Dark Matter Archives

November 16, 2024November 16, 2024 by Alan Boyle

America’s Particle Physics Plan Spans the Globe — and the Cosmos

Illustration showing subatomic particles and galaxies in collision — Particle physics experiments address mysteries at subatomic and astronomical levels. (Illustration by Olena Shmahalo for U.S. Particle Physics)

RALEIGH, N.C. — Particle physicist Hitoshi Murayama admits that he used to worry about being known as the “most hated man” in his field of science. But the good news is that now he can joke about it.

Last year, the Berkeley professor chaired the Particle Physics Project Prioritization Panel, or P5, which drew up a list of multimillion-dollar physics experiments that should move ahead over the next 10 years. The list focused on phenomena ranging from subatomic smash-ups to cosmic inflation. At the same time, the panel also had to decide which projects would have to be left behind for budgetary reasons, which could have turned Murayama into the Dr. No of physics.

Although Murayama has some regrets about the projects that were put off, he’s satisfied with how the process turned out. Now he’s just hoping that the federal government will follow through on the P5’s top priorities.

October 23, 2024October 25, 2024 by Matt Williams

Neutron Stars May be Shrouded in Extremely Light Particles Called Axions

Image from a computer simulation of the distribution of matter in the universe. Orange regions host galaxies; blue structures are gas and dark matter. Credit: TNG Collaboration

Since the 1960s, astronomers have theorized that the Universe may be filled with a mysterious mass that only interacts with “normal matter” via gravity. This mass, nicknamed Dark Matter (DM), is essential to resolving issues between astronomical observations and General Relativity. In recent years, scientists have considered that DM may be composed of axions, a class of hypothetical elementary particles with low mass within a specific range. First proposed in the 1970s to resolve problems in the Standard Model of particle physics, these particles have emerged as a leading candidate for DM.

In addition to growing evidence that this could be the case, researchers at CERN are developing a new telescope that could help the scientific community look for axions – the CERN Axion Solar Telescope (CAST). According to new research conducted by an international team of physicists, these hypothetical particles may occur in large clouds around neutron stars. These axions could be the long-awaited explanation for Dark Matter that cosmologists have spent decades searching for. What’s more, their research indicates that these axions may not be very difficult to observe from Earth.

October 18, 2024October 18, 2024 by Matt Williams

Check Out This Sneak Peek of the Euclid mission’s Cosmic Atlas

This mosaic made by ESA’s Euclid space telescopes constitutes about 1% of the wide survey that Euclid will capture during six years. Credit: ESA/Euclid/Euclid Consortium/NASA/CEA Paris-Saclay/J.-C. Cuillandre, E. Bertin, G. Anselmi

On July 1st, 2023 (Canada Day!), the ESA’s Euclid mission lifted off from Cape Canaveral, Florida, atop a SpaceX Falcon 9 rocket. As part of the ESA’s Cosmic Vision Programme, the purpose of this medium-class mission was to observe the “Dark Universe.” This will consist of observing billions of galaxies up to 10 billion light-years away to create the most extensive 3D map of the Universe ever created. This map will allow astronomers and cosmologists to trace the evolution of the cosmos, helping to resolve the mysteries of Dark Matter and Dark Energy.

The first images captured by Euclid were released by the ESA in November 2023 and May 2024, which provided a glimpse at their quality. On October 15th, 2024, the first piece of Euclid‘s great map of the Universe was revealed at the International Astronautical Congress (IAC) in Milan. This 208-gigapixel mosaic contains 260 observations made between March 25th and April 8th, 2024, and provides detailed imagery of millions of stars and galaxies. This mosaic accounts for just 1% of the wide survey that Euclid will cover over its six-year mission and provides a sneak peek at what the final map will look like.

October 6, 2024October 6, 2024 by Matt Williams

Primordial Holes Could be Hiding in Planets, Asteroids, and Here on Earth

An artistic take on primordial black holes. Credit: NASA’s Goddard Space Flight Center

Small primordial black holes (PBHs) are one of the hot topics in astronomy and cosmology today. These hypothetical black holes are believed to have formed soon after the Big Bang, resulting from pockets of subatomic matter so dense that they underwent gravitational collapse. At present, PBHs are considered a candidate for dark matter, a possible source of primordial gravitational waves, and a resolution to various problems in physics. However, no definitive PBH candidate has been observed so far, leading to proposals for how we may find these miniature black holes.

Recent research has suggested that main-sequence neutron and dwarf stars might contain small PBHs in their interiors that are slowly consuming their gas supply. In a recent study, a team of physicists extended this idea to include a new avenue for potentially detecting PBHs. Basically, we could search inside objects like planets and asteroids or employ large plates or slabs of metal to detect PBHs for signs of their passage. By detecting the microchannels these bodies would leave, scientists could finally confirm the existence of PBHs and shed light on some of the greatest mysteries in cosmology today.

September 19, 2024September 19, 2024 by Mark Thompson

Slime Mold Can Teach Us About the Cosmic Web

This image from Farhanul Hansan’s paper in the Astrophysical Journal shows the large-scale matter distribution and cosmic “filaments” of the universe are more faithfully captured by the slime mold model than the existing standard framework. (Image courtesy Farhanul Hasan)

Computers truly are wonderful things and powerful but only if they are programmed by a skilful mind. Check this out… there is an algorithm that mimics the growth of slim mold but a team of researchers have adapted it to model the large scale structure of the Universe. Since the Big Bang, the universe has been expanding while gravity concentrates matter into galaxies and clusters of galaxies. Between them are vast swathes of empty space called voids. The structure, often referred to as the cosmic web.

September 8, 2024September 8, 2024 by Matt Williams

Largest Dark Matter Detector is Narrowing Down Dark Matter Candidate

Technicians scanning for dust on the LUX-ZEPLIN (LZ) Dark Matter Detector. Credit: LZ Experiment

In 2012, two previous dark matter detection experiments—the Large Underground Xenon (LUX) and ZonEd Proportional scintillation in Liquid Noble gases (ZEPLIN)—came together to form the LUX-ZEPLIN (LZ) experiment. Since it commenced operations, this collaboration has conducted the most sensitive search ever mounted for Weakly Interacting Massive Particles (WIMPs) – one of the leading Dark Matter candidates. This collaboration includes around 250 scientists from 39 institutions in the U.S., U.K., Portugal, Switzerland, South Korea, and Australia.

On Monday, August 26th, the latest results from the LUX-ZEPLIN project were shared at two scientific conferences. These results were celebrated by scientists at the University of Albany‘s Department of Physics, including Associate Professors Cecilia Levy and Matthew Szydagis (two members of the experiment). This latest result is nearly five times more sensitive than the previous result and found no evidence of WIMPs above a mass of 9 GeV/c². These are the best-ever limits on WIMPS and a crucial step toward finding the mysterious invisible mass that makes up 85% of the Universe.

August 31, 2024August 31, 2024 by Mark Thompson

Estimating the Basic Settings of the Universe

This snapshot compares the distribution of galaxies in a simulated universe used to train SimBIG (right) to the galaxy distribution seen in the real universe (left). Bruno Régaldo-Saint Blancard/SimBIG collaboration

The Standard Model describes how the Universe has evolved at large scale. There are six numbers that define the model and a team of researchers have used them to build simulations of the Universe. The results of these simulations were then fed to a machine learning algorithm to train it before it was set the task of estimating five of the cosmological constants, a task which it completed with incredible precision.

August 30, 2024August 30, 2024 by Mark Thompson

New Limits on Dark Matter

LZ’s central detector, the time projection chamber, in a surface lab clean room before delivery underground. Credit: Matthew Kapust/Sanford Underground Research Facility

As it’s name suggests, dark matter is dark! That means it’s largely invisible to us and only detectable through its interaction with gravity. One of the leading theories to explain the stuff that makes up the majority of the matter in the Universe are WIMPs, Weakly Interacting Massive Particles. They are just theories though and none have been detected. An exciting new experiment called LUX-ZEPLIN has just completed 280 days of collecting data but still, no WIMPs have been detected above 9 Gev/c2. There are plans though to narrow the search.

August 13, 2024August 13, 2024 by Mark Thompson

Primordial Black Holes Could Kick Out Stars and Replace Them.

This artist's illustration shows what primordial black holes might look like. In reality, the black holes would struggle to form accretion disks, as shown. Image Credit: NASA’s Goddard Space Flight Center

Primordial black holes formed during the earliest stages of the evolution of the universe. Their immense gravity may be playing havoc in stellar systems. They can transfer energy into wide binary systems disrupting their orbits. Like celestial bullies their disruption might lead to extreme outcomes though like the ejection of a star, only to be replaced by the black hole itself! A new paper studies the interactions of systems like these and looks at ways we might be able to detect them.

July 27, 2024July 27, 2024 by Mark Thompson

Giant Collision Decouples Dark Matter from Regular Matter

This artist's concept shows what happened when two massive clusters of galaxies, collectively known as MACS J0018.5, collided: The dark matter in the galaxy clusters (blue) sailed ahead of the associated clouds of hot gas, or normal matter (orange). Both dark matter and normal matter feel the pull of gravity, but only the normal matter experiences additional effects like shocks and turbulence that slow it down during collisions. Credit: W.M. Keck Observatory/Adam Makarenko

Dark matter is a mysterious and captivating subject. It’s a strange concept and we don’t really have a handle on what it actually is. One of the strongest pieces of evidence that dark matter is a particle comes from cosmic collisions. These collisions chiefly occur when clusters of galaxies interact such as the famous Bullet Cluster. Gravitational lensing reveals how the dark matter component couples from gas and dust in the cluster but now, astronomers have found another galaxy cluster collision but it is different, showing the collision from a new angle.