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"According to the special theory of relativity nothing can travel faster than light, so that if light cannot escape, nothing else can either. The result would be a black hole: a region of space-time from which it is not possible to escape to infinity." -Stephen Hawking You may have encountered objects that are the same size as one another, but have very different masses. Image credit: Basic Science Supplies / © Accelerate Media. This is because they're made out of different elements. The higher you go in the periodic table, the larger and more massive your individual atoms are, and so…

So I gave a public lecture last (Monday) night called, "Afraid of the Dark: How We Know What We Can't See" and videotaped it. Now, I'm pretty good at what I'm doing right now (research in theoretical cosmology), but I'm really good at public speaking and teaching, and here is me telling a public audience all about dark matter, how we know it exists, what makes it different from normal matter, and what I'm trying to do to find it/discover its nature for a good 40 minutes. (The intro and question/answers are cut out). It was a lot of fun; the audience was wonderful, and actually kept me for…