National Aeronautics and Space Administration Logo
Follow this link to skip to the main content NASA Banner
Solar System Exploration
News & Events
NASA Spacecraft Confirms Theories, Sees Surprises at Mercury
NASA Spacecraft Confirms Theories, Sees Surprises at Mercury
16 Jun 2011
(Source: NASA/JHUAPL)

Targeted color imaging: Degas crater.
Targeted color imaging -- Degas crater. This spectacular view of the crater Degas was obtained as a high-resolution targeted observation (90 m/pixel). Impact melt coats its floor, and as the melt cooled and shrank, it formed the cracks observed across the crater. For context, Mariner 10's view of Degas is shown at left. Degas is 52 km in diameter and is centered at 37.1 degrees N, 232.8 degrees E. Image Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington

WASHINGTON -- NASA scientists are making new discoveries about the planet Mercury. Data from MESSENGER, the first spacecraft to orbit Mercury, is giving scientists important clues to the origin of the planet and its geological history and helping them better understand its dynamic interior and exterior processes.

NASA's MErcury Surface, Space ENvironment, GEochemistry, and Ranging spacecraft, or MESSENGER, has been orbiting Mercury since March 18. To date the spacecraft has provided tens of thousands of images showing detailed planetary features. The planet's surface previously had been seen only at comparatively low resolution but is now in sharper focus.

The spacecraft also has collected extensive measurements of the chemical composition of Mercury's surface and topography and gathered global observations of the planet's magnetic field. 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.

"We are assembling a global overview of the nature and workings of Mercury for the first time," said MESSENGER principal investigator Sean Solomon of the Carnegie Institution of Washington. "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."

Flyby images of Mercury had detected bright, patchy deposits on some crater floors. Without high-resolution images to obtain a closer look, these features remained only a curiosity. Now new detailed images have revealed these patchy deposits to be clusters of rimless, irregular pits varying in size from several hundred feet to a few miles wide. These pits are often surrounded by diffuse halos of more reflective material and are found on central peaks, peak rings, and rims of craters.

"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) in Laurel, Md., and a member of the MESSENGER imaging team. "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."

One of two instruments on the spacecraft designed to measure the quantity of key chemical elements on Mercury has made several important discoveries since the orbital mission began. Elemental ratios averaged over large areas of the planet's surface show that Mercury's surface differs markedly in composition from that of the moon.

Observations have revealed substantial amounts of sulfur at Mercury's surface, lending support to prior suggestions from ground-based telescopic observations that sulfide minerals are present. This discovery suggests that the original building blocks from which Mercury formed may have been less oxidized than those that formed the other terrestrial planets. The result also hints that sulfur-containing gases may have contributed to past explosive volcanic activity on Mercury.

Topography data of Mercury's northern hemisphere reveal the planet's large-scale shape and profiles of geological features in high detail. The north polar region is a broad area of low elevations, whereas the overall range in topographic heights seen to date exceeds 5 miles (9 kilometers).

Two decades ago, Earth-based radar images showed deposits thought to consist of water ice and perhaps other ices near Mercury's north and south poles. These deposits are preserved on the cold, permanently shadowed floors of high-latitude impact craters. MESSENGER is testing this idea by measuring the floor depths of craters near Mercury's north pole. The craters hosting polar deposits appear to be deep enough to be consistent with the idea that those deposits are in permanently shadowed areas.

During the first of three Mercury flybys in1974, Mariner 10 discovered bursts of energetic particles in the planet's Earth-like magnetosphere. Four bursts of particles were observed on that flyby. Scientists were puzzled that no such strong events were detected by MESSENGER during any of its three flybys of the planet in 2008 and 2009. But now that the spacecraft is in near-polar orbit around Mercury, energetic events are being seen regularly.

The spacecraft was designed and built by APL. The lab manages and operates the mission for NASA's Science Mission Directorate (SMD) in Washington. The mission is part of NASA's Discovery Program, managed for SMD by the agency's Marshall Space Flight Center in Huntsville, Ala.

For more information about the mission, visit: http://www.nasa.gov/messenger


Dwayne Brown
Headquarters, Washington
202-358-1726
dwayne.c.brown@nasa.gov

Paulette Campbell
Johns Hopkins University Applied Physics Laboratory, Laurel, Md.
240-228-6792
paulette.campbell@jhuapl.edu

RELEASE : 11-186

News Archive Search  Go!
Show  results per page
 
 
Awards and Recognition   Solar System Exploration Roadmap   Contact Us   Site Map   Print This Page
NASA Official: Kristen Erickson
Advisory: Dr. James Green, Director of Planetary Science
Outreach Manager: Alice Wessen
Curator/Editor: Phil Davis
Science Writer: Autumn Burdick
Producer: Greg Baerg
Webmaster: David Martin
> NASA Science Mission Directorate
> Budgets, Strategic Plans and Accountability Reports
> Equal Employment Opportunity Data
   Posted Pursuant to the No Fear Act
> Information-Dissemination Policies and Inventories
> Freedom of Information Act
> Privacy Policy & Important Notices
> Inspector General Hotline
> Office of the Inspector General
> NASA Communications Policy
> USA.gov
> ExpectMore.gov
> NASA Advisory Council
> Open Government at NASA
Last Updated: 16 Jun 2011