Time Travel 'Impossible,' Scientists Say

From Family Matters to The Simpsons and, of course, Back to the Future, the idea of time travel has become a common theme in American pop culture. There's no doubt, then, that many will be disappointed to hear of a new report from a group of Hong Kong scientists which suggests that traveling through time is simply impossible.

The report comes from the Hong Kong University of Science and Technology, where researchers under the direction of Professor Shengwang Du have concluded that single photons (the absolute smallest particle of light) simply can't travel faster than light. The finding is significant because in order for time travel to work, photons have to disobey the laws of physics. (Source: time.com)

Report: Effects Can't Occur Before Their Cause

"The results add to our understanding of how a single photon moves," Du said.

"By showing that single photons cannot travel faster than the speed of light, our results bring a closure to the debate on the true speed of information carried by a single photon. Our findings will also likely have potential applications by giving scientists a better picture on the transmission of quantum information."

What Du's report does is demonstrate that a single photon must obey the universe's speed limit, and that "an effect cannot occur before its cause." (Source: pcmag.com)

Scientists Likely to be Surprised, Disappointed

The report is likely to disappoint more than sci-fi nerds.

It will also come as something of a surprise for members of the scientific community, who in the past few years have been paying more attention to the idea of time travel. That's because it wasn't long ago that scientists discovered "superluminal propagation of optical pulses" -- which, in layman's terms, means that optical pulses could conceivably move faster than the speed of light, meaning time travel might actually be possible.

Du says that was all just a superficial effect and that the phenomenon known as "superluminal propagation of optical pulses" is incapable of processing and transmitting actual information.