New Horizons: Live Briefing

Having survived yesterday’s fly-by, follow the live-briefing from the Nasa New Horizons mission to Pluto as they reveal the first hi-resolution images from the dwarf planet system nearly 5 billion km away.

Adds The big news is that Pluto, and Charon, may still be geologically active.

There are 3,500metre (11,000feet) high water-ice mountains on the surface of Pluto in a region now called Tombaugh Regio after Pluto’s discoverer, Clyde Tombaugh – some of his ashes are on-board the New Horizons spacecraft. It’s a geologically young surface with no craters.

The icy mountains of Pluto [Image credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute]

New Horizons Pluto surface detail

From the New Horizons New Horizons press release.

The mountains on Pluto likely formed no more than 100 million years ago — mere youngsters in a 4.56-billion-year-old solar system. This suggests the close-up region, which covers about one percent of Pluto’s surface, may still be geologically active today.

“This is one of the youngest surfaces we’ve ever seen in the solar system,” said Jeff Moore of the New Horizons Geology, Geophysics and Imaging Team (GGI) at NASA’s Ames Research Center in Moffett Field, California.

Unlike the icy moons of giant planets, Pluto cannot be heated by gravitational interactions with a much larger planetary body. Some other process must be generating the mountainous landscape.

“This may cause us to rethink what powers geological activity on many other icy worlds,” says GGI deputy team leader John Spencer, SwRI.

The new view of Charon reveals a youthful and varied terrain. Scientists are surprised by the apparent lack of craters. A swath of cliffs and troughs stretching about 600 miles (1,000 kilometers) suggests widespread fracturing of Charon’s crust, likely the result of internal geological processes. The image also shows a canyon estimated to be 4 to 6 miles (7 to 9 kilometers) deep. In Charon’s north polar region, the dark surface markings have a diffuse boundary, suggesting a thin deposit or stain on the surface.

The new view of Charon [Image credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute]

New Horizons Charon

From the BBC’s spaceman Jonathan Amos on their live-blog

Any analysis at this stage still carries a fair bit of speculation because not all of the complementary data is in. But perhaps the biggest news is the suggestion that some of these bodies are still active, that they are not dull objects that died 4.5 billion years ago.

In the highest resolution image of Pluto, which showed a field of view just 250km across, there were no craters. This is indicative of a young surface, one that may well have experienced recent geological activity.

Now, we’ve seen this kind of thing on moons of giant planets where gravitational tides from the bigger parent can heat up the satellite and deform it. Think of Europa at Jupiter; think of Enceladus at Saturn. But where do you get the heat to drive activity on Pluto? It’s sitting out on its own in the Kuiper Belt with nothing to squeeze it gravitationally. Charon certainly couldn’t do it; it’s too small.

So, what this tells us is that you do not need ongoing tidal heating to power geology on icy worlds. In science terms that’s certainly a big wow.

And, also via the BBC live-blog