One Star Could Answer Many Unsolved Questions About Black Holes

Detection of an unusually bright X-Ray flare from Sagittarius A*, a supermassive black hole in the center of the Milky Way galaxy. Credit: NASA/CXC/Stanford/I. Zhuravleva et al.

A supermassive black hole (SMBH) likely resides at the center of the Milky Way, and in the centers of other galaxies like it. It’s never been seen though. It was discovered by watching a cluster of stars near the galactic center, called S stars.

S stars’ motions indicated the presence of a massive object in the Milky Way’s center and the scientific community mostly agreed that it must be an SMBH. It’s named Sagittarius A*.

But some scientists wonder if it really is a black hole. And one of the S stars could answer that question and a few others about black holes.

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Searching for Dark Matter Inside the Earth

Dark matter remains one of the greatest mysteries in science.  Despite decades of astronomical evidence for its existence, no one has yet been able to find any sign of it closer to home.  There have been dozens of efforts to do so, and one of the most prominent just hit a milestone – the release and analysis of 8 years of data.  The IceCube Neutrino Observatory will soon be releasing results from those 8 years, but for now let’s dive in to what exactly they are looking for.

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The Milky Way’s Central bar Spin-Rate is Slowing Down Thanks to Dark Matter

Credit: Data: ESA/Gaia/DPAC, A. Khalatyan(AIP) & StarHorse team; Galaxy map: NASA/JPL-Caltech/R. Hurt (SSC/Caltech)

If it were’t for an enormous halo of dark matter enveloping our galaxy, the spin-rate of our central bar should stay pretty constant. But researchers have recently inferred that it has slowed down by almost 25% since its formation, a clear sign of the presence of dark matter.

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A Dark Matter map of our Local Cosmic Neighborhood

Simulation of dark matter and gas. Credit: Illustris Collaboration (CC BY-SA 4.0)

Since it was first theorized in the 1970s, astrophysicists and cosmologists have done their best to resolve the mystery that is Dark Matter. This invisible mass is believed to make up 85% of the matter in the Universe and accounts for 27% of its mass-energy density. But more than that, it also provides the large-scale skeletal structure of the Universe (the cosmic web), which dictates the motions of galaxies and material because of its gravitational influence.

Unfortunately, the mysterious nature of Dark Matter means that astronomers cannot study it directly, thus prevented them from measuring its distribution. However, it is possible to infer its distribution based on the observable influence its gravity has on local galaxies and other celestial objects. Using cutting-edge machine-learning techniques, a team of Korean-American astrophysicists was able to produce the most detailed map yet of the local Universe that shows what the “cosmic web” looks like.

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Dark Matter Could Change the Temperature of Exoplanets, Allowing us to Detect it

Artist view of a Jupiter-like exoplanet. Credit: NASA/Goddard Space Flight Center/S. Wiessinger

Ah, dark matter, you continue to allude us. The stuff is incredibly difficult to study. It doesn’t interact with light, so our evidence of it is based upon its gravitational effects on light and visible matter. And the biggest difficulty is that we still don’t know what it is. Efforts to detect dark matter directly have come up empty, as have indirect methods such as looking for evidence of dark matter through things such as excess gamma-rays in the Milky Way. But astronomers continue to think up new ways to detect the stuff, such as a recent study published in Physical Review Letters.

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New All-Sky Map of the Milky Way’s Galactic Halo

The outer reaches of the Milky Way galaxy are a different place.  Stars are much harder to come by, with most of this “galactic halo” being made up of empty space.  But scientists theorize that there is an abundance of one particular thing in this desolate area – dark matter.  Now, a team from Harvard and the University of Arizona (UA) spent some time studying and modeling one of the galaxy’s nearest neighbors to try to tease out more information about that dark matter, and as a result came up with an all new way to look at the halo itself.

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One Idea to Explain Dark Matter – Ultralight Bosons – Fails the Test

Dr. Kip Thorne made it clear that black is not the primary hue of Black Holes. His guidance offered to Nolan raised science fiction to a new level. Credit: Paramount Pictures/Warner Bros.

Dark matter continues to resist our best efforts to pin it down. While dark matter remains a dominant theory of cosmology, and there is lots of evidence to support a universe filled with cold dark matter, every search for dark matter particles yields nothing. A new study continues that tradition, ruling out a range of dark matter candidates.

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Jupiter Could Make an Ideal Dark Matter Detector

NASA/JPL-Caltech/SwRI/MSSS/Kevin M. Gill (wikimedia commons)

So, you want to find dark matter, but you don’t know where to look? A giant planet might be exactly the kind of particle detector you need! Luckily, our solar system just happens to have a couple of them available, and the biggest and closest is Jupiter. Researchers Rebecca Leane (Stanford) and Tim Linden (Stockholm) released a paper this week describing how the gas giant just might hold the key to finding the elusive dark matter.

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Is Dark Matter Responsible for Extra Gamma Rays Coming From the Center of the Milky Way?

A Brilliant Star in Milky Way's Core
A Brilliant Star in Milky Way's Core

For years astronomers have puzzled over a strange excess of gamma rays coming from the galactic center. Annihilating dark matter has always been a tantalizing explanation, and new research claims that it’s the best answer.

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