I've Been Thunderstruck

Thumbing through the June 2007 issue of Wired magazine the other day, I came across an article titled "Thought Experiments" on page 64. I thought them interesting enough some of them over the next few posts. The first one is called "Hawking’s Turtles:"

The 1988 book A Brief History of Time begins with a story of a scientist giving a lecture on astronomy. At the conclusion of his talk, a woman insists he’s wrong: Earth is a flat plate carried on the back of a giant turtle. The scientist asks what the turtle is standing on, and the woman says, "It’s turtles all the way down!" Stephen Hawking used the story to caution fellow cosmologists against piling one unproven theory upon another.

How many times do you do something similar during your day?

Want to go somewhere in North America and weigh less than you do at home? Head over to the Hudson Bay area region of Canada, and, due to lower levels of gravity that has stumped scientists for over 40 years, you’ll actually weigh less than at home! The reason is that weight is a product of mass times gravity. If your mass remains the same, but the effect of gravity decreases, you’ll produce less of a force on the scale, and thus will weigh less. Similar to what would happen if you weighed yourself on the moon!

The mystery started in the 1960′s when a detailed study of the earth’s gravity fields were being charted. It was noted that gravity levels in the Hudson Bay region were less than at other places on the earth. Two theories about what’s going on have been postulated, and are reported in this article at howstuffworks.com :

One theory centers on a process known as convection occurring in the Earth’s mantle. The mantle is a layer of molten rock called magma and exists between 60 and 124 miles (100 to 200 km) below the surface of the Earth . Magma is extremely hot and constantly whirling and shifting, rising and falling, to create convection currents. Convection drags the Earth’s continental plates down, which decreases the mass in that area and decreases the gravity.

A new theory to account for the Hudson Bay area’s missing gravity concerns the Laurentide Ice Sheet, which covered much of present-day Canada and the northern United States. This ice sheet was almost 2 miles (3.2 km) thick in most sections, and in two areas of Hudson Bay, it was 2.3 miles (3.7 km) thick. It was also very heavy and weighed down the Earth. Over a period of 10,000 years, the Laurentide Ice Sheet melted, finally disappearing 10,000 years ago. It left a deep indentation in the Earth.

The second theory is particularly amazing. What it suggests is that the ice sheets that occupied the area so long ago were actually so heavy that they depressed the earth itself, effectively reducing the mass of the earth in those areas. Less mass means less gravity. It turns out that both of the theories are correct, and are both explained in more depth in the article, which I encourage you to read.

The Hudson Bay area is going to have less gravity for a long time. It’s estimated that the Earth has to rebound more than 650 feet to get back to its original position, which should take about 5,000 years. But the rebound effect is still visible. Although sea levels are rising around the world, the sea level along Hudson Bay’s coast is dropping as the land continues to recover from the weight of the Laurentide Ice Sheet.

So, if you have a weigh in that you need to weigh a specific weight at, head over to the Hudson Bay region and get weighed in there. But hurry, you only have about 5,000 years until gravity levels return to normal!

This video absolutely falls under the category of things that astound and amaze me. We have here a huge canyon in Columbia with no real way in or out of the village. The Columbian government won’t build a bridge across the river because it says there aren’t enough people in the village to warrant the cost. The solution? A cable that crosses the river and allows people to come in and out of the village. The catch? It’s 1200 feet above ground!

I struggle to understand why anybody would need to test the effects of LSD on combat troops. Never having taken it myself, but having heard of the standard reactions, I imagine that the military was looking for some way to enhance performance on the battlefield. Judging by the results below, getting LSD into the water supply of enemy combatants might be the quickest way to get them to laugh themselves to death!

"Want me to get mad at you?"

That was the question a woman asked her approximately 3 year old daughter in Fatburger today during lunch. Her daughter was doing the normal things a 3 year old do at a fast food establishment…climbing on the seats, sliding under the table, generally being a young girl with little impulse control as most 3 year olds are. Nothing that any reasonable parent would think bad.

It left me wondering what kind of answer she expected from her daughter.

"Yes, mom, could you please get really made at me? Perhaps give me a nice spanking here in the restaurant?"

"No…please don’t beat me like you usually do!"

"Yes…I like the shade of red on your face when you get furious at me!"

"No…I understand you’re angry at me, and I promise to stop what I’m doing immediately."

Her mom probably expected the latter, while the reality of the situation is that it’s probably a mix of the first three. But, anyway you cut it, the question is as dumb as this post is. No real point to it, other than to illustrate another odd human interaction.