"Cosmologists have an embarrassing problem: we don't know what shape the universe is. The cosmos has three possible geometries—positively curved like a sphere, flat like an infinite plane, or negatively curved like a saddle—but geometry alone doesn't determine shape."
"Our touchstone for settling the question is the cosmic microwave background (CMB). This is the faint thermal afterglow from some 380,000 years after the big bang that was unleashed when the hot, foglike plasma that filled the early universe cooled and cleared."
"The most legible postulated signature of a topologically nontrivial universe would be pairs of circles on the CMB sky with precisely matching temperature patterns: finding an identical ring of hot and cold patches in two different directions could mean we're looking at the same region of space from two different vantage points."
Cosmologists face uncertainty regarding the universe's shape, which can be positively curved, flat, or negatively curved. Geometry does not solely determine shape, as a flat universe can wrap in various ways. Einstein's general theory of relativity effectively describes local curvature but does not address global topology. The cosmic microwave background (CMB) serves as a crucial tool for understanding the universe's shape, with missions like the Planck space observatory mapping this ancient signal. Identifying matching temperature patterns in the CMB could indicate a topologically nontrivial universe.
Read at www.scientificamerican.com
Unable to calculate read time
Collection
[
|
...
]