Cosmic Microwave Background

space · light · universe · discovery

Ancient Light Everywhere. The cosmic microwave background is faint radiation that fills the entire universe. You can't see it with your eyes or even a regular telescope, but special radio telescopes pick up its glow coming from every direction in space.

Stronger Than All Stars. The energy in this background radiation is actually more powerful than all the light from every star that has ever existed in the universe combined. That's an amazing amount of ancient energy still traveling through space today.

Left From the Big Bang. This radiation is like a baby picture of the universe. It came from when the universe was very young and incredibly hot, and it has been cooling down and spreading out ever since.

Accidental Discovery. Scientists Arno Penzias and Robert Wilson found the cosmic microwave background by accident in 1964 while working with a radio telescope. They noticed a strange background hum and glow that wasn't coming from any star or galaxy, and it turned out to be one of the biggest discoveries in astronomy.

Microwave Waves Everywhere. The radiation is strongest in the microwave part of the light spectrum, which is the same type of waves your microwave oven uses to heat food. This background radiation is extremely faint compared to those kitchen microwaves, though.