bg Theoretical astrophysics : Asaf Pe'er - downloads
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Asaf Pe'er
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    • Physics for all

    During their transition year (10th grade), high school students visit the physics department in UCC for one week. At the end of this week, the students are asked to write a question in physics, of their interest. I collect this questions, and attempt to provide accurate answers accessible to all.
    I quote the questions as given to me, without any modification. The only thing I did was to group the question in accordance to the subject.

    Student ? Feel free to ask me any question in physics you have ! I will make an effort to answer it properly, and post it on this webpage.

    Expert ? I would be grateful for any suggestions / typos or any other mistake that might have occured in my answers.

    Special thanks to David Rea and Niall O'Murchadha for their help.

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    Preliminary: What is physics

  • What is Physics?
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    Philosophy

  • Does everything exist / happen at once?
  • Is the universe made of time?
  • Are there parallel universes?
  • What technology will we have in the future thanks to physics?
  • Where do the laws of physics come from?
  • How many dimensions are there and how come I can only move through three?
  • Can physics prove whether God exists?
  • How do I kill a mocking bird?
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    Experimental facts

  • Why can nothing travel faster than the speed of light?
  • Why is there 24hrs in a day?
  • Why does gravity not repel things or like charges attract?
  • Is the speed of light in a vacuum constant? Why/why not? If not, how can one vary it?
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    Astrophysics and relativity

  • Does the universe ever end, i.e. what lays beyond or is there anything beyond?
  • Is time travel possible?
  • What is a black hole?
  • Did the Big Bang happen?
  • Is the world going to dissolve to nothing?
  • What is dark matter?
  • What is dark energy?
  • What is space?
  • Where does water come from? How was it first created?
  • If the earth disappeared in the morning, would anyone out there notice?
  • What is the universe made of?
  • Theoretically, could you go far enough into space to slow down time enough for it to stop?
  • What causes gravity?
  • What is outside the universe? What was there before the Big Bang?
  • Does the Sun orbit around anything? What is a t the centre of the galaxy?
  • Where is the centre of the universe? Is there light in a black hole?
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    Waves, light and color

  • How can you make black if black is the absence of colour?
  • Why is part of the sky red/orange/pink during sunset/sunrise, yet it isn't those colours during the day?
  • Myth: Owls and other animals can see ultra-violet or infra-red light. If an object was coloured infra-red or ultra-violet, how would this hypothetical object appear to humans?
  • How does auto-tune work? When it changes the speed is the pitch changed and vice versa?
  • How do humans determine the source of a sound, and how accurately can they do this?
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    Mechanics

  • If every action has an equal opposite reaction, why isn't the world at a stand-still?
  • If a fly jumps up and down at the resonance frequency of a building, would it fall or seriously shake?
  • Why is the world round?
  • How heavy is the Earth? What method is used to figure this out?
  • Why is the solar system flat?
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    Particle and atomic physics

  • What does string theory prove?
    How possible is string theory?
  • What is anti-matter?
  • What is the Higgs Boson?
  • How is a massless particle possible? If something exists, must it have mass?
  • How strong can nuclear bombs get?
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    Chemical physics

  • Is there a limit to the number of elements that can exist? Why/why not?
  • Why are clouds white and fluffy? Why are they not a different colour and flat?
  • What state of matter is a flame - or is it?
  • Q: Why was the noble gas sad? A: Because all his friend argon.
    Q: Why are all his friend gone? A: He just can't seem to bond with other elements.
  • Why does glue not stick to the inside of the tube?
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    Electricity & Magnetism

  • How do windmills create electricity?
  • Why do electromagnetic waves move in an oscillatory motion when they come across an electron?
  • Can lightening strikes be used as energy source? (if a conductor is connected to a generator on something like that)
  • Can radio telescopes get FM signals, i.e. can I listen to Red FM in space?
  • How can birds stand on electrical power lines without being executed?
  • Why are magnets magnetic - what makes things magnetic?
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    Quantum mechanics

  • What causes "spooky force" between entangled particles?
  • How do quantum computers take advantage of quantum mechanics?
  • Why does matter have well defined boundaries as opposed to a pobablistic mess, like the positions of quantum particles such as electrons?
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    Biological physics

  • Why is it that we stop growing but yet our hair and nails continue to grow?
    • Created by Asaf Pe'er. First created: Nov. 12th, 2002. update: May. 5th, 2004, Nov.24th, 2004, Nov. 30th, 2010, Nov. 18th, 2015. Webpage last update: Sep. 15th, 2016