The spaces between galaxies actually contain more matter than the galaxies themselves. First, the intergalactic medium is filled with gas that feeds stellar formations in galaxies. In addition, astronomers have discovered there stars that are called intergalactic or wild. At the edge of the Milky Way, they were counted 650. According to some estimates, there may be trillions …
The vast spaces between galaxies stretch for millions of light years and can appear empty. However, they actually contain more matter than the galaxies themselves.
“If you take one cubic meter, there’s less than one atom in it,” Michael Shull, an astronomer at the University of Colorado at Boulder, told Live Science. add to this all the space, then there will already be from 50% to 80% of the total amount of ordinary matter."
But where did all this matter come from? And what could happen to her?
Typically, the matter between galaxies - often called the intergalactic medium or IGM for short - is hot and ionized hydrogen (hydrogen that has lost its electrons) with some heavier elements such as carbon, oxygen and silicon. Although all of these elements tend to shine less brightly and remain invisible, scientists know that they are there by analyzing the trail they leave in transmitted light rays.
In the 1960s, astronomers first discovered quasars - incredibly bright and active galaxies in outer space - and soon thereafter noticed that the light from quasars was missing individual components. They were absorbed by something located between the quasars and the telescopes of astronomers - and it turned out that it was the gas of the intergalactic medium. In the decades that followed, astronomers discovered vast clusters and jets of gas, as well as heavy elements, which contain more matter than all galaxies combined. Some of this gas is likely to have remained from the Big Bang, but the presence of heavier elements indicates that some of them were previously contained in the stardust that galaxies spread.
Since the most remote regions of the intergalactic environment will be eternally isolated from neighboring galaxies as the universe expands, more “suburban” regions play an important role in galactic life. Under the influence of galactic gravitational attraction, the intergalactic medium is slowly being pulled into the galaxy at the rate of one solar mass (equal to the mass of one sun) per year, and this roughly corresponds to the rate of formation of stars on the disk of the Milky Way.
“The intergalactic medium is the gas that powers the stellar formations in galaxies,” Schall said. "If the gas attracted by gravity has not yet fully expired, then the star formations will slowly stop until this gas (in the galaxy) runs out."
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To study the intergalactic environment, astronomers have also begun to pay attention to frequent bursts of radio emission coming from distant galaxies. Using both of these techniques, as well as the results of studying quasars, astronomers continue to analyze the characteristics of the intergalactic medium to determine its changing temperature and density.
“By measuring the temperature of a gas, we can get a clue to its origin,” Schall said. "This way it becomes clear to us how it heated up and how it got there."
Although the gas is widespread between galaxies, there are other elements as well, and astronomers have found stars there. Sometimes referred to as intergalactic or rogue stars, they appear to have been torn away from their home galaxies by black holes, or by collisions with other galaxies.
In fact, stars floating in voids can be quite common. In 2012, a study published in the Astrophysical Journal listed more than 650 such stars at the edge of the Milky Way, and by some estimates there could be trillions of such stars.
“Our results from the Cosmic Infrared Background Experiment show that nearly half of all starlight comes from stars outside galaxies,” he said in an interview with Live Science. Michael Zemcov of the Rochester Institute of Technology, who published his research in 2014 in Science magazine. "However, the question remains about how many intergalactic stars there are."
Mara Johnson Groh