Thirty-three years after NASA got the first clear pictures of the surface of the planet Mercury, the Messenger spacecraft has transmitted surprising information and images of a mysterious formation that no one can yet explain.
From 125 miles up, Messenger sent home pictures of an enormous formation that NASA scientists have dubbed “The Spider.” It’s a 26- mile-wide crater with more than 50 steep-sided, flat-bottomed valleys radiating out from it.
What created it and the relationship between the crater and the troughs is unknown. Did the crater come first and the troughs afterward? Is it the result of volcanic activity or the movement of dust? Scientists have not been able to even hazard a guess.
“It’s not entirely clear what created them,” says Louise Prockter, an instrument scientist at Johns Hopkins University’s Applied Physics Laboratory who worked on the Mercury imaging system. “It was a real mystery and a very unexpected find.”
Says Sean Solomon, Messenger’s principal investigator and director of the Department of Terrestrial Magnetism at the Carnegie Institution in Washington, D.C.: “The spider feature is unlike anything we’ve ever seen anywhere in the solar system.”
NASA’s Messenger spacecraft traveled 2.2 billion miles, taking 3 1/2 years, to get to Mercury. It flew by the solar system’s innermost planet on Jan. 14.
Messenger’s instruments collected more than 1,200 images as it whizzed by. It’s the first time scientists have gotten a clear look at the surface since Mariner 10 flew over the planet on March 16, 1975.
Another conundrum is that Mercury appears to be the only other inner planet besides Earth to have a strong magnetic field — a north and south pole, Solomon says.
Messenger confirmed readings taken by the Mariner 10. But astronomers are puzzled. The Earth’s magnetic field is created by spinning molten metal at its core. Mercury is the solar system’s smallest…
Tags: information, Space
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