Molecular oxygen has been spotted beyond the Milky Way for the first time
For the first time, astronomers have found molecular oxygen — the same gas humans need to breathe — in a galaxy outside the Milky Way. Oxygen is the third most common element in the cosmos, after hydrogen and helium. So astronomers once thought molecular oxygen, O2, would be common in the space between the stars. But despite repeated searches, no one had ever seen molecular oxygen beyond our galaxy — until now. Junzhi Wang, an astronomer at Shanghai Astronomical Observatory in China, and his colleagues spotted the molecule’s calling card in a galaxy named Markarian 231. Lying 560 million light-years away in the constellation Ursa Major, Markarian 231 is the nearest galaxy to Earth that contains a quasar, where gas whirls around a supermassive black hole and gets so hot that it glows brilliantly. (SN: 8/31/15). Using radio telescopes in Spain and France, the astronomers saw radiation at a wavelength of 2.52 millimeters, a signature of O2’s presence, the team reports in the Feb....