NASA Scientists Detect Ice on Mercury, the Closest Planet to the Sun

NASA scientists have confirmed a vast amount of ice at the north pole on Mercury, the planet closest to the sun. The findings come from the space agency's Mercury-orbiting probe, Messenger, and the subject of three scientific papers released on Thursday by the journal Science.

The ice is located in regions of Mercury's north pole that are always in shadows, or essentially, impact craters. It is believed that the ice is at least 1 1/2 feet deep, and possibly as much as 65 feet deep. The south pole is believed to harbor ice as well, but there is not yet any hard data to support it. Messenger orbits closer to the north pole than the south.

David Lawrence of the Applied Physics Laboratory at Johns Hopkins University, one of the paper's authors, said:

"If you add it all up, you have on the order of 100 billion to 1 trillion metric tons of ice. The uncertainty on that number is just how deep it goes."

Lawrence said that there is enough polar ice on Mercury to bury an area the size of Washington D.C. by two to 2 1/2 miles deep.

Radar measurements from earth have suggested for two decades now the presence of ice at Mercury's poles. Scientists now know for sure thanks to Messenger, the first spacecraft to orbit Mercury.

It is thought that the water almost certainly came from impacting comets, or possibly asteroids. Ice is found at the surface, as well as buried under a dark material.

Messenger was launched in 2004 and went into orbit around Mercury 1 1/2 years ago. Temperatures on Mercury reach 800 degrees Fahrenheit. NASA is hoping to continue observations well into next year.