Scientists learn about the Universe by collecting Wave- Energy from the Electromagnetic Spectrum.
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Transcript of Scientists learn about the Universe by collecting Wave- Energy from the Electromagnetic Spectrum.
The Electromagnetic- Spectrum is a continuum depicting the full range of
Electromagnetic Radiation,
with the longest wavelength at one
end, and the shortest at the other.
Electromagnetic Radiation is energy in the form of a Wave, resulting from the motion of electric charges and the magnetic fields that they produce.
The Spectroscope and the Visible Spectrum
When light passes through a prism and out again, they are refracted, or bent, forming a band called the Visible Spectrum.
Stars emit light that falls within the visible spectrum.
Scientists use an instrument called a Spectroscope to separate this starlight into its colors so that it can be studied.
Spectroscopes break light into three different types.
• Continuous Spectrum
• Emission Spectrum
• Absorption Spectrum
Each element gives a unique spectrum. The position of the lines relative to one another changes from element to element. As a result, the emission spectrum is a fingerprint of the element/molecule that generates it.
By studying these different spectra, and comparing the emission/absorption spectra of stars to those of gaseous elements in a lab, astronomers can determine the types of elements that make up the atmospheres of the stars that emitted the light.
Emission Spectrum of Hydrogen
Absorption Spectrum of Hydrogen
The Doppler Effect
Scientists use Spectral Analysis to not only determine what gases are present in stars, but also how they are moving relative to the Earth.
This is possible because of a phenomenon called the Doppler Effect.
Person A
Person B
Fire Engine at Rest
Fire Engine moving to the right, and toward Person B
Waves stretched Waves compressed
Scientists have even been able to use Doppler Shift to detect
the “wobble” of Stars with orbiting massive planets.
Stars emit energy in wavelengths that include…
1. Visible Light
2. Infrared3. Ultraviolet
4. X-Rays 5. Gamma Rays.
Optical Telescopes
1. Telescopes gather far more light than the unaided eye can gather.
2. Telescopes magnify images.
Refracting Telescope
Refracting Telescope- Uses two lenses.
The Lense, at the front of the tube, gathers light.
The Eyepiece magnifies the image collected by the lense. (limited in size by tendency of large lenses to bend)
Reflecting Telescope- Uses one large lense to gather and focus light, then reflect the image to a small mirror, then to an eyepiece on the side. Since the lense is supported, reflecting telescopes can be much larger.
Reflecting Telescope
Radio Telescopes
(technical term for really big satellite dishes)
Used to detect energy waves given off at frequencies lower than visible light.