On July 29, with ESA’s Rosetta spacecraft in orbital tow, the 2.5-mile 4-kilometer -long Comet 67P/Churyumov-Gerasimenko fired its brightest jet yet since Rosetta’s arrival just over a full year ago, on Aug. 6, 2014.

via Rosetta’s Comet Fires its Most Spectacular Jet Yet : Discovery News.