galaxies Archives

January 6, 2025January 6, 2025 by Brian Koberlein

A Dragon Reveals Individual Stars From A Time When the Universe Was Half Its Present Age

The galactic cluster Abell 370, with the Dragon Arc highlighted. Credit: NASA, ESA, the Hubble SM4 ERO Team and ST-ECF

One powerful way to study the galaxies is to study individual stars. By looking at the ages, types, and distribution of stars in the Milky Way, we’ve captured a detailed snapshot of how our galaxy formed and evolved. The only problem with this approach is that we can only do this for a handful of galaxies. Even with the most powerful telescopes, we can only see individual stars in the Milky Way and nearby galaxies such as Andromeda. For galaxies billions of light years away, individual stars blur together, and the best we can do is observe the overall spectra of galaxies, not individual stars. But thanks to a chance alignment, we can now observe dozens of stars in a galaxy so distant we see it at a time when the Universe was half its present age.

December 16, 2024December 16, 2024 by Evan Gough

We Might Finally Know How Galaxies Grow So Large

Spiral galaxies and elliptical galaxies both contain bulges, also called spheroids. How these spheroids form and evolve is a puzzling question, but new research brings us closer to an answer. Image Credit: ESA

Astronomers have spent decades trying to understand how galaxies grow so large. One piece of the puzzle is spheroids, also known as galactic bulges. Spiral galaxies and elliptical galaxies have different morphologies, but they both have spheroids. This is where most of their stars are and, in fact, where most stars in the Universe reside. Since most stars reside in spheroids, understanding them is critical to understanding how galaxies grow and evolve.

New research focused on spheroids has brought them closer than ever to understanding how galaxies become so massive.

December 13, 2024December 13, 2024 by Brian Koberlein

Webb Weighs an Early Twin of the Milky Way

A central oval identifies the Firefly Sparkle galaxy, which is similar to a young Milky Way. Credit: NASA, ESA, CSA, STScI, C. Willott (NRC-Canada), L. Mowla (Wellesley College), K. Iyer (Columbia)

What was the Milky Way like billions of years ago? One way we can find out is by looking at the most distant galaxies in the observable Universe. Seeing those far galaxies is one goal of the James Webb Space Telescope. It has revealed some surprising facts about early galaxies, and now it is starting to reveal the story of our own.

December 9, 2024December 9, 2024 by Evan Gough

Webb Sees a Supercluster of Galaxies Coming Together

Using the NASA/ESA/CSA James Webb Space Telescope, an international team of astronomers have found new galaxies in the Spiderweb protocluster. Because Webb can see infrared light very well, scientists used it to observe regions of the Spiderweb that were previously hidden to us by cosmic dust, and to find out to what degree this dust obscures them. This image shows the Spiderweb protocluster as seen by Webb’s NIRCam (Near-InfraRed Camera). Image Credit: ESA/Webb, NASA & CSA, H. Dannerbauer

As a species, we’ve come to the awareness that we’re a minuscule part of a vast Universe defined by galaxy superclusters and the large-scale structure of the Universe. Driven by a healthy intellectual curiosity, we’re examining our surroundings and facing the question posed by Nature: how did everything get this way?

We only have incremental answers to that huge, almost infinitely-faceted question. And the incremental answers are unearthed by our better instruments, including space telescopes, which get better and more capable as time passes.

Enter the James Webb Space Telescope.

November 26, 2024November 26, 2024 by Brian Koberlein

Fantastic New Image of the Sombrero Galaxy From Webb

NASA’s James Webb Space Telescope recently imaged the Sombrero Galaxy, resolving the clumpy nature of the dust along the galaxy’s outer ring. Credit: NASA, ESA, CSA, STScI

NGC 4594 is an unusual galaxy. It was discovered in 1781 by Pierre Méchain, and is striking because of a symmetrical ring of dust that encircles the visible halo of the galaxy. Images taken of the galaxy in 2003 show this dusty ring in detail, where it almost resembles the brim of a large hat. So it’s understandable that NGC 4594 is more commonly known as the Sombrero Galaxy. Now the James Webb Space Telescope has captured an amazingly sharp image of the galaxy, and it’s revealing some interesting surprises.

November 25, 2024November 25, 2024 by Evan Gough

We’re Living in an Abnormal Galaxy

The Milky Way. This image is constructed from data from the ESA's Gaia mission that's mapping over one billion of the galaxy's stars. Image Credit: ESA/Gaia/DPAC

Astronomers often use the Milky Way as a standard for studying how galaxies form and evolve. Since we’re inside it, astronomers can study it in detail with advanced telescopes. By examining it in different wavelengths, astronomers and astrophysicists can understand its stellar population, its gas dynamics, and its other characteristics in far more detail than distant galaxies.

However, new research that examines 101 of the Milky Way’s kin shows how it differs from them.

November 18, 2024November 18, 2024 by Brian Koberlein

The Large Magellanic Cloud Survived its Closest Approach to the Milky Way

Illustration of the Large Magellanic Cloud passing through the halo of the Milky Way. Credit: NASA, ESA, Ralf Crawford (STScI)

The Large Magellanic Cloud is a small galaxy, just a tenth of the Milky Way’s mass. It is about 160,000 light years away, which is remarkably close in cosmic terms. In the southern hemisphere it spans the width of 20 Moons in the night sky. While the galaxy seems timeless and unchanging to our short human lives, it is, in fact, a dynamic system undergoing a near collision with our galaxy. Now astronomers are beginning to observe that process.

November 18, 2024November 18, 2024 by Nancy Atkinson

Three More “Galactic Monster” Ultra-Massive Galaxies Found

These three "red monster" galaxies are extremely massive and dusty galaxies in the first billion years after the Big Bang. © NASA/CSA/ESA, M. Xiao & P. A. Oesch (University of Geneva), G. Brammer (Niels Bohr Institute), Dawn JWST Archive.

One of the surprise findings with the James Webb Space Telescope is the discovery of massive galaxies in the early Universe. The expectations were that only young, small, baby galaxies would exist within the first billion years after the Big Bang. But some of the newly found galaxies appear to be as large and as mature as galaxies that we see today.

Three more of these “monster” galaxies have now been found, and they have a similar mass to our own Milky Way. These galaxies are forming stars nearly twice as efficiently as galaxies that were formed later on in the Universe. Although they’re still within standard theories of cosmology, researchers say they demonstrate how much needs to be learned about the early Universe.

November 14, 2024November 14, 2024 by Paul M. Sutter

Yes, Virginia, The Universe is Still Making Galaxies

Scientists are getting their first look with the NASA/ESA/CSA James Webb Space Telescope’s powerful resolution at how the formation of young stars influences the evolution of nearby galaxies. The spiral arms of NGC 7496, one of a total of 19 galaxies targeted for study by the Physics at High Angular resolution in Nearby Galaxies (PHANGS) collaboration, are filled with cavernous bubbles and shells overlapping one another in this image from Webb’s Mid-Infrared Instrument (MIRI). These filaments and hollow cavities are evidence of young stars releasing energy and, in some cases, blowing out the gas and dust of the interstellar medium they plough into. Until Webb’s high resolution at infrared wavelengths came along, stars at the earliest point of their lifecycle in nearby galaxies like NGC 7496 remained obscured by gas and dust. Webb’s specific wavelength coverage (7.7 and 11.3 microns), allows for the detection of polycyclic aromatic hydrocarbons, which play a critical role in the formation of stars and planets. In Webb’s MIRI image, these are mostly found within the main dust lanes in the spiral arms. In their analysis of the new data from Webb, scientists were able to identify nearly 60 new, undiscovered embedded cluster candidates in NGC 7496. These newly identified clusters could be among the youngest stars in the entire galaxy. At the centre of NGC 7496, a barred spiral galaxy, is an active galactic nucleus (AGN). An AGN is a supermassive black hole that is emitting jets and winds. The AGN glows brightly at the centre of this Webb image. Additionally, Webb’s extreme sensitivity also picks up various background galaxies,far distant from NGC 7496, which appear green or red in some instances. NGC 7496 lies over 24 million light-years away from Earth in the constellation Grus.In this image of NGC 7496, blue, green, and red were assigned to Webb’s MIRI data at 7.7, 10 and 11.3, and 21 microns (the F770W, F1000W and F1130W, and F2100W filters, respectively

Despite the fact that our universe is old, cold, and well past its prime, it’s not done making new galaxies yet.

November 2, 2024November 2, 2024 by Brian Koberlein

Webb Confirms a Longstanding Galaxy Model

JWST image of the grand design spiral galaxy NGC 628. Credit: NASA / ESA / CSA / Judy Schmidt (CC BY 2.0)

Perhaps the greatest tool astronomers have is the ability to look backward in time. Since starlight takes time to reach us, astronomers can observe the history of the cosmos by capturing the light of distant galaxies. This is why observatories such as the James Webb Space Telescope (JWST) are so useful. With it, we can study in detail how galaxies formed and evolved. We are now at the point where our observations allow us to confirm long-standing galactic models, as a recent study shows.