Radio Explorations of a Faraway Galaxy
We use radio waves in telecommunications. They carry signals for radio and TV broadcasts, cellular phones and beepers, and other satellite communications. Radio emissions have the longest wavelengths in the spectrum. This enables them to reach Earth's surface, where we detect them with radio telescopes.
A familiar galaxy like M81 (left) in Ursa Major looks very different in radio wavelengths. The Very Large Array radio telescopes studied hydrogen clouds in this spiral galaxy.
Hydrogen is an important ingredient needed to form new stars. The bright colors in this image are areas where cold hydrogen gas is plentiful in the spiral arms. These gas-rich regions could become stellar nurseries.