COBE revolutionized our understanding of the early cosmos. It precisely measured and mapped the oldest light in the universe — the cosmic microwave background. The cosmic microwave background spectrum was measured with a precision of 0.005%. The results confirmed the Big Bang theory of the origin of the universe.

What does the CMB tell us?

The CMB is useful to scientists because it helps us learn how the early universe was formed. It is at a uniform temperature with only small fluctuations visible with precise telescopes.

What key measurement was made by the WMAP experiment?

To address its key scientific questions, WMAP measures small variations in the temperature of the cosmic microwave background radiation. These variations are minute: one part of the sky has a temperature of 2.7251° Kelvin (degrees above absolute zero), while another part of the sky has a temperature of 2.7249° Kelvin.