Dark Matter Archives

February 25, 2023February 25, 2023 by Carolyn Collins Petersen

A New Survey of the Sky Contains Over One Billion Galaxies

Ten areas in the sky were selected as “deep fields” that the Dark Energy Camera imaged several times during the survey, providing a glimpse of distant galaxies and helping determine their 3D distribution in the cosmos. The image is teeming with galaxies — in fact, nearly every single object in this image is a galaxy. Some exceptions include a couple of dozen asteroids as well as a few handfuls of foreground stars in our own Milky Way. Credit: Dark Energy Survey/DOE/FNAL/DECam/CTIO/NOIRLab/NSF/AURA Acknowledgments: T.A. Rector (University of Alaska Anchorage/NSF’s NOIRLab), J. Miller, M. Zamani & D. de Martin (NSF’s NOIRLab) — Ten areas in the sky were selected as “deep fields” that the Dark Energy Camera imaged several times during its survey, providing a glimpse of distant galaxies and helping determine their 3D distribution in the cosmos. Nearly every single object in this image is a galaxy. Credit: Dark Energy Survey/DOE/FNAL/DECam/CTIO/NOIRLab/NSF/AURA Acknowledgments: T.A. Rector (University of Alaska Anchorage/NSF’s NOIRLab), J. Miller, M. Zamani & D. de Martin (NSF’s NOIRLab)

What contains a petabyte of data on more than a billion galaxies in one of the most extensive sky maps? The answer: the ever-expanding Dark Energy Spectroscopic Instrument (DESI) Legacy Imaging Survey. The galaxies it charts are part of the largest two-dimensional map of the sky ever made. And, just recently, it grew even larger with the addition of new data from telescopes in the U.S. and Chile.

February 15, 2023February 15, 2023 by Evan Gough

A Galaxy has Been Found that’s Almost Entirely Dark Matter

This is the galaxy Dragonfly 44, which is an Ultra Diffuse Galaxy (UDG.) It's about as massive as the Milky Way, but only 1% as luminous. Astronomers think it's almost entirely made of dark matter. Now scientists have found another one like it. Image Credit: By Teymursaif - Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=95121595

Astronomers have discovered a galaxy with very little or no stellar mass. Galaxies like these are called ‘dark galaxies.’ It contains clouds of gas but very few stars, possibly none. This is the only isolated dark dwarf galaxy in the local universe.

December 29, 2022December 29, 2022 by Brian Koberlein

New Measurements of Galaxy Rotation Lean Towards Modified Gravity as an Explanation for Dark Matter

Although dark matter is a central part of the standard cosmological model, it’s not without its issues. There continue to be nagging mysteries about the stuff, not the least of which is the fact that scientists have found no direct particle evidence of it. Despite numerous searches, we have yet to detect dark matter particles. So some astronomers favor an alternative, such as Modified Newtonian Dynamics (MoND) or modified gravity model. And a new study of galactic rotation seems to support them.

December 23, 2022December 23, 2022 by Matt Williams

Anti-Helium Generated in the Large Hadron Collider can Help in the Search for Dark Matter

The ALICE detector on CERN's Large Hadron Collider. Credit: A Saba/CERN

For decades, astrophysicists have theorized that the majority of matter in our Universe is made up of a mysterious invisible mass known as “Dark Matter” (DM). While scientists have not yet found any direct evidence of this invisible mass or confirmed what it looks like, there are several possible ways we could search for it soon. One theory is that Dark Matter particles could collide and annihilate each other to produce cosmic rays that proliferate throughout our galaxy – similar to how cosmic ray collisions with the interstellar medium (ISM) do.

This theory could be tested soon, thanks to research conducted using the A Large Ion Collider Experiment (ALICE), one of several detector experiments at CERN’s Large Hadron Collider (LHC). ALICE is optimized to study the results from collisions between nuclei that travel very close to the speed of light (ultra-relativistic velocities). According to new research by the ALICE Collaboration, dedicated instruments could detect anti-helium-3 nuclei (the anti-matter counterpart to He₃) as they reach Earth’s atmosphere, thus providing evidence for DM.

December 9, 2022December 9, 2022 by Andy Tomaswick

If Dark Matter is Made of Axions, This Could be the Detector That Finds Them

As we’ve noted in plenty of other articles, science also moves forward by constraints. Understanding the limits of a physical phenomenon helps to develop better methods of looking for it, especially in its absence. Dark matter is an archetype of a missing phenomenon, but there are plenty of potential explanations for it. One of them is known as the axion, which was originally developed as a hypothetical particle that could plug a hole in the Standard Model of particle physics but could also solve the problem of dark energy. That is if they actually exist. Now a new experiment from researchers at CERN can help the scientific community better define where to look for those axions.

December 9, 2022December 9, 2022 by Brian Koberlein

Want to Learn More About Dark Matter? Send an Atomic Clock Close to the Sun

Artist's impression of a space atomic clock used to uncover dark matter. Credit: Kavli IPMU

Dark matter continues to vex astronomers around the world. We see its effects in the clustering of galaxies and the gravitational lensing of light within galaxies, and it seems to comprise about 80% of the matter in the universe, but we still haven’t detected it on Earth. So what about at least detecting it in our solar system? That might be possible according to a new study in Nature Astronomy.

October 31, 2022October 31, 2022 by Carolyn Collins Petersen

In a New Hubble Image, Dark Matter Anchors the Giant Galaxy Cluster Abell 611

abell 611 and its galaxies and dark matter — Hubble Space Telescope offers a cosmic cobweb of galaxies and invisible dark matter in the cluster Abell 611. Credit: ESA/Hubble, NASA, P. Kelly, M. Postman, J. Richard, S. Allen

Dark matter. It’s secret. It’s dark because it doesn’t give off any light. We can’t see it, taste it, touch it, smell it, or even feel it. But, astronomers can measure this dark secret of the universe. How? By looking at galaxies and galaxy clusters. Dark matter exerts a gravitational influence on those regions, and that CAN be measured.

August 7, 2022August 7, 2022 by Carolyn Collins Petersen

Dwarf Galaxies Found Without Influence From Dark Matter

Dwarf galaxy in Fornax. — The dwarf galaxy NGC1427A flies through the Fornax galaxy cluster and undergoes disturbances which would not be possible if this galaxy were surrounded by a heavy and extended dark matter halo, as required by standard cosmology. Courtesy ESO.

Ask astronomers about dark matter and one of the things they talk about is that this invisible, mysterious “stuff” permeates the universe. In particular, it exists in halos surrounding most galaxies. The mass of the halo exerts a strong gravitational influence on the galaxy itself, as well as on others in the neighborhood. That’s pretty much the standard view of dark matter and its influence on galaxies. However, there are problems with the idea of those halos. Apparently, some oddly shaped dwarf galaxies exist that look like they have no halos. How could this be? Do they represent an observationally induced challenge to the prevailing ideas about dark matter halos?

August 3, 2022August 3, 2022 by Brian Koberlein

Astronomers Measure the Signal of Dark Matter From 12 Billion Years ago

Visualization of how dark matter lenses distant light. Credit: Reiko Matsushita (Nagoya University)

Although the particles of dark matter continue to allude us, astronomers continue to find evidence of it. In a recent study, they have seen its effect from the edge of visible space, when the universe was just 1.5 billion years old.

July 25, 2022July 25, 2022 by Andy Tomaswick

The World’s Most Sensitive Dark Matter Detector has Come Online

Individual contributors have become less and less prominent in scientific fields as the discipline itself has matured. Some individuals still hold the public spotlight for their discoveries, such as Peter Higgs with the Higgs boson, which several other physicists also theorized around the same time he did. However, the actual data that eventually gave Dr. Higgs and François Englert their Nobel prize were collected by the Large Hadron Collider, arguably one of the largest technical projects that took thousands of scientists decades to design, build, and test.