Dark Matter Archives

January 17, 2020January 17, 2020 by Brian Koberlein

The Debate Over Cold Dark Matter Warms Up As Astronomers Take Its Temperature

An artist's impression of the cosmic web, the filamentary structure that fills the entire Universe. Credit: M. Weiss/CfA

Dark matter has long been one of the most mysterious things in the cosmos. It was first proposed in the 1930s as an idea to address stellar motion in some galaxies. The first solid evidence of dark matter was gathered by Vera Rubin, who studied the rotational motion of galaxies. The motion of these galaxies didn’t add up unless they contained a large amount of unseen mass. There must be some exotic, invisible matter unlike anything known before.

If dark matter exists, then it must have two major properties. First, it cannot interact strongly with light, otherwise we would see it and it wouldn’t be “dark.” Second, it must interact with other matter gravitationally, to make visible matter move in strange ways. We know of several things that satisfy those conditions, such as neutrinos or tiny black holes, but these can’t be dark matter. We know this in part because we are now able to take its temperature.

January 11, 2020January 11, 2020 by Matt Williams

Hubble Finds Teeny Tiny Clumps of Dark Matter

Using the gravitational lensing technique, a team was able to examine how light from distant quasar was affected by intervening small clumps of dark matter. Credit: NASA/ESA/D. Player (STScI)

To put it simply, Dark Matter is not only believed to make up the bulk of the Universe’s mass but also acts as the scaffolding on which galaxies are built. But to find evidence of this mysterious, invisible mass, scientists are forced to rely on indirect methods similar to the ones used to study black holes. Essentially, they measure how the presence of Dark Matter affects stars and galaxies in its vicinity.

To date, astronomers have managed to find evidence of dark matter clumps around medium and large galaxies. Using data from the Hubble Space Telescope and a new observing technique, a team of astronomers from UCLA and NASA JPL found that dark matter can form much smaller clumps than previously thought. These findings were presented this week at the 235th meeting of the American Astronomical Society (AAS).

December 12, 2019December 12, 2019 by Evan Gough

Dark Matter Could Be A Source of Gamma Rays Coming from the Center of the Milky Way

A map of gamma ray emissions throughout the Milky Way galaxy, based on observations from the Fermi Gamma-ray Space Telescope. The inset depicts the Galactic Center Excess – an unexpected, spherical region of gamma ray emissions at the center of our galaxy, of unknown origin. Credit: NASA/T. Linden, U.Chicago

There’s a lot of mysterious goings-on at the center of the Milky Way. The supermassive black hole that resides there is chief among them. But there’s another intriguing puzzle there: an unexpected spherical region of intense gamma ray emissions.

A new study suggests that dark matter could be behind those emissions.

November 26, 2019November 26, 2019 by Brian Koberlein

A Fifth Fundamental Force Could Really Exist, But We Haven’t Found It Yet

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

The universe is governed by four fundamental forces: gravity, electromagnetism, and the strong and weak nuclear forces. These forces drive the motion and behavior of everything we see around us. At least that’s what we think. But over the past several years there’s been increasing evidence of a fifth fundamental force. New research hasn’t discovered this fifth force, but it does show that we still don’t fully understand these cosmic forces.

October 19, 2019October 19, 2019 by Matt Williams

The Most Massive Galaxies Spin More Than Twice as Fast as the Milky Way

Hubble Space Telescope image of Messier 77 spiral galaxy. A version of this image won second place in the Hubble’s Hidden Treasures Image Processing Competition. Image: NASA, ESA & A. van der Hoeven, 2013

It’s a difficult thing to wrap your head around sometimes. Though it might feel stationary, planet Earth is actually moving at an average velocity of 29.78 km/s (107,200 km/h; 66600 mph). And yet, our planet has nothing on the Sun itself, which travels around the center of our galaxy at a velocity of 220 km/s (792,000 km/h; 492,000 mph).

But as is so often the case with our Universe, things only get more staggering the farther you look. According to a new study by an international team of astronomers, the most massive “super spiral” galaxies in the Universe rotate twice as fast as the Milky Way. The cause, they argue, is the massive clouds (or halos) of Dark Matter that surround these galaxies.

September 9, 2019September 10, 2019 by Matt Williams

Gravitational Wave Detectors Might be Able to Detect Dark Matter Particles Colliding With Their Mirrors

The early universe. Credit: Tom Abel & Ralf Kaehler (KIPACSLAC)/ AMNH/NASA

The field of astronomy has been revolutionized thanks to the first-ever detection of gravitational waves (GWs). Since the initial detection was made in February of 2016 by scientists at the Laser Interferometer Gravitational-wave Observatory (LIGO), multiple events have been detected. These have provided insight into a phenomenon that was predicted over a century ago by Albert Einstein.

As it turns out, the infrastructure that is used to detect GWs could also help crack another astronomical mystery: Dark Matter! According to a new study by a team of Japanese researchers, laser interferometers could be used to look for Weakly-Interacting Massive Particles (WIMPs), a major candidate particle in the hunt for Dark Matter.

August 7, 2019August 8, 2019 by Matt Williams

Maybe Dark Matter is Warm, Not Cold

Since the “Golden Age of General Relativity” in the 1960s, scientists have held that much of the Universe consists of a mysterious invisible mass known as “Dark Matter“. Since then, scientists have attempted to resolve this mystery with a double-pronged approach. On the one hand, astrophysicists have attempted to find a candidate particle that could account for this mass.

On the other, astrophysicists have tried to find a theoretical basis that could explain Dark Matter’s behavior. So far, the debate has centered on the question of whether it is “hot” or “cold”, with cold enjoying an edge because of its relative simplicity. However, a new study conducted led by the Harvard-Smithsonian Center for Astrophysics (CfA) revits the idea that Dark Matter might actually be “warm”.

July 29, 2019July 29, 2019 by Evan Gough

Great News! The Large Synoptic Survey Telescope Might be Named for Vera Rubin

The LSST, or Vera Rubin Survey Telescope, under construction at Cerro Pachon, Chile. Image Credit: LSST

The U.S. House of Representatives have passed a bill to change the name of the Large Synoptic Survey Telescope (LSST.) Instead of that explanatory yet cumbersome name, it will be named after American astronomer Vera Rubin. Rubin is well-known for her pioneering work in discovering dark matter.

May 17, 2019May 17, 2019 by Paul M. Sutter

Is Dark Matter Made of Axions? Black Holes May Reveal the Answer

What is dark matter made of? It’s one of the most perplexing questions of modern astronomy. We know that dark matter is out there, since we can see its obvious gravitational influence on everything from galaxies to the evolution of the entire universe, but we don’t know what it is. Our best guess is that it’s some sort of weird new particle that doesn’t like to talk to normal matter very often (otherwise we would have seen it by now). One possibility is that it’s an exotic hypothetical kind of particle known as an axion, and a team of astronomers are using none other than black holes to try to get a glimpse into this strange new cosmic critter.

May 2, 2019May 2, 2019 by Matt Williams

Dark Matter Detector Finds the Rarest Event Ever Seen in the Universe

Since the 1960s, scientists have theorized that the Universe is filled with a mysterious, invisible mass. Known as “dark matter“, this mass is estimated to make up roughly 85% of the matter in the Universe and a quarter of its energy density. While this mass has been indirectly observed and studied, all attempts at determining its true nature have so far failed.

To address this, multiple experiments are being carried out that rely on immensely sophisticated instruments. One of these, called XENON, recently observed a process that had previously avoided multiple attempts at detection. These results could help scientists to improve their understanding of neutrinos, which some scientists believe is what dark matter is made up of.