If we faced a countdown to destruction, could we build a spacecraft to take us to new and habitable worlds? Can we Evacuate Earth? This documentary special examines this terrifying but scientifically plausible scenario by exploring how we could unite to ensure the survival of the human race.
We’ve covered a lot of incredible stuff, but this week we’re talking about the weirdest objects in space: BLACK HOLES. Stellar mass black holes form when a very massive star dies, and its core collapses. The core has to be more than about 2.8 times the Sun’s mass to form a black hole. Black holes come in different sizes, but for all of them, the escape velocity is greater than the speed of light, so nothing can escape, not matter or light. They don’t wander the Universe gobbling everything down around them; their gravity is only really intense very close to them. Tides near a stellar mass black hole will spaghettify you, and time slows down when you get near a black hole — not that this helps much if you’re falling in.
Astronaut Mike Massimino explores Venus, a hellish planet covered in active volcanoes and dense clouds. Using cutting edge technology, he decodes the secrets beneath this volatile planet and investigates if Earth could be heading towards the same fate.
Today on Crash Course Astronomy, Phil explains comets. Comets are chunks of ice and rock that orbit the Sun. When they get near the Sun the ice turns into gas, forming the long tail, and also releases dust that forms a different tail. We’ve visited comets up close and found them to be lumpy, with vents in the surface that release the gas as ice sublimates. Eons ago, comets (and asteroids) may have brought a lot of water to Earth -- as well as the ingredients for life.
Kevin explores and probes second by second what it takes to 'lift off' into space. With Tim only days into his six-month mission, he helps Kevin answer what keeps astronauts safe and on track as they are propelled into orbit. How do you control the energy of 300 tonnes of liquid fuel? What happens to your body if you don't wear a spacesuit? And how do you catch up with a space station travelling at 17,500 mph to finally get inside? With explosive live experiments, guest astronauts in the lecture theatre, and planetary scientist Monica Grady direct from the launch pad in Kazakhstan, we learn all this and more as those thrilling minutes of lift off are recreated.