Re:A new Einstein cross is discovered
by pixl97 on Monday March 25, 2019 @01:57PM
(#19484858)
The shape of the universe currently prevents this. For what we can tell the universe is flat, which means at no point will it collapse on itself, unless something major changes. That said, major changes have happened, around 8 billion years ago expansion appears to have sped up.
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I'm no expert (so correct me if I'm wrong), but from what I'm read, flat, concave, and convex universes are all possibilities and they would all look flat to us because our measurements take place on such a small scale.
Re:A new Einstein cross is discovered
by sandworm101 on Monday March 25, 2019 @03:15PM
(#19485786)
Our measurements occur across billions of light-years. By comparing redshift agaist the standard candles we measure relative speeds of vastly distant objects. And given the speed of light, we are also measuring what those speeds were billions of years ago. It is a very big ruler.
Re:A new Einstein cross is discovered
by roywiggins on Monday March 25, 2019 @04:11PM
(#19486322)
We've measured the flatness of the universe on the scale of the cosmic microwave background, which is essentially as big a ruler as could possibly exist.
https://map.gsfc.nasa.gov/mission/sgoals_parameters_geom.htm...