
The CMB: The most important discovery in cosmic history | By Ethan Siegel | Start with an explosion! | February 2025
This composite image shows the microwave sky according to the three generations of spatial CMB missions: Cobe (1990), WMAP (2000) and Planck (2010). Over time, we have become more sensitive to the temperature of lower magnitude and the polarization characteristics at progressively smaller angular scales. (Credit: Smoot Cosmology Group/lbl/ESA) First discovered in the mid -1960s,…