NASA Finds Mercury Has Liquid Metal Core, Magnetic Field

The final hurrah for NASA’s MESSENGER probe has made scientists reconsider what they know about Mercury. The probe recently reached the end of its life by crashing into the surface of the closest planet to the sun, but not before sending back a last set of mind-boggling data.

NASA Finds Mercury Has Liquid Metal Core, Magnetic Field
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Scientists knowledge of Mercury vastly improved by MESSENGER

Since it began orbiting Mercury in 2011, MESSENGER sent back reams of data which greatly improved our knowledge of Mercury, which had previously only been visited by NASA’s Mariner 10 probe around 40 years ago. Over the course of its life, MESSENGER beamed information back to Earth before reaching the end of the line on April 30.

The Mariner 10 probe found that Mercury possessed a magnetic field 100 times weaker than that of the Earth, but of a similar type. The field is generated by liquid metal moving around the planet’s core, as is the case on Earth. Scientists did not think that Mercury was large enough to contain a significant quantity of metal, and thought that any metal that was present would have cooled quickly.

The discovery means that scientists now have to reassess their theories on the evolution of Mercury, which is the only rocky planet in our solar system, apart from Earth, to possess such a magnetic field.

MESSENGER vastly exceeds expectations

MESSENGER was launched in 2004, and orbited Mercury for 4 years following its arrival. The mission was only expected to last for a year, and scientists were surprised by both the longevity of the mission and the data that it sent back.

“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,” said study lead author Catherine Johnson, a planetary geophysicist at the University of British Columbia in Vancouver. “This in turn helps us understand more about planetary evolution in general.”

The paper was published online on May 7 by the journal Science.