Over the summer, the big physics news was the discovery of a new particle which is, in all likelihood, the Higgs boson. I’m not going to give a detailed explanation of what the Higgs is and how it was found — Bruce Bassett wrote a great post about that here, there’s a more detailed post here, and a set of more detailed posts here.
Instead, here’s an e-mail exchange I had with a friend about the Higgs — he had a question, and I answered it, but there’s a bit more to it than that…
Read more "Epistolary Higgs"
This is a picture taken by a robot over one-and-a-half million kilometers away from the earth — over three times farther away than the moon — of the oldest light in the universe. This is impossibly faint light: it took a full year for the robot to collect enough light to take this picture. And even if it weren’t so faint, we wouldn’t be able to see this light with our eyes because it’s beyond the range of visible light, stretched by the expansion of the universe over the last 14 billion years…
Read more "Postcard from the Edge"
Energy isn’t conserved. It can be — and is — created and destroyed. Your high school physics teacher lied to you. Or, more likely, your high school physics teacher was mistaken. And your college physics professor was probably mistaken too….
Read more "Getting Nothing for Something (and Vice Versa)"
This is not a drill. This is the real thing. If you live in the US, your access to the Internet — the greatest medium for the free distribution of information that the world has ever known — will effectively be placed under government control if the Protect IP bill passes…
Read more "Seriously?"
Apparently, a team of scientists working at CERN have found evidence suggesting that neutrinos can travel faster than the speed of light. While this has turned a few heads, the wide consensus is that this will probably turn out to be some kind of systematic error and not a real effect. Extraordinary claims require extraordinary evidence, and this evidence has to pass a hell of a lot more tests — and be reproduced by a lot more people — before anyone, including the team who produced the results, will feel comfortable saying that they’ve found a way around the ultimate speed limit. But why would this be such an extraordinary claim? The speed of light is a hard limit in Einstein’s relativity, but why?…
Read more "Neutrinos and Flux Capacitors"
Figuring out what happened during the first billionth of a billionth of a second after the Big Bang is rather hard, mostly because there’s no light we can see from that time. In fact, there’s no light that we can see from the first 380,000 years after the Big Bang. For most of that time, light was trapped in a plasma, a dense soup of electrically charged particles a lot like the interior of the Sun….
Read more "What I Do: Part II"
Physicists are notorious for oversimplifying things in the name of mathematical modeling. There’s the old joke about spherical cows, radiating milk isotropically, which I’ll spare you here, but the reason we do this is that you can often learn an awful lot about something by simplifying it down to the interesting and easy-to-model parts — which are hopefully the same! The trick is knowing which parts can safely be ignored, but if you do that right, you can get an amazing amount of information about something with a very simple model of it….
Read more "What I Do"
Global warming is real. Humans are causing it. The data are overwhelming. There is a wide scientific consensus on this. If you honestly don’t believe that this is true, then either you have been intentionally misled or you are unaware of the facts. But that’s okay — there are plenty of facts to go around, and they all point to the same conclusion: we are making the planet warmer. The fact that many politicians in this country believe that global warming is not real, or that it is real but humans are not causing it, is a sign of wildly dangerous incompetence that we can’t ignore….
Read more "The More You Know™"
Astronomy and cosmology involve some big numbers: a hundred million miles to the sun; six trillion miles in a light-year; two million light-years — ten billion billion miles, a one with 19 zeros after it — to the nearest galaxy. These are huge numbers, and it’s hard to get your head around them directly. But with a little bit of work, it’s not too bad. For example, a million isn’t actually that big of a number: get a cube of something small (marbles? BBs?) with a hundred objects on each side, and there are a million of those objects in that cube. Get a thousand of those cubes — a bigger cube, with ten of the smaller cubes on each side — and you’ve got a billion. A million seconds is only 11 and a half days; a billion seconds is 31 and a half years….
Read more "Big Numbers and Really Big Numbers"