The Juno spacecraft in orbit around Jupiter’s poles continues to send back jaw-dropping views of the giant planet’s turbulent atmosphere, including this down-the-throat look into a 2,000-kilometre-wide (1,200 miles) cyclonic storm at 49 degrees north latitude. Jupiter is composed mostly of hydrogen and helium, but some of the colour in the clouds seen here may be the result of sulphur and phosphorus gases rising from the warmer interior. Citizen-scientist Kevin M. Gill processed this image, captured by the Junocam instrument on 3 November at an altitude of about 8,500 kilometres (5,300 miles) during Juno’s 23rd close flyby.
A team of scientists has documented atmospheric changes on Io, Jupiter’s volcanically active satellite, as the giant planet casts its shadow over the moon during daily eclipses. Io’s thin atmosphere collapses as the sulfur dioxide gas emitted from volcanoes freezes when shaded by Jupiter. The atmosphere reforms when Io moves out of eclipse and the ice sublimates.
A four-planet system orbiting the star Kepler-223 in the constellation Cygnus is actually a rarity: Its planets, all miniature Neptunes nestled close to the star, are orbiting in a unique resonance that has been locked in for billions of years. For every three orbits of the outermost planet, the second orbits four times, the third six times and the innermost eight times.
In the small hours of Friday, 16 October, innermost planet Mercury reaches its greatest westerly elongation from the Sun. For those of you in the UK with a flat, unobscured eastern horizon and willing to get up an hour before sunrise, the next few days provide your best opportunity to see Mercury from the Northern Hemisphere during 2015.