Translation introduction:

In the second third of September, the James Webb Telescope was able to capture an amazing set of details of two regions of the night sky called the Orion Nebula and the Spider Nebula.

In the new images and accompanying data, scientists have shown with a degree of precision never before seen how new stars arise from clouds of gas and dust in nebulae, which contributes to revealing the origins of our solar system.

Well, let's remember that James Webb is the most powerful human space telescope ever, and its data is expected to be released very quickly, and only one week will pass with a new detection, then we will be exposed to a lot of news of this unique piece of technology continuously, so we found in the field that It is necessary to have detailed material that explains the objectives of this telescope, its importance and the way in which it works to achieve its goals, and the background of all this.

In fact, we did not find a better article than this article, which was published by one of the largest and most sedate scientific platforms, the American magazine "New Scientist".

Translation text:

The James Webb Space Telescope released its first scientific images on July 12, unveiling a new era in astronomy.

This event had a strong impact as it aroused interest and curiosity.

After years of delays, and especially suspenseful waiting, during those long months that officials spent testing the telescope before its launch, James Webb finally won the title of the most powerful telescope ever made. Which we will guide to answers related to questions that we thought the answer to is just a far-fetched dream, after previous telescopes were unable to answer them.

Thanks to a combination of special abilities, James Webb will be our guide to a deeper understanding of the universe's distant past than ever before.

Its ability to monitor infrared rays, and to provide it with a huge mirror floating in an orbit wider than the moon’s, enables it to collect light from the faintest stars and galaxies (that is, the most faint) and the most distant from us, meaning that it is able to collect light that has been expanded to reach infrared wavelengths As he travels through the vast expanse of space for billions of years.

Because of the telescope's accuracy, which is unmatched by its accuracy, we will be able to see these things in exquisite detail, and providing it with an infrared spectrograph will enable us to distinguish the properties of particles hidden in the atmosphere of planets outside our solar system "exoplanets". , which is likely to be habitable.

The real motive behind this feverish pursuit that never subsided, is simply man's curiosity to understand what is going on around him in this vast universe, a fact rooted in human beings.

So the data we will receive from the James Webb telescope will help us unravel some of the biggest mysteries of the universe, from how the first stars and galaxies were formed and how fast the universe expanded, to the possibility of extraterrestrial life.

Below we will discuss 7 questions that James Webb will shed light on, that will change the way we understand the universe.

Spider Nebula (networking sites)

Where were the first stars formed?

And when did that happen?

The Big Bang was followed by the so-called "cosmic dark ages", and the universe was formed at this stage either from dark matter that does not emit or reflect light, or a substance composed of a mixture of hydrogen and helium gases.

Over the course of a few hundred million years, the gas began to coalesce into the first stars, hence the first flash of light in space.

The radiation from these first stars ionized the surrounding neutral gas, so it was called the “reionization period.” After that, the universe transitioned from a primordial soup to galaxies, stars, and perhaps even planets lined up in a very symmetrical position (after the Big Bang, the universe was about a primordial, superheated soup of fundamental particles, especially quarks and gluons).

It is true that we are aware of all this happening, but we have not found a way to explain how it happened.

Jehan Kartaltepe of the Rochester Institute of Technology in New York spent about 256 hours supervising James Webb. Similar: What were the first types of stars the universe saw?

And in what kind of galaxies were they formed?

At what early stage did reionization occur?

And how long did that all take?

It is a tale of curiosity, then, that drives man from ages ago to this day to penetrate into the depths of the universe in an attempt to probe its depths. However, James Webb’s predecessors of telescopes did not satisfy mankind’s obsession with knowing more about the secrets of the universe, and about this Kartaltepe says: “If we use a telescope Hubble, for example, to detect a primitive galaxy, the telescope will not show it as a galaxy as much as it will show it as a smudge or a small spot in the image, and all you can do is only determine how bright it is, but things have changed now with James Webb, as the latter will enable us to measure the masses of The stars in these galaxies, determine their structure, and then the role of physics will help us understand the fluctuating nature of the universe.”

As we can see, the Kartaltepe project will allow us to take a comprehensive look at the reionization process, and commenting on that: “The reionization process did not occur all at once throughout the universe, but began in the form of small spots, and then expanded with time to become large ionized bubbles. ".

In the same context, Rohan Naidoo of Harvard University says that he was able to identify one of these small foci, which he believes is the place where the cosmic dawn broke out for the first time, saying: "We believe that what we observed are the first galaxies that formed after the Big Bang."

(communication Web-sites)

We can measure the distance of objects in deep space by a phenomenon called red shift.

This phenomenon describes how light shifts toward shorter or longer wavelengths as objects, stars or galaxies, move toward or away from us.

This shift moves toward red as galaxies get farther and older (and galaxies move away from Earth because the fabric of space itself is expanding).

It is believed that the cosmic dawn began when the redshift was 10 degrees, then the universe was about 500 million years old, but Naidoo believes that we may find evidence that the first stars formed in an ionized bubble that we can observe now if this bubble shifted towards the red by 9 degrees, This small patch of sky is a very special location, because it holds within it a quarter of the galaxies that are candidate for high redshift.

Commenting on this, Naidoo says: "I was very excited, and I can't wait to see these galaxies that have reached high degrees of redshift, because this may eventually allow us to see the first stars that formed in the universe."

What is the origin of giant black holes?

Black hole (networking sites)

Black holes are one of the strangest cosmic bodies ever. They are regions in space-time that are so dense and twisted that they have such strong gravitational force that they grab what they encounter and devour what they encounter, to the point that even a ray of light fails to escape their grasp.

There are different types of black holes, including stellar black holes that arise when massive stars collapse, and their mass reaches a few hundred the mass of the sun, and giant black holes, those that settle in the centers of most galaxies, have a mass of millions to billions of times the mass of the sun.

These unrelenting abyssal monsters play a role in the evolution of galaxies, because they gather together to release powerful jets or bursts of radiation that destabilize everything around them.

One of the most perplexing things about astrophysics is that we see giant black holes already billions of times the mass of the sun when the universe itself was much less than a billion years old. The stars and gases must have started as large as thousands of suns, and unfortunately we have no idea how this happened because our current models lack the power to reach our desired goals of explaining what is happening.

Scientists have put forward two main hypotheses to explain how supermassive black holes formed in the early universe.

The first hypothesis indicates that black holes were formed either from the collapse of a huge gas cloud on itself, and turned directly into a giant black hole, or that this cloud initially turned into a massive star, and then this star collapsed later, leaving behind a giant black hole.

The second hypothesis indicates that black holes formed from dense clusters or constellations of stars that merged with each other, and as they increased in size and continued to expand, they ended up turning into a black hole.

To learn more about supermassive black holes, Professor Xiaohui Fan, from the University of Arizona in the United States, decided to observe distant quasars (or so-called quasars), the very hot and bright objects surrounding supermassive black holes, which are generated by the flow of gas at high speeds. high in these black holes, releasing massive bursts of particles and radiation.

So, if Van and his colleagues closely monitored three of the most distant quasars we know, and were able to measure the speed of a cloud or disk of gas spinning in a spiral as it fell into black holes, then he would immediately be able to measure the mass of black holes.

But if we combine that with a measure of the luminosity of those objects, we will also get the rate of accumulation of the material that makes up the black hole, and this will allow scientists to know the initial mass of the black hole, and when these initial huge seeds were formed, which grew into giant black holes with the beginnings of the formation of the universe.

The question of who originated first, black holes or galaxies;

It's an eternal chicken-and-egg puzzle, but one that's hard to answer in a precise and reliable way, so instead of asking who originated first, Van and his colleagues should shed light on how large these holes are, and how their size affects the evolution of galaxies.

We know that the most massive galaxies contain the largest black holes, but which came first, and whether one was responsible for the other, remains a cosmic mystery.

However, the James Webb Telescope came to bring us deep consolation thanks to its capabilities, accuracy and extreme sensitivity, as we will witness for the first time the light from stars in galaxies that contain these black holes, and the ability of the telescope to monitor infrared radiation will enable us to determine the ages of these holes Black holes, and then we will understand when stars and galaxies formed when compared to the expansion of black holes.

Is dark matter cold?

We now come to what scientists know as "dark matter", an elusive and mysterious substance that seeps through the universe, and its existence can only be inferred through its gravitational effects.

Scientists have concluded that "dark matter" represents about 85% of the majority of matter in the universe, but we do not know the types of particles that make up this matter, and whether it actually consists of particles (as matter does not necessarily consist of atoms, but it can be Most of them consist of something completely different.)

What we know so far is that dark matter is "cold";

This means that they move slowly, allowing small masses to aggregate and expand into larger structures known as "halos." What we have now as the best current picture of how the universe evolved indicates that dark matter played a crucial role in the formation and evolution of the universe. Auras are gas that gathered together and then collapsed to form stars and galaxies, which means that dark matter is the totality and end of everything that makes up the universe.

The sizes of dark matter vary from one type to another. Some types have a mass of millions of billions of the mass of the sun, while other types reach less than the mass of the Earth.

But if we pay some attention to dark matter halos, we will discover that in order to attract enough gas to form galaxies, they must be more than 10 million times the mass of the Sun.

According to our understanding of cosmic evolution, our universe contains hidden pockets that hide what we do not see, and from here it is assumed that we are surrounded by many such pockets that carry dark matter in its pocket.

Meanwhile, Professor Anna Nirenberg of the University of California and her colleagues decided to run a simulation model to test whether dark matter is really cold and slow, or if this is just an assumption.

As the team observes quasars, the light they emit will be either reflected or bent by the gravitational pull of a dark matter halo, which does not contain galaxies.

In this case, the light will be deflected in such a way that it creates repeating images in the telescope, which is exactly the goal of Nirenberg and colleagues' experiment.

And who knows?!

Perhaps this experience will turn into a guide towards understanding the world more accurately and comprehensively.

Commenting on this, Nirenberg says:

How do huge stars turn into "supernovas"?

Supernova (Shutterstock)

Somewhere in the universe, when a star the size of our sun reaches the end of its life, it quietly fades into the dark fabric of the universe, but this process does not go in this calm pattern with the largest stars, as the latter does not accept to fall into the abyss in peace as if it had never been Rather, it explodes violently at the height of its glory in a monstrous spectacle, leaving behind an unparalleled brightness and a huge amount of energy in its surroundings, and this process is called a "supernova explosion" or "supernova" caused by the collapse of the stellar core (core-collapse supernovae).

As a result of the shock waves generated by the heat of the explosion, new generations of stars are born.

When a supernova explodes, it unleashes a flood of all kinds of chemical elements and nuclear reactions, and those elements are responsible for enriching the gas clouds that make planets like ours.

It's true that we see supernovas all the time, but for a star to throw itself into a stream of violent outbursts, it must be at least eight times the mass of the Sun, and once it reaches that size it ends up exploding.

At some point in a star's life, its core is unable to support the weight of its outer layers, so it loses its viability, collapses and explodes, leaving a supernova behind.

We may be fascinated by all of this, but the mechanism adopted by these explosions is what makes our awareness about them bewildered, not knowing anything about it.

A star can transform into a supernova in one of two ways;

Either by “electron capture.” In this case, the star carries a nucleus of oxygen, neon and magnesium in its sleeve. These materials hold together due to the pressure of the electrons of these atoms. Electron (an electron-capture reaction).

This interaction reduces the pressure, which in turn leads to the gravitational collapse of the outer layers of the star, and as a result of this imbalance, the star finds itself hitting the sides of the universe that has neither harm nor benefit for itself, and ends up exploding.

(communication Web-sites)

The second method is called "iron-core collapse".

In this case, the star's core is formed from iron, and because iron is a very stable element, it cannot combine with other elements to release energy, and as a result, nuclear reactions lose their ability to balance gravity;

Which eventually leads to the collapse of the star.

It is impossible to know what happens inside the star at the moment of its explosion, because the outer layers cover the inner core and block our view, but at the same time, astronomer “Tia Tamim” - from Princeton University in the United States - is trying to take advantage of James Webb by unveiling a little bit about what happens inside the star’s core when Its explosion, by closely observing the "Crab nebula", is the remnant of a supernova explosion of a star 8-10 times the mass of the Sun.

Astronomers first observed the Crab Nebula in 1054, and this nebula is one of the most astronomical objects that scientists have devoted an effort to study meticulously at all times.

If we examine this nebula well, we may be able to know how it exploded, because each of the two possible explosion mechanisms will leave their fingerprints, and these fingerprints appear in the form of different proportions of iron and nickel elements stable in the material ejected by the star after its explosion.

For her part, Tamim says, the Crab Nebula has a very complex ionization structure, and fortunately, James Webb's merit requires discerning the two possible ways the star explodes.

Where do planets like Earth get their water?

We are fortunate enough to have a planet saturated with water from oceans, lakes, rivers, and waterfalls, but according to our current understanding of the history of our solar system, our planet, manifested as a faint blue dot in this vast space, was not at all that blue at the beginning of its formation, when the Earth formed about 4.5 years ago. Billions of years from a mixture of gas and dust, it lay at the "snowline", the radius outside which the temperature outside is low enough to turn all the water into ice.

At that time, the sun was releasing enormous amounts of energy than it does today, as well as radiation pressure that pushed any water vapor near the earth beyond the snow line, which means that the material that formed the earth did not carry any water source.

Commenting on this, Isabel Rebolido, from the Space Telescope Science Institute in Baltimore, Maryland, America, says: "Our conclusions confirm to us that the Earth's water has come from somewhere outside the range of our planet."

Planetary scientists believe that the source of water on our planet may have come later from asteroids or comets in a period known as the "Late Heavy Bombardment".

What we sometimes forget is that the secondary effects of the motions of the gas giant planets in the outer solar system may have played a role in pushing ice-formed debris into our solar system;

Which led to sending water to Earth, in addition to creating many lunar craters (which are impact craters on the surface of the moon, which are craters resulting from the violent collision of rocky masses such as meteorites).

To confirm this theory, Rebolido decided to observe 5 planetary systems outside our solar system at a similar stage of evolution, the stage at which gas giant planets have already formed, and their movements destabilize the material around them.

Along the same lines, Rebolido says, "One possible explanation for the source of the gas we find in the inner regions of planetary systems is that solid and icy bodies sent from the outer regions are evaporating."

This means that icy bodies can actually be transported from regions outside the solar system to rocky planets within the snow line, giving arid worlds a blue color indicating the presence of water on the planet's surface.

Is there life on other planets?

Soon, this question captured the human mind, and it kept hovering aimlessly in his head, leaving him bewildered for centuries.

To answer this question, scientists resorted to searching for "biosigns" or traces of life in the atmospheres of planets outside our solar system "exoplanet".

These effects appear in the form of certain groups of molecules, such as methane and carbon dioxide, the presence of which indicates the possibility of the existence of life on these planets, but all of this depends mainly on the presence of an atmosphere or not.

(communication Web-sites)

To learn about the atmosphere of exoplanets, experts use the "transit technique".

When a planet passes in front of its host star, the various molecules in its atmosphere interact with the star's light, emitting or absorbing infrared radiation at specific wavelengths that form the chemical fingerprints of these planets' molecules, which indicate whether these planets are fit to harbor life inside.

Fortunately, James Webb has a "spectrograph" that is very sensitive to the chemical signatures of planetary molecules.

Commenting on this, Megan Mansfield, an astronomer at the University of Arizona, USA, says: "The James Webb Telescope will revolutionize astronomy, because the Hubble and Spitzer telescopes had relatively limited wavelength ranges, so our information about the atmosphere of exoplanets was somewhat scarce." .

But even with James Webb's unprecedented capabilities, it is likely that he could only find biosignatures or traces of life on planets orbiting cold, low-mass stars called "red dwarfs" or "M dwarfs."

This means that a very attractive and distinct group of exoplanets will fall into our view.

Among the thousands of stars known for hosting exoplanets, a wonderful star known as TRAPPIST-1 stands out, a small star around which 7 rocky planets were discovered by scientists in 2016. As we can see, this star contains a large number of planets that enjoy a large temperature Suitable for retaining more liquid water on its surface than any other system we know of.

On the other hand, Mansfield believes that despite all this, we still do not know whether planets orbiting the star Trappist, or any other worlds orbiting red dwarfs, can retain their atmospheres long enough for life to develop in them, because red dwarfs They are much more active than other stars like our Sun, and the copious amount of high-energy radiation they emit can strip planets of their atmosphere, hence one of James Webb's most important roles, which is the search for extraterrestrial life by determining whether Whether or not the exoplanets orbiting red dwarfs had atmospheres.

On the other hand, Kevin Stevenson - from Johns Hopkins University in Maryland, USA - decided to observe 5 exoplanets orbiting the nearest red dwarf star, including one planet from the TRAPPIST system, and about this he says: “If none of the five planets has an atmosphere This tells us that the atmospheres of planets orbiting the red dwarf are rare, and then we will have to direct our efforts towards observing planets orbiting other types of stars."

But if we discover, on the other hand, that these planets have an atmosphere on their surface, we will have good candidates to observe them, but getting to this step is not easy even with James Webb's extraordinary capabilities.

So, commenting on this, Stephenson says: "It is true that I have no idea whether or not we will achieve our desired goals in the next 10 years with the help of James Webb, but we have no other choice but to keep trying."

Is the universe's expansion rate jeopardizing our best cosmological model?

We live in a dynamic universe that must be in a state of constant motion and expansion, as galaxies are moving away from each other at a rate known as the Hubble constant.

Scientists can measure these distances either directly, by determining the distances between us and distant astronomical objects, or indirectly by comparing our observations of the early universe with our best theory of how the universe evolved, but the main problem remains the inconsistency The two standards, in the sense that the final results of the two methods contradict each other.

Hubble Telescope (Shutterstock)

Our current cosmological model (a comprehensive description of the universe's current shape and evolution over time) assumes that the universe consists of radiation and matter (including cold dark matter), as well as dark energy, a bewildering form of energy thought to be responsible for the expansion we're observing.

To measure the expansion rate of the universe, scientists used data from the radiation of the remnants of the Big Bang known as the "cosmic microwave background radiation or the cosmic microwave background", and then added this data to the current model of the universe, and found that the universe is expanding at a rate of 67 kilometers per second per megaparsec (which equals 3.26 million light-years).

But the problem that faced astronomers when they measured the Hubble constant is their discovery that the value of the expansion of the universe is equivalent to 73 kilometers per second per megaparsec.

This discrepancy between the two values, known as the Hubble tension coefficient, could point to a serious error in our understanding of cosmic evolution.

Nevertheless, the standard cosmological model is still very successful, because it is able to explain all kinds of observations and questions, so abandoning it is not easy at all, and James Webb plays a role in resolving this controversy.

In order to get a value for the Hubble constant, astronomers use the "cosmic distance ladder" (a series of methods for determining the distances between celestial bodies), this ladder is based on stars known as "Cepheids", which are very bright stars, and their brightness changes at a rate It is related to how bright they are in absolute, which allows us to measure the distance between us and them.

Moving to the next rung of the ladder using "standard candles"

Despite all this, many doubts remain about these measurements.

To extricate us from this spiral of doubt, Wendy Friedman, professor of astronomy and astrophysics at the University of Chicago, decided to measure the distance using a variety of “standard candles.” For example, “Cepheid stars” are often surrounded by other young stars, and the accuracy of the images provided by James will help. Webb is designed to measure how bright these Cepheid stars are relative to their neighbors, as well as the high sensitivity of the telescope to observing these stars in distant galaxies.

Because man was instinctive to find a unique pleasure in understanding, and trying to comprehend the universe, Friedman decided to combine measurements of Cepheid stars with other methods of measuring the distance between us and other galaxies, and its purpose is to provide a better understanding of the accuracy of our calculations of the Hubble constant.

If these independent methods succeed in making the same measurements as the Hubble constant, then we will make sure that the astronomical measurements are effective and robust, and at the same time the Hubble tension will disappear. But the most important question here remains: What if the astronomical measurements still differ from the cosmological model?

To answer that, Soyo says, "It would be really interesting if it turns out that there is a new physics with which we haven't created a smooth bridge yet."

Even if astronomers who got stints in the first observational cycle of the James Webb Telescope find exactly where they're supposed to look, that doesn't stop them getting excited about the prospect of seeing something unexpected.

"I hope we discover something we weren't expecting," says Wendy Friedman.

Kristen McQueen - from Rutgers University in New Jersey - is also very excited about questions that we do not think and do not even have enough information to ask, and cites a picture taken by the Hubble telescope in 2004 after directing it to a random small spot in space, only to be surprised that there are thousands The twinkling stars and galaxies that were older than anyone imagined, and this result hit their expectations against the wall, and this attractive image reshaped the universe in a vibrant and impressive way, and changed the cosmology completely.

In the end, when scientists create a new instrument such as the James Webb Telescope, it is a new window open to worlds brimming with possibility, says Friedman, who concludes: “Almost every field of astronomy will have its share of new things to be added to the His credit, as well as discoveries that no one would ever expect, involve a great deal of excitement and suspense."

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This article is translated from New Scientist and does not necessarily reflect the Medan website.

Translation: Somaya Zaher.