Shulou(Shulou.com)11/24 Report--

This article comes from the official account of Wechat: Earth knowledge Bureau (ID:diqiuzhishiju), author: forget the year, drawing: devil Fish / proofread manuscript: Chao Qian / Editor: devil Fish

Recently, the journal Nature published a new study. Astronomers have found six strange red galaxies with the same mass as the Milky way in images sent back from the James Webb Space Telescope.

These galaxies may have stars with tens or even hundreds of billions of times the mass of the sun.

(figure: NASA) ▼

But the weird thing is that redshift measurements show that their light came from more than 13 billion years ago! It is only about 13.8 billion years since the birth of the universe.

At that time, the first stars in the universe had just formed, and it was impossible for galaxies as big as the Milky way to appear in that place. If this result is confirmed, it means that the existing cosmology and galaxy formation theory will face challenges.

The upper limit of the Webb telescope is much higher than that of the Hubble telescope.

(reference: Quantamagazine) ▼

What was the galactic "beast" that appeared out of thin air in the universe 13 billion years ago? Why do their discoveries attract so much attention? Let's first look at how galaxies are formed based on existing theories.

The cosmic player of "gluttonous Snake" is like Darwin's theory of evolution that life is not innate, but evolves slowly from simple to complex. According to modern cosmology, all galaxies and stars are not eternal, but the product of the Big Bang 13.8 billion years ago.

Back 13.8 billion years ago, galaxies and stars had not yet formed, and the universe was in the "Dark Ages" of hundreds of millions of years. At that time, excluding dark energy and background radiation, the material part of the universe was mainly composed of hydrogen and helium gases produced after the Big Bang, accounting for about 15%; and dark matter, accounting for about 85%.

After the Big Bang, most of the baryon matter in the universe cooled to form neutral hydrogen.

In this process, photons are released and become today's cosmic microwave background radiation.

The universe enters the Dark Ages (Picture: wiki) ▼

The dominant dark matter gradually gathers under the gravitational interaction to form a "dark matter halo". On the other hand, the gas falls into the gravitational potential well of the dark matter halo and further cools and condenses through electromagnetic radiation.

About 400 million years after the Big Bang, the first generation of stars began to form from gas, and stars and the gas that created them condensed in the center of the dark matter halo, forming the seeds of galaxies. The scene at this time is very much like an embryo, with dark matter halo like the "egg yolk" that wraps and protects the galaxy.

Dark matter does not absorb, reflect, or emit light.

At present, its existence can only be observed indirectly through the effect of gravity.

(figure: wiki) ▼

After that, galaxies can grow in two ways. One is to gently collect gas from the surrounding cosmic environment, gradually forming new stars and getting bigger.

The other is more violent, because of the mutual attraction of gravity, larger galaxies may directly gobble up smaller galaxies nearby to grow up. It is also possible that two galaxies of about the same size collide and merge violently into a whole new form of galaxy.

The two galaxies collided head-on, forming a rare wheeled galaxy.

(the big guy on the right) (figure: NASA) ▼

Does that sound familiar? Every galaxy has been a cosmic "gluttonous snake" player since childhood. The same is true of our Milky way Milky way. From the young seeds of galaxies more than 13 billion years ago, they have experienced thousands of difficulties, constantly upgraded to fight monsters, and have survived to this day, and finally become a huge system containing hundreds of billions of stars.

Moreover, the Milky way still stores a lot of gas and is constantly making new stars. Around the Milky way, more than a dozen large satellite galaxies are orbiting, waiting to become food for the future.

Among the satellite galaxies in the Milky way, the more famous is the large Magellanic Galaxy (LMC).

And the small Magellanic Galaxy (SMC) (figure: wiki) ▼

But you can't be happy too soon. Observations show that the Milky way is approaching the nearest Andromeda galaxy and is expected to collide in 4 billion years' time. Because the two are similar in size, they will eventually merge into a giant elliptical galaxy.

Fortunately, the collision of galaxies is not as hard as the collision of rigid bodies, and our solar system will not suffer a fatal disaster because of the huge gaps between stars. On the contrary, mankind at that time is expected to see the most spectacular night sky in history.

The simulated photos show the blending of the Milky way and Andromeda galaxies.

(figure: NASA) ▼

In the 1920s, the famous astronomer Edwin Hubble classified and studied galaxies according to their morphology through a large number of observations. Hubble divides galaxies into three categories: spiral galaxies, elliptical galaxies and irregular galaxies, and further divides them into different subtypes according to their ellipticity or spiral arm states.

Hubble's classification is called Hubble sequence, also known as Hubble tuning fork classification.

(figure: wiki) ▼

The rich and varied shapes and colors of galaxies stem from their unique history of growth and merger. For example, young galaxies are bluer, indicating that they still contain large amounts of cold gas, are producing stars, and newborn star clusters emit more blue radiation.

In older galaxies, gas is scarce and new stars are no longer formed, leaving only old stars, radiating reddish.

The bluer the color, the shorter the life of the star.

Basically, red dwarfs and brown dwarfs are the ones with long life.

(reference: wiki) ▼

If galaxies are formed in an uneven cosmic environment and more matter is sucked in in a particular direction, it may bring angular momentum and form spiral galaxies.

On the other hand, the central galaxy at position C of the super-large galaxy cluster is often a giant elliptical galaxy, which has been formed by randomly gobbling up a large number of satellite galaxies in its long history.

As for the dwarf galaxies that will be preyed on around the large galaxies, they are strongly influenced by the host galaxies and will be distorted or even torn out of long tidal tails.

The torn tidal tail of the tadpole galaxy

(figure: wiki) ▼

When one galaxy engulfs another, the entry of new matter may provide a large amount of gaseous fuel for the growth of the galaxy, triggering intense star formation, which is called starburst galaxies. But it can also be counterproductive, leading to indigestion and quenching its own star-forming activity.

Starburst galaxies are accompanied by the extreme violence aesthetics of birth and annihilation.

(figure: wiki) ▼

With the rapid development of computer numerical simulation technology, in recent years, astronomers have been able to reproduce the history of the formation of cosmic structure and the evolution of galaxies on computers for 13 billion years from the very early days after the Big Bang to today. and use refined models to restore complex physical processes inside galaxies.

The latest high-precision cosmological numerical simulation IllustrisTNG50

The ups and downs of the evolution of a galaxy experienced accretion, merging, tearing, reorganization, and finally transformed from a spiral galaxy to an elliptical galaxy.

(source: tng-project.org) ▼

Space-time tunnel through the universe with the continuous progress of telescope technology, astronomers also try to verify and optimize the theoretical model of galaxy formation and evolution by observing samples of galaxies in the real universe.

We know that because of the limited speed of light, the farther you look in astronomical observations, the longer you can see the time of the past. On the galactic scale, the human field of vision has expanded to tens of billions of light-years away, and the retrospective time is approaching the age of the entire universe.

In 2012, the Hubble Space Telescope accumulated a decade of observations and took a picture of the Hubble Deep Field (Hubble eXtreme Deep Field, HXDF).

This photo contains many important discoveries made by scientists.

(figure: NASA) ▼

This picture contains 5500 distant galaxies, of which the darkest galaxies are 100, 1/100000000 visible to the human eye, and the farthest galaxies are more than 10 billion light-years away, still in the infancy of the universe.

Astronomers have found that the properties of distant galaxies are systematically different from those of nearby galaxies.

Our celestial field of vision is close to the edge of the event horizon.

Have a chance to see a more chaotic and primitive universe.

(figure: wiki) ▼

For example, distant galaxies are denser and intergalactic collisions are more frequent. This is because 10 billion years ago, the universe did not expand as much as it is today, and space became more crowded.

By comparing samples of galaxies near and far, we have actually seen how galaxies solidified in the long river of time and in the real universe have evolved to this day. This is a real tunnel of time and space.

Tens of billions of years is the limit of Webb, but maybe not the limit of the universe.

(reference: BBC) ▼

Can the Hubble Space Telescope keep us seeing the starting point of galaxy formation? Unfortunately, because the earlier the universe is, the farther away the galaxies are and the smaller the mass is, so they darken quickly.

In addition, as the universe expands, the wavelengths of light from distant galaxies are stretched as they reach Earth, causing farther away galaxies to look redder until they become infrared.

This phenomenon, known as redshift, is seen in the ultra-deep field photos of the Webb telescope.

The redshift value z of the Glass-13 galaxy in the frame even reaches 13.

(figure: NASA / CSA / ESA / STScl) ▼

The Hubble Telescope mainly works in the optical band. In order to continue to extend this space-time tunnel to the depths of the universe, we need a stronger telescope that can see the infrared band.

The successor to this task is the James Webb Telescope, which was launched in 2021. In order to see galaxies with earlier and higher redshifts in the universe, Webb was designed as an infrared telescope, so the structure is very different from that of Hubble, and its aperture is 6.5 meters, nearly three times the size of Hubble.

Different telescopes cover different segments of the electromagnetic spectrum.

Therefore, the Webb Telescope has a great advantage over Hubble in astronomical observation.

(reference: BBC) ▼

With its excellent performance, we expect the Webb Telescope to lead us to the formation of galaxies and first-generation stars in the universe more than 13 billion years ago, to further verify existing physical models.

Where does the Ghost Galaxy come from? The latest findings mentioned at the beginning of this article come from the first batch of data sent back by Webb last July. In fact, some of the six bizarre galaxies discovered this time have been captured by Hubble in some bands, but they are blurred in Hubble's images and go unnoticed.

In the various optical bands of Hubble, six galaxies do not appear or are very weak

(shot by Webb Telescope on the right) ▼

According to the current theory of galaxy formation, galaxies should have been in their infancy 13 billion years ago. The six galaxies discovered this time, according to preliminary measurements, have the same mass as today's Milky way, but appeared directly in the universe 13 billion years ago.

As mentioned earlier, it takes a long time for galaxies to grow. It took more than 10 billion years for the Milky way to grow from infancy to today. Compared with the Milky way, these six galaxies have grown 20 times faster than the average in the entire history of the Milky way in the hundreds of millions of years after the birth of the universe. Under the existing theories of cosmology and galaxy formation, this growth cannot be explained.

However, the technological leap from Webb to Hubble took only more than 30 years.

The further improvement of the theory can be expected in the future.

(photo: selfie of special pupil lens of Webb telescope) ▼

Our original goal was to take a baby picture of the universe with the Webb telescope, but a group of adult galaxies appeared in the picture. It's as if a paleontologist dug up a human skeleton in Cambrian strata where trilobite fossils were buried 500 million years ago.

On how to explain the six "should not appear" galaxies, some scholars pointed out that the crux of the problem may be that there was some unknown mechanism in the early universe that allowed stars to form in a more efficient way than previously thought.

In an interview, the authors also speculated that the suspect may have something to do with the dark matter halo that gave birth to galaxies, but there should not have been such a large dark matter halo in the universe at that time. There are also views that these six mysterious galaxies or hidden supermassive black holes.

The mystery of dark matter needs to be unraveled by astronomers.

(figure: wiki) ▼

The research team that published the paper once wondered if they had made any mistakes. For this reason, the authors use seven different methods to fit the redshift and mass of these galaxies, but the results are consistent.

a. The author uses seven different methods to determine the star mass of these galaxies.

B. the redshift (representing the distance from us) ▼ obtained by 7 methods

However, the existing analysis is only based on photometric data, and the most sure way to verify it is to wait for subsequent accurate spectral measurements to obtain more detailed information about their metal abundance, morphological types and so on.

In this way, it may take a long time for the mystery to be finally solved. However, regardless of the final outcome, reviewing the history of human observation of the universe, every innovation in telescope technology has brought about a subversive progress in human understanding of the universe. We are never afraid of new discoveries overturning existing theories, but we are always looking forward to what kind of door it will open to our scientific boundaries.

The only thing that restricts human beings to continue to explore is imagination!

Reference:

1. The original paper published in Nature: Labb é, I., van Dokkum, P., Nelson, E. et al. A population of red candidate massive galaxies ~ 600Myr after the Big Bang. Nature (2023). Https://doi.org/ 10.1038 / s41586,023-05786-2

two。 IllustrisTNG results display of High Precision Cosmological Galaxy formation numerical Simulation website: https://www.tng-project.org/ media/

3. Hubble Galaxy Deep Field Project website: https://www.nasa.gov/ content / discoveries-hubbles-deep-fields

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.