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New Horizons: Nasa releases historic Pluto close-up images New Horizons: Nasa releases historic Pluto close-up images
(35 minutes later)
Nasa is presenting the first images acquired by the New Horizons probe during its historic flyby of Pluto. Nasa has presented the first images acquired by the New Horizons probe during its historic flyby of Pluto.
Chief scientist Alan Stern said the new images showed evidence of geological activity and mountains in the Pluto system.Chief scientist Alan Stern said the new images showed evidence of geological activity and mountains in the Pluto system.
The team has also named the prominent heart-shaped region on Pluto after the world's discoverer Clyde Tombaugh.
The spacecraft sped past the dwarf planet on Tuesday, grabbing a huge volume of data.The spacecraft sped past the dwarf planet on Tuesday, grabbing a huge volume of data.
In an initial communication, it confirmed that the pass took place without incident. Mission scientist John Spencer told journalists that one image of Pluto's surface showed a terrain that had been resurfaced by some geological process - such as volcanism - in the last 100 million years.
"We have not found a single impact crater on this image. This means it must be a very young surface," he said.
This active geology needs some source of heat. This has only been seen on icy moons, where it can be explained by "tidal heating" caused by gravitational interactions with the host planet.
"You do not need tidal heating to power geological heating on icy bodies. That's a really important discovery we just made this morning," said Dr Spencer.
This same image shows mountains at the edge of the heart-like region that are up to 11,000ft high and which team members compared to North America's Rocky Mountains.
John Spencer said the methane and nitrogen ice that coats Pluto's surface were not strong enough to form mountains, so they were probably composed of Pluto's water-ice bedrock.
The pictures were sent back to Earth during the course of two data downlinks on Wednesday.The pictures were sent back to Earth during the course of two data downlinks on Wednesday.
The cache is expected to include more shots of Pluto and its main moon, Charon. Scientists have named the heart-shaped region Tombaugh Regio, after the astronomer who discovered Pluto in 1930.
Some new views of two of the minor moons, Hydra and Nix are also expected.
The American space agency scheduled a media briefing at 19:00 GMT (20:00 BST) to release the material publicly.
Significantly, all these images are at a much higher resolution than anything we have seen so far.Significantly, all these images are at a much higher resolution than anything we have seen so far.
The mission team has told New Horizons this week to send down only a small fraction of the total data it carries.The mission team has told New Horizons this week to send down only a small fraction of the total data it carries.
Part of the reason is that the probe continues to do science, observing Pluto from its night side.Part of the reason is that the probe continues to do science, observing Pluto from its night side.
The intention is to keep looking at it for about two more full rotations, or 12 Earth days.The intention is to keep looking at it for about two more full rotations, or 12 Earth days.
'New things every day'
Scientists say a crescent view of the dwarf planet is more likely to reveal the presence of clouds and hazes.
Turning the cameras to look past Pluto in the direction of the Sun also offers the best chance of detecting any faint ring system that might exist around it.
"This is all so special," Dr Cathy Olkin, a deputy project scientist on the mission, told the BBC.
"All of this is new. We're learning new things every day.
"Every time the spacecraft communicates with the deep-space network and sends its data down - we learn something new.
"It's just remarkable to me that all this data is sitting on the spacecraft, just waiting for us to unlock its secrets."
Team-members confess to being just a bit giddy as they marvel at what they are learning about Pluto.
For researchers working on New Horizons' Ralph colour camera, Tuesday was particularly significant.
They lost data 10 days ago when the probe had a technical upset. This meant that the final information they got from Ralph just before the flyby came with a sudden jump in quality.
And when they stretched the colours in their images of Pluto and Charon, they were able to see surface differences that had previously gone undetected.
"We got smacked in the face big time, and it was thoroughly enjoyable," said Dr Carly Howett from the Southwest Research Institute.
"Because we missed that intermediate step, we went from having only six pixels across to all of a sudden seeing surface features in the colour," Dr Howett said.
"We were as giddy as kites looking at the data."
New Horizons has been called the mission of "delayed gratification", because of the length of the journey to get to Pluto and the time it will take to downlink all its data.
The vast distance to the dwarf, combined with the modest power of the probe's transmitter, means the transmission bit rates are extremely slow.
The team will first command the data to come down in a compressed form, and then in an uncompressed form. This whole process will not be compete for 16 months.