Astrophysicists normally assume that huge systems like the universe, are indifferent to details of smaller systems contained within it. Scientists from the University of Hawaii at Manoa (Kevin Croker and Joel Weiner) have shown that this hypothesis can fail when it comes to compact objects that remain after the collapse and explosion of huge stars.
For over fifty years, scientists have theorized that roughly 85% of matter in the Universe’s is made up of a mysterious, invisible mass. Since then, multiple observation campaigns have indirectly witnessed the effects that this “Dark Matter” has on the Universe. Unfortunately, all attempts to detect it so far have failed, leading scientists to propose some very interesting theories about its nature.
A new study using data from NASA's Chandra X-ray Observatory and ESA's XMM-Newton suggests that dark energy may have varied over cosmic time, as reported in our latest press release. This artist's illustration helps explain how astronomers tracked the effects of dark energy to about one billion years after the Big Bang by determining the distances to quasars, rapidly growing black holes that shine extremely brightly.
It’s embarrassing, but astrophysicists are the first to admit it. Our best theoretical model can only explain 5% of the universe. The remaining 95% is famously made up almost entirely of invisible, unknown material dubbed dark energy and dark matter. So even though there are a billion trillion stars in the observable universe, they are actually extremely rare.
During the 1930s, astronomers came to realize that the Universe is in a state of expansion. By the 1990s, they realized that the rate at which it is expansion is accelerating, giving rise to the theory of “Dark Energy”. Because of this, it is estimated that in the next 100 billion years, all stars within the Local Group – the part of the Universe that includes a total of 54 galaxies, including the Milky Way – will expand beyond the cosmic horizon.
Astronomers have used NASA's Hubble Space Telescope to make the most precise measurements of the expansion rate of the universe since it was first calculated nearly a century ago. Intriguingly, the results are forcing astronomers to consider that they may be seeing evidence of something unexpected at work in the universe.
Humans have made a staggering amount of scientific and technological progress over the past century. We’ve created technology that has transformed our society; scientific advances have helped us answer fundamental questions about who we are and the world that we inhabit. And, yet, mysteries persist.
Dark matter and dark energy are mysterious, unknown substances that are thought to make up more than 96% of the universe. While we may have never directly seen them, they beautifully explain how stars and galaxies move and how the universe is expanding. But a new study, published in The Astrophysical Journal, suggests they may not exist after all.
Two teams of astronomers have found a way to observe the presence of the missing matter connecting the galaxies in the universe. This discovery can improve our understanding of how galaxies were formed in the years following the Big Bang.