The earliest galaxies shone brightly in the young universe

By Georgina Torbet Published May 12, 2019

This artist’s illustration shows what one of the very first galaxies in the universe might have looked like. High levels of violent star formation and star death would have illuminated the gas filling the space between stars, making the galaxy largely opaque and without a clear structure. James Josephides (Swinburne Astronomy Productions)

Observations from NASA’s Spitzer Space Telescope have shown the earliest galaxies in the universe were brighter than previously thought, shedding light onto the way that the universe evolved.

The new study has revealed that the earliest galaxies formed in our universe were much brighter than galaxies are today. This enhanced brightness was specific to certain wavelengths of infrared light, but it applied to a large number of galaxies in this early period of less than 1 billion years after the Big Bang.

Recommended Videos

“We did not expect that Spitzer, with a mirror no larger than a Hula-Hoop, would be capable of seeing galaxies so close to the dawn of time,” Michael Werner, Spitzer’s project scientist at NASA’s Jet Propulsion Laboratory in Pasadena, California, said in a statement. “But nature is full of surprises, and the unexpected brightness of these early galaxies, together with Spitzer’s superb performance, puts them within range of our small but powerful observatory.”

The findings give more information about a period of transition in the early universe called the Epoch of Reionization. This was the time at which the smooth substance of the universe, called the intergalactic medium, began to form into the first luminous sources such as stars, galaxies, and quasars. Before this, light struggled to cross space as is was blocked by the hydrogen, so the universe was generally opaque.

This change happened between 100 million and 200 million years after the Big Bang, and scientists are still not quite sure what caused the birth of the earliest stars. At some point the hydrogen gas that made up the intergalactic medium began to coalesce into stars, which then formed galaxies. This is known as reionization because electrons were stripped away from the hydrogen, forming hydrogen ions.

“These results by Spitzer are certainly another step in solving the mystery of cosmic reionization,” Pascal Oesch, an assistant professor at the University of Geneva and a co-author of the study, said in the same statement. “We now know that the physical conditions in these early galaxies were very different than in typical galaxies today. It will be the job of the James Webb Space Telescope to work out the detailed reasons why.”

The findings are published in the journal Monthly Notices of the Royal Astronomical Society.

Topics

Georgina Torbet

Space Writer

Georgina has been the space writer at Digital Trends space writer for six years, covering human space exploration, planetary…

Space

Hubble spots three galaxies pulled into an unusual shape

The subject of this image is a group of three galaxies, collectively known as NGC 7764A. They were imaged by the NASA/ESA Hubble Space Telescope, using both its Advanced Camera for Surveys and Wide Field Camera 3.

This week's image from the Hubble Space Telescope shows a group of three galaxies that are so close together that they have been given one collective name: NGC 7764A. When galaxies come close together, they can interact as their gravity affects one another, leading to them being pulled into different shapes or even, in extreme cases, merging together or destroying one of the galaxies.

"The two galaxies in the upper right of the image appear to be interacting with one another," the Hubble scientists explained in a statement. "The long trails of stars and gas extending from them give the impression that they have both just been struck at great speed, thrown into disarray by the bowling-ball-shaped galaxy to the lower left of the image. In reality, interactions between galaxies happen over very long time periods, and galaxies rarely collide head-on with one another. It is also unclear whether the galaxy to the lower left is interacting with the other two, although they are so relatively close in space that it seems possible that they are."

Space

James Webb Space Telescope launched on mission to uncover secrets of the universe

Arianespace's Ariane 5 rocket with NASA’s James Webb Space Telescope onboard, is seen at the launch pad, Thursday, Dec. 23, 2021, at Europe’s Spaceport, the Guiana Space Center in Kourou, French Guiana.

A new era in astronomy is underway, with the successful launch today of the world's most powerful space telescope. The James Webb Space Telescope blasted off safely early this morning after long delays and great anticipation.

Arianespace's Ariane 5 rocket with NASA’s James Webb Space Telescope onboard, is seen at the launch pad, Thursday, Dec. 23, 2021, at Europe’s Spaceport, the Guiana Space Center in Kourou, French Guiana. NASA

Space

Hubble image captures a stunning spiral galaxy in the constellation of Aquila

This astronomical portrait from the NASA/ESA Hubble Space Telescope showcases an edge-on view of the majestic spiral galaxy UGC 11537. The infrared and visible light capabilities of Hubble’s Wide Field Camera 3 have captured the galaxy’s tightly wound spiral arms swirling around its heart. The image reveals the bright bands of stars and the dark clouds of dust threading throughout the galaxy.

This week's image from the Hubble Space Telescope captures the glorious spiral galaxy UGC 11537, seen at an angle that shows off both its long spiral arms and the bright clump of stars at its center. It is located 230 million light-years away in the constellation of Aquila (Latin for "eagle").

As well as being pleasing to look at, this image was collected to further scientific knowledge about the enormous black holes at the galaxy's heart. "This image came from a set of observations designed to help astronomers weigh supermassive black holes in the centers of distant galaxies," Hubble scientists wrote. "Hubble’s sharp-eyed observations along with data from ground-based telescopes allowed astronomers to make detailed models of the mass and motions of stars in these galaxies, which in turn helps constrain the mass of supermassive black holes."