3 ms·

Well keep in mind that it's not the rotation that's stopping, or reversing. So far there's debate, but the data supports the core is spinning 0.1 degrees per y

by sliken 4y ago

Well keep in mind that it's not the rotation that's stopping, or reversing. So far there's debate, but the data supports the core is spinning 0.1 degrees per year faster or slower. Other researchers think it's changes in the surface of the core (not the rotation). What we do know is that earthquakes show waves that travel slightly faster or slower than we'd expect if the core's rotational speed was constant with the rest of the planet. But overall it's nearly in the noise compared to the other energies involved. The flows involved are turbulent and move like fluids, but at the pressures and viscosties involved they change rather slowly. Some models show it switching from slightly faster (0.1 degrees per year) to slightly slower ever 35 years or so.

luxuryballs 4y ago
if the waves don’t behave how we expect maybe we just don’t understand how we should expect them to behave, it seems like a lot of assumptions have to be made in order to make any broad conclusions from such readings
- sliken 4y ago
  Sure, it's under heavy debate. While the idea or the planet spinning at different speeds weird to think about, the physics do work out. After all not like the atmosphere spins at exactly the same speed as the planet. Why should the core of the planet in a pool of magma spin at exactly the same rate? The discussed difference is only 0.1 degrees per year, on the surface of the planet that's only 7 miles. So what's under the surface today might be 7 miles different in a year. The movement that deep is quite a bit less than 7 miles since the circumference at that depth is much less. Additionally it's not rock and dirt at that depth, but a liquid magma with an average speed of a foot a day is not too surprising. Humans think of these things as constant, but the length of the day and the distance of the moon are changing because tides are transferring rotational energy of the earth into the moon. Said forces aren't directly impacting the spin of the core, so it might well be catching up and oscillating around the speed of the earth's rotation every 35 days.

by sliken 4y ago

luxuryballs 4y ago

if the waves don’t behave how we expect maybe we just don’t understand how we should expect them to behave, it seems like a lot of assumptions have to be made in order to make any broad conclusions from such readings

sliken 4y ago
Sure, it's under heavy debate. While the idea or the planet spinning at different speeds weird to think about, the physics do work out. After all not like the atmosphere spins at exactly the same speed as the planet. Why should the core of the planet in a pool of magma spin at exactly the same rate? The discussed difference is only 0.1 degrees per year, on the surface of the planet that's only 7 miles. So what's under the surface today might be 7 miles different in a year. The movement that deep is quite a bit less than 7 miles since the circumference at that depth is much less. Additionally it's not rock and dirt at that depth, but a liquid magma with an average speed of a foot a day is not too surprising. Humans think of these things as constant, but the length of the day and the distance of the moon are changing because tides are transferring rotational energy of the earth into the moon. Said forces aren't directly impacting the spin of the core, so it might well be catching up and oscillating around the speed of the earth's rotation every 35 days.