Dark Matter Archives

May 29, 2021May 29, 2021 by Matt Williams

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.

May 4, 2021May 4, 2021 by Andy Tomaswick

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.

April 9, 2021April 9, 2021 by Scott Alan Johnston

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.

April 5, 2021April 4, 2021 by Paul M. Sutter

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

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.

March 10, 2021March 8, 2021 by Paul M. Sutter

Did Supermassive Black Holes Form Directly From Dark Matter?

This illustration depicts a gas halo surrounding a quasar in the early Universe. The quasar, in orange, has two powerful jets and a supermassive black hole at its centre, which is surrounded by a dusty disc. The gas halo of glowing hydrogen gas is represented in blue. A team of astronomers surveyed 31 distant quasars, seeing them as they were more than 12.5 billion years ago, at a time when the Universe was still an infant, only about 870 million years old. They found that 12 quasars were surrounded by enormous gas reservoirs: halos of cool, dense hydrogen gas extending 100 000 light years from the central black holes and with billions of times the mass of the Sun. These gas stashes provide the perfect food source to sustain the growth of supermassive black holes in the early Universe.

Supermassive black holes are just a little bit too supermassive – astronomers have difficulty explaining how they got so big so quickly in the early universe. So maybe it’s time for a new idea: perhaps giant black holes formed directly from dark matter.

March 1, 2021March 1, 2021 by Brian Koberlein

An Exotic Explanation for the Most Extreme Gravitational Wave Detected so far

Illustration of a merger of two boson stars. Credit: Nicolás Sanchis-Gual and Rocío García Souto

In May of 2019, the gravitational wave observatories LIGO and Virgo detected the merger of two black holes. One had a mass of 85 Suns, while the other was 66 solar masses. The event was named GW190521 and was the largest merger yet observed. It produced a 142 solar mass black hole, making it the first gravitational wave observation of an intermediate mass black hole. But the event also raised several questions.

February 9, 2021February 10, 2021 by Scott Alan Johnston

A New Technique to Find Cold Gas Streams That Might Make up the Missing (Normal) Matter in the Universe

Credit: Mark Myers, OzGrav/Swinburne University

Where is all the missing matter? That question has plagued astronomers for decades, because the Universe looks emptier than it should, given current theories about its makeup. Most of the Universe (70%) appears to be composed of Dark Energy, the mysterious force which is causing the Universe’s rate of expansion to increase. Another 25% of the Universe is Dark Matter, an unknown substance which cannot be seen, but has been theorized to explain the otherwise inexplicable gravitational forces which govern the formation of galaxies. That leaves Baryonic Matter – all the normal ‘stuff’ like you, me, the trees, the planets, and the stars – to make up just 5% of the Universe. But when astronomers look out into the sky, there doesn’t even seem to be enough normal matter to make up 5%. Some of the normal matter is missing!

February 8, 2021February 9, 2021 by Matt Williams

Nearby Ancient Dwarf Galaxies Have a Surprising Amount of Dark Matter

An artist's impression of the four tails of the Sagittarius Dwarf Galaxy (the orange clump on the left of the image) orbiting the Milky Way. The bright yellow circle to the right of the galaxy's center is our Sun (not to scale). Image credit: Amanda Smith (University of Cambridge)

Around the Milky Way, there are literally dozens of dwarf galaxies that continue to be slowly absorbed into our own. These galaxies are a major source of interest for astronomers because they can teach us a great deal about cosmic evolution, like how smaller galaxies merged over time to create larger structures. Since they are thought to be relics of the very first galaxies in the Universe, they are also akin to “galactic fossils.”

Recently, a team of astrophysicists from the Massachusetts Institute of Technology (MIT) observed one of the most ancient of these galaxies (Tucana II) and noticed something unexpected. At the edge of the galaxy, they observed stars in a configuration that suggest that Tucana II has an extended Dark Matter halo. These findings imply that the most ancient galaxies in the Universe had more Dark Matter than previously thought.

February 4, 2021February 6, 2021 by Paul M. Sutter

Narrowing Down the Mass of Dark Matter

A section of the virtual universe, a billion light years across, showing how dark matter is distributed in space, with dark matter halos the yellow clumps, interconnected by dark filaments. Cosmic void, shown as the white areas, are the lowest density regions in the Universe. Credit: Joachim Stadel, UZH

Most of the matter of the universe is of a form unknown to physics. While we don’t know what the identity of the dark matter is, a new insight provided by quantum gravity is helping to drastically narrow down its mass.

February 3, 2021February 6, 2021 by Paul M. Sutter

By Measuring Light From Individual Stars Between Galaxy Clusters, Astronomers Find Clues About Dark Matter

dark matter shown in blue — This image from the NASA/ESA Hubble Space Telescope shows the galaxy cluster MACS J0416. This is one of six clusters that was studied by the Hubble Frontier Fields programme, which yielded the deepest images of gravitational lensing ever made. Scientists used intracluster light (visible in blue) to study the distribution of dark matter within the cluster.

Astronomers have been able to measure an extremely faint glow of light within galaxy clusters, and that measurement came with a surprise: it traced the amount of invisible dark matter, something that scientists have been trying to pin down for decades.