The distant ice giant Uranus may not have been visited by a spacecraft since Voyager 2’s “Grand Tour” flyby in 1986 but the data gathered then is still being used today to make new discoveries. Most recently, researchers think they have found evidence of two previously unknown moons around Uranus, potentially bringing the planet’s count up to 29.
Rosetta is down. I repeat: Rosetta is down.
This morning, Sept. 30, 2016, just after 10:39 UTC (6:39 a.m. EDT) ESA’s Rosetta spacecraft ended its mission with an impact onto the surface of the comet 67P/Churyumov-Gerasimenko. The descent, begun with a final burn of its thrusters about 14 hours earlier, was slow, stately, and deliberate, but even at a relative walking pace Rosetta was not designed to be a lander like its partner Philae and thus ceased operation upon contact with the comet.
With the comet 446 million miles (719 million km) from Earth at the time, the final signals from Rosetta were received 40 minutes after impact, officially confirming mission end.
Round and round they go… the animation above, made from 14 raw images taken by NASA’s Cassini spacecraft on August 23, 2016, shows the moons Prometheus and Atlas orbiting Saturn within the Roche Division gap between its A (top right) and F (center) rings. The gravitational tug of Prometheus (92 miles / 148 km long) is strong enough to pull on the fine, smoke-like icy particles of the F ring, creating streamer and “clump” features that follow it along.
The much smaller Atlas (23 miles / 37 km wide) follows a path around Saturn just past the outer edge of the A ring. It was once thought to be a “shepherd moon” of the A ring, but it’s now known that the pull of the more distant Janus and Epimetheus are responsible for that.
Atlas does have its very own ring, though—a very faint (i.e., not visible above) band of material that runs along its orbit named R/2004 S 1, discovered by the Cassini mission in July 2004.
Image credit: NASA/JPL-Caltech/SSI. Animation by Jason Major.