Enceladus’ Cometary Plumes

Enceladus' blue jets.
Enceladus' blue jets.

Today the Cassini spacecraft is due to swoop over the south pole of Enceladus, one of the inner moons of Saturn, at a height of 50 km (30 miles), sampling its celebrated south polar plumes. The analyzers will “sniff and taste” the plume. Information on the density, size, composition and speed of the gas and…


More on Mercury’s Mysteries

Mercury in colour
Mercury in colour

“[Those] who have an excessive faith in their theories or in their ideas are not only poorly disposed to make discoveries, but they also make very poor observations.” —Claude Bernard (1813-78) French physiologist, 1865. MESSENGER flew 200 kilometres above Mercury’s surface on 14 January at a speed of 6 kilometres per second relative to the…