Physical Address
304 North Cardinal St.
Dorchester Center, MA 02124
Nature hates a Emptiness, so the saying goes, but no one told the universe. Space is filled with cosmic voids, which are vast areas, mostly devoid of matter, that have opened up between dense threads of matter that form a cosmic web.
Far from being vacant isolated regions with little study, these voids may contain solutions to some of the cosmology’s most pressing mysteries, such as the behavior of gravity, The nature of dark energyand so-called Hubble tensionIt’s an observational mismatch in the universe’s expansion rate that has been causing headaches for astronomers for years.
“With voids, we have the ability to solve most of the most interesting cosmological mysteries,” says Alice Pisani, a research professor in cosmology working at the Center for Particle Physics in Marseille (CPPM) of the French National Center for Scientific Research. She adds that because there is little interference from the material, there is a “high signal-to-noise ratio” in terms of what researchers can observe.
The emergence of new telescopes and advanced simulations has strengthened the field, inspiring a growing community of scientists around the world to specialize in voids as unique cosmic laboratories. Some experts argue that we may be living inside a massive vacuum, a situation that could change our view of the universe in consequential ways.
For spaces defined by scattering, voids have a cosmic weight, where the laws of physics can be observed with extraordinary clarity.
“From a cosmological perspective, it’s a very exciting time,” Pisani says.
What are cosmic voids?
After the Big Bang, the universe was a uniform soup of subatomic particles. But over millions of years, as matter cooled and settled into atoms, the faint outlines of the cosmic web began to emerge.
Over billions of years, the Internet has pulled gas clouds, galaxy clusters and other cosmic objects onto its scaffolding. As more matter was attracted to the mesh, the gaps between its strands widened, leading to the formation of voids.
Small “sub-voids” can open between galaxy clusters, which may be only 10 or 20 million light-years across. But the voids can get bigger. Much bigger. The Boötes Vacuum, also known as “The Great Thing,” extends more than 300 million light-years across.
Calling them cosmic voids can be “misleading, because at the end of the day we think that vacuum means emptiness,” Pisani says. But in reality, the voids we’re looking at are never empty. There are very small, low-mass galaxies inside those low-density regions. For example, Boötes Void contains a few dozen galaxies, although this is still far fewer than the thousands that would be expected in a similarly sized region.
Because they are relatively devoid of matter, cosmic voids remained beyond observation until the late 1970s. Up until that point, the locations of galaxies had been determined as two-dimensional points in the sky, but the development of three-dimensional maps of galaxy distribution revealed the contours of the cosmic web for the first time, revealing the existence of voids.
In recent years, a host of new telescopic surveys have unleashed an explosion of new void discoveries, such as the Dark Energy Survey Instrument (DESI) in Arizona and the European Vacuum Survey Instrument. Euclid Space Telescope. These instruments are expected to map more than 100,000 voids in space, providing an unprecedented glimpse into these structures. However, these surveys will only capture a small fraction of the many millions of voids estimated to exist in the observable universe.
“In just the last 10 years, this field has developed significantly thanks to new technologies,” says Nico Schuster, a cosmologist and cosmic vacuum expert at CPPM. “All of this really enables us to observe more galaxies than we could before, and this allows us to really probe the cosmic web at a much deeper depth, find more voids and solve them better.”
