# The tides are the result of the rotation of the Earth and the whirlpools

Discussion in 'Pseudoscience' started by Fermer05, Apr 3, 2018.

1. ### DaveC426913Valued Senior Member

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I muffed up the quote.
Most of that is Michael's words.
I have corrected my post, above.

3. ### Michael 345Looking for Bali in NovValued Senior Member

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True. 9.8m/s^2 would be the terminal velocity, it would start off slower.

Does not change the detail it is weightless in orbit, and indeed remains so until it contacts ground/sea

5. ### DaveC426913Valued Senior Member

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Er. Did you want to revise that?

7. ### billvonValued Senior Member

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What?

Astronauts are not "attracted to the mass of the station" in any significant way nor do they need to be in "the air inside the station" for microgravity to act on them. Astronauts working outside experience exactly the same forces.

The two most significant forces on the ISS are tidal (the farthest and closest parts want to be in different orbits) and drag (drag slows it down.) Those forces are the primary reasons why it's not perfect "zero gravity" (i.e. no observable acceleration) inside the station.

8. ### Michael 345Looking for Bali in NovValued Senior Member

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Near the surface of the Earth, an object in free fall in a vacuum will accelerate at approximately 9.8 m/s2, independent of its mass

https://en.m.wikipedia.org/wiki/Free_fall

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9. ### Michael 345Looking for Bali in NovValued Senior Member

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• Gravity between the spacecraft and an object within it may make the object slowly "fall" toward a more massive part of it. The acceleration is 0.007 μg for 1000 kg at 1 m distance
https://en.m.wikipedia.org/wiki/Micro-g_environment

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10. ### DaveC426913Valued Senior Member

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Better. What you wrote in post 122 was ... eyebrow-raising.

11. ### DaveC426913Valued Senior Member

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While technically true, this effect is negligible - certainly much smaller than the other dynamics at play.

12. ### Michael 345Looking for Bali in NovValued Senior Member

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From my post #126 The acceleration is 0.007 μg (microgravity) for 1000 kg at 1 m distance

13. ### Michael 345Looking for Bali in NovValued Senior Member

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You should know what I mean

Bit distracted with friends at shopping centre with ice cream and coffee

When I get home still have a large tree in back garden from cyclone Marcus 27th last month while I was away in Bali

14. ### billvonValued Senior Member

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That's only true if the mass is a point source to one side of the astronaut.

Since astronauts are inside the space station, and it surrounds them, there are contributions from all sides. In the center of a cylinder (which most of the ISS is) the net is zero. Outside of the ISS the truss and the solar panels are _nearly_ symmetric so again almost zero contributions. The radiators are on one side so they might contribute a bit.

15. ### Michael 345Looking for Bali in NovValued Senior Member

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For a large orbital vehicle, like the space shuttle or the International Space Station (ISS), the centre of mass is the best place to locate sensitive experiments, because disturbances increase with distance from the centre

https://www.britannica.com/science/microgravity

16. ### Fermer05Registered Member

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In cosmonautics it is already a proven fact that the area of the attraction of the moon is limited to 10 thousand kilometers from the surface of the moon,
artificial satellites of the moon with an orbit radius of more than 10 thousand km. break from the orbit.

17. ### Gawdzilla SamaValued Senior Member

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Show us the math.

18. ### DaveC426913Valued Senior Member

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OK, Fermer has crossed the threshold from making contentious claims to demonstrating an outright ignorance of physics.

There is no way to discuss physics with someone who doesn't understand the first thing about it.

19. ### Gawdzilla SamaValued Senior Member

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But enough about his first post.

Michael 345 likes this.
20. ### billvonValued Senior Member

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Right. Most of that comes from tidal forces.

21. ### billvonValued Senior Member

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During the Apollo mission, the CM/third stage fired its engines in Earth orbit to start it on its way towards the Moon. As it climbed away from Earth (coasting along its trajectory) it kept slowing down until it was 40,000km from the Moon. At that point lunar gravity became stronger than Earth gravity, and it started accelerating towards the Moon.

Looks like reality once again has intruded on your imagination.

22. ### sideshowbobSorry, wrong number.Valued Senior Member

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That isn't what I'm asking. I'm asking whether you think artificial satellites of the earth are pulled "upward" by the moon, like the tides. The conventional understanding of gravity is that they are but you seem to think they're not and that that confirms your conjecture.

23. ### Michael 345Looking for Bali in NovValued Senior Member

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??? Wonder what the barrier is at 10 thousand kilometres from the surface of the moon that stops gravity going any further??

Sounds like something which could be used as antigravity if science can make it stronger