Expert: Courtney Seligman - 8/24/2009

Question
Hi, I saw a special on tv that theorized that time travel was possible either through the use of a machine that can spin particles faster than the speed of light or through a worm hole.  However, I understood nothing can go past the speed of light.  A person could not therefore go back in time, but, perhaps a message.  A subatomic, molecular message, that could go back in time to the point where a machine were invented to create this spin.  Is this possible. Don't all messages, be they subatomic, orf molecular contain mass, and therefore it will not work. Thanks.

Answer
You are correct in presuming that given our current understanding of the laws of physics, none of what you refer to is in any way possible. This is, unfortunately, quite common in tv programs. Even ones that have some basis in fact tend to veer off into topics that although interesting and exciting, have no connection to reality. The producers think that makes the programs more interesting, and ignore the fact that it makes them more fiction than science.