Yes, You ARE the Center of the Universe (in one sense...)

http://youtu.be/HEheh1BH34Q The New Year is upon us, and for many folks it's a time for taking stock. So on this final day of 2014, I thought I'd take a step back, waaay back... My starting point is the video above, which has been making the social media rounds lately. It offers a visually compelling comparison of the sizes of planets and stars, all leading to a central message spelled out in big type at the end: "No, you are not the center of the universe." I also find an implied — and unnecessarily alienating — message in the video: "As a human being, you are an insignificant mote in the unimaginable vastness of the cosmos." This is only true if you make an absolute comparison between your own size and, say, the Milky Way galaxy. But another comparison tells a very different story. And that's the purpose of this post. I can't really say whether the creator of the video, someone with the pseudonym "Morn1415", intended to convey a notion of human insignificance. He or she (I'm guessing the former, since Morn was a Lurian male on Star Trek Deep Space Nine) uploaded it to Youtube in 2009. Since then it has been viewed more than 10.6 million times. And for good reason: It's beautiful, and it effectively conveys a sense of cosmic scale. But it only goes so far. I spotted it for the first time a couple of days ago on a friend's Facebook page. He's a renown environmental scientist who heads a major scientific institution, and he enjoys a wide audience. So I decided to take on that implied message of human insignificance in a reply on his page — and now here: This depressing message about humanity and its place in the cosmos is just plain wrong — and I suspect that it has served to alienate countless ordinary folks from science. With this meme being so common, is it any wonder that so many people cling to nonsense like Creationism? The fact is that there is more to our place in the cosmic scheme of things than, "No, you are not the center of the universe." Much, much more. To tackle this issue, let's first be clear about one salient fact: Saying that we are not at the center of the universe implies that somewhere, some thing is central. But this is false. The universe has no physical center. You can find an excellent explanation of this difficult idea here. Suffice it to say that the Big Bang more than 14 billion years ago wasn't an explosion of stuff in space. It was an explosion of space itself. As a result, since then every point in space has been expanding away from every other point uniformly, with no center to the expansion. So it's true. We are not at the center of the universe. (Yes, I know this contradicts my headline. But stick with me...) Moreover, as the video demonstrates so effectively, we are infinitesimally small when compared to things like red supergiant stars, galaxies, and galaxy clusters. But there are smaller things than us. Much, much smaller. So where humanity fits in the cosmic scheme of things doesn't depend simply on how we measure up to the really, really big things. It also depends on how we compare to the really, really tiny things. To take on this notion, I'll start with a key observation by renown cosmologist Joel Primack of the University of California, Santa Cruz. He is one of the principal originators and developers of the cold dark matter theory, which is the foundation of the modern picture of structure formation in the universe.