Why Don't The Planets Appear to be Spinning?

[Yvonne G]

Now here's another question I'd like an answer to:

Put some water in a bucket the, holding the bucket by the handle spin around in a circle. The centrifical force keeps the water in the bottom of the bucket.

Now soak a tennis ball in water then place the ball on the table and give it a spin. The spinning motion forces the water off the ball.

So, the earth is more like the tennis ball than like the bucket, so why doesn't everything fly off the earth as it spins?

 

[jeff kushner]

I would guess Y that the method of the applying the same force, is the only difference between the two.

The bucket swinging in a circle is identical to the tennis ball spinning as the water will be flung in a direction opposite of where the force is applied....outward.

Good question though........

Since the earth spins there is both inertia from the mass and centrifugal force but we also have gravity from that mass & an atmosphere which moves with the planet, things not taken into account in our experiments.

Some of the guys with actual degrees can prob give you a qualified answer though.....LOL

 

[TammyJ]

Ahhhh... coffee, anyone?

 

[Cathie G]

Now here's another question I'd like an answer to:

Put some water in a bucket the, holding the bucket by the handle spin around in a circle. The centrifical force keeps the water in the bottom of the bucket.

Now soak a tennis ball in water then place the ball on the table and give it a spin. The spinning motion forces the water off the ball.

So, the earth is more like the tennis ball than like the bucket, so why doesn't everything fly off the earth as it spins?

It's pure and simply if there was a hole in the bucket it would go flying out too. The sides of the bucket keep it in 🤔 because they are tall. If it was a little bucket you'd be making a mess 😜

 

[Yossarian]

Now here's another question I'd like an answer to:

Put some water in a bucket the, holding the bucket by the handle spin around in a circle. The centrifical force keeps the water in the bottom of the bucket.

Now soak a tennis ball in water then place the ball on the table and give it a spin. The spinning motion forces the water off the ball.

So, the earth is more like the tennis ball than like the bucket, so why doesn't everything fly off the earth as it spins?

The force of gravity exeeds the centrifugal force generated by the earth spinning. Think of it like a 3d well and we are falling towards the bottom. Anywhere on earth you are, you are falling to the center of the earths gravity well. Gravity exists regardles of spin, the moon does not spin and yet has gravity for example.

So, the earth spins at 1600 kmph (roughly) and would need to spin at about 25,000 kmph for the centrifugal force to overcome the gravity well and fling us off.

Interestingly, a person weighs about .5% less at the equator than they would at the poles due to the centrifugal force counteracting gravity. A person also weighs less the farther they are from the bottom of the well as gravity has less of an effect on them. Interestingly on Mt Everest for example a person weighs abuot .4% less than they would at sea level due to this effect. To further complicate this all, the earth, moon and everything else is in the gravity well of the sun. If the sun ceased to exist the earth would no longer have any orbit, it would travel in a straight line from the moment the gravity well dissappeared.

If you are really interested in this stuff, check out a youtube channel called PBS Spacetime - he explains how these things work and coveres topics from the relatively simple like this, up to very complex concepts.

 

[Yossarian]

I thought it might be interesting to include Chat GPTs Response:

The phenomenon you're describing with the bucket and the tennis ball is related to centripetal force and how objects in motion tend to move. Let's break it down:

1. Bucket with Water: When you spin a bucket filled with water, the water stays at the bottom of the bucket due to centripetal force. Centripetal force is directed toward the center of rotation (in this case, the center of the bucket) and keeps the water from flying out. This is why you don't feel the water sloshing out as long as the speed of rotation isn't too high.
2. Tennis Ball: When you spin a wet tennis ball on a table, the water does indeed get flung off. This is because there isn't a container (like the bucket) providing a centripetal force to keep the water attached to the ball. The water gets flung outward due to the centrifugal force generated by the spinning motion.

Now, let's consider Earth:
Earth is like the bucket, not the tennis ball, in this analogy. Earth has gravity, which acts as the centripetal force, pulling everything toward its center. This gravitational force is much stronger than the centrifugal force generated by the Earth's rotation. As a result, objects on Earth's surface, including the atmosphere and everything on it, are held in place by gravity.
In essence, the gravitational force is what prevents everything from "flying off" the Earth as it spins. The Earth's rotation does generate a slight outward force at its equator due to centrifugal force, but gravity is dominant and keeps everything in place.
So, in summary, it's the balance between gravity (acting as a centripetal force) and the centrifugal force due to the Earth's rotation that keeps everything on Earth's surface from being flung into space. Earth is more like the bucket with water than the spinning tennis ball in this context.

 

[Yvonne G]

The force of gravity exeeds the centrifugal force generated by the earth spinning. Think of it like a 3d well and we are falling towards the bottom. Anywhere on earth you are, you are falling to the center of the earths gravity well. Gravity exists regardles of spin, the moon does not spin and yet has gravity for example.

So, the earth spins at 1600 kmph (roughly) and would need to spin at about 25,000 kmph for the centrifugal force to overcome the gravity well and fling us off.

Interestingly, a person weighs about .5% less at the equator than they would at the poles due to the centrifugal force counteracting gravity. A person also weighs less the farther they are from the bottom of the well as gravity has less of an effect on them. Interestingly on Mt Everest for example a person weighs abuot .4% less than they would at sea level due to this effect. To further complicate this all, the earth, moon and everything else is in the gravity well of the sun. If the sun ceased to exist the earth would no longer have any orbit, it would travel in a straight line from the moment the gravity well dissappeared.

If you are really interested in this stuff, check out a youtube channel called PBS Spacetime - he explains how these things work and coveres topics from the relatively simple like this, up to very complex concepts.

Thanks for the link to the youtube channel. Yes, I really was interested in knowing the answer!

 

[Cathie G]

Would a hole in the bucket be kinda like a hole in the ozone?

 

[Yossarian]

Would a hole in the bucket be kinda like a hole in the ozone?

no, the ozone layer is just gas but it blocks harmful UVB radiation from reaching the surface of the planet - without it most life would not exist. The magnetosphere does protect our atmosphere but not from earths spin, it protects us from solar wind that otherwise would slowly blow our atmosphere away like it did on mars.

 

[jeff kushner]

Great explanations Yo!

I hate gptchat though,........I have never used it and I read everything!

What I see is a lockdown of info that used to be easy to find......funny how that coincides with a "guide" to help.

 

[Yossarian]

Great explanations Yo!

I hate gptchat though,........I have never used it and I read everything!

What I see is a lockdown of info that used to be easy to find......funny how that coincides with a "guide" to help.

Honestly, think of it like the next iteration of google, it will have that kind of impact or more just as a command prompt interface. Its far from perfect now but it is already changing the way research and education is done. Its a very useful tool as long as you understand the parameters and can be a laugh to do things like paste other peoples questions into.

 

[jeff kushner]

the next iteration of google

We view some things very differently........and that's cool.

"Tech" as a whole, has been very very good to me, it came in right after I settled down, so /I never got caught for the bad stuff that I did before there were cameras everywhere, my cars always went 100,000 miles without repairs, I used tech to date on whole different dimension than most could wrap their heads around and it's allowed me to explore in a heartbeat, places I might never otherwise see around the world and beyond with the amazing pics that Space is generating.

I'm quite grateful, mostly that I fell into that timeslot! I hit the Home run of timing! All the good, none of the bad!

I do not think tech will be as advantageous to those coming up...what can be, and what will be......hmmmm.

I'm not making judgements.....I don't need to because it depends on what y'all choose to do with it. I wish you well! (That's in my best Morgan Freeman voice).