The Biggest Misconception in Physics

The typical example people use to illustrate that energy isn't conserved is that photons get red-shifted and lose energy in an expanding universe. See this excellent Veritasium video [0]. But there's a much more striking example that highlights just how badly energy conservation can be violated. It's called cosmic inflation. General relativity predicts that if empty space in a 'false vacuum' state will expand exponentially. A false vacuum occurs if empty space has excess energy, which can happen in quantum field theory. But if empty space has excess energy, and more space is being created by expansion, then new energy is being created out of nothing at an exponential rate! Inflation is currently the best model for what happened before the Big Bang. Space expanded until the false vacuum state decayed, releasing all this free energy to create the big bang. Alan Guth's book, The Inflationary Universe, is a great book on the topic that is very readable. [0] [this video]