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  • Richard Farr

Vesto Slipher and the expanding universe

One minor character in my Ghosts n the Machine is the Slipher Space Telescope. This is me giving a big fat fictional hint to NASA, in honor of Vesto Slipher, one of the greatest and most inadequately recognized American astronomers.

Along with many other achievements, in 1912 Slipher established for the first time the very high relative velocity of the Andromeda ‘nebula’ (galaxy), and thus, along with Henrietta Swann Leavitt and others, paved the way for Edwin Hubble’s momentous discovery that the universe is expanding. Hubble is sometimes incorrectly credited with both discoveries.

A note for the nerdy: Slipher showed that Andromeda is moving at about 300 km/s towards us. The enormously high velocity was puzzling, and encouraged a general survey of Doppler shift in ‘nebular’ light. Only after much more data had been collected did it become clear that Andromeda is a special case of gravitational attraction within the Local Group, and that in general the galaxies are flying apart.

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