James Webb spots early galaxies similar to our Milky Way

By Georgina Torbet January 7, 2023

As the James Webb Space Telescope looks back at some of the earliest galaxies, it is helping us learn not only about galaxies very different from our own but also about how galaxies similar to the Milky Way were first formed. Recently astronomers announced they have used Webb to discover some of the earliest galaxies with a feature called stellar bars, making them similar to our barred spiral galaxy seen today.

A galaxy bar refers to a strip of dust and gas that forms a structure across the center of a galaxy, and which is frequently visible as a bright stripe across a galaxy in images. It is thought that these structures develop as a galaxy ages, as dust and gas are drawn toward the galactic center. So it was remarkable to see a bar in a galaxy from a very early period when the universe was 25% of its current age.

The power of JWST to map galaxies at high resolution and at longer infrared wavelengths than Hubble allows it look through dust and unveil the underlying structure and mass of distant galaxies. This can be seen in these two images of the galaxy EGS23205, seen as it was about 11 billion years ago. In the HST image (left, taken in the near-infrared filter), the galaxy is little more than a disk-shaped smudge obscured by dust and impacted by the glare of young stars, but in the corresponding JWST mid-infrared image (taken this past summer), it’s a beautiful spiral galaxy with a clear stellar bar. — Two images of the galaxy EGS23205, seen as it was about 11 billion years ago. In the HST image (left, taken in the near-infrared filter), the galaxy is little more than a disk-shaped smudge obscured by dust and impacted by the glare of young stars, but in the corresponding JWST mid-infrared image (taken this past summer), it’s a beautiful spiral galaxy with a clear stellar bar. NASA/CEERS/University of Texas at Austin

An earlier image of galaxy EGS23205 taken by Hubble was smudgy and hard to see any structure in, but the new image from Webb shows a bright bar structure much more clearly.

Recommended Videos

“I took one look at these data, and I said, ‘We are dropping everything else!’” said one of the researchers, Shardha Jogee of the University of Texas at Austin, in a statement. “The bars hardly visible in Hubble data just popped out in the JWST image, showing the tremendous power of JWST to see the underlying structure in galaxies.”

Another galaxy, EGS-24268, was also imaged by Webb and is thought to be from 11 billion years ago. Finding these structures in very early galaxies is intriguing as it suggests astronomers will have to adjust their models of how galaxies evolve.

Bars are thought to be important for the development of galaxies as they move gas around and help to provide the building materials for new stars to form.

“Bars solve the supply chain problem in galaxies,” Jogee said. “Just like we need to bring raw material from the harbor to inland factories that make new products, a bar powerfully transports gas into the central region where the gas is rapidly converted into new stars at a rate typically 10 to 100 times faster than in the rest of the galaxy.”

Topics

Tech News

Georgina Torbet

Space Writer

Georgina is the Digital Trends space writer, covering human space exploration, planetary science, and cosmology. She…

Space

One galaxy, two views: see a comparison of images from Hubble and Webb

The peculiar galaxy NGC 3256 takes centre stage in this image from the NASA/ESA Hubble Space Telescope. This distorted galaxy is the wreckage of a head-on collision between two spiral galaxies which likely occurred 500 million years ago, and it is studded with clumps of young stars which were formed as gas and dust from the two galaxies collided.

It might not seem obvious why astronomers need multiple different powerful space telescopes. Surely a more powerful telescope is better than a less powerful one? So why are there multiple different telescopes in orbit, either around Earth or around the sun?

The answer is to do with two main factors. One is the telescope's field of view, meaning how much of the sky it looks at. Some telescopes are useful for looking at large areas of the sky in less detail, working as survey telescopes to identify objects for further research or to look at the universe on a large scale -- like the recently launched Euclid mission. While others, like the Hubble Space Telescope, look at small areas of the sky in great detail, which is useful for studying particular objects.

Space

James Webb spots the most distant active supermassive black hole ever discovered

Crop of Webb's CEERS Survey image.

As well as observing specific objects like distant galaxies and planets here in our solar system, the James Webb Space Telescope is also being used to perform wide-scale surveys of parts of the sky. These surveys observe large chunks of the sky to identify important targets like very distant, very early galaxies, as well as observe intriguing objects like black holes. And one such survey has recently identified the most distant active supermassive black hole seen so far.

While a typical black hole might have a mass up to around 10 times that of the sun, supermassive black holes are much more massive, with a mass that can be millions or even billions of times the mass of the sun. These monsters are found at the heart of galaxies and are thought to play important roles in the formation and merging of galaxies.

Space

Saturn as you’ve never seen it before, captured by Webb telescope

Saturn captured by the James Webb Space Telescope

NASA has shared a gorgeous image of Saturn captured recently by the James Webb Space Telescope (JWST).

Webb’s first near-infrared observations of the second largest planet in our solar system also show several of Saturn’s moons: Dione, Enceladus, and Tethys.