2015 in review: a year of spectacular planetary missions and discoveries

High-resolution view of Pluto from New Horizons, showing rugged mountains and vast icy plains. Image Credit: NASA/JHUAPL/SwRI
High-resolution view of Pluto from New Horizons, showing rugged mountains and vast icy plains. Image Credit: NASA/JHUAPL/SwRI

To say that 2015 has been a great year for planetary exploration would be an understatement, with fantastic new discoveries from around the Solar System. From our first ever close-up look at Pluto and its moons, to more evidence for ancient lakes and rivers on Mars (and current briny streams) to weird bright spots and mountains on Ceres, to the continuing study of Saturn and its moons, notably Enceladus, to spectacular close-up views of a comet, it has indeed been quite a year.

Read More2015 in review: a year of spectacular planetary missions and discoveries

New NASA planetary science proposals include Venus and ‘metallic asteroid’ missions

Artist’s conception of the VERITAS spacecraft in orbit around Venus. Image Credit: NASA/JPL-Caltech
Artist’s conception of the VERITAS spacecraft in orbit around Venus. Image Credit: NASA/JPL-Caltech

Looking ahead to future planetary missions, NASA has selected five new science investigations for refinement over the next year. Later, one or two of those missions will be chosen to actually be launched, perhaps as early as 2020. The selections are part of NASA’s Discovery Program, which had requested the proposals in November 2014. Initially, 27 proposals had been submitted, from which the five current finalists were chosen. The five proposals would study Venus, near-Earth objects, an unusual metallic asteroid and Trojan asteroids.

Read MoreNew NASA planetary science proposals include Venus and ‘metallic asteroid’ missions

Just add water: scientists explain Saturn’s powerful thunderstorms

A giant storm in Saturn’s northern hemisphere, which now extends around the planet, as seen by the Cassini spacecraft. Photo Credit: NASA/JPL-Caltech
A giant storm in Saturn’s northern hemisphere, which now extends around the planet, as seen by the Cassini spacecraft. Photo Credit: NASA/JPL-Caltech

Thunderstorms are a powerful force of nature, but the ones we experience on Earth are dwarfed by the ones on the gas giant planet Saturn. They are huge and can be larger than Earth itself, and now scientists think they know why they tend to appear most prominently every 20-30 years, encircling the entire planet with intense lightning and massive cloud disturbances.

Read MoreJust add water: scientists explain Saturn’s powerful thunderstorms