Scientists believe Pluto could have a polar ice cap, after analysing the first images received from the New Horizons spacecraft.
Although the dwarf planet appears as little much more than a pixelated blob, astronomers are excited by differences in light observed on the surface of the icy planet.
"They may just be blurry dots, but they are blurry dots of an unprecedented sort," says the Washington Post.
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The variations could be attributed to geology or changes in topography, but that seems unlikely. "It's rare to see any planet in the Solar System at this low resolution display such strong surface markings," principal investigator Alan Stern told the BBC.
New Horizons left earth nine years ago and has since crossed five billion kilometres of space to capture the first ever close-up images of Pluto. It is the fastest spacecraft ever launched, travelling further than any space mission in history.
"New Horizons is one of the great explorations of our time," says the project's Hal Weaver. "There's so much we don't know, not just about Pluto, but other worlds like it. We're not rewriting textbooks with this historic mission – we'll be writing them from scratch."
With just 97 million kilometres left to travel, it is expected to make its historic encounter on July 14, collecting images that are likely to revolutionise scientists' understanding of Pluto.
"This is just an appetite whetter," says Stern. "We're over 98 percent of the way through the journey, and we’re very excited to be on Pluto’s doorstep. The images are only going to get better and better from here on out."
His team will post daily images online, to the delight of space fans around the world. "We hope you can share in the excitement," said Hal Weaver, from Johns Hopkins University.
"By the time we get to the closest approach to Pluto, it's going to blow us all away."
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