Scientists have just announced Thanks to NASA’s new flagship James Webb Space Telescope, an intriguing discovery has been made that some of the earliest formed galaxies in the universe have been detected.
“This is the first large sample of a candidate galaxy beyond the range of the Hubble Space Telescope,” astronomer Haojin Yang said yesterday at the American Astronomical Society’s press conference in Seattle. Yang, who is at the University of Missouri, led the newly published research. More sensitive, his JWST can see even deeper into space than his predecessor Hubble, so it can essentially go back in time. In his new catalog of 87 galaxies that astronomers have used it to discover, some may date back to about 13.6 billion years ago, just 200 million years after the Big Bang. That’s when the galaxy gave off the light we see today. However, these systems of stars, gas, and dust, if they still existed, would have changed dramatically since then.
Scientists have studied other distant galaxies dating back to when the universe was still young, but the discovery by Yang and his colleagues could break those records by hundreds of millions of years. But at the moment they are all considered “candidate galaxies”, so their date of birth should be confirmed.
Determining the age of galaxies can be a difficult problem. This includes measuring its “redshift”. This is a measurement of how much the light emitted by galaxies is stretched towards longer red wavelengths. This shows astronomers how fast galaxies are moving away from us in a rapidly expanding universe. This allows astronomers to know the distance between the galaxy and Earth. More precisely, it’s the distance a photon from a star had to travel at the speed of light to reach a near-Earth space telescope like her JWST. The light from the stars in this collection’s most distant galaxy may have been emitted 13.6 billion years ago, likely shortly after young galaxies converged.
These newly estimated distances should be confirmed in the spectrum. That means we need to measure the light emitted by galaxies across the electromagnetic spectrum and identify their unique features. Still, Yan expects many of them to be accurately dated to the early universe.
Yan’s team imaged these galaxies with JWST’s NIRCam at six near-infrared wavelengths. To estimate the distances of galaxies, astronomers used the standard “dropout” technique. The hydrogen gas that surrounds galaxies absorbs certain wavelengths of light, so the wavelength at which an object is visible or invisible limits its distance. be able to These 87 candidate galaxies look like blobs detectable only at the longer (and thus redder) near-infrared wavelengths detectable by NIRCam.
However, some of them may be much closer than you might expect. I mean, it’s not that old. For example, their light may be too weak to be detected at some wavelengths. Until Yan is able to gather more detailed data, we can’t be sure.
