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 |
|---|---|
| Diffuse Nebula |
A gaseous nebula. The use of the adjective diffuse dates from a time when all objects of fuzzy appearance were classed as nebulae, and it was necessary to distinguish between them. In current terminology, star clusters and galaxies are no longer called nebulae, the word being reserved for diffuse clouds of gas and dust.
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