ASTR 102 Study Guide - Final Guide: Red-Giant Branch, Electron Degeneracy Pressure, Inverse-Square Law
20 Feb 2017
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It"s pretty pricey to send physical matter into space, but light hits earth for free and travels. Sooo fast, so we can use that. (3. 0x10^8 m/s) sun to earth: 8. 32 light mins andromeda galaxy to earth: 3. 5 million light years. Light is a wwwaaaaaaavveeeeee. an electromagnetic wave to be speci c. Charged particles interact w every other particle in the universe!! however the force gets weaker rapidly with distance. Light requires no medium! diffraction is where we see bright spots and dark holes cause be interference. Frequency (f)- the # of waves passing per second. Period (t)- the amount of time it takes for one wave to go by. [ t=1/f ] higher frequency = more energy= shorter wavelength lower f = less energy= longer wavelength long wavelength= red, cooler short wavelength= blue, hot. The atmosphere is opaque to uv, x-rays, gamma rays & most infrared emission. (keeps us alive). 2 times the radius = 4 times the brightness.
