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The Journey of Flight.pdf - Valkyrie Cadet

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<strong>The</strong> Milky Way Galaxy<br />

An extended halo <strong>of</strong> gas surrounding the Milky<br />

Way was generated by thousands <strong>of</strong> exploding stars<br />

as the galaxy evolved. Roughly football-shaped, this<br />

hot gas halo extends between five thousand and ten<br />

thousand light years above and below the galactic<br />

plain, thinning out with distance. Although the halfmillion-degree<br />

gas halo has been known for some time,<br />

scientists were not certain how it came to be there or<br />

remained hot.<br />

Observations made with NASA’s Far Ultraviolet<br />

Spectroscopic Explorer (FUSE) spacecraft revealed<br />

an extensive amount <strong>of</strong> oxygen VI in the halo. Oxygen<br />

six — oxygen atoms that have had five <strong>of</strong> their eight<br />

surrounding electrons stripped away — could only<br />

have been created through collision with the blast<br />

waves from exploding stars. Such star explosions are<br />

actually a record <strong>of</strong> star formation, and comparison <strong>of</strong><br />

these supernovae generated halos among galaxies may allow scientists to compare the star formation<br />

histories <strong>of</strong> the galaxies.<br />

Nova and Supernova<br />

Novas are stars that are not stable; they flare, subside and flare again. This type <strong>of</strong> existence has<br />

been observed just before the star “dies.” It is not known if this is part <strong>of</strong> the normal life cycle <strong>of</strong> a star.<br />

A supernova occurs when a star gives up great mass in one giant explosion <strong>of</strong> light and energy.<br />

Nova Supernova<br />

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