Space exploration began with the launch of Sputnik and Astrophysics was born as the application of physics to the phenomena observed by Astronomy, which etymologically means laws of the stars.
There are 2759 entries in this glossary.| Term | Definition |
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| Vulcan |
A hypothetical planet travelling round the Sun within the orbit of Mercury for which searches were made during the late nineteenth century. It is now known not to exist.
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