A leading biological anthropologist has proposed that the mysterious beings behind countless UFO sightings could be time-travelling humans from Earth's future, returning to monitor their ancestors as ...

Professor Carol Oliver suggests that time dilation, a cosmic phenomenon, may deter aliens from visiting Earth, as ...

Aliens could, in theory, reach Earth but would never truly go home again, according to physicists who say Einstein's laws of ...

From phone boxes and flux capacitors to black holes and hot tubs, sci-fi has created plenty of ways to explore the fourth dimension. When you purchase through links on our site, we may earn an ...