Warning: Creating default object from empty value in /homepages/14/d426594527/htdocs/wp-content/themes/editorial/functions/admin-hooks.php on line 160

N ew images taken during an October fly-by of Mercury reveal the Solar System’s innermost planet experienced widespread volcanic eruptions – a far more dynamic past than previously thought.

Data transmitted from NASA’s MESSENGER spacecraft show that about 40 percent of the planet is covered by smooth plains, and the majority of that surface is likely volcanic in origin, said Brett Denevi, a postdoctoral research associate in the School of Earth and Space Exploration at Arizona State University.

Denevi is the lead author of a paper in Science that analyzes high-resolution and multi-spectral images of Mercury. The researchers determined that volcanic activity was widespread across the entire planet and that a significant portion of Mercury’s crust was formed by volcanic eruptions.

Key to that conclusion is the fact that this new understanding of Mercury sets it apart from the Earth’s moon, which the limited information available prior to MESSENGER suggested Mercury resembled.

“We might not have the same kind of crust as there is no the moon, which is what people have been thinking,” Denevi said.

The October 6 flyby of Mercury by MESSENGER – formally the MErcury Surface, Space ENvironment, GEochemistry, and Ranging spacecraft – was the second of three close passes made by the probe before it settles into orbit around Mercury.

The only previous spacecraft sent to study Mercury was Mariner 10, which conducted three flybys in 1974 and 1975, and returned limited data and was only able to observe one hemisphere. The MESSENGER camera has nearly 100 times the resolution of the Mariner 10 imaging.

“We didn’t really have very much know about Mercury until just a year and a half ago,” Denevi said. “Now that we’ve seen about 90 percent of the planet, we can start to look at the bigger picture and what sort of processes helped to form it’s crust.”

Using data from MESSENGER’s two cameras – a high resolution one and second, wide-angle camera that captures 11 wavelengths of light – Denevi distinguished three major terrain types: smooth plains, intermediate terrain and low-reflectance material.

The smooth plains are the key for Denevi’s research. The Moon is about 16 percent covered by the similar volcanic plains. Mercury’s 40 percent coverage indicates a far more dynamic past.

“There’s great evidence that many of them are of volcanic origin and those cover a very large percentage of the planet’s surface,” she said. “Mercury is revealing its secrets slowly. Of the terrestrial planets, it might have a different past, and that would provide another model.”

The new revelations about Mercury’s early geologic history could give scientists new insights into the formation of the Earth’s crust.

“For Earth, we don’t have a good record of the very early history,” Denevi said. “On earth, everything is getting recycled by plate tectonics and erosion. There’s not much evidence about what the very first crust of the earth was like. Now we have perhaps another model in Mercury.”

Despite the startling new insights into Mercury, this flyby data is just a trickle compared to the flood of data awaiting scientists studying the planet.

“These flybys are just a snap shot. So we’re seeing whatever terrain happens to be illuminated at that time,” Denevi said. “For the next flyby we can really point the cameras at the most interesting areas and get the best data.”

Once MESSENGER settles into orbit around Mercury in 2011, the data streaming every day will be equal to twice what the flybys were able to gather. Also, the spacecraft’s various spectrometers are not well suited to a flyby.

“Even now that we have all this new data, it’s so exciting, but that just leads to new questions,” Denevi said. “I think Mercury will definitely have its own distinct past.”

Published June 30, 3009 in Tech News Arizona.

Tags: , , ,

Eric Swedlund is a writer, photographer and editor living in Tucson, Arizona. His music writing has appeared regularly in the Tucson Weekly, Phoenix New Times, East Bay Express, The Rumpus and Souciant Magazine.

No comments yet.

Leave a Reply

You must be logged in to post a comment.