Metamaterials are periodic structures that can be engineered to steer light in specific ways. The trick is to manipulate the properties of the "electromagnetic space" in which light travels by controlling the values of the permittivity and permeability of this space.
In recent years, physicists have had a great deal of fun using metamaterials to build all kinds of exciting devices, the best known being invisibility cloaks which steer light around an object, thereby concealing it from view.
But metamaterials have a more profound application because there is a formal analogy between the mathematics of electromagnetic spaces and the mathematics of general relativity and the spacetime it describes.
That means it is possible to reproduce inside a metamaterial an exact copy of many of the features of spacetime. We've looked at a number of these ideas, such as how to build a black hole and even create a multiverse.
Today, Igor Smolyaninov at the University of Maryland, College Park, says it is possible to recreate the arrow of time inside a metamaterial. Such an experiment, he says, allows the experimental study of one of the great outstanding mysteries in science: why the cosmological arrow of time is the same as the thermodynamic arrow of time.
At the same time, the exercise gives a curious insight into the potential for time travel.
To read the rest of the article, click here."Hogwash. The paper is good, but the MIT Tech writer is exaggerating. The paper does not prove the impossibility of time travel to the past. That claim is false in my opinion." - Jack Sarfatti