Flashcards
Electromagnetic waves, red-shift and the expanding universe
Cards in this deck (9)
- 1Physics P1 6.1 Electromagnetic Waves
- 2All electromagnetic waves travel at the speed of 300 million m/s through space or in a vacuum.The wave equation
- 3The Doppler effectRed Shift
The light waves are stretched out if the star or galaxy is moving away from us. The wavelength of the waves is increased. We call this red-shift because the spectrum of light (from a galaxy or star) is shifted towards the red part of the spectrum.
- 4The faster a distant galaxy is moving away from us, the greater its red-shift.The further away a distant galaxy is from us, the greater its red-shift.
- 5Blue shift The light waves are squashed together if the star or galaxy is moving towards us. The wavelength of the waves is reduced. We call this a blue-shift because the spectrum of light is shifted to the blue part of the spectrum.Red-shift shows us that the universe is expanding because the stars or galaxies are moving away from us.
receding/recession - moving away - 6Big Bang The universe is expanding after exploding suddenly in a BIg Bang from a very small point. Space, time and matter were created in the Big Bang.Cosmic microwave background radiation
CMBR can only be explained by the Big Bang. It was created as high-energy gamma radiation just after the Big Bang. It has been travelling through space since then. As the universe expanded, it stretched out to longer wavelengths and is now microwave radiation. It has been mapped out using microwave detectors on the ground and on satellites. - 7Steady sate theory galaxies are being pushed apart because of matter entering the universe through white holes.Dark energy - unknown energy that is causing galaxies/stars to move away from each other and therefore acts against gravity.
- 8If the density of the universe is less than a certain amount, it will expand forever. The stars will die out and so will everything else as the universe heads for a BIG YAWN.If the density of the universe is more than a certain amount, it will stop expanding and go into reverse. Everything will head for a BIG CRUNCH.
- 9Microwaves are used for satellite phone, TV links and satellite broadcasting . This is because they can travel between satellites and they spread out less.Radio waves
The shorter the wavelengths:
the more info they can carry
the shorter their range
the less they spread out
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- Flashcards on Untitled, created by aj02firestar on 06/01/2015.
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- aj02firestar · Jan 2015
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- Feb 19, 2016
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