This Week's Puzzler

Imagine that you are flying in a small airplane with a skydiver. The door has been removed (as is common) so that the skydiver can easily jump out. You are positioned with a perfect view out of the door, so you can watch the skydiver as he jumps.

The airplane climbs to 10,000 feet high, flying straight and level at 90 MPH. The skydiver picks his jump point and leaps out of the airplane as you watch. From your perspective (and assuming that the airplane doesn't change course or speed itself), how would you describe the motion of the skydiver? Assume you can still see him for the first 30 seconds or so of his fall…

Last Week's Puzzler...

…must have been boring – only three people answered it, and all three of them got it right!

Let's see if I can do better this week…

A Heretic Speaks Out...

Freeman Dyson – famous and accomplished scientist, and proud scientific heretic – has a new essay at Edge. I'm always eager to read something by Dyson, as it's always good brain exercise – fully of tasty ideas and fresh perspectives. This one did not disappoint. Here's a sample, on one of my favorite topics:

My first heresy says that all the fuss about global warming is grossly exaggerated. Here I am opposing the holy brotherhood of climate model experts and the crowd of deluded citizens who believe the numbers predicted by the computer models. Of course, they say, I have no degree in meteorology and I am therefore not qualified to speak. But I have studied the climate models and I know what they can do. The models solve the equations of fluid dynamics, and they do a very good job of describing the fluid motions of the atmosphere and the oceans. They do a very poor job of describing the clouds, the dust, the chemistry and the biology of fields and farms and forests. They do not begin to describe the real world that we live in. The real world is muddy and messy and full of things that we do not yet understand. It is much easier for a scientist to sit in an air-conditioned building and run computer models, than to put on winter clothes and measure what is really happening outside in the swamps and the clouds. That is why the climate model experts end up believing their own models.

There is no doubt that parts of the world are getting warmer, but the warming is not global. I am not saying that the warming does not cause problems. Obviously it does. Obviously we should be trying to understand it better. I am saying that the problems are grossly exaggerated. They take away money and attention from other problems that are more urgent and more important, such as poverty and infectious disease and public education and public health, and the preservation of living creatures on land and in the oceans, not to mention easy problems such as the timely construction of adequate dikes around the city of New Orleans.

Don't miss the whole thing!

New Moon Rising

Just a few minutes ago, I was outside with our dogs in the early morning twilight, and spotted this beautiful new moon. You may have to enlarge the photo to spot it!

We live in a location that's close to ideal for watching new moons, which are the thinnest when the moon is very close to the sun. Here we have clear skies nearly every morning, very little man-made “light pollution”, and a nice little mountain range to block the sun in the morning. My view this morning took perfect advantage of this setup – most of the glare (caused by Mies scattering) from the morning sun is being blocked by the mountains you see at the bottom of the photo, and the moon contrasts very nicely with the still-dark sky above.