Dr. J. Richard Gott – Professor of Astrophysical Sciences Princeton University
Richard Gott introduced the idea of cosmic string back in 1991. As the name suggests, these are stringlike objects that some scientists believe were formed in the early universe.
These strings may weave throughout the entire universe, thinner than an atom and under immense pressure. Naturally, this means they’d pack quite a gravitational pull on anything that passes near them, enabling objects attached to a cosmic string to travel at incredible speeds and benefit from time dilation. By pulling two cosmic strings close together or stretching one string close to a black hole, it might be possible to warp space-time enough to create what’s called a closed timelike curve.
Using the gravity produced by the two cosmic strings (or the string and black hole), a spaceship theoretically could propel itself into the past. Gott is the author of Time Travel in Einstein’s Universe:The Physical Possibilities of Travel Through Time.