The cosmic time machine: how the James Webb Space Telescope allowed us to see the universe's first galaxies
It’s been an exciting week with the release of amazing photos of our Universe by the James Webb Space Telescope (JWST). Images like the one below give us the opportunity to see distant, faint galaxies as they did more than 13 billion years ago. The field image in SMACS 0723 was taken with just a 12.5 hour exposure. The faint galaxy in this image emitted this light more than 13 billion years ago. NASA, ESA, CSA and STScI This is a great time to step back and appreciate our first class ticket to the depths of the Universe and how these images allow us to look back in time. These images also raise an interesting point about how the expansion of the Universe factors into the way we calculate distances on a cosmological scale. Modern time travel Looking back in time may sound like a strange concept, but that’s what space researchers do every day. Our Universe is bound by the rules of physics, with one of the best known “rules” being the speed of lig