From the birth of the devil in ancient Persia, where a beloved family dog becomes a seething beast, to a searing story of saintliness among macaque monkeys, join an exploration into the human potential for change. One of history's greatest monsters is transformed into one of its shining lights.
2020 • Astronomy
In what kind of world can a child born in 2020 expect to grow up? When did our slide into planetwide environmental destruction begin? Enter the possible world that awaits a 2020 baby in her twenties: one darkened by our refusal to confront the real and mounting challenges we face but one which still offers a message of hope.
2020 • Astronomy
In summer 2013, the black hole at the centre of the Milky Way was getting ready to feast. A gas cloud three times the size of our planet strayed within the gravitational reach of our nearest supermassive black hole. Across the globe, telescopes were being trained on the heart of our galaxy, some 27,000 light years from Earth, in the expectation of observing this unique cosmic spectacle. For cosmic detectives across the Earth, it was a unique opportunity. For the first time in the history of science, they hoped to observe in action the awesome spectacle of a feeding supermassive black hole.
Massive stars fuse heavier elements in their cores than lower mass stars. This leads to the creation of heavier elements up to iron. Iron robs critical energy from the core, causing it to collapse. The shock wave, together with a huge swarm of neutrinos, blast through the star’s outer layers, causing it to explode. The resulting supernova creates even more heavy elements, scattering them through space. Also, happily, we’re in no danger from a nearby supernova.
The multiverse hypothesis, suggesting that our universe is but one of perhaps infinitely many, speaks to the very nature of reality. Join physicist Brian Greene, cosmologists Alan Guth and Andrei Linde, and philosopher Nick Bostrom as they discuss and debate this controversial implication of forefront research and explore its potential for redefining the cosmic order. Moderated by Robert Krulwich and featuring an original musical interlude, inspired by parallel worlds, by DJ Spooky.
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.
Were "little green men" trying to contact us? Over 40 years ago, extremely constant pulses were detected reaching the Earth from outer space. It caused a great sensation. Using a radio telescope larger than a baseball field, scientists looked for the source of these signals and found - pulsars.