By simulating the removal of craters left on the lunar surface by asteroid impacts, astronomers peered over 4 billion years back in time.
Earth’s highest, coldest, rarest clouds are back. How to see the eerie ‘noctilucent clouds’ this summer.
Look North as the stars appear in June and July to have a chance of seeing rare noctilucent (or ‘night-shining’) clouds with the naked eye.