The Kepler orbital telescope was designed to find planets around other stars, and it's doing a great job. The past week, astronomers announced another 461 more planets. The grand total is over 3,500 planets known. Now we can start doing some statistical analysis. And one result is that at least one in six sun-like stars has an Earth-like planet. Sun-like stars are quite common...
Double suns and double weather (New Scientist)
Going on about other star systems, astronomers have have found that binary stars can indeed have planets. The next thing they've found is that those planets often have orbits that take them through wild swings of temperature, in toward the heat, then out into the cold. The closer together the pair of suns are, the more stable the seasons, though, and an ocean helps stablize temperatures a lot too.
A recent article by Kevin Drum, in Mother Jones Magazine, finds an interesting correlation between the use of leaded gasoline and crime rate. The correlation is pretty robust: crime goes up and down in the same pattern as prevalence of tetraethyl lead in the gasoline, with a time lag for people who were exposed in infancy or in utero to grow up. And it varies according to place as well as date.
It's plausible. Lead is a neurotoxin. But it's still correlation, not causation, and they still haven't looked at individual cases, only populations. The Discover article looks at the cautions needed in such research.
Paying to slave (Nature)
Danish Egyptologist Kim Ryholt has found some interesting old contracts from 2200 years ago. At that time, in Egypt, people would pay to become slaves. For a small monthly fee (which means they needed a paying job on the side), people would enlist as temple slaves. Ryholt believes people would do this because temple slaves were not subject to being conscripted for forced labor.