//crash course in the big bang! --/ --> our universe is expanding - the space between objects is increasing (objects are becoming fundamentally smaller) --> einstein --> different cosmological models created by the GR equations, added a new term called the cosmological constant, creating his model - this model dictated that space was curved in a way (non-euclidean geometry) - also showed you could go around the entire universe - could circumnavigate the globe - **fatal flaw** --> if there are density differences there will not be a static universe! the original GR equations created by einstein showed us that the universe was hotter and smaller in the past, and at a finite point in the past the universe had a size of 0 competing hypothesis --> there was an explosion event steady-state theory: as space expands, matter is spontaneously created, keeping a fixed average density, # Dark Matter and Dark Energy //brief rundown //why special - only 1/6th of our universe is made of protons - 5/6ths of the matter does not interact with light - this forces the universe to expand, increasing the space between galaxies/celestial objects - the expansion of the universe has accelerated - we would expect the expansion of the universe to decrease! # The Topology of the Universe - A Persistent Problem --> universe flatness - horizon problems - if inflation occured - if space kept expanding and spawning baby universes (multiverse theory)