Time Travel Impossible, Mini "Big Bang" Hints
A new material that simulates the motion of particles after the big bang shows that time can move in just one direction, physicists say.
In a new study, Igor Smolyaninov and Yu-Ju Hung of the University of Maryland simulated the birth of the universe using advanced materials that can bend light in unusual ways.
Their device supports the idea that the forward marching "arrow of time" cannot curve back on itself to undo events that have already happened.
So far time travel hasn't been possible in real life, Smolyaninov said, and this new material suggests it won't ever be possible. (Related: "Time Will End in Five Billion Years, Physicists Predict.")
The new big bang simulator is tiny—just fractions of an inch (20 micrometers) wide. It's built from alternating strips of gold and
