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"
Here’s a question I’ve gotten several times since starting this blog a few days ago (and several dozen times over the last few years):
“Scientists make a lot of noise about being ‘objective’ and using data to determine the truth, but at the end of the day, science has an untested — and untestable — core belief: that we can learn the nature of reality by actively studying the physical world. So doesn’t this mean that science is a form of faith, no different from any other system of belief?”
Short answer: yes to the first part, no to the second part.
Long answer…Read more "How Do We Know That Science Works?"
What’s this picture?
The easy answer is that it’s a computer-generated image from the Millennium Simulation of what we think the universe looks like on the largest scales. That’s not quite true, though. It’s certainly an image from the Millennium Simulation, but it’s not what we think the universe “looks” like, at least not literally; those luminous dots indicate dark matter, not galaxies, meaning they’re not made of anything that actually gives off light of any kind. More importantly, it’s not what we think our universe looks like because it’s not a map of our universe. It’s a map of a fake universe, a wholly simulated construction living inside a computer…Read more "Faking It"