Extragalactic

Distant Galaxy Has Similar Icy Dust to the Milky Way. So, Similar Planets?

By Carolyn Collins Petersen - June 12, 2025

For most of us, dust is just something we have to clean up. For astronomers, interstellar dust is a hindrance when they want to study distant objects. However, recent James Webb Space Telescope (JWST) observations of a distant galaxy are changing that. This infrared-sensitive observatory is letting them find a way to use dust to understand the evolution of early galaxies. In addition, it uncovered a special property of that galaxy's ice-covered dust, indicating it could be similar to the materials that formed our Solar System.

Colliding Galaxies Tearing at Each Other with Gravity and Radiation

By Carolyn Collins Petersen - June 10, 2025

Astronomers recently used a pair of powerful telescopes to zero in on a cosmic battle going on some 11 billion light-years away from us. The combatants are a pair of galaxies charging at each other over and over again, at velocities upwards of 500 kilometers per second. According to one of the scientists studying the scene, one galaxy is cutting into the heart of the other with a blast of radiation.

The Webb Captures Faint Galaxies from the Universe's Ancient Past

By Evan Gough - May 27, 2025

The galaxy cluster Abell S1063 dominates the center of this JWST image. It's a massive cluster of galaxies about 4.5 billion light-years away. While it dominates the picture, it's not the primary target. It serves as a gravitational lens that magnifies even more distant galaxies that appear as glowing streaks of light around its circular edges.

The Location of a Galaxy's Gas Plays a Role in Star Formation

By Mark Thompson - May 22, 2025

Galaxies are stellar factories generating stars at different speeds—some working at a breakneck pace while others trickling along! We have known for a long time that the availability of raw materials makes a difference to stellar formation, but according to a new paper which surveyed 1,000 galaxies the location of the matter plays a role too. Those with a high stellar formation rate seem to have a high volume of gas reserves in the heart of their densest star clusters with the highest concentration of stars.

The Small Magellanic Cloud is Being Pulled in Different Directions

By Evan Gough - May 15, 2025

The Small Magellanic Cloud is one of our closest galactic neighbours. It's a dwarf irregular galaxy about 200,000 light-years away, containing several hundred million stars. New research based on massive stars in the SMC shows it's being stretched along two different axes.

It's Either the Milky Way's Farthest Known Star Cluster or the Smallest Known Galaxy.

By Brian Koberlein - May 05, 2025

How do you distinguish a galaxy from a mere cluster of stars? That's easy, right? A galaxy is a large collection of millions or billion of stars, while a star cluster only has a thousand or so. Well, that kind of thinking won't get you a Ph.D. in astronomy! Seriously, though, the line between galaxy and star cluster isn't always clear. Case in point, UMa3/U1.

A Fast-Moving Pulsar Fractures the Milky Way's Galactic Bone

By Evan Gough - May 02, 2025

The center of the Milky Way is a busy place, tightly packed with stars and dominated by the supermassive black hole Sagittarius A*. It also features powerful magnetic fields that regulate star production, influence gas dynamics and gas cloud formation, and even affect the accretion processes around Sagittarius A*. Gigantic filaments of gas that look like bones form along the magnetic field lines, and one of them appears to be fractured.

Astronomers Observe Dark Matter Bridge in the Perseus Cluster

By Matthew Williams - April 30, 2025

For decades, astronomers considered the Perseus cluster to be a stable grouping of galaxies, but more recent observations have shown signs that it experienced a merger in the past. Thanks to an international team of astronomers using the Subaru Telescope at Maunakea, Hawaii, a "Dark Matter bridge" connecting Perseus to a subcluster of galaxies has been discovered.

Hubble Spots a Magnetar Zipping Through the Milky Way

By Carolyn Collins Petersen - April 26, 2025

Magnetars are among the rarest - and weirdest - denizens of the galactic zoo. They have powerful magnetic fields and may be the source of fast radio bursts (FRBs). A team of astronomers led by European Space Agency researcher Ashley Chrimes recently used the Hubble Space Telescope to track one of these monsters called SGR 0501+4516 (SGR0501, for short, and SGR stands for Soft Gamma Repeater). It's whipping through the Milky Way at a rate that could be as high as 65 kilometers per second. The big challenge was to find its birthplace and figure out its origin.

Vera Rubin Could Triple the Number of Known Satellite Galaxies Around the Milky Way

By Evan Gough - April 24, 2025

The Milky Way has more than 30 known satellite galaxies. The Large and Small Magellanic Clouds are the largest and most well-known; other lesser-known ones, like the Sagittarius Dwarf Galaxy, are also on the list. Astronomers think there are many more small satellites that are difficult to detect but essential in understanding the Milky Way. The Vera Rubin Observatory should help astronomers find many more of them.

What Do Famous Astronomical Objects Look Like... in 3D?

By David Dickinson - April 23, 2025

It's a cosmic shame, that we tend to only see flat-looking, 2-dimensional views of deep-sky objects. And while we can't just zoom out past the Andromeda galaxy for another perspective, or see the Crab Nebula from another vantage point in space, we can use existing data to simulate objects in 3D. A recent collection released by Marshall Space Flight Center's Chandra X-ray Center and the Harvard-Smithsonian Center for Astrophysics shows us familiar objects in a new way.

Spiral Galaxy Seen Near the Beginning of Time

By Mark Thompson - April 22, 2025

On any clear, moonless night, the light from the billions of stars in our Milky Way Galaxy can be seen arching across the sky. A large spiral galaxy, the Milky Way we see today is the result of billions of years of galactic evolution. A team of astronomers have announced the discovery of a galaxy very similar to our own but this one is less than a billion years old! Typically galaxies like the Milky Way with a developed central bulge and spiral arms are only seen in nearby galaxies suggesting it's a process that takes time. This latest discovery challenges that theory!

Astronomers Push Webb to its Limits to Visualize the Most Distant Galaxies Of All!

By Matthew Williams - April 15, 2025

When JWST launched, it found the most distant known galaxy: JADES-GS-z14-0, with a redshift of 14.32, and seen about 290 million years after the Big Bang. Now, a team of astronomers has gone even deeper, searching for galaxies in the redshift 15-30 range, which would be galaxies from 270 to 100 million years after the beginning of the Universe. They've found a few candidates in the 15-20 range, but these could be closer, low-mass dusty galaxies.

Red Galaxies Aren't Necessarily Dead Galaxies

By Mark Thompson - April 11, 2025

The human perception of stars is that they are largely unchanging although of course in reality stars and their host galaxies do change over time, just very VERY slowly. When galaxies deplete their star forming materials, they traditionally become redder as short lived stars die while long lived dwarf stars persist for trillions of years. However, recent research challenges this understanding.

The Small Magellanic Cloud is Being Torn Apart

By Mark Thompson - April 10, 2025

The two most prominent satellite galaxies of the Milky Way are the Large and Small Magellanic Clouds. A team of astronomers have recently tracked the movements of 7,000 stars in the Small Magellanic Cloud (SMC) and found that many of them are being pulled away towards the Large Magellanic Cloud! It seems the SMC is being pulled apart, perhaps leading to its eventual destruction as the tidal forces strip away its stars!

Our Understanding of the Physical Properties of Galaxies Could Be Wrong

By Andy Tomaswick - April 08, 2025

Up until recently, astronomy was reliant entirely on electromagnetic waves. While that changed with the confirmation of gravitational waves in 2016, astronomers had developed fundamental frameworks in the electromagnetic spectrum by that point. One critical framework broke the spectrum into three categories based on their wavelength - infrared, optical, and ultraviolet. To astronomers, each of these categories was created by a different physical phenomenon, and monitoring each gave its insight into what that phenomenon was doing, no matter what the other spectra said. This was especially prevalent when researching galaxies, as infrared and optical wavelengths were used to analyze different aspects of galaxy formation and behavior. However, Christian Kragh Jespersen of Princeton's Department of Astrophysics and his colleagues think they have found a secret that breaks the entire electromagnetic framework - the optical and infrared are connected.

Hubble's New Image of a Star Factory in the Small Magellanic Cloud

By Mark Thompson - April 08, 2025

NGC346 is a young star cluster in the Small Magellanic Clouds with an estimated 2,500 stars. It's about 200,000 light years away and this image, taken by the Hubble Space Telescope reveals a beautiful region of star formation. The bright blue stars are many times more massive than the Sun and will live short lives ending in spectacular supernova explosions. The image helps us to understand the stellar formation process in a galaxy that has fewer metals than our own Galaxy.

The Most Distant Known Galaxy Already Had Oxygen

By Brian Koberlein - March 24, 2025

One of the surprising discoveries of the James Webb Space Telescope (JWST) is that galaxies formed very early in the Universe. JWST has discovered about two dozen galaxies at a redshift of around z = 14, meaning that we see them at a time when the cosmos was just 300-500 million years old. The most distant galaxy, JADES-GS-z14-0, is seen at an age of less than 300 million years. All of these galaxies are rich with stars and have a basic structure similar to what we see in more modern galaxies. This discovery challenged our understanding of galactic evolution. Now a new discovery challenges it even further.

This Precocious Galaxy is Surprisingly Mature for its Age

By Evan Gough - March 11, 2025

Looking back in time can seem like a sci-fi fantasy. But the nature of the Universe allows us to do it if we have the right telescope. The JWST is the right telescope, and as part of its observations, it frequently examines ancient galaxies whose light is only reaching us now. One of those ancient galaxies is both bright and enriched with metals, both signs of maturity.

Andromeda's Dwarf Galaxies Reveal Unique Star Formation Histories

By Evan Gough - February 28, 2025

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