Science Top Ten Lists

Why is the sky blue? Facts you should know. A journalist asked ten scientists to name one question all high school graduates should be able to answer. My favorite is "What is it that makes diseases caused by viruses and bacteria hard to treat?" because it requires conceptual knowledge of genetics and evolution and applies that knowledge to a real issue. I'm happy to report that I got all of them right, although I was off by 0.2 billion years on the age of the first fossils, which is either a lot or nothing at all, depending on how you look at it. Hat tip to the science goddess.

Top Ten Ways to Destroy Earth. Note that we're talking about destroying the whole planet, not human life or even all life. My favorite is definitely #2, both elegant and devious:

A von Neumann machine is any device that is capable of creating an exact copy of itself given nothing but the necessary raw materials. Create one of these that subsists almost entirely on iron, magnesium, aluminum and silicon, the major elements found in Earth's mantle and core. It doesn't matter how big it is as long as it can reproduce itself exactly in any period of time. Release it into the ground under the Earth's crust and allow it to fend for itself. Watch and wait as it creates a second von Neumann machine, then they create two more, then they create four more. As the population of machines doubles repeatedly, the planet Earth will, terrifyingly soon, be entirely eaten up and turned into a swarm of potentially sextillions of machines.

Hat tip for help procrastinating. (And here's some, um, clarification about the nature of a strangelet...).

And I'm not sure I should be excited about the release of this film... but I am.