galactic evolution 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 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.

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.

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!

May 11, 2024May 11, 2024 by Brian Koberlein

Supermassive Black Holes Got Started From Massive Cosmic Seeds

The J0148 quasar circled in red. Two insets show, on top, the central black hole, and on bottom, the stellar emission from the host galaxy. Credit: NASA

Supermassive black holes are central to the dynamics and evolution of galaxies. They play a role in galactic formation, stellar production, and possibly even the clustering of dark matter. Almost every galaxy has a supermassive black hole, which can make up a small fraction of a galaxy’s mass in nearby galaxies. While we know a great deal about these gravitational monsters, one question that has lingered is just how supermassive black holes gained mass so quickly.

April 29, 2024April 29, 2024 by Mark Thompson

Galaxies Evolved Surprisingly Quickly in the Early Universe

Anyone familiar with astronomy will know that galaxies come in a fairly limited range of shapes, typically; spiral, elliptical, barred-spiral and irregular. The barred-spiral galaxy has been known to be a feature of the modern universe but a study from astronomers using the Hubble Space Telescope has recently challenged that view. Following on observations using the James Webb Space Telescope has found the bar feature in some spiral galaxies as early as 11 billion years ago suggesting galaxies evolved faster in the early Universe than previously expected.

January 31, 2024January 31, 2024 by Brian Koberlein

Even Early Galaxies Grew Hand-in-Hand With Their Supermassive Black Holes

An artist’s impression of a quasar. Credit: NASA / ESA / J. Olmsted, STScI

Within almost every galaxy there is a supermassive black hole. This by itself implies some kind of formative connection between the two. We have also observed how gas and dust within a galaxy can drive the growth of galactic black holes, and how the dynamics of black holes can both drive star formation or hinder it depending on how active a black hole is. But one area where astronomers still have little information is how galaxies and their black holes interacted in the early Universe. Did black holes drive the formation of galaxies, or did early galaxies fuel the growth of black holes? A recent study suggests the two evolved hand in hand.

January 24, 2024January 24, 2024 by Brian Koberlein

Webb Sees Dozens Of Young Quasars in the First Billion Years of the Universe

Artist's impression of blue quasar in the early universe. Credit: S. Munro / CC BY 4.0

Within almost every galaxy is a supermassive black hole. Millions, sometimes billions of solar masses locked within an event horizon of space and time. They can power luminous quasars, drive star formation, and change the evolution of a galaxy. Because of their size and abundance, supermassive black holes must have formed early in cosmic history. But how early is still an unanswered question. It’s a focus of a recent study on the arXiv.

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.

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.