Over 50,000 submissions are made for images on U.S. stamps every year, and out of those, about 40 are turned into real stamps. For Kevin Luhman, professor of astronomy and astrophysics at Penn State, ...

The Necklace Nebula, formed by two doomed stars, glows with bright gas clumps like a cosmic diamond ring. Located 15,000 light-years away in the Sagitta constellation, it shines as a stunning ...