Radiant Energy • Radiant energy comes from the sun, or other stars. • It reflects off objects like the Earth, Moon, Planets, and Satellites. • Radiant energy is classified by its wavelength in a system called the electromagnetic spectrum.
Electromagnetic Spectrum • The electromagnetic (E-M) spectrum includes 8 different types of E-M waves that travel through space. • AM/FM • TV • Microwaves • Infrared • Visible Light • Ultraviolet Light • X-Rays • Gamma Rays
Arranged from left to right • Longest wavelength (Radio) to shortest wavelength (Gamma Rays). • Lowest frequencies (Radio) to highest frequencies (Gamma Rays).
Visible light: • This is made up of the colors of the rainbow ROY G BIV • Refraction: Bending of light as it passes from one substance to another.
- Telescopes Four Views of the Crab Nebula • Different type of telescopes collect electromagnetic radiation at different wavelengths. Astronomers are able to learn a great deal about the Crab Nebula by examining these different images. The images are shown at different scales.
Spectroscopes • These scopes bend light reflected from an object into colors. • Spectroscopes are used to obtain information about stars • Chemical Composition • Each star has its own unique chemical composition, fingerprint. • Each element absorbs different wavelengths, and each wavelength is recorded as a dark line on a spectrum.
Temperature • Elements at different temperatures have different line spectrums. • By comparing a star’s line spectrum with the known spectrums of elements at different temperatures we can infer how hot a star is.
Star Spectrums • Astronomers use line spectrums to identify the chemical elements in a star. Each element produces a characteristic pattern of spectral lines.