You're not seeing double; these are two images of the same world: icy, cratered Rhea, the second-largest natural satellite of Saturn.
The moon is at its best for observing when it is around its first-quarter phase.
The first day of Spring began with some dazzle in Europe and the Arctic with a solar eclipse.
This week, the moon will completely cover the disk of the sun, creating a solar eclipse that only a small part of the world can see.
A previously undiscovered moon crater has been provisionally named after the famous US aviator Amelia Earhart.
The moon's past was livelier and more complex than scientists had thought, new results from China's first lunar rover suggest.
It's not a spare moon of ours, exactly, but Earth does have a sort of gravitational buddy out there, in the mellifluously named 3753 Cruithne. It orbits the sun, just like us, and is locked with Earth in what scientists call orbital resonance.
Chemical engineers have created a theoretical model of a type of alien cell that might be able to support life on Titan.
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