Dark Matter and the Ultimate Fate of the Universe
Join UCSD Physicist Kim Griest as he takes you on an exploration of two of the major unsolved questions in the physical sciences: What might be the fate of the universe and what is the nature of the dark matter which ultimately decides this fate?
Once the notion that the universe started with a rapid inflation nicknamed the Big Bang became accepted by the majority of scientists, the ultimate fate of the universe became a valid cosmological question, one depending upon the physical properties of the mass/energy in the universe, its average density, and the rate of expansion.
The theoretical scientific exploration of the ultimate fate of the universe became possible with Albert Einstein’s 1916 theory of general relativity.
The dark matter problem has been around for decades, and there is now consensus that we don’t know what the most common material in the Universe is. It is “seen” only gravitationally, and does not seem to emit or absorb substantial electromagnetic radiation at any known wavelength.
It dominates the gravitational potential on scales from tiny dwarf galaxies, to large spiral galaxies like the Milky Way, to large clusters of galaxies, to the largest scales yet explored.
The universal average density of dark matter determines the ultimate fate of the Universe, and it is clear that the amount and nature of dark matter stands as one of the major unsolved puzzles in science.