The oldest galaxy ever spotted was born just 300 million years after the Big Bang

The Hubble telescope has spotted the oldest galaxy in the universe. It's a frenetic cauldron of hot blue stars, and it's only about 480 million years younger than the Big Bang itself.

This particularly galaxy may not be much to look at - you can see it in the bottom right corner up top, or a slightly more colorful view of it down below - but its age is simply incredible. The light that the Hubble Space Telescope detected took 13.2 billion years to reach Earth. Precise measurements indicate the light of this galaxy dates back to about 480 million years after the Big Bang, although the galaxy itself probably formed about 100 to 200 million years before that.


Technically speaking, this is really a proto-galaxy, a clump of stars that hadn't yet really organized themselves into galaxies like those of today. Astronomer Richard Bouwens explains:

"We're seeing these galaxies - 'star cities' - that are building themselves up over cosmic time. You start out with these little seeds in the very early Universe which would eventually have formed stars, then star clusters, baby galaxies then eventually these large majestic galaxies that we know today. It's very exciting to see this complicated physical process actually take place somewhere that no man has seen before.

Let's try to put this galaxy's existence in some perspective. This galaxy could have first formed about 280 million years after the Big Bang. In cosmic terms, that's absolutely nothing - our Sun will live for almost forty times as long as that. The length of time between the beginning of everything and this galaxy's formation isn't much longer than the time between right now and the earliest dinosaurs. These just aren't the kind of units of time we usually talk about when discussing cosmic events.


Just imagine what it would be like to live in that galaxy 13.2 billion years ago, to be the tiniest part of the light that we're only now observing. (Obviously, it's next to impossible that planets would have formed and life would have evolved only a couple hundred million years after the galaxy formed. But work with me here.) You'd look out on a night sky that was so fundamentally smaller than what we see today.

You could see 480 million light-years in any given direction, because light from beyond that distance hadn't yet had time to reach you. These days, that would be enough to see all of our fellow galaxies in the Virgo Supercluster, but most of the other millions of superclusters in our universe would be completely beyond our purview.


So what's next? We may soon be coming to the end of possible observable galaxies, although as our instruments get ever more sensitive and powerful there's always a chance we'll detect a still earlier light source. We won't, however, end up finding the light of the Big Bang, as we already know where that is - it's the cosmic microwave background, as was explained in this earlier post.


But for now, I think it's best just to take another look at that image and realize we're looking at the oldest thing anyone has ever seen. That's more than amazing enough for me.

[Hubble via BBC News]


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