Scientists have unlocked one of the biggest mysteries of quasars -- the brightest, most powerful objects in the Universe -- by discovering that they are ignited by galaxies colliding. Scientists have ...
Learn about Earth Day founder Gaylord Nelson (1916–2005) and how environmental disasters of his day inspired the creation of Earth Day in 1970. On December 7, 1972, Apollo 17 astronauts captured a now ...
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