When then-International Space Station resident and European Space Agency astronaut Alexander Gerst tweeted a surreal photo of an aurora down on Earth, he said he struggled with its caption.
1. "Words can't describe how it feels flying through an #aurora," he wrote. "I wouldn't even know where to begin..."
At the time of the tweet, Gerst had been living and working aboard the station for months. A little bit of familiarity can dull appreciation for almost anything, but he was still wonder-struck by the incredible visuals.
There's something about each of the following photos that similarly defies description. They're full of interstellar majesty that tugs at our hunter-gatherer heartstrings, making us want to build big things and explore great expanses. (And maybe just stop and stare a while in awe.)