Crazy planet Earth physics - 9/11

[Owledge]

OK, first I watched some science videos on youtube (Vsauce). He talked about a space elevator - how once a building reaches a certain height, the centrifugal force of Earth's rotation will counteract the gravitational force.

Now I thought: Hey, wouldn't that at some point significantly slow down Earth's rotation? You know how when you spin on an office chair and you stretch out your legs, your rotation slows down?

 

Now the WTC towers were two big chunk of mass, and pretty high. Regardless of how insignificant the figured might be, but their collapse must have sped up Earth's rotation, no?

 

 

P.S.: Here's another fun fact from Vsauce: If you imagine Earth were a perfect sphere and you tightly wrap a rope around it, and then you increase the length of the rope by just 6 meters, the rope would now fit loosely around the planet with one meter (!) distance from the ground.

Edited March 14, 2013 by Owledge

[Marblehead]

I think gravity would bring the building down with little or no effect to the earth's rotation. Gravity has been bringing mountains down for billions of years.

 

I don't do rope tricks. Hehehe.

[thelerner]

Hmnn, I'd say No. Scale plays into these things. The weight of a grain of sand and the weight of the buildings might be relatively the same in comparison to the extreme mass of the entire earth, ie both inconsequential. I mean the collapse of two buildings is like an ant jumping vs a person jumping versus the energy of a earthquake. From the Net '8.0 is 6,270,000 tons, and 9.0 is 99,000,000 tons of TNT. As you can imagine, 99 million tons of TNT is enough to destroy just about anything, and is the equivalent of about 25,000 nuclear bombs' or the a hurricane which is reportedly 'In fact, during its life cycle a hurricane can expend as much energy as 10,000 nuclear bombs!<from Nasa>'.

 

Ofcourse never believe such round numbers. Still you get the idea. Nature releases powers way beyond our puny imaginings. Earth's rotational spin dwarfs all human energy production. The Moon slows Earth's rotation, but even with all its mass, its only a tiny bit, hardly measurable each year.

 

 

 

Strangely 9/11 played into our global weather.

After the attacks, the U.S. government temporarily grounded every plane in the nation (including crop dusters and those little planes that tow ad banners -- no, that is not a joke). Inbound flights that were already in the air were rerouted to other countries, and some airports stayed closed until as late as October, because as we all know, terrorists have only ever killed people in airplanes.

The problem with that is, unbeknownst to most, contrails (those white vapor trails that form out of airplane exhaust) act as mirrors, reflecting heat away from the Earth's surface. Those thousands and thousands of vapor trails have actually had a cooling effect that has counteracted global warming to some extent for years -- each airborne plane is sort of like Captain Planet zipping around with a UV shield tied to his boots.

 

With so many planes grounded all at once, the atmosphere suddenly found itself without the mirror it had grown accustomed to over the past half century, and the temperature in the United States increased by 2 degrees in just three days. That may not sound like much, but consider this: Global warming typically only causes about a 0.5-degree increase every year. Grounding all of the planes caused a 2-degree increase, 400 percent of the average annual rate, in three goddamned days.

[Owledge]

Interesting and ironic detail about the contrails. Yes, clouds are a freakin' massive influence on temperature. Maybe they even counteract the supposed warming influence due to CO₂.

I mean, measures just like this, blocking sunlight by various means, were part of suggestions for counteracting supposed global warming.

Looking further, nuclear power plants are said to be CO₂ neutral, but they also emit huge amounts of cloud-density water vapor, so it would be an interesting (though surely extremely inaccurate) calculation to compare their cloud cooling effect with the heat emission of those very clouds.

 

Bottom line is probably that it's not worth obsessing over details in chaotic systems. Too much doomsaying in past and present.

Edited March 14, 2013 by Owledge