ASTR 101 Chapter Notes - Chapter 5-6: Inverse-Square Law, Electromagnetic Spectrum, Photon Energy
Document Summary
Oscillation of electrons causes magnetic and electric fields. They move at the speed of light in a vacuum. Horizontal length of one wave cycles is wavelength. Number of wave cycles passing a point per second is frequency. Light can behave like a packet of energy called a photon. Light can behave as a wave and as a particle. Increase in area that light must cover is proportional to the square of the distance traveled by the light (inverse square law) If twice as far, 4 times less light is received. Alpha centauri a emits about the same energy as the sun, but is 270,000 times farther (73 billion times fainter) Gamma rays have shortest wavelengths (lower than 0. 01 nm) Generated inside stars and phenomena such as star deaths and merging of stellar corpses. X-rays have wavelengths between 0. 01 nm and 20 nm. This and gamma rays can only be studied by sending instruments to space.
