Image credits: NASA/JHUAPL/SwRI.NASA’s New Horizons spacecraft spied several features on Pluto that offer evidence of a time millions or billions of years ago when — thanks to much higher pressure in Pluto’s atmosphere and warmer conditions on the surface — liquids might have flowed across and pooled on the surface of the distant world. “In addition to this possible former lake, we also see evidence of channels that may also have carried liquids in Pluto’s past,” said Alan Stern, Southwest Research Institute, Boulder, Colorado—principal investigator of New Horizons and lead author of the scientific paper.
This feature appears to be a frozen, former lake of liquid nitrogen, located in a mountain range just north of Pluto’s informally named Sputnik Planum. Captured by the New Horizons’ Long Range Reconnaissance Imager (LORRI) as the spacecraft flew past Pluto on 14 July 2015, the image shows details as small as about 430 feet (130 metres). At its widest point the possible lake appears to be about 20 miles (30 kilometres) across.
In the latter part of June, Pluto is best seen low in the southern UK sky around 2am local time and reaches opposition on 7 July. The dwarf planet passes less than 1/20th of a degree south of naked-eye star pi (π) Sagittarii on 26—27 June in the deep twilight of the UK, but Southern Hemisphere observers will have the best views.
Juno’s visible camera had a bird’s-eye view of Jupiter’s four largest moons over the last few weeks, recording the satellites in their orbital ballet around the giant planet as the spacecraft approached from above Jupiter’s north pole.
A new close-up image of Pluto from New Horizons reveals a vast, craterless plain that appears to be no more than 100 million years old. This frozen region is north of Pluto’s icy mountains, in the centre-left of the heart feature, informally named “Tombaugh Regio” (Tombaugh Region) after Clyde Tombaugh, who discovered Pluto in 1930.