Hong Kong scientists announced that they had determined the idea of time travel is impossible by proving nothing can travel faster than the speed of light.

The finding is contained in a study done by a research team from Hong Kong University of Science and Technology.

The study was published Monday in a scientific journal "Physical Review Letters" in the United States.

"The study, which showed that single photons also obey the speed limit c, confirms Einstein's causality, that is, an effect cannot occur before its cause," the university said on its website.

"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." said Professor Du Shengwang, who led the study.

The possibility of time travel was raised 10 years ago when scientists discovered the optical pulses in some specific medium might propagate information in a faster-than-light speed.

"Our findings will also likely have potential applications by giving scientists a better picture on the transmission of quantum information." Du said.

Source: Global Times