A generation of physicists has referred to the dark energy that permeates the universe as “the cosmological constant.” Now the largest map of the cosmos to date hints that this mysterious energy has been changing over billions of years.
“Gravity pulls matter together, so that when we throw a ball in the air, the Earth’s gravity pulls it down toward the planet,” Mustapha Ishak-Boushaki, a professor of physics in the School of Natural Sciences and Mathematics (NSM) at UT Dallas, and member of the DESI collaboration, said in a statement. “But at the largest scales, the universe acts differently. It’s acting like there is something repulsive pushing the universe apart and accelerating its expansion. This is a big mystery, and we are investigating it on several fronts. Is it an unknown dark energy in the universe, or is it a modification of Albert Einstein’s theory of gravity at cosmological scales?”
DESI’s data, however, shows that the universe may have evolved in a way that isn’t quite consistent with the Lambda CDM model, indicating that the effects of dark energy on the universe may have changed since the early days of the cosmos.
“Our results show some interesting deviations from the standard model of the universe that could indicate that dark energy is evolving over time,” Ishak-Boushaki said. “The more data we collect, the better equipped we will be to determine whether this finding holds. With more data, we might identify different explanations for the result we observe or confirm it. If it persists, such a result will shed some light on what is causing cosmic acceleration and provide a huge step in understanding the evolution of our universe.”
The weird, faint star system—the tiniest Milky Way satellite ever found—could be under the influence of dark matter.
The 3,200-megapixel LSST camera is the size of a compact car and weighs in at 3 metric tons, which is about half the weight of a male African bush elephant. The LSST’s wide-field view will attempt to solve lingering mysteries surrounding dark energy, the force that accounts for around 70% of our universe’s matter-energy content and causes the expansion of the cosmos to accelerate.
The LSST will also investigate dark matter, the mysterious substance that accounts for around 85% of all stuff in the cosmos despite being invisible to us, as well as answer other astronomical questions as it creates what Željko Ivezić, Director of Rubin Observatory’s construction, describes as the “greatest movie of all time and the most informative map of the night sky ever assembled.”
A tiny clump of stars orbiting our galaxy should have been ripped apart by the Milky Way, but its continued existence hints it may be held together by a massive amount of dark matter.
By Leah Crane
Black holes are one of the most elusive objects in the space, but this simulation created by researchers in Netherlands might help us know more about their mysteries.
Dark matter is one of science’s greatest mysteries. It doesn’t absorb, reflect or emit light, so we can’t see it. But its presence is implied by the gravitational effects it appears to have on galaxies.
Although dark matter makes up about 85% of the cosmos, scientists know very little about its fundamental nature.
Theories abound, and research by Clemson University postdoctoral fellow Alex McDaniel provides some of the most stringent constraints on the nature of dark matter yet. His research also reveals a small hint of a signal that if real, could be confirmed sometime in the next decade or so.
This new view of the black holes Sagittarius A. and Messier 87 has shown their magnetic fields are strikingly similar.
Our universe is getting bigger and bigger really fast — something all the theories about space agree on, but none of them can totally explain. Now, there’s a new idea in town: Maybe our universe is expanding because it keeps bumping into and soaking up “baby” universes.
When scientists look at the afterglow of the Big Bang, known as the cosmic microwave background, they see that our universe is swelling up quicker and quicker. To make sense of this, physicists use something called the Standard Cosmological Model, which says there’s this weird stuff called dark energy pushing the universe to expand.
