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.
The Ship of the Imagination ventures on an epic voyage to the bottom of a dewdrop to explore the universe on the smallest scale and observe exotic life forms invisible to the naked eye. Then, host Neil deGrasse Tyson explains the neural network in our brains which determine our sense of smell and memory, and later, he travels deep beneath the surface of the Earth to discover the most mysterious particle we know.
The first part, Everything, sees Professor Al-Khalili set out to discover what the universe might actually look like. The journey takes him from the distant past to the boundaries of the known universe. Along the way he charts the remarkable stories of the men and women who discovered the truth about the cosmos and investigates how our understanding of space has been shaped by both mathematics and astronomy.