NASA finds signs of an old frozen lake on Pluto

NASA has released an image of what was likely a lake long, long ago in Pluto's past. The image shows a frozen, somewhat random smooth patch on an otherwise rocky landscape, one that looks very similar to a lake or pond surrounded by hills and mountains. The image was taken by the space agency's New Horizons spacecraft, which also found evidence of possible past liquid channels that flowed across the planet's surface.

NASA released the image last week, and described a possible past where "millions or billions of years ago" liquid flowed on the icy planet's surface. This would have been made possible thanks to a combination of the then-warmer surface temperatures combined with Pluto's high-pressure atmosphere.

The image above shows what this suspected lake looked like — of course, there's no flowing liquid on the planet now. Says NASA, the lake shown above would have been composed of liquid nitrogen, and it is found within the so-called Sputnik Planum, the 'heart' visible in distant shots of the planet. The photo was taken in July of last year using the Long Range Reconnaissance Imager, also known as LORRI instruction.

Said New Horizons principal investigator Alan Stern: "In addition to this possible former lake, we also see evidence of channels that may also have carried liquids in Pluto's past." Details on those channels weren't provided, however NASA says the lake above is about 430 feet long and about 20 miles at its widest point.