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25 Cards in this Set
- Front
- Back
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Edexcel P1 Topic 3
Waves & the Universe |
Waves & the Universe |
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What galaxy is the Solar System part of?
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Milky way galaxy
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What is a galaxy?
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A collection of stars
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What is the universe made up of?
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All the galaxies
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What is spectroscopy?
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When a CD, DVD or prism is used to split up the colours of visible light into a spectrum in order of wavelength
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What other data have scientists been able to collect due to modern day telescopes? |
* observation of galaxies much further away in greater detail * the observation of astronomical objects that don't emit visible light e.g. radiowaves * the ability to collect more data |
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Why are some telescopes located outside the Earth's atmosphere?
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So that the telscope can detect all waves that are normally blocked out by the earth's atmosphere. Also, the light waves will not be relected or refracted by clouds and dust that are found in the earth's atmosphere. |
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What are landers and how can they gather evidence for life beyond earth?
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They can do experiments on the soil of other planets to look for chemical changes that may have been caused by living organisms. |
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What are space probes and how can they gather evidence for life beyond earth?
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They can scan and photograph planets so that scientists can look for evidence like channels created by flowing water- that could suggest there was or is life on another planet.
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What are rovers and how can they gather evidence for life beyond earth?
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Rovers can take close up pictures of rocks and soil, and can cover the surface of planets.
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What is SETI?
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Search for extraterrestrial intelligence. They analyse the waves coming in from space, to see if there are signals that could have been created by intelligent beings.
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What is the lifecycle of an average star?
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Nebula -> protostar -> average star -> red giant -> white dwarf
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What is a nebula?
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A large cloud of gas and dust |
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What is the role of gravity in the life cycle of stars?
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* Gravity pulls together the nebula, and as the contracting star gets more dense, it heats up and begins to glow. It gets compressed even more and forms a protostar.* Gravtiy balances the pressure of the fusion reactions
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What is the lifecycle of a massive star?
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Nebula -> protostar -> massive star -> red supergiant -> supernova -> neutron star / black hole
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What is a supernova?
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An explosion caused by the rapid collapse of a red supergiant- outer layers blow out into space making the star shine very, very brightly.
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When is a neutron star formed?
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If the supernova leaves behind a core of around two solar masses, it forms a neutron star- which is very dense and made out of neutrons.
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When is a black hole formed instead?
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If a supernova leaves behind a core of four or more solar masses, then a black hole is created- which has such a strong gravitational pull that even light can't escape it.
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What is the steady state theory?
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A theory about the universe that states that the universe has always existed, is constantly expanding, and new matter is being created all the time.
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What is the big bang theory?
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A theory about the universe that states that the universe started out as a tiny point of concentrated matter 13.5 billion years ago, and has constantly been expanding.
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What is the evidence for the big bang theory?
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* Red shift- where galaxies look red becasue they are moving away from us * Cosmic background radiation- the whole universe radiates microwaves, as a decreasing result of the big bang.
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Why is the big bang theory accepted as the main theory today?
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Because although the steady state theory can explain red shift, it can't explain why cosmic background radiation exists.
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What is the Dopler effect?
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It explains that if a wave source is moving relative to an observer, there will be a change in the observed pitch e.g. when a moving source goes away from you, its waves become 'stretched'; the wavelength is longer; the pitch is lower. |
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How does this link to red shift?
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Red shift occurs when galaxies move away from us- the light waves behind a galaxy become stretched, making the frequency lower- and red is the lowest frequency of the spectrum of visible light.
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Which galaxies have the most red shift-
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The ones furthest away and therefore travelling at the highest speed. |
