The discovery of two previously unseen galaxies 29 billion light years away implies that our knowledge of the early cosmos is woefully inadequate.
Introducing REBELS-12-2 and REBELS-29-2, two galaxies we had no idea existed until recently. Because these objects originated shortly after the Big Bang, the light from these galaxies took 13 billion years to reach us. These ancient galaxies are around 29 billion light years away from Earth due to the universe’s continuous expansion.
REBELS-12-2 and REBELS-29-2 may have eluded discovery until now because our view of these galaxies is obscured by vast layers of cosmic dust, according to new study published in Nature. The Hubble Space Telescope, despite its immense power, was unable to see through the heavenly cloud. The galaxies were discovered by mistake by the ALMA radio telescope in Chile, which is very sensitive.
We were looking at a sample of very distant galaxies that the Hubble Space Telescope had already discovered. Then we saw that two of them had a neighbour who we didn’t expect to see,” Pascal Oesch, an astronomer at the Niels Bohr Institute in Copenhagen’s Cosmic Dawn Center, revealed in a statement. “Due to the dust that surrounds each of these adjacent galaxies, some of their light is obstructed, rendering them opaque to Hubble.
The new research explains how ALMA and a novel observational approach developed by Oesch and colleagues might help find similarly shrouded ancient galaxies. And it appears that there are many more waiting to be discovered. According to Oesch, the scientists matched the two newly discovered galaxies to previously known galactic origins in the early cosmos, which led them to believe that “up to one in five of the oldest galaxies may have been absent from our picture of the skies.”
“Before we can begin to grasp when and how galaxies evolved in the Universe, we need a comprehensive accounting,” he continued. Indeed, the new study claims that there were more ancient galaxies in the early cosmos than previously thought. This is crucial because the first galaxies served as the foundation for later galaxies. As a result, astronomers may be working with a defective or otherwise wrong picture of the early cosmos until we obtain a “proper accounting,” as Oesch phrased it.
The problem now will be to locate these missing galaxies, and happily, a forthcoming instrument, the Webb Space Telescope, promises to make this work much simpler. “This next-generation telescope will be far more sensitive than Hubble and capable of investigating longer wavelengths,” Oesch added, “which should allow us to discover these hidden galaxies with ease.”
The new article may thus be put to the test, since Webb’s findings are likely to confirm, refute, or revise the researchers’ predictions. The space telescope is set to launch from French Guiana at 7:20 a.m. ET on Wednesday, December 22. (4:30 a.m. PT).