# How does water not spin off the earth?

Discussion in 'Physics & Math' started by Spencer666, Dec 26, 2019.

1. ### Spencer666Registered Member

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The earth rotates (so science claims)

The earth is spherical (so science claims)

The seas/oceans bulge at the equator (so science claims)

Water has a very low viscosity and does not ''stick'' to things.

How can there possibly be water above and below the equator when there is no mechanics to hold the water in those locations on a spinning sphere?

3. ### exchemistValued Senior Member

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Ha ha, very funny. Happy Christmas. Why not try again when you're sober? - should you ever find yourself in that state.

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5. ### Spencer666Registered Member

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I am very sober and there is nothing funny about the truth of fluid dynamics !

If the earth is spherical and spins as science claims, there would be no water North of South of the centrifuge force of the equator .

Enough centrifuge force to oblate the earth shape !

Are you saying I am incorrect ? I think not !

7. ### James RJust this guy, you know?Staff Member

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It looks like you've forgotten about gravity, Spencer666.

There are three forces acting on each bit of water on the ocean's surface: the force of gravity, the centrifugal force (if you want to think of it like that) due to the Earth's rotation, and upwards normal force from the water below. These add up to give no net force (in the rotating frame), so water doesn't flow towards the equator due to the Earth's rotation.

To be a little more accurate, if the Earth was a rotating sphere, then the centrifugal force would cause an imbalance, so that water would tend to flow towards the equator, changing the shape of the water surface until it was an appropriate oblate spheroid, with the precise shape being determined by the rate of rotation. And guess what? That's exactly the shape the Earth has.

8. ### Michael 345New year. PRESENT is 72 years oldlValued Senior Member

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Are you per chance a Flat Earther?

9. ### JeevesValued Senior Member

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That's all we need to know about that.

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10. ### exchemistValued Senior Member

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"...there would be no water North of South of the centrifuge force of the equator."

Somehow I don't think discussing science with you will be a productive exercise.

And somehow I don't think you want it to be, either.

Best thing is probably to leave you alone until you go back under your bridge.

11. ### Spencer666Registered Member

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I did not forget about gravity at all !

In fluid dynamics , water has a low viscosity ! Water runs down mountains and things such as branches on a tree . The reason is because water has a low viscosity and does not stick to things . An example is condensation running down a window .

By what physics can water , which does not stick to things , ignore the force of a centrifuge ?

This can be simply demonstrated using a bucket of water and using a food mixer to create a whirlpool centrifuge

The water has no viscosity to stick or remain in position .

''Down'' relative to water on Earth , would be in the direction of the equator because of the centrifuge force .

I am sorry but you have explained no physics that disproves my question or explained how the centrifuge force is enough to compress earths y-axis to an oblate shape when it is made of ''rock'' but does not have enough centrifuge force to position all the water at the equator in a centrifuge disk formation .

Somebody somewhere . not necessarily meaning you , is telling porky science !

12. ### Spencer666Registered Member

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Actually no , I am not a flat earther .

I suspect the Earth is spherical but a considerable super massive amount bigger than we are lead to believe . I suspect what we are shown as the entire earth , is actually just the north or south pole of a much bigger super earth .

Consider a circle surrounded by a wall of ice , on top of a ''football''

RICHARD BYRD a land the size of America discovered ?

Last edited: Dec 26, 2019
13. ### Michael 345New year. PRESENT is 72 years oldlValued Senior Member

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Since you seem to have a tentative grip on reality (ie observations on the Earth and oceans seem to agree more with those lying scientists than your, non stated, but implied "it should not be"

I WAS going to ask what YOU would propose as to why the Earth is the way it is. Turns out you had already posted your explanation

Of course your explanation is soooo much better than the dummkopf Flat Earthers

Look forward to your upcoming Nobel Prize winning published paper

Think I will book my next holiday on this inside the Earth football of which you speak

And the crown of ice has to be at North Pole because Australia where I live does not exist according to Flat Headers, sorry I mean Earthers

14. ### JeevesValued Senior Member

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Hey, I always had that sneaking suspicion, too, but didn't want to say, in case my ocean spilled out. So, then, how do the sun and moon stay up in the sky? I know the stars are just painted on, but the sun moves, so, is it on a pulley or what?

15. ### Gawdzilla SamaValued Senior Member

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Okay, you caught us. Water DOES fly off into space, as does everything else. Including you. We've been trying to hide this from you because, you know, learning hurts.

16. ### James RJust this guy, you know?Staff Member

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Spencer666:

So you just messed up the force analysis, then.

Viscosity is irrelevant to the problem, because the water isn't flowing anywhere at sea level (ignoring ocean currents etc.) Like I said above, the net force on a water molecule at sea level is zero.

It doesn't ignore it. The centrifugal force is what causes the Earth to bulge at the equator, as a I said previously. That includes the water.

No. Locally, "Down" is determined by the sum of the centrifugal force and the gravity force.

This is why I said you've forgotten gravity. Do the force analysis properly and your problem will disappear.

Are you asking me to teach you the basics of force analysis for a particle on the surface of a rotating Earth?

What texts have you looked at so far? Have you done the obvious google searches for explanations? Assuming you have, perhaps you can point me to one of your sources and show me the step in the mathematical argument where you think the error was made.

Okay. Show me the analysis that backs up your claim. I mean the maths, the vector analysis and so on, not just more of the same wordy stuff.

I mean, I assume you've drawn the relevant diagram and have done the maths. Got a screenshot?

It's not. It's an oblate spheroid, as I mentioned earlier.

Bigger in what way? Diameter? Mass? Something else? What's your evidence for that?

Are the photos from space all lies, then?

Sounds a lot like a flat earth picture to me.

But considering your model, can you please explain to me why all that low-viscosity water doesn't pile up against the surrounding ice wall, due to the centrifugal force?

Last edited: Dec 26, 2019
17. ### Beer w/StrawTranscendental Ignorance!Valued Senior Member

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Why water, why not Mercury?

MUST PLAY VIDEO GAMES!

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...

19. ### Spencer666Registered Member

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Physics 101

The earth spins ~1000mph

20. ### originHeading towards oblivionValued Senior Member

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I am impressed that you can use a food processor!! Wait did you just see a video of a food processor...

21. ### exchemistValued Senior Member

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No. Rate of spin is measured in revolutions per unit time. The Earth rotates at 1/60 x 24. = 1/1440 rpm, or 1/24 revs per hour.

But as it's Boxing Day, what the hell:

- The radius of the Earth is ~4000miles, so its circumference, say at the equator is 2 x π x 4000 which comes to ~25,000miles.

- The tangential speed at the equator is therefore 25000miles/day, which is close to 1000mph, I agree.

- The centripetal acceleration needed to keep an object moving with tangential velocity v, in a circle of radius r, is v²/r. (Physics 101). So, for an object at the equator, the apparent centrifugal acceleration it experiences, counter to the acceleration of gravity, will be 1,000,000/4000 = 250 miles/hr².

What we need to know is how this acceleration compares with g, the acceleration due to gravity, which is about 10m/sec². To do that, we need to get this result into the same units as g is quoted in:-

1 mile is ~1600m. And 1hr is 3600 seconds. So 250 miles/hr² becomes 250 x 1600/(3600)² = 25 x 16/(360 x 36) = 25 x 4/(360 x 9) = 100/3240 = ~ 0.03 m/sec².

So the centrifugal force at the equator, as a proportion of the force of gravity, is of the order of 0.03/10 =0.003, or 0.3%.

In other words, it is nowhere near strong enough to cause water or anything else to be flung off.

P.S. To check my arithmetic, I went to the people who faked the moon landings

....and got a similar figure. Details here: https://www-spof.gsfc.nasa.gov/stargaze/Srotfram1.htm

So either you have to agree they are right, or you have to dispute F = mv²/r, i.e. Physics 101. Have fun!

22. ### Janus58Valued Senior Member

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At the equator. For instance, where I live near the 45th parallel, the surface only moves at about 70% of that speed.
And in terms of centrifugal "force" the speed relative to the axis of rotation is not enough information. You also need to know the distance from the axis of rotation. For example, if I were to try and go around a sharp mountain road corner at 60 mph, the centrifugal effect would overcome the friction between road and tires, and the car would go skidding of the road. However I can take a curve on a freeway at the same speed and never even feel it because curve in the freeway are much more gentle and have a much larger radius than that sharp mountain road curve.
The Earth has a really large radius, so at the Equator, even moving at 1000 mph produces very little centrifugal effect. It works out to be about 1/3 of one percent the strength of gravity at the Equator. So, the tendency for gravity to pull objects toward the center of the Earth and hold them on the surface far overpowers any tendency for them to fly off into space due to the spin of the Earth.

"Down" would be due to the total combined effect of gravity and centrifugal "force".

Thus in the diagram below, Gravity is the red arrow pointing towards the center of the Earth, Centrifugal force in the yellow arrow pointing away form the axis of rotation, and the orange arrow the resultant direction of perceived "down".

The solid blue circle is the shape water would take due to gravity alone and the dotted ellipse the shape it takes from the combined effect. Everywhere on the surface of that ellipse, "down" is exactly perpendicular to the ellipse at that point. In other words, for the water to continue to flow towards the equator from this shape, the water would have to flow "Up hill". This shape represents where the water is resting at its "lowest" point.
Now for the Earth itself, we don't see the oceans bulge out like this relative to the Earth itself because the Earth itself is not a solid object, it is mostly fluid on the inside with a really thin crust. So the shape of the Earth itself tends to follow the more elliptical cross-section; forming an slightly oblate spheroid, (very slight, Due to the fact that the centrifugal effect is so small compared to gravity, the oblateness isn't enough to even be noticeable by just looking at the Earth by eye. I had to really overemphasize it in the diagram above for illustration purposes.)

23. ### RainbowSingularityValued Senior Member

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water has mass it creates gravity

water moves upward, sideways, diagonaly in all directions, with gravity & against Gravity as it condenses on to a trees leaves...
water is magic !