Stupid point hides an important point
A badly written article on Jupiter's magnetosphere.

On Earth, we typically think of alternating and direct currents (AC and DC) in terms of electronics. Famously, in the late 19th century, inventors Thomas Edison and Nikola Tesla disagreed sharply over which method should be used to deliver power to electrical devices. DC power doesn't convert as easily between different voltages, according to the U.S. Department of Energy (DOE), so Tesla wanted to turn the more-easily convertible AC into the standard. Edison, guarding his DC-dependant patents, resisted the change and spread misinformation that AC was more dangerous, according to the DOE.

Tesla won out in the end, and AC became the standard for U.S. power plants. However, according to the DOE, direct current has regained favor as more battery-powered devices have come to market. Your lights are probably running on AC power, but there's a good chance the device you're reading this on relies on DC. (That's why your laptop requires an AC adapter.)

Tesla vs Edison in the 1890s is overstated and misdescribed.

Direct current has regained favor for power transmission, but NOT because batteries are more common. Battery-powered devices were UNIVERSAL before both Edison and Tesla. DC battery-powered devices have ALWAYS been common. That's unrelated to the change in distribution.

Now HV distribution is going back to DC because solid-state inverters can turn the distributed DC into AC just before each transformer. Why the extra step? EDISON WAS RIGHT ALL ALONG. DC is more efficient in long wires because it doesn't stir up changing magnetic fields that create reactive counterforces. The increase of efficiency isn't dramatic, so it wasn't worth the trouble until high-power inverters were practical.

If you can get past the stupid part, here's the smart part:

In the space around Jupiter, the proportion of AC to DC isn't determined by feuding pre-modern inventors, but by the behavior of ions in the planet's atmosphere. Jupiter has powerful currents than Earth for several reasons, including its huge size, its fast rate of spin and the excess of charged particles (ions) pumped out from volcanoes on the moon Io.

Smarter than me! A simple and obvious point that I'd never thought about before. A spinning magnet in a constant field is a generator. A bigger and faster spinning magnet is a more powerful generator.

Speculative extension: For the last century the north magnetic pole has been moving closer to the north rotational pole. When the magnet is tilted considerably from the rotational axis, the magnet itself is spinning more, thus generating more current. When the magnet is the same as the rotational pole, there's no movement of the magnetic field. North stays in the same place, South stays in the same place. So the ion currents have been gradually decreasing for the last 100 years. Less ion current means less daily variation in energy available to affect bacteria and clouds, thus more tendency for jet streams and fronts to stay in the same place. Which is what we're observing.

Labels: Carbon Cult, Constants and Variables

  ¶ 12:55 AM