Hubble is the Old Faithful of telescopes—a device so remarkably durable, it has been chugging along for over 25 years. And as the telescope hurtles further into deep space, it keeps outdoing itself. Today, NASA and the ESA announced that Hubble has seen the oldest galaxy ever spotted—and released a picture that lets people literally look back in time.
The “new” galaxy is called GN-z11, and it’s located 13.4 billion light years away. To put that in context, that means that the galaxy existed just 400 million years after the Big Bang.
Scientists calculated the distance by measuring its redshift. As objects get farther and farther away, the visible light they emit stretches out and shifts more toward the red side of the spectrum. Researchers use these changes in the light’s wavelength relative to what the light would be for a stationary source to figure out how far away the galaxy is—all based on Edwin Hubble's theory that the universe is expanding at a constant rate.
The find smashes researchers’ wildest expectations for the craft, which has been in space since 1990. “We are closing in on the first galaxies that formed in the Universe,” writes NASA in the release. It appears that the galaxy is about 25 times smaller than the Milky Way.
GN-z11 is astonishingly old, but it’s exciting for another reason: its brightness. Scientists didn’t realize that such large, starry galaxies existed so far in the past. They hope to keep studying similar galaxies both with Hubble and with the super-powered James Webb Space Telescope, which will launch in 2018.
What else will the far-flung galaxy reveal about the universe’s origins? It remains to be seen—but for now, it’s worth relishing an image that literally lets you look back in time.