Gravity

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spot
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Gravity

Post by spot »

Somewhere I saw an article in which the relative strength of gravity and electromagnetism was compared rather vividly.

Take two planets the size of Earth, it started. Strap each to the back of an electrically insulated volunteer. Place the volunteers nose to nose.

Normally you'd expect the volunteers to be crushed as gravity draws the planets together.

But, went the article, if you merely increase the number of electrons on each person by 10%, the system will be balanced and nothing will move.

I suspect the volunteers would actually become uncomfortable, to be honest, but I thought it was a deeply satisfying demonstration of matched electrical charges repelling.
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Post by Snowfire »

Gravity is one of those strange phenomena that I cant get my head around. It seems counter intuitive to me.

I'm not suggesting for a moment that I have the right to understand it. Scientists, after all, don't really understand gravitational forces, fully.

That the gravitational influence of the moon from 250,000 miles away, can move the seas to bulge toward it but I can easily lift my foot up from the floor with ease, just blows my mind. That the sun can influence the life and capture a comet from billions of miles is astonishing. Some comets have orbits that last for hundreds, if not thousands of years, all being forever held in the suns clutches.
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Post by spot »

The unit of mass which generates this gravitational attraction isn't a planet, it's each of the subatomic particles which makes up the planet. We've become used to averaging the effect of all those subatomic particles but it's each of them, one by one, which attracts. They attract their neighbours, and the other subatomic particles on the other side of the planet, and each of the subatomic particles in the neighbouring planets.

What I find difficult is that a subatomic particle currently located in my fingernail is, even as I type, attracting another subatomic particle in one of the stars of the Andromeda galaxy.

I find that difficult because it would seem even such an extremely small force is calculable, and so it's presumably measurable and real. We can see the effect of all these subatomic particles because the Andromeda Galaxy is consequently hurtling toward us faster [1] than a speeding bullet. All, without exaggeration, because of my fingernail and others like it acting over an admittedly longish time.





[1]: 300 times faster, thinking about it.
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Post by Bruv »

Should I cut my fingernails again ?
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Post by Snowfire »

Bruv;1495222 wrote: Should I cut my fingernails again ?


If you don't, those collective atoms will accelerate Andromeda even further.

Apparently, when the inevitable happens and Andromeda meets with the Milky Way and Mankind is still here, we will know very little about it. There is so much empty space between all the suns and solar systems, we will pass like ships in the night....but then the gravity will have a field day and swirl us about a bit more and the two galaxies may even separate again
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Post by ZAP »

spot;1495216 wrote: The unit of mass which generates this gravitational attraction isn't a planet, it's each of the subatomic particles which makes up the planet. We've become used to averaging the effect of all those subatomic particles but it's each of them, one by one, which attracts. They attract their neighbours, and the other subatomic particles on the other side of the planet, and each of the subatomic particles in the neighbouring planets.

What I find difficult is that a subatomic particle currently located in my fingernail is, even as I type, attracting another subatomic particle in one of the stars of the Andromeda galaxy.

I find that difficult because it would seem even such an extremely small force is calculable, and so it's presumably measurable and real. We can see the effect of all these subatomic particles because the Andromeda Galaxy is consequently hurtling toward us faster [1] than a speeding bullet. All, without exaggeration, because of my fingernail and others like it acting over an admittedly longish time.





[1]: 300 times faster, thinking about it.


I wish I could understand this better but when I try to concentrate, my mind flits off to Andromeda or other galaxies, wondering about what it's like there. But I certainly admire minds like yours Spot, that can state these things so concisely.
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Post by spot »

Snowfire;1495224 wrote: then the gravity will have a field day and swirl us about a bit more and the two galaxies may even separate again
I've known women like that.
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Post by spot »

ZAP;1495226 wrote: when I try to concentrate, my mind flits off to Andromeda or other galaxies, wondering about what it's like there.


Rain with occasional dry spells, according to the BBC 3-day forecast.
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Post by spot »

Bruv;1495222 wrote: Should I cut my fingernails again ?


Their ability to attract doesn't depend on their being attached. You should definitely stop biting them though.
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Post by ZAP »

spot;1495229 wrote: Rain with occasional dry spells, according to the BBC 3-day forecast.


:thinking: Good, I love rain!
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Post by ZAP »

spot;1495228 wrote: I've known women like that.


Sort of like a whirling dervish?
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Post by LarsMac »

Snowfire;1495224 wrote: If you don't, those collective atoms will accelerate Andromeda even further.

Apparently, when the inevitable happens and Andromeda meets with the Milky Way and Mankind is still here, we will know very little about it. There is so much empty space between all the suns and solar systems, we will pass like ships in the night....but then the gravity will have a field day and swirl us about a bit more and the two galaxies may even separate again


Well, I'd like to see all of that, but I suspect that by the time that happens, All that I am, now, will have been swirling about the solar system for a few millennia without my really being involved.
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Post by Snowfire »

LarsMac;1495235 wrote: Well, I'd like to see all of that, but I suspect that by the time that happens, All that I am, now, will have been swirling about the solar system for a few millennia without my really being involved.


I'd like to get the chance to pop back in another 4 or 5 billion years to see it. The night sky will look spectacular with the Milky Way which we can see clearly now and the looming Andromeda lighting up the night sky quite brightly.
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Post by Bruv »

spot;1495228 wrote: I've known women like that.


You old rogue.
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Post by spot »

LarsMac;1495235 wrote: Well, I'd like to see all of that, but I suspect that by the time that happens, All that I am, now, will have been swirling about the solar system for a few millennia without my really being involved.


A proportion of what you are was someone else not that long ago. It's been estimated that about 50 of your atoms were once part of Julius Caesar.

I'm by no means convinced that they've traveled between then and now, either. I think all these things we think of as subatomic particles are all permanently in the same location as each other and that among their individual properties are each of their coordinate locations, and that depending on what time you look at them you can find out where they are. And that if you don't interpret too much of a dimensional property as location you can interpret the rest as a more precise velocity, or if you don't interpret too much of a property as a velocity you can tie down the location more firmly, but that the overall dimensional location-and-velocity property occupies a predetermined fixed bit-length. That's how I'd design the universe if the mood took me.

Which means you and Julius have only apparently been separated all this "time" (whatever time might actually mean in this scenario). There might be a point of view from which those atoms are part of you while also being part of Julius, in which case your swirling about the solar system bit did already will have happened. I hope I got that tense right.
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Post by Bruv »

Spot took the words out of my mouth.
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Post by spot »

I, being poor, have only my dreams;

I have spread my dreams under your feet;

Tread softly.
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Post by FourPart »

Magnetism is much stronger than Gravity. A simple Fridge Magnet proves that. It can hold its own against the force of Gravity trying to pull it down.

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