nebula summary

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Below is the article summary. For the full article, see nebula.

Planetary Nebula Hen 1357, as photographed by the Hubble Space Telescope. It is located about 18,000 light-years from Earth and lies in the constellation Ara the Altar. This expanding cloud of gas was expelled from an aging star in the nebula's centre.

nebula , Any of various tenuous clouds of gas and dust in interstellar space. Nebulae constitute only a small percentage of a galaxy’s mass. Dark nebulae (e.g., the Coalsack) are very dense, cold molecular clouds that appear as large, obscure, irregularly shaped areas in the sky. Bright nebulae (e.g., the Crab Nebula, planetary nebula) appear as faintly luminous, glowing surfaces; they emit their own light or reflect that of stars near them. The term nebula also formerly referred to galaxies outside the Milky Way Galaxy.

Hubble Space Telescope Summary

Hubble Space Telescope (HST), the first sophisticated optical observatory placed into orbit around Earth. Earth’s atmosphere obscures ground-based astronomers’ view of celestial objects by absorbing or distorting light rays from them. A telescope stationed in outer space is entirely above the

planetary nebula Summary

Planetary nebula, any of a class of bright nebulae that are expanding shells of luminous gas expelled by dying stars. They have a relatively round compact appearance rather than the chaotic patchy shapes of other nebulae—hence their name, which was given because of their resemblance to planetary

Sir John Herschel, 1st Baronet Summary

Sir John Herschel, 1st Baronet was an English astronomer and successor to his father, Sir William Herschel, in the field of stellar and nebular observation and discovery. An only child, John was educated briefly at Eton and then privately. In 1809 he entered the University of Cambridge in the

Edwin Hubble Summary

Edwin Hubble was an American astronomer who played a crucial role in establishing the field of extragalactic astronomy and is generally regarded as the leading observational cosmologist of the 20th century. Hubble was the son of John Powell Hubble, a businessman who worked in the insurance