Now that gravitational waves are definitely a thing, it’s time to think about some of the crazy things we can figure out with them. In some cases we’re going to need a gravitational wave observatory - in fact, we've already built one.
Astronomers study a lot of gorgeous things, but nebulae might be the most breathtakingly beautiful of them all. Nebulae are clouds of gas and dust in space. They can glow on their own or reflect light from nearby stars. When they glow it’s usually predominantly red from hydrogen and green from oxygen, and when they reflect and scatter light it’s from massive hot stars, so they look blue. Stars are born in some nebulae, and create new ones as they die. Some nebulae are small and dense, others can be dozens or hundreds of light years across.
The universe is unbelievably big – trillions of stars and even more planets. Soo… there just has to be life out there, right? But where is it? Why don’t we see any aliens? Where are they? And more importantly, what does this tell us about our own fate in this gigantic and scary universe?
Apollo astronauts and engineers tell the inside story of Apollo 8, the first manned mission to the moon. The U.S. space program suffered a bitter setback when Apollo 1 ended in a deadly fire during a pre-launch run-through. In disarray, and threatened by the prospect of a Soviet Union victory in the space race, NASA decided upon a radical and risky change of plan: turn Apollo 8 from an earth-orbit mission into a daring sprint to the moon while relying on untried new technologies. Fifty years after the historic mission, the Apollo 8 astronauts and engineers recount the feats of engineering that paved the way to the moon.
2018 • Astronomy