If everybody walked....?

Question

What would happen to earth's rotation, if everyone in this planet including animals traveled to only one direction? East, West, North, South. eeryone on a same path, would that change the psychics of Earth? just curious

Answer 1

If (for example) everybody traveled east, then (the rest of) the earth would slow down its rotation by a tiny, tiny bit--way too small to measure.

Also, the change would be reversed as soon as we stopped walking. When we walk east, our feet push westward on the earth. But in order to STOP walking, we'd have to push eastward on something; that'll make the earth "speed up" again.

A (slightly) more realistic example is the angular momentum that is "stolen" by spacecraft when we launch them. We almost always launch them toward the east, to give them a "boost" from the speed of the earth's rotation. But that boost comes at the cost of the planet's angular momentum; the planet slows down very slightly every time we launch a satellite.

Usually we get this momentum back when the satellite comes back down (through orbit decay or through a planned re-entry). It's heading east, so it "pushes" eastward on the planet when it hits the atmosphere.

But occasionally the spacecraft doesn't come down (e.g. interplanetary probes). In those cases, the craft steals our angular momentum and never gives it back (sometimes it gets transferred to Mars, etc.)

However, the amounts we're talking about are trivially small. They pale in comparison to the amount of angular momentum that the moon is stealing from us. That amount is actually measurable, and is gradually causing the earth to slow its rotation.

Answer 2

Think about the Earth's oceans. They cover 75% of the Earth and the waters are always moving. Sometimes they move dramatically as in the case of the Gulf stream, tidal effects, or how about a tsunami. If all that water doesn't affect the Earth's rotation, then animals can't do it.

Answer 3

Earth's mass = 5.9736×10^24 kg with an orbital rotation speed of 66,000 mph.

Human's mass = 81 kg * 6,500,000,000 = 5.265x10^11 kg

In other word's, the Earth wouldn't even remotely flinch.

Answer 4

Nope. But it probably would get Americans to lose some weight. Seems like a World Record is the only thing to get their fat butts off the couch.

*****(NOTE: I'm just joking. I'm an American, too.)

Answer 5

No. The mass of the earth is so large that this would have a negligible effect.

Answer 6

no