If you’ve been following the astronomy community on Twitter, or perhaps Captain America himself, you’ve probably come across a story about the James Webb Space Telescope’s latest find: the “oldest galaxy we’ve ever seen.”
This is exactly what the James Webb Space Telescope promised us. Just a week ago, the world’s collective jaw dropped when the first stunning images were revealed. Now, the telescope is properly starting its myriad science programs, but researchers have already had access to a wealth of data collected during JWST’s commissioning phase and released soon to researchers around the world.
That’s how we ended up finding “the oldest galaxy” so quickly. The scientists examined a particular data set looking for distant galaxies and found a candidate they’ve dubbed GL-z13, a nod to the current confirmed record holder, GNz11.
There is more work to be done to confirm that GL-z13 is actually the new record, some of which will require more time to pin Webb to the galaxy, but even so, several publications have already crowned this galaxy as the universal champion.
So how did we get here? And is this the “oldest galaxy” ever seen?
In the past 24 hours, two different research groups uploaded papers (one here , the other here ) to arXiv detailing their search for very distant galaxies in the James Webb data.
The website “arXiv” (I pronounce it “ark-siv” because I’m a heathen, but others assure me it’s pronounced “archive”) is a preprint repository, a place for scientists to release studies so they can be quickly disseminated to colleagues . It’s a great place to quickly get new research in the world, especially for astronomy and astrophysics, with the caveat that findings usually haven’t been peer-reviewed, an important checkpoint for validating the study and the their methods.
Hubble and James Webb Space Telescope images compared: see the difference
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I don’t want to poop at the GL-z13’s party, but I just want to be a little cautious. By communicating the findings with such certainty, there is the potential for readers to lose faith in the scientists if GL-z13 turns out to be something else. Several astronomers I spoke to believe the data is pretty convincing and that the galaxy probably resides far (very) far away, but until there is confirmation, GL-z13 can’t claim the title of “oldest galaxy.”
And for some, even that title is a bit misleading.
You see, GL-Z13 isn’t really “the oldest galaxy ever,” but rather comes from a time when the universe was barely 330 million years old. The light of this galaxy? Well, yes, it’s super old. It has traveled a long time to get to the JWST. But the galaxy itself, if confirmed, is likely the youngest galaxy ever seen, according to Nick Seymour, an astrophysicist at Curtin University in Western Australia.
“At 330 million years after the Big Bang, it can’t be more than 100 million years old at best,” Seymour said. “So this is really a baby galaxy at the dawn of time.”
Getting excited about record-breaking space feats is a given. As a science journalist, I do this practically every day. But when reporting on new discoveries, it’s important to convey uncertainty. In the headlines, in social publications, in the way we talk about scientific progress. We need to set the right benchmark and leave ourselves in that uncertainty. The story of GL-z13 is wonderful and it is just beginning. Astronomers now have to study it much more to make sure the distances are correct.
“Obviously there’s a lot of follow-up work to do, but it’s really kind of a glimpse of where things are going with James Webb,” said Michael Brown, an astrophysicist at Monash University.
It was only in April, before Webb roamed the cosmos, that astronomers announced that they may have discovered the most distant galaxy yet, HD1. This galaxy is believed to be from a time when the universe was about 330 million years old. Brown noted at the time that it was worth being cautious about handing the title to HD1 because the data could point to a galaxy billions of light years closer to Earth. To confirm its distance, as with GL-z13, we need more observations.
Do you know which telescope could do that? You guessed it: JWST.
We’re fascinated by records being broken, but perhaps the most interesting point of all this is that if Webb works as well as expected (and it appears to be working better than even scientists dreamed), the title of “the galaxy older” will change. hands as much as the WWE Hardcore 24/7 Championship. We will be finding new galaxies from further back in time at a rate we could not dream of.
If that’s the case, I hope it won’t be too long before the record drops.
Updated July 22: Changed title, added context to older galaxy paragraph.