ASTR 101 Study Guide - Quiz Guide: Diffraction, Electromagnetic Spectrum
Document Summary
Roemer (1680"s) was the first to measure the speed of light using jupiter"s moons -> c=299,790 km/sec or about 185,000 mi/sec. Maxwell (1850"s) showed that light is energy carried in the form of opposite but supporting electric and magnetic fields in the shape of waves, i. e. self- propagating electromagnetic waves. The wavelength of the light determines its characteristics. For example, short wavelengths are high energy gamma-rays and x-rays, long wavelengths are radio waves. The whole range of wavelengths is called the electromagnetic spectrum. Astronomy is a passive science, but observing phenomenon at different wavelengths has several advantages to overcome the lack of making experiments. There are different physics at different wavelengths, for example, high energy magnetic fields are seen in the x-ray, radiation from heat is seen in the infrared. However, note that observing at different wavelengths requires vastly different technology and conditions.
