It would take a civilization far more advanced than ours, unbelievably advanced, to begin to manipulate negative energy to create gateways to the past. But if you could obtain large quantities of negative energy-and that's a big "IF" - then you could create a time machine that apparently obeys Einstein's equation and perhaps the laws of quantum theory.
Michio KakuIf you could meet your grandkids as elderly citizens in the year 2100 … you would view them as being, basically, Greek gods… that's where we're headed.
Michio KakuA hundred years ago, Auguste Compte, ... a great philosopher, said that humans will never be able to visit the stars, that we will never know what stars are made out of, that that's the one thing that science will never ever understand, because they're so far away. And then, just a few years later, scientists took starlight, ran it through a prism, looked at the rainbow coming from the starlight, and said: "Hydrogen!" Just a few years after this very rational, very reasonable, very scientific prediction was made, that we'll never know what stars are made of.
Michio Kaku