Cosmology Archives

September 23, 2024September 23, 2024 by Mark Thompson

A New Catalog Charts the Evolution of the Universe Over Time

The William Herschel Telescope in La Palma, Spain. Image credit: PAUS team.

An atlas doesn’t seem to be an essential item in cars these days but think about them and most people will think about distances. An atlas of the stars not only covers distances but must also take into account time too. The Andromeda galaxy for example is so far away that its light takes 2.5 million years to reach us. A team of researchers have now built a catalogue that contains information on millions of galaxies including their distance and looks back in time up to 10 billion years!

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 15, 2024September 15, 2024 by Matt Williams

Early Dark Energy Could Resolve Two of the Biggest Mysteries in Cosmology

This is a small portion of the field observed by NASA’s James Webb Space Telescope’s NIRCam (Near-Infrared Camera) for the Cosmic Evolution Early Release Science (CEERS) survey. It is filled with galaxies. The light from some of them has traveled for over 13 billion years to reach the telescope. Credit: NASA, ESA, CSA, Steve Finkelstein (University of Texas at Austin)

Of all the mysteries facing astronomers and cosmologists today, the “Hubble Tension” remains persistent! This term refers to the apparent inconsistency of the Universe’s expansion (aka. the Hubble Constant) when local measurements are compared to those of the Cosmic Microwave Background (CMB). Astronomers hoped that observations of the earliest galaxies in the Universe by the James Webb Space Telescope (JWST) would solve this mystery. Unfortunately, Webb confirmed that the previous measurements were correct, so the “tension” endures.

Since the JWST made its observations, numerous scientists have suggested that the existence of Early Dark Energy (EDE) might explain the Hubble Tension. In a recent study supported by NASA and the National Science Foundation (NSF), researchers from the Massachusetts Institute of Technology (MIT) suggested that EDE could resolve two cosmological mysteries. In addition to the Hubble Tension, it might explain why Webb observed as many galaxies as it did during the early Universe. According to current cosmological models, the Universe should have been much less populated at the time.

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 25, 2024August 21, 2024 by Paul M. Sutter

What Makes a Supercluster?

Illustration of the Laniakea Supercluster. Credit: Andrew Z. Colvin

By eye, it’s impossible to pick out the exact boundaries of the superclusters, which are among the largest structures in the universe. But that’s because they are not defined by their edges, but by the common motion of their components.

August 18, 2024August 18, 2024 by Andy Tomaswick

Galaxies in Dense Environments Get Larger

The picture shows Abell 2218, a rich galaxy cluster composed of thousands of individual galaxies. It sits about 2.1 billion light-years from the Earth (redshift 0.17) in the northern constellation of Draco. When used by astronomers as a powerful gravitational lens to magnify distant galaxies, the cluster allows them to peer far into the Universe. However, it not only magnifies the images of hidden galaxies, but also distorts them into long, thin arcs. Several arcs in the image can be studied in detail thanks to Hubble's sharp vision. Multiple distorted images of the same galaxies can be identified by comparing the shape of the galaxies and their colour. In addition to the giant arcs, many smaller arclets have been identified.

Galaxies are some of the largest clearly defined structures in space. There are trillions of them, and many are clustered around each other. But how does that clustering affect them? That’s been a question for a while, and older papers have yielded contradictory results. Now, a new paper analyzing millions of galaxies from researchers at the University of Washington, Yale, and several other institutions shows a clear pattern that had been debated before – galaxies surrounded by other galaxies tend to be larger.

August 17, 2024August 17, 2024 by Andy Tomaswick

Webb Relieves the Hubble Tension

Sometimes, when scientists measure things differently, they get different results. Whenever that happens with something as crucial to humanity’s long-term future as the universe’s expansion rate, it can draw much attention. Scientists have thought for decades that there has been such a difference, known as the Hubble Tension, in measurements of the speed at which the universe is expanding. However, a new paper by researchers at the University of Chicago and the Carnegie Institution for Science using data from the James Webb Space Telescope (JWST) suggests that there wasn’t any difference at all.

July 23, 2024July 23, 2024 by Mark Thompson

New Horizons Measures the Background Light of the Universe

The locations of the NCOB, DCAL, SCAL, and IPD fields are shown on the IRIS full-sky 100 µm map in Galactic coordinates.

Think about background radiation and most people immediately think of the cosmic background radiation and stories of pigeon excrement during its discovery. That’s for another day though. Turns out that the universe has several background radiations, such as infrared and even gravitational wave backgrounds. NASA’s New Horizons is far enough out of the Solar System now that it’s in the perfect place to measure the cosmic optical background (COB). Most of this light comes from the stars in galaxies, but astronomers have always wondered if there are other sources of light filling our night sky. New Horizons has an answer. No!

June 30, 2024June 30, 2024 by Carolyn Collins Petersen

Galaxies Filled With Old Stars Seen Shortly After the Big Bang

Astronomers used JWST to investigate three mysterious objects in the very early Universe. These little red dots contain extremely ancient stars and supermassive black holes. Courtesy JWST/Penn State University.

How can young galaxies in the early Universe have ancient stars? That’s the question a team of astronomers set out to answer using JWST as a probe. They first spotted the massive objects in 2022 and are still working to explain what these things are.