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Mercury Shrinking Faster Than Previously Thought
Confirmed
In Short: Planetary scientists have discovered that Mercury is shrinking at a faster rate than previously believed, suggesting the planet has a larger inner core and higher initial temperature.
Planetary scientists have found that Mercury is shrinking at a faster rate than previously thought, according to reports from IFLScience. This new analysis suggests that the actual rate of contraction has been underestimated, indicating that Mercury has less light elements in its core, a larger inner core, and a higher initial temperature.
Nishiyama, a planetary scientist, explained, 'This result suggests that Mercury has less light elements in the core, a larger inner core, and a higher initial temperature and so on,' as reported by IFLScience. He also noted that with the BepiColombo Laser Altimeter (BELA), they expect to capture Mercury's topography with better resolution, which could further refine these estimates.
The BepiColombo mission, a joint European and Japanese effort, is currently on its way to Mercury. The mission consists of two orbiters: ESA’s Mercury Planetary Orbiter (MPO) and JAXA’s Mercury Magnetospheric Orbiter (MMO, or ‘Mio’). The spacecraft’s Mercury Transfer Module (MTM) successfully separated from the rest of the stack on September 3, 2026, marking the beginning of the mission’s 'arrival phase.
Mercury’s surface shows signs of aging through hills and ridges, called shortening structures, across its surface. Scientists have long known that Mercury’s interior was shrinking, but the new study suggests it may have shrunk by up to 23 kilometers, or about 14 miles, rather than the previously estimated 11 kilometers, as presented by Byrne at a 2013 conference.
The BepiColombo mission aims to provide more reliable information on Mercury’s contraction features and roughness, which could further corroborate the findings. Professor Colombo, who first identified the resonance responsible for Mercury’s rotation, 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.
With the transfer module gone, the 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. This mission is the first European mission to Mercury and is the first to send two spacecraft to make complementary measurements of the planet and its dynamic environment at the same time.
What's confirmed
- Planetary scientists have found that Mercury is shrinking at a faster rate than previously thought, according to reports from IFLScience. This new analysis suggests that the actual rate of contraction has been underestimated, indicating that Mercury has less light elements in its core, a larger inner core, and a higher initial temperature.
- Nishiyama, a planetary scientist, explained, 'This result suggests that Mercury has less light elements in the core, a larger inner core, and a higher initial temperature and so on,' as reported by IFLScience. He also noted that with the BepiColombo Laser Altimeter (BELA), they expect to capture Mercury's topography with better resolution, which could further refine these estimates.
- The BepiColombo mission, a joint European and Japanese effort, is currently on its way to Mercury. The mission consists of two orbiters: ESA’s Mercury Planetary Orbiter (MPO) and JAXA’s Mercury Magnetospheric Orbiter (MMO, or ‘Mio’). The spacecraft’s Mercury Transfer Module (MTM) successfully separated from the rest of the stack on September 3, 2026, marking the beginning of the mission’s 'arrival phase.
- Mercury’s surface shows signs of aging through hills and ridges, called shortening structures, across its surface. Scientists have long known that Mercury’s interior was shrinking, but the new study suggests it may have shrunk by up to 23 kilometers, or about 14 miles, rather than the previously estimated 11 kilometers, as presented by Byrne at a 2013 conference.
- The BepiColombo mission aims to provide more reliable information on Mercury’s contraction features and roughness, which could further corroborate the findings. Professor Colombo, who first identified the resonance responsible for Mercury’s rotation, 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.
- With the transfer module gone, the 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. This mission is the first European mission to Mercury and is the first to send two spacecraft to make complementary measurements of the planet and its dynamic environment at the same time.
What's still developing
- The process is ongoing, and it might be happening faster than we thought.
- BepiColombo pictured zooming away from Mercury a few years back.
- If all the planets are roughly the same age, why is Mercury so wrinkly?