largest galaxies in the universe are formed. Some galaxies also grow by absorbing smaller galaxies. According to some evidence, the Milky Way has experienced such a collision in the past, and its signs can be seen in the form of remnants of galaxies that it has absorbed in the past.

History of the world

The largest galaxies, such as the Milky Way, have a supermassive black hole at their center; Although how these black holes formed is still a mystery, it is clear that they are very old. The European Space Agency has released an image of an ancient galaxy known as UDFj-39546284, which appears to be a small red dot in the image. This spot is actually the oldest quasar observed by astronomers and dates back to 380 million years after the Big Bang.

Quasars are among the brightest objects in the world, which are created by the feeding of the supermassive black hole at the center of a galaxy from the surrounding material. The big question here is how these black holes have reached these dimensions at a high speed. According to a study published in the journal Nature, supermassive black holes appear to have formed suddenly from turbulent cold gas in the early universe. In the right conditions, black holes were formed with great intensity and suddenly as a result of the collapse of streams of initial materials grew to dimensions exceeding 40,000 times the mass of the Sun.

Today, the Milky Way is a spiral galaxy, but it hasn’t always been this way. The spiral galaxy formed in a galactic disk, but the Milky Way disk formed about ten billion years ago. This means that our galaxy spent its first three billion years without a disk and therefore had no spiral arm.

The disk of a spiral galaxy contains a large part of the material of that galaxy. In such galaxies, star birth often occurs in spiral arms, as stars are formed from vast clouds of gas and dust slowly swirling around the galactic core. How and why spiral arms and disks are formed is still not completely clear, although this phenomenon has been observed frequently in the sky.

Some galactic disks appear to be very old. The oldest galactic disk ever seen is the Wolf disk. This old spiral galaxy dates back to when the universe was only 1.5 billion years old. Of course, due to the distance of this galaxy, we have no information about its new appearance.

One of the milestones in world history can be related to dark energy; The mysterious force that controls the expansion of the universe. No one knows exactly what dark energy is, although astronomers can measure its effects. Until a long time ago, the universe was in a tug-of-war between the force of gravity and the repulsive force of dark energy. At some point around 5-6 billion years ago, dark energy won the race. As the universe continued to expand, dark energy overcame gravity and accelerated the expansion of the universe.

The effect of dark energy on the future of the universe is still unclear. Without knowing more about dark energy or how it works, there’s no way to know. Although dark energy appears to make up a large part of the universe, its specifics are still shrouded in mystery. According to a possibility, this energy can be one of the inherent characteristics of space itself.

The sun is almost a third of the entire universe. This star was formed about 4.6 billion years ago. With the formation of the sun, the clouds of gas and dust around it formed planets such as Earth and many moons of the solar system.

The sun is one of the population’s 1 stars. Such stars are among the newest stars in the universe and are rich in heavy elements, examples of which can be found on Earth. According to a hypothesis, the shock wave resulting from a supernova was the cause of the formation of the solar system from vast dust clouds. The traces of this supernova exist in the form of radioactive isotopes in the entire solar system; So a star died so we could live.

According to scientists, the story of the formation of the earth goes back to 4.6 billion years ago. Our planet formed in a disk-like cloud of gas and dust around the primordial Sun. Inside this disk, gas and dust particles of different sizes were rotating at different speeds in the orbit of the sun and in this way, they collided and stuck to each other. Finally, the tiny particles turned into huge rock fragments and objects called asteroids, whose diameters ranged from one to hundreds of kilometers.

Asteroids eventually gained enough gravity to clear their orbits and attract other bodies through collisions, becoming larger bodies several thousand kilometers in diameter and forming planets.

Life on Earth is the only life we ​​know of in the entire universe. Life first appeared about 3.7 billion years ago, shortly after the formation of the Earth itself. Thus known life is roughly a quarter of the age of the universe, although the complex life that would eventually become humans is much more recent.

Carbon is an essential element for life and appears to have been unavailable until 1.5 billion years after the Big Bang. For this reason, it is still not possible to estimate with certainty the first form of life in the entire universe. Maybe other parts of the world have different chemistry or different elements than life on Earth.

To quote the late astronomer Carl Sagan, “We are a way of knowing the world.” Humans are part of the world like the most distant stars or galaxies. In other words, at least a part of the world is capable of thinking and observing other parts. The oldest early humans appeared on earth approximately 2.4 million years ago; This means that humans and our direct ancestors only existed in 0.02% of the entire history of the world. On a cosmic scale, it seems like we were born just yesterday. However, humans may not be the only civilization in the world.

The question about the existence of other civilizations in the galaxy has a long history. Half of all Sun-like stars could host habitable universes; Therefore, there is no shortage for the formation of civilizations. According to a relatively conservative study, there should be at least 36 space civilizations capable of communicating in the Milky Way. According to another research, there are more than 42 thousand civilizations in the Milky Way. Currently, there is no way to find out the existence of these civilizations. With more accurate telescopes, we may be able to find evidence that we are not alone in this infinite universe.