AST201H1 Lecture Notes - Lecture 4: Hydrostatic Equilibrium

• School: UTSG
• Department: Astronomy & Astrophysics
• Course: AST201H1
• Professor: Bryan Gaensler

Document Summary

Sun is made mostly of hydrogen, a little helium, and tiny amounts of other elements. When you pass sunlight through a prism, it appear to separate into a perfectly smooth rainbow. White light is the sum of all colours. A prism splits sunlight up into a spectrum. The wavelength of light determines its colour (and energy) The shorter the wavelength, the bluer (and more energetic) the light. All colours travel at the speed - c. The sun appears to have a continuous spectrum: it has some of every colour of light. As you heat an opaque object (blackbody) it emits more light. As you heat an opaque object, the wavelength at which it emits the most light shifts to shorter wavelengths. Tell us what the sun and other stars are made of. To transition between two orbitals, an electron has to absorb or emit exactly the right amount of energy / wavelength / colour of light.