Edwin Hubble’s work on galaxies is legendary. In 1923 the astronomer, working at Mount Wilson Observatory in California, proved that M31, the “spiral nebula” in Andromeda, was another galaxy. In one ...

The Tucson Amateur Astronomy Association (TAAA) established the Chiricahua Astronomy Complex (CAC), a 16-acre dark-sky observing site in southeastern Arizona, to combat light pollution affecting their ...

NASA’s Earth Observing System provides nearly 30 years of continuous, high-quality measurements of Earth’s land, oceans, atmosphere, and ice, supporting climate research and long-term environmental ...