The birth of our Solar System was both violent and chaotic. As planets formed around our Sun, gravity and luck determined their fate: some are tossed into the Sun, others thrown into interstellar space, never to return. It is survival of the fittest, on an interplanetary scale.
Right now researchers are hunting for extra-terrestrial life on several fronts. To find out just how close we might be to a breakthrough, astrophysicist Dr Graham Phillips visits telescopes, swims among the stromatolites on the remote West Australian coastline, and chats with scientists from around the world
Today Phil follows up last week’s look at the death of low mass stars with what comes next: a white dwarf. White dwarfs are incredibly hot and dense objects roughly the size of Earth. They also can form planetary nebulae: huge, intricately detailed objects created when the wind blown from the dying stars is lit up by the central white dwarf. They only last a few millennia. The Sun probably won’t form one, but higher mass stars do.
The episode, devoted to the planet Mars, begins with scientific and fictional speculation about the Red Planet during the late nineteenth and early twentieth centuries (H. G. Wells' The War of the Worlds, Edgar Rice Burroughs' science fiction books, and Percival Lowell's false vision of canals on Mars). It then moves to Robert Goddard's early experiments in rocket-building, inspired by reading science fiction, and the work by Mars probes, including the Viking, searching for life on Mars. The episode ends with the possibility of the terraforming and colonization of Mars and a Cosmos Update on the relevance of Mars' environment to Earth's and the possibility of a manned mission to Mars.
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.