EarthSky News - March 12 - Mystery Craters Explained (Again!)

March 12 Mystery Craters Explained (Again!) New explanation for Siberia's mystery craters This was the weirdest story of last year, now with a new and less scary explanation! Night launch MMS spacecraft tonight A stack of four identical spacecraft will study magnetic reconnection - when magnetic fields connect and disconnect explosively, accelerating particles up to nearly the speed of light. Earth-directed solar X-flare yesterday First X-flare of 2015.  It caused a brief radio blackout at some frequencies. Possible aurora alert ahead. This dog can smell cancer Meet Frankie, a German shepherd mix. He can sniff out thyroid cancer in patients’ urine samples with 88% accuracy ... Visit the EarthSky store Help support EarthSky, and get tips and tools for astronomy. Bright star Arcturus is a harbinger of spring Arcturus, the brightest star in the constellation Bootes the Herdsman, rises in the east around mid-evening in early March. TODAY'S IMAGE Rare straight lightning over Zimbabwe Captured by Peter Lowenstein.