Head outside at sunset tonight and look up at the sky. If the full moon seems a tad larger than normal to you, that means one of two things: You are exceptionally perceptive, or you were already expecting to be dazzled, after hearing some of the buzz about this year's "supermoon."
It turns out that all full moons are not created equal. That's because the moon's orbit around the Earth isn't a perfect circle — it's an ellipse. And tonight, we're in luck.
It won't trigger any catastrophes, according to scientists, but the Moon will orbit to its closest proximity to the Earth on Saturday night. It's called a "super moon": when a full moon reaches perigee near our planet.
A hundred years ago — and that's when this picture was taken, in 1912 — men didn't leave home without a hat. Boys wore caps. This is a socialist political rally in Union Square in Manhattan. There may be a bare head or two in this crowd, but I think those heads are women's.
Here's another rally, Union Square again. This time it's an Occupy Wall Street demonstration. A hundred years have passed. Same place. Same kind of crowd. But this time: hardly a hat.
For decades, teachers, managers and parents have assumed that the performance of students and employees fits what's known as the bell curve — in most activities, we expect a few people to be very good, a few people to be very bad and most people to be average.
The bell curve powerfully shapes how we think of human performance: If lots of students or employees happen to show up as extreme outliers — they're either very good or very bad — we assume they must represent a skewed sample, because only a few people in a truly random sample are supposed to be outliers.