In recent years, astronomers have been leapfrogging one other into the distant past. Last week, a team of researchers using the Hubble Space Telescope announced that they had discovered what they believe to be the most distant and earliest star ever discovered. The star, nicknamed Earendel, twinkled 12.9 billion years ago, only 900 million years after the Big Bang, and was discovered using the Hubble Space Telescope.
In the latest announcement, an international team of astronomers, working with some of the world’s most powerful telescopes, claims they have discovered what appears to be the universe’s oldest and most distant collection of starlight ever observed: an orange-reddish blob, appropriately named HD1, that was ejecting massive amounts of energy only 330 million years after the Big Bang. So yet, no one has ventured into that world of time. HD2, another blob, looks to be nearly as far away as HD1.
While astronomers wait for their turn to examine these blobs with the upcoming James Webb Space Telescope, they can only speculate about what they are — galaxies, quasars, or something else completely — they can only speculate about what they are. However, scientists believe that whatever they are, they might give insight on a critical stage in the evolution of the universe from immaculate primordial fire to planets, life, and ultimately humans.
Dr. Pacucci was a member of a team headed by Yuichi Harikane of the University of Tokyo that spent 1,200 hours searching for extremely early galaxies using several ground-based telescopes. Dr. Harikane is now a professor at the University of Tokyo. Their results were published on Thursday in the Astrophysical Journal and the Monthly Notices of the Royal Astronomical Society, which are both peer-reviewed publications. They were also featured in an article in Sky & Telescope magazine earlier this year about their research.
Objects are travelling away from us quicker as the universe expands, and the further an item is from us, the faster it is moving away from us. A moving object’s light shifts to longer redder wavelengths, similar to how the sound of a distant ambulance siren changes to a lower pitch as the vehicle moves away from it. In their quest for the most distant galaxies, the researchers sorted through almost 70,000 objects, and HD1 was the reddest galaxy they could discover.
The redshift, on the other hand, is the gold standard of cosmic distances, and it is determined by acquiring a spectrum of the object and measuring how much the wavelengths emitted by distinctive components have risen or moved to the red side of the spectrum. Dr. Harikane and his colleagues obtained a provisional redshift for HD1 of 13, which means that the wavelength of light emitted by an oxygen atom has stretched to 14 times its wavelength at rest, using the Atacama Large Millimeter/submillimeter Array, or ALMA, a cluster of radio telescopes in Chile. The redshift of the other blob has not yet been established.
That put the assumed galaxy barely 330 million years after the beginning of time, right in the hunting grounds of the Webb Space Telescope, which will also be able to corroborate the redshift calculation.
Dr. Pacucci said that at first, they assumed HD1 and HD2 were what are known as starburst galaxies, which are bursting with new stars as they spiral inward. However, following additional investigation, scientists determined that HD1 seemed to be creating stars at a rate that was more than ten times quicker than the normal rate for such galaxies.
Another theory, according to Dr. Pacucci, is that this galaxy was responsible for the creation of the first ultraluminous Population 3 stars. Alternatively, it has been suggested that all of this light is the result of material pouring into a supermassive black hole with a mass 100 million times that of the sun. However, scientists are baffled as to how a black hole could have grown to such a massive size so early in the history of the universe.
