9 ms·

I'm not sure about FE, but the "we're spinning right now at 1000mph" disintegrates under any reasonable interrogation. For example, consider you're looking at

by sudsy7 3y ago

I'm not sure about FE, but the "we're spinning right now at 1000mph" disintegrates under any reasonable interrogation. For example, consider you're looking at a disk shaped cloud 10 miles above that is 20 miles long from the center. If you're on Earth spinning below it at 1000mph you would be looking back at the cloud in less than 2 minutes. So how do clouds linger above us on a fast spinning earth? May not be a convincing question for some, but it's made me think.

rexpop 3y ago
The cloud is suspended in a fluid that is also spinning. The atmosphere is an ocean we live at the bottom of, and where it makes contact with the earth friction between the fluid and the solid conveys inertia from the solid to the fluid. Inertia is likewise conveyed, by friction, up the viscous column of atmosphere. It is the same principle by which stirring your coffee causes the entire contents of the cup to swirl, and not just that touched immediately by the surface of the spoon.
- sudsy7 3y ago
  OK, so if you take a sphere spinning on its axis and put it in a spherical aquarium I could see it all spinning together. But what I don't see is how that works in an atmosphere which is mostly near the earth's surface. It seems like you would lose a lot of energy as you entered the stratosphere because the air density increasingly falls, there's less room for friction to cohere the atmosphere. High clouds should be less effected which would make them appear to move much faster than low clouds. Is there a good source somewhere on how this works that takes this into account? The stuff I've seen just assumes its own model and works backwards.
labrador 3y ago
The atmosphere is spinning with the Earth. It has to be, otherwise you'd have 1000 mph winds at Earth's surface. How? It gets dragged along by friction with the surface
- sudsy7 3y ago
  OK, but how does that account for the fact that the atmosphere thins? I'm not a physicist but it seems to me that given entropy and the thinning of the atmosphere as elevation increases that clouds would not a) not appear to float in place and b) only move in one direction. Low clouds would appear to float in place but high clouds would move quickly away from the spin of the earth.
  - s1artibartfast 3y ago
    High clouds do move more quickly! Not sure how someone would go about proving this with household tools
    - sudsy7 3y ago
      I don't know either, but one fun fact is that you can measure the temperature of reflected moonlight with a $20 laser thermometer. It's reflecting sunlight right, so why does moonlight register as colder than shaded spots. It's a real easy and fun experiment.
      - s1artibartfast 3y ago
        That one is probably out of my pay grade. One guess is that the Moon is not a perfect reflector and the photon density per unit area coming off the Moon is a lot lower. You could test this hypothesis by pointing a laser thermometer at a light bulb and a pile of dirt reflecting the light from the bulb. The Moon is basically made out of gray dirt.
        sudsy7 3y ago
        Ground in the shade may have some insulation? You'd think open ground would be warmer at night because it's unshaded, and because the moon is supposed to be reflecting sunlight. The fact that it's colder is counterintuitive. It would be interesting to try the experiment on a moonless night to check the difference between open and shaded ground. If they are the same the shade doesn't likely matter (given a sufficient time from sundown).
s1artibartfast 3y ago
This is what I love about FE people. The desire to question, learn, and understand on a fundamental and intuitive level. I would love to sit down, have a beer, and try to figure out how the clouds work. Not just what Wikipedia says happens, but really understanding why. Reminds me of people who build rocket ships in their back yard or nuclear reactors in their garages. -SE believer
lusus_naturae 3y ago
I am sorry to ask, but do you think the astronauts in the ISS are liars? Or that satellite imagery is faked?
- sudsy7 3y ago
  Well, if they bothered to fool everybody into thinking earth was a spinning ball a few lies from astronauts and some fake photos isn't really a stretch.
  - lusus_naturae 3y ago
    If you look through a telescope you can see other celestial bodies that are spherical, so why would earth be exceptional?

by sudsy7 3y ago

rexpop 3y ago

The cloud is suspended in a fluid that is also spinning. The atmosphere is an ocean we live at the bottom of, and where it makes contact with the earth friction between the fluid and the solid conveys inertia from the solid to the fluid. Inertia is likewise conveyed, by friction, up the viscous column of atmosphere. It is the same principle by which stirring your coffee causes the entire contents of the cup to swirl, and not just that touched immediately by the surface of the spoon.

sudsy7 3y ago
OK, so if you take a sphere spinning on its axis and put it in a spherical aquarium I could see it all spinning together. But what I don't see is how that works in an atmosphere which is mostly near the earth's surface. It seems like you would lose a lot of energy as you entered the stratosphere because the air density increasingly falls, there's less room for friction to cohere the atmosphere. High clouds should be less effected which would make them appear to move much faster than low clouds. Is there a good source somewhere on how this works that takes this into account? The stuff I've seen just assumes its own model and works backwards.

labrador 3y ago

The atmosphere is spinning with the Earth. It has to be, otherwise you'd have 1000 mph winds at Earth's surface. How? It gets dragged along by friction with the surface

sudsy7 3y ago
OK, but how does that account for the fact that the atmosphere thins? I'm not a physicist but it seems to me that given entropy and the thinning of the atmosphere as elevation increases that clouds would not a) not appear to float in place and b) only move in one direction. Low clouds would appear to float in place but high clouds would move quickly away from the spin of the earth.
- s1artibartfast 3y ago
  High clouds do move more quickly! Not sure how someone would go about proving this with household tools
  - sudsy7 3y ago
    I don't know either, but one fun fact is that you can measure the temperature of reflected moonlight with a $20 laser thermometer. It's reflecting sunlight right, so why does moonlight register as colder than shaded spots. It's a real easy and fun experiment.
    - s1artibartfast 3y ago
      That one is probably out of my pay grade. One guess is that the Moon is not a perfect reflector and the photon density per unit area coming off the Moon is a lot lower. You could test this hypothesis by pointing a laser thermometer at a light bulb and a pile of dirt reflecting the light from the bulb. The Moon is basically made out of gray dirt.
      - sudsy7 3y ago
        Ground in the shade may have some insulation? You'd think open ground would be warmer at night because it's unshaded, and because the moon is supposed to be reflecting sunlight. The fact that it's colder is counterintuitive. It would be interesting to try the experiment on a moonless night to check the difference between open and shaded ground. If they are the same the shade doesn't likely matter (given a sufficient time from sundown).

s1artibartfast 3y ago

This is what I love about FE people. The desire to question, learn, and understand on a fundamental and intuitive level. I would love to sit down, have a beer, and try to figure out how the clouds work. Not just what Wikipedia says happens, but really understanding why. Reminds me of people who build rocket ships in their back yard or nuclear reactors in their garages. -SE believer

lusus_naturae 3y ago

I am sorry to ask, but do you think the astronauts in the ISS are liars? Or that satellite imagery is faked?

sudsy7 3y ago
Well, if they bothered to fool everybody into thinking earth was a spinning ball a few lies from astronauts and some fake photos isn't really a stretch.
- lusus_naturae 3y ago
  If you look through a telescope you can see other celestial bodies that are spherical, so why would earth be exceptional?