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Index/Topics/Cosmic Microwave Background

Cosmic Microwave Background

The cosmic microwave background radiation and its role in understanding the universe's composition and evolution.

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Jan 14, 2026
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What observational signatures would a bubble‑collision in the CMB produce and have any been reliably seen?

Bubble collisions in eternal‑inflation scenarios would leave large, azimuthally symmetric imprints in the cosmic microwave background (CMB) — roughly disk‑shaped temperature and polarization modulatio...

Jan 26, 2026

How can we not know where most of the matter and energy in the universe is

Most of the universe — roughly 95% by mass–energy — is in forms astronomers cannot see directly: about 27% is dark matter and about 68% is dark energy, leaving familiar atoms at only ~5% . The reason ...