Dark Matter

In search of dark matter with pendulums Astrophysics

In search of dark matter with pendulums

Current experiments that search for dark matter are mostly based on the idea that dark matter should somehow show up, i.e. by interacting with normal matter. Now, however, the only thing we really know about this important part of the universe is that an interaction with normal matter occurs via gravity. This is what first made researchers realize that dark matter exists. Is it perhaps because the search has so far been fruitless? Then a method could help, which researchers of the NIST and their colleagues presented now. "Our proposal is based purely on gravitational coupling, the only coupling…
Galaxies in a cosmic spider web made of dark matter Astrophysics

Galaxies in a cosmic spider web made of dark matter

Using ESO's Very Large Telescope (VLT), astronomers have found six galaxies orbiting a supermassive black hole when the universe was less than a billion years old. The galaxies are in a kind of cosmic "spider web" of gas that covers an area 300 times the size of the Milky Way. "The filaments of the cosmic web are like spider web threads," explains Marco Mignoli, astronomer at the National Institute of Astrophysics (INAF) in Bologna, Italy, and lead author of the new research published today in Astronomy & Astrophysics. "The galaxies grow where the filaments cross, and gas flows -…
Hexaquark d*(2380): a new candidate for dark matter Astrophysics

Hexaquark d*(2380): a new candidate for dark matter

One of the biggest mysteries of our universe is what is dark matter made of. Its existence is suggested by several astronomical observations, among them peculiarities in the rotation of galaxies. Dark matter would have to make up at least 63% of all matter in the universe and to date, physicists have no idea about its exact nature. All that is clear is that dark matter interacts with normal matter only via gravity. These could be, among other things, so-called WIMPs (Weakly Interacting Massive Particles), which would be considered cold dark matter. However, researchers are not making very quick…
Hubble detects small clumps of dark matter Astrophysics

Hubble detects small clumps of dark matter

Dark matter holds galaxies together and gives the visible universe its structure. Even though it makes up about five-sixths of all the mass in the cosmos, to date nobody has been able to figure out what it’s made of. On the other hand, there have been some indications about what dark matter is not made of, but researchers still need to determine if dark matter is hot, cold, or possibly even fuzzy, with the temperature designation here referring to the speed at which the particles of dark matter are moving. NASA’s Hubble telescope has now pushed the probabilities a…
How a universe made out of fuzzy dark matter might look Astrophysics

How a universe made out of fuzzy dark matter might look

The exact composition of 84 percent of all the matter in the universe is unknown. That is the portion, called dark matter, which neither emits radiation nor interacts with conventional matter that we already know of in any other way than through gravity. Cosmologists believe they can use the standard model of the universe, Lambda-CDM, to get to the bottom of dark matter. This model assumes that dark matter is “cold” (cold dark matter - CDM). In physics, “cold” means that something is moving slowly. So-called “WIMPs” (weakly interacting massive particles) would have to be previously unknown particles, heavier…
What dark matter is (not) made of Astrophysics

What dark matter is (not) made of

“When you have eliminated the impossible, whatever remains, however improbable, must be the truth,” the detective, Sherlock Holmes, says to Dr. Watson in “The Sign of the Four.” Cosmologists searching for dark matter, which should make up 85 percent of the universe’s mass, seem to be following a similar process right now. They are eliminating one component after another. Recently, they succeeded in eliminating two more possibilities. Dark matter is not made up of tiny black holes. This result was shown by astronomers with the help of the Japanese Subaru telescope. Their strategy was very interesting. According to theories…
Why does dark matter behave differently in small galaxies than in large ones? Astrophysics

Why does dark matter behave differently in small galaxies than in large ones?

The most important characteristic of dark matter is that it interacts only by way of gravity. And as the only one of the four fundamental forces, gravity is always attractive. Therefore, no matter where it occurs, dark matter must always collect at the mass center of the respective structure, regardless of whether it is a small galaxy or a giant galaxy cluster. But in reality, things look quite different: in galaxy clusters, dark matter exhibits the expected behavior, but in smaller galaxies it is distributed much more widely than it should be. This arrangement could be explained in that…
Dark matter: the universe has gotten lumpier Space

Dark matter: the universe has gotten lumpier

Four-fifths of the matter in the universe is invisible. Nevertheless, this “dark matter” will determine the fate of the cosmos. But how is it distributed? That can be determined by measuring its gravitational effects. Gravity also changes the path that light takes as it travels from distant galaxies. The Hyper Suprime-Cam (HSC) of the Japanese Subaru telescope has studied these effects for approximately ten million galaxies. The farther away a galaxy is, the longer it takes its light to reach us, and the farther back we can see into the past. This allows us not only to measure the…