The LARGE POP TREMENDOUS EXPLOSION GIANT POW ENORMOUS WALLOP BIG BANG(theory)!
What IS the Big Bang? One of many plausible theories that tries to answer the question: How did the universe get to be the way it is now? Where does it come from? Currently most popular theory Would have happened 13.7 Billion years ago NOT a regular, 3D explosion
Big Bang an explosion? WRONG 3D Explosion: - Central event - Already exists in 3D space - High pressure in the middle, forces stuff to fly out CORRECT Space itself expands - No center - No density/pressure change - The space between things is getting bigger, but things are not getting bigger!
WHAT OBSERVATIONS LEAD US TO THE IDEA OF A BIG BANG?
1. The Universe is: Our Observations spread out relatively evenly all over the universe Physical laws of reality seem to act the same everywhere Idea: the Cosmological Principle If the Universe was lumpy, uneven, or lopsided, the Big Bang model wouldn t work so well
Our Observations 1. (continued) Cosmic Background Radiation Temperature of 3 Kelvin, uniformly spread out in all directions Afterglow of the Big Bang? Evidence of cosmological principle?
Our Observations 2. Distances between galaxies are getting larger - Not like bomb fragments from an explosion - Space itself is expanding - The farther away it is, the faster it recedes (Hubble Constant). V = Hd Things farther away recede from us faster than things close to us Get out the rubber bands!
So, are Galaxies really rushing away from us at high speeds? No. The dots on the rubber band aren t flying away relative to space. The space is expanding, making the distances longer and stretching out the distance the light has to travel. Galaxies are barely moving!
Rewind the Tape If the universe is currently expanding, in the past it must have been smaller. How far back can we see? 1x10-43 seconds after BB Planck Era
Olber s Paradox Q: Why is there darkness between the stars at night? Discuss with your table
Olber s Paradox A: The rest of the stars are so far away, light hasn t had time to reach us yet. SOME light will NEVER reach us! Minute Physics!!! This can only be true if the universe is expanding.
How Large is the Observable Universe? Discuss with your table
How Large is the Observable Universe? WRONG 13.7 billion years old, so the radius is 13.7 billion light years. CORRECT Because space is expanding, the distance the light has gone in 13.7 billion years ends up being longer. The distance to the farthest object we can see is 46 billion light years! (about 3 times farther)
Hubble s Law &Constant Can galaxies move away from us faster than the speed of light? Discuss with your table
Hubble s Constant WRONG The more distant the galaxy, the faster it recedes from us, but never is faster than light. - I mean, come on, nothing can travel faster than light! CORRECT Yes, really far away stuff can recede FASTER THAN LIGHT, because Einstein s rules apply to stuff in space, not space itself. - The distance at which things recede at c: Hubble Distance -Currently 14 billion ly, but is getting larger
So, can we see past the Hubble Distance? Discuss with your table
So, can we see past the Hubble Distance? WRONG No way. If stuff is receding at the speed of light or faster, light will NEVER catch up to us! CORRECT Yes again! The rate of expansion of the universe is changing, so the Hubble Distance is getting larger. HOWEVER, anything farther than 16 bly away (right now!) will never be seen by us.
Are WE expanding too?? If space is expanding, does that mean stuff within space, like us is also expanding? Discuss with your table
Are WE expanding too?? WRONG Yes. If the universe is expanding, and we re in it, then of course we re also expanding. CORRECT No. Space is getting bigger, but objects in space stay pretty much the same size. The expanding force exerted on your body (and everything else) is in equilibrium with all other forces...for now.
What is our FATE? Will the universe keep expanding forever? Is the expansion constant, or will it slow down or speed up? How will it affect us?
Currently Two main forces are acting on the universe on the largest scale: Gravity (pulling things in) Dark Energy (pushing the universe apart) Right now, Dark Energy is thought to cause the expansion of the universe to accelerate.
Open model of the Universe Universe expands forever, things eventually get virtually infinitely far away from each other. Ends in a Big Freeze or Big Rip
Closed Model Universe expansion slows and eventually comes to a stop, then rushes back in on itself. Ends in a Big Crunch
What If the Big Crunch led to a Big Bounce?!?!
So that s the Universe. What about the laws of the Universe? MOMMY, WHERE DOES PHYSICS COME FROM?
The Beginning of Physics As the universe came into creation, energy and matter still had to sort itself out Physics, as we know it today, was not always like it is now If initial conditions had been different, physics (and everything else!) would be different too!
The Large Hadron Collider (LHC) at CERN Trying to re-create Big Bang-like conditions Different fundamental forces evolved at different points in the universe s creation, condensing out of one unified force.
The Beginning of Physics
The Beginning of Physics Gravity: matter attracting other matter, warping spacetime Strong Nuclear Force: Holds particles together in the nucleus Weak Nuclear Force: Causes nuclear decay, particles transform Electromagnetism: Positive and negative charges between particles, light, magnetism
It s uneven! The Problem with Physics Of the Four FF, Gravity is billions of times weaker than the other three. Different sets of laws for Quantum world, Newtonian world, and Relativistic world.
The ULTIMATE GOAL: T.O.E. A Theory of Everything, that explains everything in the universe, at all speeds and size scales. Combines Gravity with the other three forces.