NASA’s New Horizons spacecraft spied extensional faults on Pluto, a sign that the dwarf planet has undergone a global expansion possibly due to the slow freezing of a sub-surface ocean. A new analysis by Brown University scientists bolsters that idea, and suggests that ocean is likely still there today.
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.
NASA’s New Horizons spacecraft took this stunning image mere minutes after closest approach on 14 July 2015. Seen here, sunlight filters through and illuminates Pluto’s complex atmospheric haze layers over portions of the nitrogen ice plains informally named Sputnik Planum, as well as mountains of the informally named Norgay Montes.
Far in the dwarf planet’s western hemisphere, scientists on NASA’s New Horizons mission have discovered what looks like a giant “bite mark” on Pluto’s surface. They suspect that the methane ice-rich surface on Pluto may be sublimating away into the atmosphere, exposing a layer of water-ice underneath.
This ethereal scene captured by NASA’s New Horizons spacecraft tells yet another story of Pluto’s diversity of geological and compositional features — this time in an enhanced colour image of the north polar area. A canyon about 45 miles wide runs close to the north pole, its degraded walls suggesting evidence for an ancient period of tectonics.
This image from NASA’s New Horizons spacecraft focuses on a section of the informally named Serenity Chasma, part of a vast equatorial belt of chasms on Pluto’s largest moon, Charon. Scientists believe that Charon’s subsurface water-ice layer may have been partially liquid in its early history, and has since refrozen, expanded and pushed the surface outward, producing the massive chasms we see today.
To help mission scientists understand the diversity of Pluto’s terrain and to piece together how the dwarf planet’s surface has formed and evolved over time, NASA’s New Horizons mission scientists have started constructing geological maps. The base map for this interpretation is a mosaic of 12 images obtained by the spacecraft’s Long Range Reconnaissance Imager (LORRI).
The nitrogen ice glaciers on Pluto appear to carry an intriguing cargo: numerous, isolated hills that may be fragments of water ice from Pluto’s surrounding uplands. Since water ice is less dense than nitrogen-dominated ice, scientists believe these water ice hills are floating in a sea of frozen nitrogen and move over time like icebergs in Earth’s Arctic Ocean.
Scientists with NASA’s New Horizons mission have assembled this highest-resolution colour view of Wright Mons, one of two potential cryovolcanoes spotted on the surface of Pluto by the New Horizons spacecraft in July 2015. The feature is 90 miles across and 2.5 miles high, which would make the largest volcano in the outer solar system.