galaxies Archives

January 18, 2024January 18, 2024 by Evan Gough

The JWST Solves the Mystery of Ancient Light

This image shows the galaxy EGSY8p7, a bright galaxy in the early Universe where light emission is seen from, among other things, excited hydrogen atoms — Lyman-alpha emission. The galaxy was identified in a field of young galaxies studied by Webb in the CEERS survey. In the bottom two panels, Webb’s high sensitivity picks out this distant galaxy along with its two companion galaxies, where previous observations saw only one larger galaxy in its place. This discovery of a cluster of interacting galaxies sheds light on the mystery of why the hydrogen emission from EGSY8p7, shrouded in neutral gas formed after the Big Bang, should be visible at all. Image Credit: ESA/Webb, NASA & CSA, S. Finkelstein (UT Austin), M. Bagley (UT Austin), R. Larson (UT Austin), A. Pagan (STScI), C. Witten, M. Zamani (ESA/Webb)

The very early Universe was a dark place. It was packed with light-blocking hydrogen and not much else. Only when the first stars switched on and began illuminating their surroundings with UV radiation did light begin its reign. That occurred during the Epoch of Reionization.

But before the Universe became well-lit, a specific and mysterious type of light pierced the darkness: Lyman-alpha emissions.

January 15, 2024January 15, 2024 by Brian Koberlein

Gigantic Galaxy Clusters Found Just Before They're Awash in Star Formation

This panchromatic view of galaxy cluster MACS0416 was created by combining infrared observations from the NASA/ESA/CSA James Webb Space Telescope with visible-light data from the NASA/ESA Hubble Space Telescope. Credit: NASA/ESA/CSA/STScI

One of the central factors in the evolution of galaxies is the rate at which stars form. Some galaxies are in a period of active star formation, while others have very little new stars. Very broadly, it’s thought that younger galaxies enter a period of rapid star formation before leveling off to become a mature galaxy. But a new study finds some interesting things about just when and why stars form.

January 3, 2024January 3, 2024 by Evan Gough

The Oldest Known Spiral Galaxy Has Ripples Like the Surface of a Pond

This simulation illustrates a galaxy disk being disturbed, leading to the propagation of a seismic ripple throughout the disk. (Credit: Bland-Hawthorn and Tepper-Garcia, University of Sydney).

Astronomers have detected pond-like ripples across the gaseous disk of an ancient galaxy. What caused the ripples, and what do they tell us about the distant galaxy’s formation and evolution? And whatever happened, how has it affected the galaxy and its main job: forming stars?

December 29, 2023December 29, 2023 by Brian Koberlein

The Early Universe Was Surprisingly Filled With Spiral Galaxies

The bluish-white spiral galaxy NGC 1376 hangs delicately in the cold vacuum of space. Credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA)

If we could travel far beyond our galaxy, and look back upon the Milky Way, it would be a glorious sight. Luminous spirals stretching from a central core, with dust and nebulae scattered along the spiral edges. When you think about a galaxy, you probably imagine a spiral galaxy like the Milky Way, but spirals make up only about 60% of the galaxies we see. That’s because spiral galaxies only form when smaller galaxies collide and merge over time. Or so we thought, as a new study suggests that isn’t the case.

December 15, 2023December 15, 2023 by Nancy Atkinson

Hubble Sees a Random Collection of Galaxies, Perfectly Lined Up

A pair of interacting galaxies, one smaller than the other. Each has a bright spot at the centre and two loosely-wound spiral arms, with threads of dark dust following the arms. They appear as a broad, soft glow in which individual stars can’t be seen. A number of bright stars and smaller, background galaxies can also be seen — three such galaxies lie in a vertical line below the right-hand galaxy of the pair.

This new image from the Hubble Space Telescope looks like a series of smaller spiral galaxies are falling out of a larger and brighter galaxy. That’s just one of the many reasons this collection of galaxies belongs to the Arp-Madore catalogue of peculiar galaxies.

December 8, 2023December 9, 2023 by Brian Koberlein

Did the Last Great Galactic Merger Create the Milky Way's Bar?

Milky Way. Image credit: NASA/JPL-Caltech/R. Hurt (SSC/Caltech)

The Milky Way is a spiral galaxy. More specifically, it is a barred spiral galaxy, meaning that within its central region, there is a bar shape off of which the spirals emanate. About two-thirds of spiral galaxies are barred spirals, and astronomers have thought this difference is just a variance in how density waves cluster stars in a galaxy. But a new study suggests that the bar of the Milky Way may have been caused by an ancient collision with another galaxy.

November 26, 2023November 26, 2023 by Carolyn Collins Petersen

The Early Universe Had No Problem Making Barred Spiral Galaxies

An artist's conception of the CEERS-2112 galaxy in the early Universe. Credit: Luca Costantin/CAB/CSIC-INTA

Spiral galaxies like the Milky Way are like cosmic snowflakes—no two are exactly alike. For many years, astronomers thought spirals couldn’t exist until the universe was about half its present age. Now, a newly discovered galaxy in the early Universe is challenging that idea.

November 23, 2023November 23, 2023 by Evan Gough

Adolescent Galaxies are Incandescent and Contain Unexpected Elements

Light from 23 distant galaxies, identified with red rectangles in the Hubble Space Telescope image at the top, were combined to capture incredibly faint emission from eight different elements, which are labelled in the JWST spectrum at the bottom. Although scientists regularly find these elements on Earth, astronomers rarely, if ever, observe many of them in distant galaxies, especially nickel. Image Credit: Aaron M. Geller, Northwestern, CIERA + IT-RCDS

If the Universe has adolescent galaxies, they’re the ones that formed about 2 to 3 billion years after the Big Bang. New research based on the James Webb Space Telescope shows that these teenage galaxies are unusually hot. Not only that, but they contain some unexpected chemical elements. The most surprising element found in these galaxies is nickel.

November 23, 2023November 23, 2023 by Evan Gough

There Aren’t Many Galaxies Like The Milky Way Nearby. Now We Know Why

Antennas of the Very Large Array against the Milky Way. Credit: NRAO/AUI/NSF/Jeff Hellerman

The Milky Way is a barred spiral galaxy, maybe even a grand design spiral galaxy. We can’t be sure from our vantage point. But one thing is certain: there aren’t many disk galaxies like it in our part of the Universe called the supergalactic plane.

November 21, 2023November 21, 2023 by Evan Gough

A Galaxy Only 350 Million Years Old Had Surprising Amounts of Metal

The JWST has the power to see the most ancient galaxies in the Universe, as shown in this image of its first deep field. Now, astrophysicists have found carbon in one of these ancient galaxies. Image Credit: NASA, ESA, CSA, and STScI

Astrophysicists working with the JWST have found a surprising amount of metal in a galaxy only 350 million years after the Big Bang. How does that fit in with our understanding of the Universe?