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It turns out black holes aren't cosmic vacuum cleaners. The Varsity's ALEX ROSS investigates. Black holes have been at the centre of rigorous scientific investigation for almost 200 years. However, the way black holes have been portrayed in science fiction has led to some strange misconceptions about how these heavenly chasms actually work. Dispelling these popular myths was the subject of "Black Holes Don't Suck," a talk hosted by the Graduate Astronomy Students' Association on November 5, as part of their monthly public tour of U of T's Department of Astronomy and Astrophysics. The talk was given by Nick Tacik, a graduate student in the department, whose current research involves simulating binary black holes using computers. "As someone who studies black holes, it actually kind of bothers me a little how they are portrayed in popular culture "” in particular in science fiction," he said. "Whenever people put black holes into science fiction, it seems like the creators throw out all of the physics we know." The French mathematician and astronomer Simon-Pierre Laplace was the first to propose the idea of the black hole in 1796. Laplace wondered if there could be a star so dense that even light couldn't escape from it. Albert Einstein then gave us the general theory of relativity, which is our current theory of gravity. Under general relativity, a mass, such as a star, curves the space around it. "Now we can imagine a star with even more gravity than this one ["¦] that it gets curved so much that if light was trying to escape from that gravity, well, the curvature would just be too powerful, and it would curve back on itself," Tacik said. The two essential components of a black hole are the event horizon and the singularity. The event horizon is an artificial boundary that delineates the point at which light cannot escape. The singularity is a point of infinite density at the centre of the black hole, which contains all of its mass. Black holes are formed when stars many times larger than our sun collapse in on themselves due to their large mass. To illustrate bad black hole physics, Tacik played the audience a clip from Star Trek: Voyager. In the clip, the starship Voyager has entered a black hole. The crew says such absurd things as: "I do know one thing "” that as we slide deeper into the singularity, the spatial distortions are increasing" and "If we find our entry point [in the event horizon], we may be able to slip out the way we came in." Why are these statements absurd? "As we saw, the singularity is a single point. How can you slide deeper into a single point?" Tacik asked. Furthermore, "General relativity tells us that once something enters the event horizon, nothing can escape the event horizon. The event horizon isn't actually some physical thing that you can rupture and go through." Tacik moved on to dispel some other misconceptions about black holes "” the first on his list being that black holes don't suck. "Black holes have been referred to as cosmic vacuum cleaners.

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