Slashdot Mirror
"Ballooning" Spiders Use Electrostatic Forces To Generate Lift
KentuckyFC writes "Many types of small spider release threads into the air which then lift and carry them significant distances. Biologists have found them at altitudes of up to 4 km. The conventional thinking is that the threads catch thermal air currents which then carry them away but this does not explain how spiders perform their trick even when there is little or no wind. Now one physicist says the explanation is the atmosphere's natural electric field which has an average downward-pointing magnitude of 120 Volts per metre. He calculates that a strand of silk need only gain a negative charge of around 30 nanoCoulombs to lift a spider. That explains how the spiders take off on windless days, how they reach such great heights and how several strands can lift heavier spiders of up to 100 milligrams."
He lives in New York, he's always swung from the multitude of high rises.
The bat signal itself doesn't fit with physics.
My parents have owned a searchlight rental business for 30 years now. For the first Batman movie they were asked to put a bat signal cutout on the searchlight to simulate the bat signal. The thing is that searchlights have too high a candlepower and the light just bends around the cutout. The light spreads more the farther away from the searchlight. It looks cool when shown against a wall, but far out in the sky it simply doesn't work. The physics of light doesn't allow it.
I've just read that one bolt of lightning powers one household with all their energy needs for a month. I'm not too sure how accurate that is; but I think we'll need a lot more than that.
I will try to plug the numbers in. Let's see how this goes.
According to the physics.org toast power article, a lightning packs "over five billion joules of energy". I will round that down to 5 billion. A watt is the same thing as "joules per second". A month has 60 * 60 * 24 * 30 = 2,592,000 seconds. Then, 5 * 10^9 J / 2,592,000 s = 1929 J/s. This means that we can run the house at a constant power consumption of 1929 watts. Converted to a standard kWh number that would be 1389kWh per month.
That's pretty much on the spot. It would indeed be enough to run a house of a small family for one month, accounting electrical heating running around winter.