Uploaded January 2008 | Updated September 2026, 3 weeks ago
As the universe expands (represented by the expanding balloon) the cosmic background (represented by the wavy line) gets stretched out to longer and longer wavelengths (distance between peaks on the wavy line).
As the universe expands (represented by the expanding balloon) the cosmic background (represented by the wavy line) gets stretched out to longer and longer wavelengths (distance between peaks on the wavy line).
