 Where did life on earth come from? The answer lies in the stars which have lives of their own Stars are responsible for the materials that form us and everything around us Including these two people Welcome back to think tank today's topic is star birth alternate title a star is born Very catchy. Is the thought visualizer ready? I'll set boss. Let's do our tech check think of a light wave We'll have to work on that Every star begins its brilliant life as an enormous dark cloud of gas and dust This cloud is very cold drifting and rotating through interstellar space exactly Wait, why is it rotating? Well, your heart press to find something in the universe that isn't rotating to some degree All right checks out Anyway, sometimes gravity can pull the dusty cloud closer and closer together which can collapse under its own weight It's crushing me space clouds. Don't feel pain This cloud breaks up into smaller clumps some of which will become new stars in this soon-to-be stellar nursery a Club can continue to collapse under its own gravity Rotating faster as it shrinks and that's how you make a star. Thanks for watching. Nope. Not quite a star yet At this stage the center of the club is called a protostar This protostar builds up more and more material with pressures greater than those found at the bottom of the ocean and temperatures that reach thousands eventually millions of degrees That's when a remarkable thing called nuclear fusion happens and this marks the beginning of a star's life Which means that at last a star is born Wait, what's nuclear fusion? That's essentially where lighter elements like hydrogen combine to make heavier elements and release energy in the process The energy released by fusion powers the star through its whole life enabling it to shine brightly For stars like our Sun this lasts for billions of years This new star goes through many changes before it settles down It doesn't even use up all the surrounding material what doesn't get blown away Sticks around in an orbiting disk. We call that useless scraps Actually, we call that you and me. It's the material that forms the planets and everything on them including life on earth But that's another story and that's our show special thanks to NASA's observatories in space as they continue to peer deep into dusty star-forming regions Helping us learn where we came from and thanks as always to my assistant for subjecting himself to the thought visualizer Thank you all for watching. We'll see you next time