The Earth is a mind-boggling 93 million miles from the sun. It takes sunlight, on average, some 8 minutes 20 seconds to reach us. Pluto, the recently demoted planetoid, is more than 39 times further away, and its take sunlight 5.5 hours to get there. The inverse square law says that the amount of light reaching a place diminishes as the square of the distance; that means that light reaching Pluto has only 0.06% of the warmth and illumination it has on Earth. Basically, the sunny side of Pluto is as dark as a cave.
Now imagine trying to take photographs of Pluto from orbit. It’s not like you can use a flash. Which makes these NASA images absolutely extraordinary.
NASA reports the craters are impact craters. That implies the chunky nitrogen ice formations, which appear quite new, are in fact old. The photos suggest that at some point Pluto’s surface was a liquid,likely a mix of liquid nitrogen,methane and carbon monoxide. The current temperature there is near absolute zero. How, at some point in Pluto’s history, it could have been warm enough for methane to be a liquid is unknown.
False color images give a different view of the data. The colors don’t occur in nature; they are added by NASA to improve viewers’ understanding. WC hasn’t heard a credible explanation of what could have created the contrasting ice formations shown in this photo.
To WC, this looks a lot like parts of the Oregon coast, where plate tectonics, coastal erosion and sand dunes create this kind of effect. You have to wonder what in the solar system created it here.
What’s cool – sorry – about this shot is that it also shows Pluto’s attenuated atmosphere and the banding of layers of suspended ice crystals. Granted it’s about as thin as atmosphere can be and make any claim to the word, but at -229° Celsius (44 degrees Kelvin above absolute zero) it stunning that the minor planet has an atmosphere at all.
Like any good space probe, New Horizons not only answers some questions – what does Pluto look like? How many moons? – but raised dozens of new ones. They aren’t likely to be answered anytime soon; it’s a time-consuming and expensive process to send anything there. But here’s to the mch maligned National Aeronautics and Space Administration, who brought off another excellent mission.