Radioactive! A Profile of the Element Plutonium
On Aug. 25, 2012, about 11 billion miles (18 billion kilometers) away from the sun, the NASA probe Voyager 1 left the heliosphere, boldly going where no object had gone before. By crossing that boundary, Voyager 1 traveled beyond the solar system and entered interstellar space, a historic first. Look…
bubmagAugust 18, 2021