The classic Star Trek episode “Tomorrow Is Yesterday” was a time travel adventure triggered by a “black star” – but what was this mystery object?
A classic episode of Star Trek saw the USS Enterprise encounter a mysterious phenomenon called a “Dark Star,” but it’s actually a very familiar space phenomenon. One of Star Trek’s most famous time travel episodes, “Tomorrow Is Yesterday,” saw the USS Enterprise stranded in the 1960s. This was because of an encounter with a mysterious phenomenon called a black star, described as an undetectable stellar object which exerts a tremendous gravitational force. Modern viewers understandably assume the black star is fictional, but in reality it’s a very familiar force.
The black star described in “Tomorrow Is Yesterday” is actually a black hole. Albert Einstein first predicted the existence of these back in 1916, as part of his General Theory of Relativity. They remained purely theoretical for decades, and were referred to by a number of different names – including “black star,” which was a fairly common one. In 1967, the physicist John Wheeler (1911-2008) coined the term “black hole,” and it quickly caught on. Not quickly enough to turn up in “Tomorrow Is Yesterday,” though, which aired that same year.
Star Trek’s Black Star Was Scientifically Accurate – For Its Time
Most viewers focus on the pseudoscience of Star Trek, from dilithium to transporters. It’s easy to forget, though, that many aspects of Star Trek’s science are based on real-world principles. The problem, though, is that Star Trek has been around for so long that the science has changed – because science is not static, but rather reflects a constant process of discovery. Black holes are no longer theoretical, because they have been observed due to their interaction with surrounding stellar material. The gas molecules in a black hole’s accretion disc heat up as they swirl around it, releasing x-rays that can indeed be detected. But nobody had come up with that idea back in 1967, which is why the so-called “black star” in “Tomorrow Is Yesterday” is said to be impossible to spot.
Star Trek Isn’t The Only Science-Fiction To Link Black Holes To Time Travel
Many science-fiction films and TV shows link black holes to time travel. In Doctor Who, for example, the Time Lords gained mastery of time and space when they managed to restrain the nucleus of an artificially-created black hole, naming this the “Eye of Harmony.” The Doctor was forced to find alternative ways to power his TARDIS after Gallifrey’s destruction. Meanwhile, in Stargate SG-1 interaction between a black hole and an artificially-created wormhole has the potential to cause time travel as well. This is all theoretically possible, although physicists disagree about the precise mechanics.
Star Trek has used black holes many times since “Tomorrow Is Yesterday.” One of the most interesting is in an episode of Star Trek: The Next Generation called “Timescape,” in which the USS Enterprise encountered a race of aliens who use the gravity wells of black holes as nests for their young. Captain Janeway and the USS Voyager had their own close encounter with a black hole in the episode “Parallax,” in which they encountered temporal distortions. Star Trek clearly remains fascinated by the idea time travel and black holes are intimately connected.