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Mercury Shrinking Faster Than We Thought, New Analysis Shows
Confirmed
In Short: Planetary scientists have discovered that Mercury is contracting at a faster rate than previously believed, suggesting the planet may have a larger metal core and less light elements mixed into its core.
Planetary scientists have discovered that Mercury is contracting at a faster rate than previously believed, suggesting the planet may have a larger metal core and less light elements mixed into its core. According to Gaku Nishiyama, a planetary scientist at the German Aerospace Center, 'More shrinking means Mercury could have a larger metal core, less light elements like silicon mixed into the metal core, or a higher starting temperature.
Mercury's surface is riddled with wrinkles, evidence of a once-larger planet that has shrunk over time. The new analysis suggests that the actual rate of shrinking has been underestimated, with the planet having shrunk by up to 23 kilometers, or about 14 miles, rather than the previously estimated 11 kilometers.
The BepiColombo mission, the first European mission to Mercury and the first to send two spacecraft to make complementary measurements of the planet and its dynamic environment at the same time, will provide higher-resolution scans of Mercury's surface in November 2026. This will help refine the estimates of the planet's contraction and provide more reliable information on its topography.
What's confirmed
- Planetary scientists have discovered that Mercury is contracting at a faster rate than previously believed, suggesting the planet may have a larger metal core and less light elements mixed into its core. According to Gaku Nishiyama, a planetary scientist at the German Aerospace Center, 'More shrinking means Mercury could have a larger metal core, less light elements like silicon mixed into the metal core, or a higher starting temperature.
- Mercury's surface is riddled with wrinkles, evidence of a once-larger planet that has shrunk over time. The new analysis suggests that the actual rate of shrinking has been underestimated, with the planet having shrunk by up to 23 kilometers, or about 14 miles, rather than the previously estimated 11 kilometers.
- The BepiColombo mission, the first European mission to Mercury and the first to send two spacecraft to make complementary measurements of the planet and its dynamic environment at the same time, will provide higher-resolution scans of Mercury's surface in November 2026. This will help refine the estimates of the planet's contraction and provide more reliable information on its topography.
What's still developing
- The process is ongoing, and it might be happening faster than we thought.
- “With the BepiColombo Laser Altimeter (BELA), we expect that Mercury's topography can be captured with a better resolution, and then we would be able to get more reliable information on contraction features and roughness. This information will definitely corroborate the findings and may further refine the estimates,” Nishiyama told IFLScience.
- BepiColombo pictured zooming away from Mercury a few years back.
- If all the planets are roughly the same age, why is Mercury so wrinkly?
- With the transfer module gone, MPO and Mio orbiters are now headed toward orbit insertion at Mercury, with MPO powering the joined spacecraft until the two orbiters separate from each other.
- It consists of two individual orbiters: ESA’s Mercury Planetary Orbiter (MPO) and JAXA’s Mercury Magnetospheric Orbiter (MMO, or ‘Mio’).
- Professor Colombo was the first to see that an unsuspected resonance is responsible for Mercury’s habit of rotating on its axis three times for every two revolutions it makes around the Sun.
- He also suggested to NASA how to use a gravity-assist swing-by of Venus to place the Mariner 10 spacecraft in a solar orbit that would allow it to fly by Mercury three times in 1974-5.