Unit 2 Flashcards
(25 cards)
absorption spectrum
spectrum showing dark lines at some narrow color regions (wavelengths). The lines are formed by atoms absorbing light, which lifts their electrons to higher orbits
blue shift
displacement of the spectrum to shorter wavelengths in the light coming from distant celestial objects moving toward the observer
compound telescope
use a combination of lenses and mirrors
continuous spectrum
Visible light can be separated into its parts by using a prism. The image you see here is a continuous spectrum of all visible light. This can also be done for other frequencies of EMR
Doppler shift
observed change in the frequency of a wave when the source or observer is moving
electromagnetic spectrum
range of wavelengths or frequencies over which electromagnetic radiation extends
frequency
number of complete wavelengths that pass a point in a given time
gamma rays
high energy, high frequency photon of electromagnetic radiation
infrared radiation
electromagnetic radiation at wavelengths longer than the red end of visible light and shorter than microwaves (roughly between 1 and 100 microns). Almost none of the infrared portion of the electromagnetic spectrum can reach the surface of the Earth, although some portions can be observed by high-altitude aircraft (such as the Kuiper Observatory) or telescopes on high mountaintops (such as the peak of Mauna Kea in Hawaii).
microwaves
electromagnetic radiation which has a longer wavelength (between 1 mm and 30 cm) than visible light. Microwaves can be used to study the Universe, communicate with satellites in Earth orbit, and cook popcorn
photon
particle of electromagnetic radiation
radiation
energy emitted in the form of waves (light) or particles (photons)
radio telescope
gather radio emissions from stars, galaxies, and quasars through the use of a radio antenna and a radiometer
radio waves
electromagnetic radiation which has the lowest frequency, the longest wavelength, and is produced by charged particles moving back and forth; the atmosphere of the Earth is transparent to radio waves with wavelengths from a few millimeters to about twenty meters
red shift
change in the wavelength of light due to an object moving away from the observer
reflecting telescope
have two mirrors–one to gather light and reflect it to the second mirror
refracting telescope
basic telescope with two lenses: one larger objective lens and a smaller lens
spectral lines
Astronomers use spectral lines to learn the following about objects in space: temperature, density, magnetic field, speed of movement, and elements present
spectroscope
device that separates EMR into its component parts
spectroscopy
an object’s light broken down into its different colors
telescope
device used to enlarge images of distant objects
ultraviolet
electromagnetic radiation at wavelengths shorter than the violet end of visible light; the atmosphere of the Earth effectively blocks the transmission of most ultraviolet light
visible light
electromagnetic radiation at wavelengths which the human eye can see. We perceive this radiation as colors ranging from red (longer wavelengths; ~ 700 nanometers) to violet (shorter wavelengths; ~400 nanometers.)
wavelength
distance from one point on a wave to the same point on an adjacent wave
