Psychedelic Pluto

A team of astronomers has measured the passing of a super-Earth in front of a bright, nearby Sun-like star using a ground-based telescope for the first time. Exoplanet 55 Cancri e, some 40 light-years away, is about twice as big and eight times as massive as the Earth.

The latest spectra from New Horizons Ralph instrument reveal an abundance of methane ice, but with striking differences from place to place across the frozen surface of Pluto. Methane ice in the dwarf planet’s north polar cap is diluted in a thick, transparent slab of nitrogen ice.

What is the origin of the large heart-shaped nitrogen glacier on Pluto revealed by NASA’s New Horizons spacecraft in 2015? Two French researchers show that Pluto’s peculiar insolation and atmosphere favour nitrogen condensation near the equator, in the lower altitude regions, leading to an accumulation of ice at the bottom of Sputnik Planum, a vast topographic basin.