Research published May 7 in the journal Science said that Mercury's magnetic field is 3.8 billion years old and may have once been as strong as Earth's. Data gathered by MESSENGER in 2014-2015 when the probe flew very close to Mercury's surface, at times as low as 9 miles above the planet, was used for the study.
Low-altitude magnetic field measurements by MESSENGER reveal Mercury’s ancient crustal field
We'd never have been able to measure them if not for these really risky low-altitude observations in the last few months of the MESSENGER mission… Being able to pin down how long Mercury has had a magnetic field helps us narrow down scenarios for the early history of Mercury and how it has changed over time.
– Catherine Johnson University of British Columbia planetary geophysicist and study lead author
The estimated age of the magnetic field, created by a core that's at least partially liquid, was based on the amount and strength of magnetized rocks found on Mercury's crust dotted by ancient craters.
The MESSENGER mission will continue to provide scientists with a bonanza of new results as we begin the next phase of this mission: analyzing the exciting data already in the archives, and unraveling the mysteries of Mercury.
– John Grunsfeld NASA Science Mission Directorate
MESSENGER crashed into the surface of Mercury April 30 as planned. The crash occurred on the opposite side of Mercury from Earth, and was not recorded visibly. The impact of the craft, which hit the planet at over 8,700 mph, was expected to create a 50-foot-wide crater to be studied later.
NASA's MESSENGER Mission Ends with Planetary Impact
NASA released images of Mercury March 16, considered the most detailed ever taken of the small planet. Among the images MESSENGER sent back are of the inside of some of the craters that house Mercury's ice.
For more than 20 years the jury has been deliberating on whether the planet closest to the Sun hosts abundant water ice in its permanently shadowed polar regions. [Messenger] has now supplied a unanimous affirmative verdict.
– Sean Solomon, principal investigator of the Messenger mission
The earliest reports of water on Mercury came in the form of radar imaging in 1991. More detailed images from Puerto Rico's microwave telescope bolstered the claim in 1999.
NASA: There’s enough ice on Mercury to encase Washington, D.C.
Since temperatures reach up to 800 degrees Fahrenheit, ice seems an unlikely tenant on the surface of Mercury. At the poles, however, temperatures can dip as low as -280 degrees, and scientists say that it's temperate a few feet below the surface elsewhere on Mercury.
Mercury Home to Ice, Messenger Spacecraft Findings Suggest
Scientists were surprised to find evidence of organic matter along with ice. The scans showed ice was mixed with a dark, volatile material they believe harbors organic compounds. More research is needed to confirm it. Carbon-based organic matter is required for life as we know it.