Age is nothing but a number, right?
For example, if we tell you that something is 300 million years old, your first reaction would probably be, Oh my gosh that is so old!
Which it is! 300 million years ago, the dinosaurs were still around 100 million years away. But when you start talking about the age of the universe, well, that's a whole other story!
To our best guess, the universe is about 13.77 billion years old. That's 13,770 million years. So when our universe was 300 million years old, in human terms it was basically a toddler. Barely walking, maybe able to say a few words, still a couple years away from going to school.
So you see, 300 million years old can be quite young. It all depends on your perspective!
And from this perspective, the new James Webb Space Telescope has just found a galaxy that dates back to the days of the toddler universe.
Known as GLASS-z13, this red glowing mass is estimated to be a stunning 13.4 billion years old!
A very long trip back in time
So how can astronomers tell that this galaxy is so old? Let's refresh our understanding of how light works.
Though it is the fastest thing in the universe, light still has a speed limit. For example, it takes about 8 minutes for light from the Sun to reach Earth. This means that we are always seeing the Sun as it was eight minutes ago.
For the most part, the time it takes light to travel between ourselves at the Sun is next-to-instantaneous. Not a lot changes in eight minutes. But the further into the universe that you go, the stranger things become.
In the case of GLASS-z13, it is so far away from us that we are only just now seeing what it looked like when the universe was still in diapers. Our solar system wouldn't even start existing for another 9 billion years! And it gets even weirder ...
? JWST has potentially smashed records, spotting a galaxy which existed when the universe was a mere 300 million years old! The light from GLASS-z13 took 13.4 billion years to hit us, but the distance between us is now 33 billion light years due to the expansion of the universe! pic.twitter.com/5AcOBwHuO1
— Dr. James O'Donoghue (@physicsJ) July 20, 2022
Yes, you read that right. In the time it has taken the light from GLASS-z13 to reach us, that galaxy is now almost three times farther away from us than it was. The expanding universe is pretty mind-blowing stuff!