Oh, no! Can it be true? Is Mercury really shrinking like a grape shriveling into a raisin?
It had been previously believed that our smallest planet is shrinking, but the amount appears to be more than at first believed, possibly up to 30% greater. At present, Mercury’s diameter seems to be less by about 14 miles, a fair change for such a small – 3,000 mile across – planet.
This information comes about from the spacecraft BepiColombo, which soon will enter orbit around Mercury. Its laser instrument should be expected to confirm how much the planet is withering, apparently as a result of internal cooling. It seems Mercury has been shrinking ever since it was formed. Its hot iron core – which is large for such a small body – is cooling and contracting along with its mantle and crust, tightening Mercury’s surface much like a girdle would do.
Because Mercury’s surface has always been shaped by debris from impact craters, this might have previously hidden the true extent of the change, as written in the Geophysical Research Letters. This could be why changes in its surface possibly aren’t as noticeable as should be, as parts of it could be buried under some of this debris.
Once BepiColombo is able to better determine the amount of this change, it is believed this information could show how this would pertain to other worlds that are shown to contract, as well.
