The only tidally locked planet in the Solar system i Mercury. But it is synchronously tidally locked 3:2, because of the relatively high eccentricity of its orbit, so doesn't turn the same side ...
What is the current accepted theory as to why Mercury, despite its size, has a similar density to Earth?
According to the NASA web page overview about Mercury, despite the planet being just a bit larger than our moon, it's density is about 98.4% of Earth's. This high density suggests a comparatively ...