James Webb: How a space telescope discovered the galaxy closest to the birth of the Universe
Image Source, NASA/ESA/CSA/STSCI/BRANT ROBERTSON ET AL.
- Author, Jonathan Amos
- Role, BBC Science Correspondent
The James Webb Space Telescope has broken its own record by discovering the most distant galaxy ever known.
The star cluster, called JADES-GS-z14-0, was seen as it existed just 290 million years after the Big Bang.
In other words, if the universe is 13 billion years old, that means we are observing a galaxy when the cosmos was only 2% of its current age.
Webb used his huge 6.5-meter-diameter primary mirror and sensitive infrared instruments to make the discovery.
Astronomers note that the most interesting aspects of the latest observations are not so much the distance in question, incredible though it is, but size and shine JADES-GS-z14-0.
Webb measured the edge-to-edge distance of the galaxy to be more than 1,600 light-years. Many of the brightest galaxies generate most of their light from gas falling into a supergiant black hole.
But the JADES-GS-z14-0 scale shows that this is not the explanation in this case. Researchers believe, however, that young stars emit light.
“Such a large amount of starlight means that the galaxy has a mass several hundred million times that of the Sun! The question becomes: How can nature create such a bright, massive and huge galaxy in less than 300 million years?” Webb expressed. astronomers Stefano Carniani and Kevin Hainlein.
Carniani is affiliated with the Scuola Normale Supérieure in Pisa, Italy, and Hainlein is affiliated with the University of Arizona in Tucson (USA).
The $10 billion James Webb Space Telescope (JWST) launched in 2021 as a joint venture between the US, European and Canadian space agencies.
It was designed specifically for explore much deeper into space and see much further in time than any other astronomical instrument.
One of its key tasks is to find the very first stars that exploded during the birth of the Universe.
These gigantic objects, perhaps many hundreds of times larger than our Sun, were composed only of hydrogen and helium.
They are believed to have lived vibrant but short lives, forging at their nuclear centers the heaviest chemical elements known in nature today.
Webb sees significant amounts of oxygen in JADES-GS-z14-0, which tells researchers that the galaxy is already quite mature.
“The presence of oxygen so early in the life of this galaxy is surprising and suggests that several generations of very large stars had already ended their lives before we observed the galaxy,” Carniani and Hainlein added.
The abbreviation JADES in the name of the object in English corresponds to “JWST Advanced Deep Extragalactic Survey”.
It is one of several observing programs that are using the telescope to study the first few hundred million years of the cosmos.
“z14” refers to “Redshift 14”. redshift is a term that astronomers use to describe distances.
Essentially, it is a measure of how light coming from a distant galaxy has been stretched into longer wavelengths by the expansion of the universe.
The greater the distance, the greater the stretch.
The light from the first galaxies ranged from ultraviolet and visible wavelengths to infrared wavelengths, the part of the electromagnetic spectrum for which James Webb’s mirrors and instruments were specially tuned.
“We would be able to detect this galaxy if it were 10 times fainter, which means we could see other, even earlier examples in the Universe – probably in the first 200 million years,” said Professor Brant Robertson from UCSF. Fe.
The JADES discovery and its implications are described in a series of dedicated papers published on Cornell University’s arXiv preprint service, which you can read in English here.
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