Why was the early universe filled with giant stars and why were they so small?

A recent study concluded that the early universe contained only gigantic sizes of stars.

According to scientists, the reason is due to the complex physics in the universe at that time, which may have led to the emergence of massive stars.

The new study finds that the first stars in the universe exceeded 10,000 times the mass of the Sun, nearly 1,000 times more massive than the largest stars in existence today.

Today, the largest stars reach only 100 solar masses.

In the past, astronomers have wondered over the years about the supposed size of the first stars;

According to the "Universe Today" website, some early estimates predicted that the first stars could be hundreds of times larger than the mass of the sun, while later simulations suggested that they would be of a slightly larger natural size, but the recent study proved that what scientists previously went to. It wasn't true.

The new study also found that these giant stars lived quickly and died very young.

In general, the larger the star, the shorter its life, and once these giants died, the conditions were not suitable for them to form again.

But why did that happen in the first place?

And why are conditions no longer in place in the universe to be this kind of giants again?

Why does the universe no longer contain giant stars?

Live Science says that the universe did not contain stars in the first place more than 13 billion years ago - that is, after the Big Bang - but was more like a "warm soup" of natural gas, which consisted almost entirely of hydrogen and helium. .

First-generation stars formed under different and more difficult conditions than the stars we know.

(European Space Agency)

Over the next hundreds of millions of years, during a period known as the cosmic dark ages, this neutral gas began to accumulate increasingly into balls of dense matter.

Usually, these balls of dense matter quickly collapse to form stars in our modern universe, but this did not happen in the cosmic dark ages.

The reason for this is that the universe now contains something that was lacking in the early universe.

It is a lot of elements heavier than hydrogen and helium, while the primitive era contained almost nothing but hydrogen and helium.

These heavier elements are very efficient at radiating energy away, allowing dense clumps to shrink very quickly and thus collapse to densities high enough to trigger nuclear fusion, the process that powers stars by combining lighter elements into heavier ones.

These heavy elements were not available in the primordial universe, because the only way to obtain them in the first place was through the process of nuclear fusion itself.

According to the NASA website, when extremely massive stars collapse on their way to death, the collapsing core becomes hot enough to support the most exotic nuclear reactions that consume helium and produce a variety of heavier elements, even iron.

This is what multiple generations of star formation, merging, and death have led to.

It enriched the universe and brought it to its present state, providing heavy materials that contribute to the formation of stars afterwards.

So the first generation of stars - in the absence of heavy elements - had to form under much different and more difficult conditions.

How do stars usually form?

Stars are born inside the dust clouds that dot most galaxies. One example of dust clouds is the Orion Nebula.

Deep disturbances within these clouds lead to the emergence of nodes of sufficient mass that gas and dust can begin to collapse under the influence of their gravity, taking a spherical shape, and that huge ball of gas and dust continues to shrink, and this shrinkage is accompanied by a rise in the temperature of the gas.

Supernova explosions carried with them the products of internal fusion reactions of heavy elements.

(NASA)

Gas usually consists of hydrogen and helium, which are the lightest elements.

The gas temperature continues to rise due to contraction, so the atoms turn into ions and free electrons in the high temperature.

This state is called plasma.

The plasma ball continues to shrink under the action of its gravity and its temperature increases until it is sufficient to start the reaction of the ionized hydrogen element to form the helium element.

This interaction is called nuclear fusion, and it produces a lot of energy, so the star begins to shine.

As for the first stars, they weren't just ordinary fusion factories;

Rather, they were giant blocks of neutral gas that ignite their fusion nuclei at once, and skip the stage in which they crumbled into small pieces, and thus the resulting stellar mass was huge.

Those first stars were also incredibly bright, though they would have very short lives, less than a million years.

While stars in the modern universe can live billions of years.

Then the star giants will die in supernova explosions.

To understand the mystery of these first stars, a team of astrophysicists turned to sophisticated computer simulations of the Dark Ages to understand what was happening back then.

The researchers found that a complex web of interactions preceded the formation of the first stars.

A neutral gas, which is the gas that has the lowest and lowest degree of interaction with other substances, begins to clump together.

The hydrogen and helium gave off little heat, allowing the neutral gas clumps to slowly reach a higher density.

But the high-density clumps became very warm, producing radiation that separated the neutral gas and prevented it from breaking up into many smaller clumps.

This means that stars made up of these masses can become gigantically large.