Data gathered from a spacecraft currently orbiting Mercury has provided some fascinating information about the planet's surface, composition, and activities, NASA revealed this week.
Since NASA's MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft first entered Mercury's orbit in late March, it has sent back tens of thousands of images with details about Mercury's features.
"We are assembling a global overview of the nature and workings of Mercury for the first time," MESSENGER principal investigator Sean Solomon said in a statement. "Many of our earlier ideas are being cast aside as new observations lead to new insights. Our primary mission has another three Mercury years to run, and we can expect more surprises as our solar system's innermost planet reveals its long-held secrets."
The MESSENGER spacecraft first left Earth in August 2004, and completed several flybys in the years before entering Mercury's orbit. Those flybys indicated bright, patchy deposits on some of Mercury's crater floors, but without high-definition images, scientists had no idea what they were. Images captured in recent months, however, indicate that the patchy deposits are clusters of rimless, irregular pits that can be up to several miles wide. They are surrounded by more reflective material and are found on central peaks, peak rings, and rims of craters, NASA said.
"The etched appearance of these landforms is unlike anything we've seen before on Mercury or the moon," said Brett Denevi, a staff scientist at the Johns Hopkins University Applied Physics Laboratory (APL). "We are still debating their origin, but they appear to be relatively young and may suggest a more abundant than expected volatile component in Mercury's crust."
As a result, the images indicate that Mercury's surface is "markedly" different from that of the moon. For one, there appears to be "substantial" amounts of sulfur on the planet's surface. This suggests that sulfide minerals are present, and that Mercury's original building blocks might have been less oxidized than those that formed other terrestrial planets. The high levels of sulfur might have also contributed to previous volcanic activity observed by scientists, NASA said.
Something that puzzled researchers during MESSENGER's last flyby was the absence of energetic particle bursts first seen during a 1974 flyby. In-orbit images, however, are now picking up these bursts on a regular basis.
"Data now confirm that bursts of energetic particles in Mercury's magnetosphere are a continuing product of the interaction of Mercury's magnetic field with the solar wind," NASA said.
For more, see the slideshow above.