Star Trek, as well as being a great sci-fi show, is known for either predicting or inspiring real-world technology. Scientists are putting artificial intelligence in “holodecks” for training purposes, are making progress towards a tricorder, and are honing in on whether a warp drive would be possible with real physics.
But no sci-fi is a perfect representation of real science, hence the “fi” at the end. One mistake, or playing loose with real-world physics, which bothers Jeremy Tinker, associate professor of physics at New York University, took place in the movie Star Trek Generations.
If you don’t want to be spoiled for this 30-year-old movie, look away now. Everybody else; during the movie, the main villain, Dr Tolian Soran, launches a missile into a local star, in an attempt to join another dimension known as the Nexus.
That’s not the part that bothers Tinker. While there is no evidence scientists have found that extra dimensions exist, it’s a pretty fun topic for sci-fi and string theory fans to explore. What bothered the professor, who outlined his gripes in a video for the university, was the physics of the missile attack itself, and the effect it had on the star.
The first problem Tinker has with the attack is how quickly the missile reaches the star. Assuming that the star was roughly Earth-distance away from the planet Picard and co were on, that wouldn’t make a lot of sense. It takes around 10 minutes for massless light from the Sun to reach Earth, and yet the missile made it to this star in seconds. But he gives the movie a pass for this – after all warp drives allow for faster-than-light travel in this universe.
“The next thing that it gets wrong is a little bit more subtle and actually really interesting point about how light is made in stars – is that they watch and as the rocket goes into the sun and stops energy production in the core of the star, the star immediately becomes very dim,” Tinker explained.
“It almost gets completely black instantaneously. And that is not actually what would happen. Even if you could manage to get fusion at the center of a star to stop, you wouldn’t notice on the surface of the star, not for a very, very long time. Because in fact, it takes photons, little bits of light, almost 30,000 years to go from the point that they’re created at the core to travel through the atmosphere of the star bouncing around all the hot dense gases before they finally actually reach the surface of the star and are then emitted as likely we would actually see.”
The star then expands and envelopes the planet in moments, once again violating the speed of light.
“However, one thing that it does get right, if a star suddenly stops being able to create energy at the core, the core will collapse and then a little bit later on, the outer part of the star will also collapse,” he continued.
“The inner part of the star will actually compress to a very dense knot and bounce back. And so when the core of the star is going out, the outer part of the star comes in. These inner and outer parts slam into each other, and that is what we call a supernova.”
While supernovas only happen with very massive stars in the real universe, he praises this portion of the movie, speculating that if you could create such a star-collapsing missile, you might be able to create an artificial supernova similar to the one depicted, albeit on a much slower timescale.
