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Black Holes Quantum Mechanics 1. We’ve seen that masses warp spacetime – the bigger the mass, the more the warping. The same mass can cause more warping.

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Presentation on theme: "Black Holes Quantum Mechanics 1. We’ve seen that masses warp spacetime – the bigger the mass, the more the warping. The same mass can cause more warping."— Presentation transcript:

1 Black Holes Quantum Mechanics 1

2 We’ve seen that masses warp spacetime – the bigger the mass, the more the warping. The same mass can cause more warping if it is more concentrated The Sun Same mass, smaller radius For reference only: The steeper the walls, the faster an object has to go to escape.

3 We’ve seen that masses warp spacetime – the bigger the mass, the more the warping. The same mass can cause more warping if it is more concentrated The Sun Same mass, smaller radius Same idea taken to an extreme A Black Hole Escape speed is greater than the speed of light The “Event Horizon” Where escape speed = the speed of light Gravitational time dilation is total!

4 Far from a black hole, the curvature of spacetime a)is the same as it would be at the same distance from a star with the same mass as the black hole. b)is greater than it would be at the same distance from a star with the same mass as the black hole. c)is less than it would be at the same distance from a star with the same mass as the black hole. d)does not indicate that the black hole is there.

5 Fundamental particles and forces Particles properties: mass, charge, spin Particles aren’t really spinning balls! It’s just a model for a property we observe.

6 Fundamental particles and forces You do NOT need to learn this! BUT, we will be referring to “fermions” and “fermionic matter” later… quarks: up, down, strange, charmed, top, bottom

7 Fundamental particles and forces However, you should understand that “antimatter” is REAL! E = m c 2 Annihilation Pair production

8 Fundamental particles and forces There are only four known forces in our universe Exchange particles: – – Charged particles exchange photons when they interact

9 What are the three properties of particles? A) mass, density, temperature B) strong, weak, electromagnetic C) spin, charge, mass D) gluons, photons, gravitons E) fermions, quarks, and leptons

10 The Uncertainty Principle We cannot precisely measure both a particles position and its momentum (velocity). Why not?

11 The Uncertainty Principle How would we measure the speed and position of this baseball? Photographs? A radar gun? In other words, we would bounce photons off of it.

12 The Uncertainty Principle What about this electron? – Bouncing photons off an electron will completely change its position and velocity! But this is much more than a technical difficulty…

13 The Uncertainty Principle Electrons aren’t really little balls… – They’re waves… Why do we say that?

14 The Uncertainty Principle If you send particles (think paintball bullets) through two separate slits, you get two spots on the wall If you send waves through two separate slits, the waves interfere with each other, and you see an interference pattern on the wall So what happens when you send electrons through two slits?

15 Electron two-slit interference pattern The Uncertainty Principle

16 Ok, electrons are waves. So what? Where is this wave? The meaning of “position” is unclear You can make the wave packet narrower, but that means making the wave that represents momentum wider. That’s the Uncertainty Principle

17 The Uncertainty Principle uncertainty in location x uncertainty in momentum ≥ Planck’s constant uncertainty in energy x uncertainty in time ≥ Planck’s constant

18 Astro-Cash Cab! Jasmyn Colt Jessica Corey

19 1) Which of the following ideas is not a consequence of the quantum revolution? All tiny particles, like photons, have a dual wave-particle nature. Particles of matter and antimatter completely annihilate each other, producing energy, when they meet. The force of gravity is a result of the curvature of spacetime. Particles belong to two categories: fermions and bosons. Quantum degeneracy pressure can prevent the core of a star from collapsing.

20 2) The distance from the center of a black hole where the escape speed is equal to the speed of light is called the _______ _________.

21 3) True or False? Gravity is the strongest known force in the universe.

22 4) How does a particle differ from its anti-particle? It has opposite mass. It has opposite charge. Its wave-function has the opposite sign. all of the above none of the above


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