BOB. We define grav- Consider the Viral theorem which states that (E)=(U) given on itational potential...

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BOB. We define grav- Consider the Viral theorem which states that (E)=(U) given on itational potential energy as equal to 0 when two bodies are very far apart. Imagine a giant gas cloud with the gas in a shell, light years apart that is, the gravitational potential energy of the cloud is 0. Now imagine the cloud shrinks to the size of the Sun giving off energy as it loses gravi- tational potential energy. Where does this energy go? The viral formula above states that the cloud, which started at 0, now has lost energy of (U). It goes into the luminosity of the Sun during contraction and before fusion starts! The gravitational potential energy of the sun today is roughly W-2GM²/Ro where Me, Ro are the mass and radius of the Sun. How long would it take the Sun to radiate away-(U) given the present luminosity of the Sun? Give the answer in years. This is called the Kelvin Helmholtz time. BOB. We define grav- Consider the Viral theorem which states that (E)=(U) given on itational potential energy as equal to 0 when two bodies are very far apart. Imagine a giant gas cloud with the gas in a shell, light years apart that is, the gravitational potential energy of the cloud is 0. Now imagine the cloud shrinks to the size of the Sun giving off energy as it loses gravi- tational potential energy. Where does this energy go? The viral formula above states that the cloud, which started at 0, now has lost energy of (U). It goes into the luminosity of the Sun during contraction and before fusion starts! The gravitational potential energy of the sun today is roughly W-2GM²/Ro where Me, Ro are the mass and radius of the Sun. How long would it take the Sun to radiate away-(U) given the present luminosity of the Sun? Give the answer in years. This is called the Kelvin Helmholtz time.

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Based on the given information and the Virial theorem Ek 12 U the energy lost by the cloud as it con... View the full answer