Media Information
 
 
 
Collection:
NASA Astronomy Picture of the Day Collection
Title:
Andromeda Island Universe
Explanation:
The most distant object easily visible to the unaided eye is M31 [ http://www.seds.org…], the great Andromeda Galaxy [ http://www.seds.org…] some two and a half million light-years away. But without a telescope, even this immense spiral galaxy - spanning over [ http://antwrp.gsfc.…] 200,000 light years - appears as a faint, nebulous cloud in the constellation Andromeda [ http://www.hawastso…]. In contrast, a bright yellow nucleus, dark winding dust lanes, gorgeous blue spiral arms and star clusters are recorded in this stunning telescopic digital mosaic [ http://astrophoto.c…]. While even casual skygazers [ http://badastronomy…] are now inspired by the knowledge that there are many [ http://antwrp.gsfc.…] distant galaxies like M31, astronomers seriously debated [ http://adsbit.harva…nph-iarticle_query?1 995PASP..107.1133T ] this fundamental concept less than 90 years ago. Were these "spiral nebulae" simply outlying components of our own Milky Way Galaxy or were they instead "island universes" -- distant systems of stars comparable to the Milky Way itself? This question was central to the famous Shapley-Curtis [ http://antwrp.gsfc.…debate20.html ] debate [ http://antwrp.gsfc.…] of 1920, which was later resolved by observations [ http://antwrp.gsfc.…] of M31 in favor of Andromeda, island universe [ http://www.astr.ua.…].
Credit and Copyright:
//antwrp.gsfc.nasa.g ov/apod/lib/ about_apod.html#srap ply">Copyright: Tony Hallas [ http://astrophoto.c…]
facet_when:
1920
facet_where:
Milky Way Galaxy
facet_where:
M31
facet_where:
Andromeda Galaxy
facet_where:
Goddard Space Flight Center (GSFC)
facet_what:
Andromeda
facet_when_year:
1920
original url:
http://antwrp.gsfc.…
UID:
SPD-APOD-ap080124

Andromeda Island Universe
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