In a precedent, the first of its kind, an international research team was able to achieve a direct observation of the growth rates of the stars of the first galaxies, this discovery helped these scientists understand our past more than 10 billion years ago, and thus enabled them to predict the future of the vast universe.
Data from this observation were published in a research paper recently accepted in the “The Astophysical Journal”, according to an official press release issued by the Max Planck Institute for Astronomy, which is participating in the study, on September 24th.
When astronomers want to learn about the history of the distant universe, they point their telescopes to the most distant galaxies from us, because the light coming from them has taken a lot of time to travel.
For example, when we look at the Andromeda galaxy in a telescope, we do not see what is happening in it now, but we see what happened there 2.5 million years ago, because the distance between us and it is 2.5 million light years.
This is what the Hubble Telescope did between 2003 and 2004, when it was directed to a region of the sky roughly one-tenth the area of the full moon, and was able to collect data from more than 10 thousand galaxies located at a distance of about 13 billion light years, meaning that they were formed Only after the Big Bang, about 800 million years or less.
Now, this international team has come to use more accurate techniques in cooperation with the Atacama Large Millimeter Array (ALMA) in order to re-study the same area, but for another purpose is to examine the evolution of quantities of ionized hydrogen in these galaxies.
Hydrogen is the fuel for stars, and the more quantities of it in a galaxy, the new stars are born at greater rates, and therefore studying the growth or shrinkage of its quantities in the first galaxies can give scientists an opportunity to understand the rates of formation of the first stars.
The end of the universe
According to the study, the amounts of ionized hydrogen in the first galaxies have been increasing over the course of 4 billion years, and this indicated that the universe – only a third of its age – had already made 50% of its stars.
After that point, the quantities of hydrogen in galaxies began to diminish, and that continues to happen until now, and the study indicated that it has only remained about 5 billion years until the quantities of hydrogen shrink to a stage during which it will not be able to form new stars.
But what is interesting about the results of the study is that at that point the number of stars in the universe will have increased by only 10% of what it is now, and this means that the universe has already formed 90% of its new stars as you read this.
These hypotheses were already there before, but it is the first time that they are experimentally verified, and the researchers of this team hope that these results will help scientists develop a better understanding of the history of the universe, especially the relationship of this history to one of the biggest mysteries of physics so far, which are dark matter and energy.