In Earth's upper atmosphere, ultraviolet light from the Sun ionizes atoms and dissociates molecules at heights between 40 and 200 miles (64 and 322 kilometers) above the planet's surface. When the fragments collide and recombine, some atoms and molecules are left with excess energy, which they release as light, known as airglow. Airglow hampers optical telescopic observations on Earth by reducing the apparent contrast between stars and space. What types of atoms are involved in the phenomenon?
John Quincy Adams
Back in the day
In the spring of 1914, the Colorado National Guard machine-gunned and torched a tent colony in Ludlow, where striking coal miners and their families had been living after being evicted from their company-owned homes some months earlier. Nineteen people, most of them women and children, were killed. For the next 10 days, the strikers attacked nearby mines and battled mine guards and militia. Federal troops were needed to put an end to the violence. Which side eventually prevailed in the strike?
Born on a day like today
A highly decorated American naval officer and WWII veteran, Beach became the naval aide to the US president following the war. In his free time, he wrote. Drawing on his wartime experiences, Beach penned 13 books. His first and best-known published work, 1955's Run Silent, Run Deep, was made into a film of the same name in 1958. In 1960, Beach commanded the first submerged circumnavigation aboard the USS Triton, an American nuclear-powered submarine unique for having two what?