Cosmologists study the cosmic microwave background to determine spatial curvature. Inflation predicts a nearly flat universe, meaning parallel lines remain parallel over cosmic scales. Observations from WMAP and Planck satellites confirm flatness within tiny margins. Curvature influences how light travels, galaxy distribution, and cosmic destiny. Understanding shape links geometry to cosmic history, all tracing back to the Big Bang.
It matters because curvature affects the universe’s evolution and fate.
It also informs models for dark energy and cosmic inflation theories.
The universe’s geometry was encoded in the first seconds after the Big Bang.
Planck Collaboration [esa.int]