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It might not be Tuesday today, but still, here's an old (yet still good) physics problem for you to take a crack at:

"An airplane (jet or turboprop) is standing on a runway with a moving surface (like a conveyer belt). The surface can move in the opposite direction to the plane, that is, towards it. It has a control system that tracks the speed of the plane and adjusts the speed of the conveyer belt in such a way that the speed at which the wheels of the plane rotate would be equal (but the opposite) to the speed of the conveyer belt. Can the plane take off from this strip?"

Just noticed that UID=1000000 has finally been registered. Lucky bastard.

I discovered an interesting (and funny) site today, called I Used To Believe. It's a collection of ideas that people thought were true when they were children. Reading the things other people used to believe reminded me of some of my beliefs. For instance, I used to believe:

- That back when my parents were kids, everything was black and white just like in the films.

- That nuclear bombs were huge, black and round -- just like the bombs in cartoons, except huge. To throw such a bomb, I reasoned, one would need a huge slingshot, or maybe a catapult.

- That after a fire, all you had to do was sweep the floor and get a new carpet

- That there was a treasure chest buried somewhere in my back yard. I spent hours digging for it. I didn't really dig deep, though.

What about you?

Some of you are probably familiar with Jared Diamond's thesis of the human destruction of the ecosystem on Easter Island. According to Diamond, "In just a few centuries, the people of Easter Island wiped out their forest, drove their plants and animals to extinction, and saw their complex society spiral into chaos and cannibalism." But now, in American Scientist, Terry L. Hunt offers an alternative explanation to the collapse of the Easter Island civilization. He presents new carbon dating evidence showing that the human colonization of Easter Island took place about four hundred years later than previously thought. Hunt then argues that contrary to previous estimations by Diamond and others, the human population of Easter Island reached a maximum of about 3,000 and remained "fairly stable" until the Europeans arrived. The actual downfall of the Rapanui resulted not from internal strife caused by a rapid degeneration of the ecosystem as previously thought (by Diamond and others), but from contact with Europeans.

Hunt finds that the deforestation cannot be explained with human activities alone. Instead, he claims that much of the damage was caused by the rats introduced to the island by the first colonists. "It was genocide, not ecocide, that caused the demise of the Rapanui. An ecological catastrophe did occur on Rapa Nui, but it was the result of a number of factors, not just human short-sightedness."