galaxies Archives

July 13, 2024July 13, 2024 by Mark Thompson

Galaxies Regulate their Own Growth so they Don’t Run Out of Star Forming Gas

A simulation of a galaxy’s ‘heart and lungs’ at work is pictured inset on an artist's impression of bi-polar jets of gas originating from a supermassive black hole at the centre of a galaxy. Credit ESA/Hubble, L. Calçada (ESO) / C Richards/MD Smith/University of Kent Licence type Attribution (CC BY 4.0)

Look at most spiral or barred spiral galaxies and you will see multiple regions where stars are forming. These star forming regions are comprised of mostly hydrogen gas with a few other elements for good measure. The first galaxies in the Universe had huge supplies of this star forming gas. Left unchecked they could have burned through the gas quickly, generating enormous amounts of star formation. Life fast though and die young for such an energetic burst of star formation would soon fizzle out leaving behind dead and dying stars. In some way it seems, galaxies seem to regulate their star formation thanks to supermassive black holes at their centre.

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.

June 24, 2024June 24, 2024 by Evan Gough

Growing Black Holes Have Much in Common With Baby Stars

Assisted by magnetic fields, a spiraling wind helps the supermassive black hole in galaxy ESO320-G030 grow. In this illustration, the core of the galaxy is dominated by a rotating wind of dense gas leading outwards from the (hidden) supermassive black hole at the galaxy’s center. The motions of the gas, traced by light from molecules of hydrogen cyanide, have been measured with the Atacama Large Millimeter/submillimeter Array. Image credit: M. D. Gorski/Aaron M. Geller, Northwestern University, CIERA, the Center for Interdisciplinary Exploration and Research in Astrophysics.

First looks would tell most observers that supermassive black holes (SMBHs) and very young stars have nothing in common. But that’s not true. Astronomers have detected a supermassive black hole (SMBH) whose growth is regulated the same way a baby star’s is: by magnetic winds.

June 20, 2024June 20, 2024 by Evan Gough

Here’s Hubble’s First Image in its New Pointing Mode

The Hubble Space Telescope captured this image of the galaxy NGC 1546 while in single gyro mode. Image Credits: NASA, ESA, STScI, David Thilker (JHU)

This is probably what the demise of the Hubble Space Telescope was always going to look like: components failing one by one, with no way to replace them. In the last few months, the Hubble has repeatedly gone into safe mode as one of its remaining three gyros keeps giving faulty readings. But the Hubble and the people operating it are resilient and resourceful. The telescope is back to science operations now, though in single gyro mode.

NASA has released the first image the Hubble captured in this mode, and it’s clear that the Hubble is performing well.

June 17, 2024June 17, 2024 by Evan Gough

Almost a Third of Early Galaxies Were Already Spirals

The graceful winding arms of the grand-design spiral galaxy M51 stretch across this image from the NASA/ESA/CSA James Webb Space Telescope. New JWST observations of the early Universe are upending our understanding of galaxy evolution. Credit: ESA/Webb, NASA & CSA, A. Adamo (Stockholm University) and the FEAST JWST team

In the years before the JWST’s launch, astronomers’ efforts to understand the early Universe were stymied by a stubborn obstacle: the light from the early Universe was red-shifted to an extreme degree. The JWST was built with extreme redshifts in mind, and one of its goals was to study Galaxy Assembly.

Once the JWST activated its segmented, beryllium eye, the Universe’s most ancient, red-shifted light became visible.

June 10, 2024June 10, 2024 by Evan Gough

The Milky Way’s Last Merger Event Was More Recent Than Thought

Our home galaxy as seen by the European Space Agency’s Gaia satellite. Image Credit: ESA/Gaia/DPAC

The Milky Way is only as massive as it is because of collisions and mergers with other galaxies. This is a messy process, and we see the same thing happening with other galaxies throughout the Universe. Currently, we see the Milky Way nibbling at its two satellite galaxies, the Large and Small Magellanic Clouds. Their fate is likely sealed, and they’ll be absorbed into our galaxy.

Researchers thought the last major merger occurred in the Milky Way’s distant past, between 8 and 11 billion years ago. But new research amplifies the idea that it was much more recent: less than 3 billion years ago.

June 4, 2024June 4, 2024 by Evan Gough

Evidence of Dark Matter Interacting With Itself in El Gordo Merger

This image is from a computer simulation of the distribution of matter in the universe. Orange regions host galaxies; blue structures are gas and dark matter. We can map dark matter, but we don't know what it is. Image Credit: TNG Collaboration

The Standard Model of particle physics does a good job of explaining the interactions between matter’s basic building blocks. But it’s not perfect. It struggles to explain dark matter. Dark matter makes up most of the matter in the Universe, yet we don’t know what it is.

The Standard Model says that whatever dark matter is, it can’t interact with itself. New research may have turned that on its head.

May 30, 2024May 30, 2024 by Mark Thompson

Webb Finds the Farthest Galaxy Ever Seen (So Far)

There are some things that never cease to amaze me and the discovery of distant objects is one of them. The James Webb Space Telescope has just found the most distant galaxy ever observed! It has the catchy title JADES-GS-z14-0 and it has a redshift of 14.32. This means its light left when the Universe was only 290 million years old! That means the light left the source LOOOONG before even our Milky Way was here! How amazing is that!

May 26, 2024May 26, 2024 by Matt Williams

Galaxies in the Early Universe Preferred their Food Cold

This illustration shows a galaxy forming only a few hundred million years after the big bang, when gas was a mix of transparent and opaque during the Era of Reionization. Data from NASA’s James Webb Space Telescope shows that cold gas is falling onto these galaxies. Credit: NASA/ESA/CSA/Joseph Olmsted (STScI)

One of the main objectives of the James Webb Space Telescope (JWST) is to study the early Universe by using its powerful infrared optics to spot the first galaxies while they were still forming. Using Webb data, a team led by the Cosmic Dawn Center in Denmark pinpointed three galaxies that appear to have been actively forming just 400 to 600 million years after the Big Bang. This places them within the Era of Reionization, when the Universe was permeated by opaque clouds of neutral hydrogen that were slowly heated and ionized by the first stars and galaxies.

This process caused the Universe to become transparent roughly 1 billion years after the Big Bang and (therefore) visible to astronomers today. When the team consulted the data obtained by Webb, they observed that these galaxies were surrounded by an unusual amount of dense gas composed almost entirely of hydrogen and helium, which likely became fuel for further galactic growth. These findings already reveal valuable information about the formation of early galaxies and show how Webb is exceeding its mission objectives.

May 17, 2024May 17, 2024 by Evan Gough

The Venerable Hubble Space Telescope Keeps Delivering

The Hubble Space Telescope is amazing! It's still going strong more than 34 years after it was launched. This Hubble image showcases a nearly edge-on view of the lenticular galaxy NGC 4753. ESA/Hubble & NASA, L. Kelsey

The world was much different in 1990 when NASA astronauts removed the Hubble Space Telescope from Space Shuttle Discovery’s cargo bay and placed it into orbit. The Cold War was ending, there were only 5.3 billion humans, and the World Wide Web had just come online.