Huge deserts of almost total nothingness that make up much of the universe may be causing the universe to expand faster, new research suggests.Which means the nothingness of these blockbusters can be explained dark energythat mysterious power, as if to burst the universe.
welcome to the desert
keep zooming solar system and Milky Way, and an interesting pattern emerged: the cosmic web, the largest pattern ever found in nature. At these scales, entire galaxies appear as small blobs of light, and astronomers have observed long, thin strings of galaxies called filaments, dense clumps called clusters, and almost complete voids between them. A vast area of nothing. These barren regions are giant cosmic voids, the smallest of which are 20 million light-years wide and the largest over 160 million light-years.
Like the gaps in a spider’s web, these voids make up the vast majority of the volume of the universe, even though hardly any matter is present.In fact, cosmic voids are the largest single space other than the cosmic web itself, which stretches from one end of the observable universe to the other. thing in the universe.
the power of nothingness
Astronomers first detected cosmic voids in the late 1970s, but they have been largely ignored since then. Astronomers and cosmologists instead focus on bright structures in the universe, such as galaxies and star clusters. Through these studies, astronomers discovered a surprise in the 1990s: dark energy.
Dark energy is the name given to the observed accelerating expansion of the universe. This means that not only is the universe expanding every day, it is expanding every day. Every moment, it expands at a faster rate.
Astronomers don’t know what drove this period of accelerated expansion, which appears to have started about 5 billion years ago. Hence the word dark energy — a cool name for a huge cosmological puzzle.
What do voids have to do with dark energy? On the one hand, the effects of accelerated expansion are not felt inside a star system or galaxy; there, the gravitational pull of matter is strong enough to completely overwhelm it. For example, neither our own solar system nor the Milky Way has gotten bigger because of dark energy. But because these voids are almost completely empty, they are more susceptible to the effects of dark energy. Therefore, it makes sense to study the nature of this accelerated expansion, as it has the strongest impact.
A new research paper led by a team of Iranian theoretical physicists takes this line of thinking a step further.In their paper, published to a preprint database in July arXiv (opens in new tab) And accepted for publication in the journal Monthly Notices of the Royal Astronomical Society: Letters, the authors claim that dark energy is not only present in the voids, but is caused by them.
from the dark
How do these vast void areas lead to accelerated expansion? According to the authors, the answer will have to look not only at the existence of cosmic voids, but also at their dynamics.
Cosmic voids don’t just exist. Like all other large structures in the universe, they grew from humble beginnings to their current gigantic stature. Billions of years ago, all matter in the universe was fairly evenly distributed; the density varied little from place to place. But over time, any place with a higher-than-average amount of matter will start attracting more matter. With more material, the area becomes more attractive, which drives more growth. Over billions of years, matter accumulates to form galaxies, groups and star clusters.
As these structures grow, voids are emptied and enlarged. But rather than seeing it as a passive process, we can think of the growth of voids as putting pressure on the structures around them. For example, as the voids grow, the galaxy walls between them gradually thin and eventually dissolve, allowing the voids to merge. Over the next billions of years, these voids will eventually dissolve the cosmic web, forcing all matter into isolated clumps separated by voids of hundreds of millions of light-years.
This stress distorts time and space Just like any other source of matter or energy in the universe. Spacetime warps mean that as the gaps expand, they push against galaxies at their boundaries, separating them despite the gravitational pull between them.
The authors found that the cumulative effect of all the large voids in the universe working together to dissolve the cosmic web leads to accelerated expansion. The strength of this cavity-driven accelerated expansion matches current estimates of dark energy.
Astronomers will need further research to test this idea. On the one hand, we need more measurements of voids to better calculate their combined pressure. In addition, we need more information about dark energy itself, especially whether its intensity has changed over the past few billion years. Still, it’s an interesting thought: maybe dark energy isn’t caused by some exotic force or process in the universe, but is just a byproduct of the normal evolution of emptiness.
Originally published on Live Science.