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Energy Through Space
• Energy is transmitted through space as electromagnetic waves.
• The movement of these waves through space supports the concept of the ‘Big Bang’ ~ particles are still moving as a result of a gigantic explosion from a small, concentrated area.
• Angstrom: Very small measurement used to measure the distance between wavelengths of EM radiation.
• Radial Velocity: The speed of a wavelength toward or away from radar.
• Doppler Shift: Change in frequency toward or away from an object. [Red shift is away and blue shift is toward]
• Radiation: The transfer of energy by waves.• Absorption Spectrum: Spectrum of light waves as
they are received. (What we see)• Radiation Spectrum: Spectrum of light waves as
they are transmitted.• Vacuum: An area with little or no pressure (outer
space).• Wavelength: Distance between wave crests.• Frequency: Number of cycle that pass in a
specific period of time.• Lambda: The frequency of a wavelength
What elements are in that star?
• We can determine which elements are found in distant stars by using a spectroscope to observe the wavelengths of energy being transmitted from the star.
For example . . .• Each element emits a
unique wavelength of light.
• The colors of the spectrum from long wave to short wave are: Red, Orange, Yellow, Green, Blue, Indigo and Violet [ROYGBIV]– Long = Red
– Short = Violet
Different light = Different spectrum
• A light bulb will emit all the colors of the spectrum, whereas gas tubes will only emit the spectra of the specific element.
• Elements can be identified by their unique, characteristic spectra.
• As the frequency of electromagnetic waves increases, the wavelength decreases. [Inverse relationship]
• The width of the visible light spectrum is a very small portion of the total spectrum.
• As we move across the spectrum from gamma rays (short waves) to radio (long waves), wavelength increases and frequency decreases. Therefore, infrared waves are longer than visible waves.
Balmer Absorption Lines
• Balmer Absorption lines are the accepted values for spectral wavelengths.
• We can determine the radial velocity and direction of wavelengths by comparing them to the Balmer lines.
Spectral analysis determines several star features:
1. Composition; Determined by distinguishing the elements found within the star by assessing the emitted wavelengths.
2. Radial Velocity; difference between actual and accepted (Balmer) wavelength value x speed of light divided by the accepted (Balmer) value.
3. Direction of movement; Red shift/away or blue shift/toward.