NASA astronaut Daniel Burbank, the commander of the International Space Station, saw what he described as a “green glowing arc” rising above the earth’s horizon on Wednesday night. What he caught sight of some 240 miles above Tasmania was actually Comet Lovejoy, a "sungrazer" (a comet on a path that takes it near the sun) recently discovered by amateur astronomer, Terry Lovejoy. Burbank was in awe of the sighting, which you can see in a video below; he called it “the most amazing thing I’ve ever seen in space.”