In this artist's impression, a close-up view of the so-called Sculptor Wall is depicted. Scientists have used NASA's Chandra X-ray Observatory and ESA's XMM- Newton to detect a vast reservoir of gas lying along a wall-shaped structure of galaxies about 400 million light years from Earth. "In particular, studies of runty 'dwarf galaxies' might test whether dark matter is icy cold as standard theory assumes, or somewhat warmer - essentially a question of how massive particles of dark matter are," Cho explained. "Within years, physicists might be able to detect particles of the stuff."īut while astronomers may soon be able to detect particles of dark matter, certain properties of the material remain unknown. "Scientists still don't know what dark matter is, but that could soon change," Cho wrote. Even though it cannot be seen, dark matter has mass, so researchers infer its presence based on the gravitational pull it exerts on regular matter.ĭark matter is thought to make up about 23 percent of the universe, while only 4 percent of the universe is composed of regular matter, which includes stars, planets and humans. These results seemed to go against basic Newtonian physics, which implies that stars on the outskirts of a galaxy would orbit more slowly.Īstronomers explained this curious phenomenon with an invisible mass that became known as dark matter. Rubin observed that there was virtually no difference in the velocities of stars at the center of a galaxy compared to those farther out. Vera Rubin, an astronomer at the Carnegie Institution of Washington, studied the speeds of stars at various locations in galaxies. In the 1960s and 1970s, astronomers hypothesized that there might be more mass in the universe than what is visible. Mahdavi (San Francisco State University)) Jee (University of California, Davis), and A. (Image credit: NASA, ESA, CFHT, CXO, M.J. The natural-color image of the galaxies was taken with NASA's Hubble Space Telescope and with the Canada-France-Hawaii Telescope in Hawaii. "Still, scientists remain optimistic that nature will cooperate and that they can determine the origins of dark energy." "Dark energy might never reveal its nature," Science staff writer Adrian Cho wrote. While dark energy is thought to make up approximately 73 percent of the universe, the force remains elusive and has yet to be directly detected. Explanations of the universe's accelerated expansion led to the bizarre and hotly debated concept of dark energy, which is thought to be the enigmatic force that is pulling the cosmos apart at ever-increasing speeds.
This groundbreaking discovery puzzled scientists, who long thought that the gravity of matter would gradually slow the universe's expansion, or even cause it to contract. In 1998, the Hubble Space Telescope, named for the astronomer, studied distant supernovas and found that the universe was expanding more slowly a long time ago compared with the pace of its expansion today. It is never gonna let us relax.” The most enticing reason to search with gravitational-wave detectors is not to find those things we think must exist, but to find those that lie waiting to be discovered.In the 1920s, astronomer Edwin Hubble discovered that the universe is not static, but rather is expanding. As Richard Feynman put it, “I think Nature's imagination is so much greater than Man's. While we can speculate on all sorts of weird events in the Universe, nature is endlessly surprising. The first microwave telescope found the Cosmic Microwave Background, which conclusively showed that our Universe began in a much smaller and hotter state: the Big Bang. Radio telescopes discovered Quasars, and the Neutron Stars responsible for them.
When Galileo used one of his first telescopes, he found moons orbiting Jupiter - providing firm evidence that the Earth was not the center of the Universe. Gravitational waves give us a powerful way to look into places astronomers have never before been able to see - hidden behind walls of luminous matter that interfere with light, or hidden in the deepest recesses of time.Įach time scientists have used new instruments to peer into the heavens, they have discovered novel phenomena. While the possibility of finding strange new things that scientists have only dreamt of is tantalizing, even more so is the chance to find objects that physicists have not yet begun to imagine.
Certainly the most intriguing prospect behind observing gravitational waves is the great unknown.
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