A natural solid object (metallic or stony/silicate) larger than 10 µm (microns) that has traveled through space, by natural means from the celestial body on which it formed, and ...
A hole or depression. Most are roughly circular or oval in outline. On Earth most natural craters are of volcanic origin. On the Moon most are of impact origin.
Term used to describe the layer of magma, hundreds of kilometers thick; thought to have covered the Moon 4. 5 billion years ago. The timing, duration, cooling rates, convection, ...
Forces that alter the path of a comet, which are not caused by gravitational interaction with the Sun and planets. Typically this refers to uneven outgassing from vents on the ...
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