The uncertainty of science: Using the spectroscopic instrument on the Webb Space Telescope, scientists have confirmed that one of the first galaxies found by Webb, dubbed Maisie’s Galaxy after the daughter of one scientist, is one of the earliest known in the universe, existing only 390 million years after when cosmologies say the Big Bang happened.
The data also showed that another one of these early galaxies spotted by Webb did not exist 250 million years after the Big Bang, but one billion years after, a date that better fits the theories about the early universe, based on the nature of this galaxy.
It turns out that hot gas in CEERS-93316 was emitting so much light in a few narrow frequency bands associated with oxygen and hydrogen that it made the galaxy appear much bluer than it really was. That blue cast mimicked the signature Finkelstein and others expected to see in very early galaxies. This is due to a quirk of the photometric method that happens only for objects with redshifts of about 4.9. Finkelstein says this was a case of bad luck. “This was a kind of weird case,” Finkelstein said. “Of the many tens of high redshift candidates that have been observed spectroscopically, this is the only instance of the true redshift being much less than our initial guess.”
Not only does this galaxy appear unnaturally blue, it also is much brighter than our current models predict for galaxies that formed so early in the universe. “It would have been really challenging to explain how the universe could create such a massive galaxy so soon,” Finkelstein said. “So, I think this was probably always the most likely outcome, because it was so extreme, so bright, at such an apparent high redshift.”
This science team is presently using Webb’s spectroscope to study ten early galaxies in order to better determine their age. Expect more results momentarily.