Thunderbolts of the Gods

robinson said:
Wrong. Don't be dumb. Any physics text will educate you on this. [that electromagnetic force is greater than gravitic.]
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Well - go ahead, give us a citation.

This was answered earlier. There is no direct way to compare them. One depends on the mass of an object and the other on it's electrical charge. How do you compare the two? It is not correct to compare the attraction of two magnets due to magnetic force to the attraction of two equivalent, demagnetized objects due to gravity.

They both obey the inverse square law. Therefore they decline in force in the same ratio of distance.

The reason why gravitation is more significant (not stronger) over astronomical distances is that all mass is affected by gravitation, and in one "direction" only - attraction. Not all matter has charge, and that that does is largely balanced by opposite charges, mostly canceling out in the long run.
 
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robinson said:
http://scienceworld.wolfram.com/physics/FundamentalForces.html
http://hyperphysics.phy-astr.gsu.edu/hbase/forces/funfor.html
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Nope. Little problem there: you're comparing apples and oranges. Every particle has mass, and therefore contributes to gravity; there is no anti-mass, so there is no anti-gravity. You can create negative gravity effects by appropriate distortions of spacetime, but you can't create antigravity with mass. However, the case for electrical forces is very different; first of all, most matter is atoms, and atoms are neutral. Second, atoms contain neutrons, which are neutral even if you separate them from the nucleus. Third, "plasma" doesn't necessarily imply either that a) all the atoms in the plasma are ionized, or b) the electrons left; the plasma might be (and they often are) electrically neutral overall, despite containing free electrons and ions. Fourth, ordinary matter we can see (which is mostly plasma, that's why we can see it, it's emitting light) makes up only about 4% of the mass of the universe. The rest we can tell is there because of its gravitational effects, but it doesn't emit light- implying that it's not plasma, and therefore cannot contribute to any electrical charge. Fifth, electric charge is conserved; galaxies, to attract one another, would have to be made from segregated electric charges, one positive, the other negative, and no mechanism for segregating these charges is proposed (and any method that would be would involve titanic energies, far beyond anything we see out there with telescopes). That'll do to go on with, I think.
 
robinson said:
Well, go argue with the entire scientific community then. They seem to be dead set on this whole laws of physics and fundamental force thing. :D
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Shadron and others are correct. It is true that physicists often speak of gravity as much weaker than electromagnetism. However this obviously depends on the objects in question; they have elementary particles in mind when they say that. The electric force between two electrons is vastly stronger than the gravitational attraction. But on the other hand the gravitational force between the earth and the moon is vastly stronger than the electric force.

The reason, as was pointed out, is that large objects are almost exactly electrically neutral, and the dipole-type electric forces which might remain fall off with distance much faster than gravity. There is no such thing as a gravitationally neutral object because there is no negative mass.

An interesting consequence of these facts is that gravity matters less and less on shorter distances. Watch the movie Microcosmos sometime... you'll see what I mean. Forces like surface tension become much more important than gravity if you're the size of an insect. Ants survive falls from any height you drop them from, and can lift 10 times their weight. Only small birds can fly. Etc.
 
:talk005: Until recently we believed the non-manifold phase space between forum users and the user agreement was empty - a vacuum. It is possible that the predominant force in the forum is not inertia or credibility. But something else..

Lisa..


 
Schneibster said:
Nope. Little problem there: you're comparing apples and oranges.
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I'm not comparing anything, you are arguing with the current theory accepted by the scientific community. Good luck with that.

sol invictus said:
Interpreting that as evidence that the sun is electric is equivalent to interpreting the recent discovery of a piece of Manchego in my refrigerator as evidence that the moon is made of cheese.
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I don't even know what you are talking about. But it sounds dumb.

sol invictus said:
Shadron and others are correct. It is true that physicists often speak of gravity as much weaker than electromagnetism. However this obviously depends on the objects in question;
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Again, the current understanding of the fundamental forces states that the EM force is 1037 times stronger than gravity. If you want to argue that, take it up with worlds scientist. They said it, not me.

Dancing David said:
Here is an APOD story on Hinode and the Alven waves.

Cool, but no electric sun!

http://antwrp.gsfc.nasa.gov/apod/ap071210.html
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I'm not sure what the electric sun really means. I find it fascinating that as we gain better ways to observe the sun and the Cosmos, we discover more and more fascinating information. The recent discoveries were predicted in 1942. Like many theoretical ideas about how the Universe works, eventually new instruments and observations allow us to get closer to what is really going on.
 
In regards to the somewhat questionable topic, I found this Los Alamos web page interesting.

Dynamical Characteristics of Plasmas

It is the global dynamics and systematic interactions of astrophysical plasmas that allow energy to be conveyed over great distances. The evolution of cosmic plasma that includes its structuring into cells results in a relative motion, however slow, of plasma clouds whose dimensions may be measured in hundreds or megaparsecs or gigaparsecs. All plasma clouds may be considered a system: they are coupled by electrical currents (charged particles beams) they induce in each other. These beams are the source of energy transfer from large, slow moving plasma to smaller plasma regions that may release the energy abruptly or cause local plasmas to pinch to the condense state.
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http://public.lanl.gov/alp/plasma/elec_currents.html

More at link.

A lot of new evidence from advanced sensing equipment is explaining, and often validating, old theories about the Universe, especially plasma and EM forces, which were almost always greeted with scorn or ignorance in the past.

Those events, like the current ones, tend to fuel my interest in matters. Like when people make absurd claims about gravity being stronger than EM. Why would anybody say something that dumb? Is ignorance of basic physics and EM really that huge? It can't be. Why would anybody say something like that?

So it gets interesting.
 
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The electric sun is the theory that the sun's energy comes not from necler fusion but from the stars recieving a charge for humongous Birkeland currents.
 
robinson said:
Well, go argue with the entire scientific community then. They seem to be dead set on this whole laws of physics and fundamental force thing. :D
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All I can say to that is: how do they make that comparison? Where is the scratch work that stands behind the declaration? Mainly, what are the hidden assumptions?

I understand you are only quoting others, but you *are* the one quoting the others, and I want to know how I'm wrong. :)
 
I'm not going to try and explain the current theories on fundamental forces. There may be some physicist here that can do that. Based on my education and current understanding, gravity is the hardest one to explain, still no particle for the force, and you actually have to switch to a different theory to talk about it.

But nobody doubts the physics of either gravity or EM. Well, nobody who knows stuff about it that is.

For a simple practical example, you can escape the gravity of the entire planet earth, as well as the sun, using a small amount of EM energy (small compared to the mass of the sun and earth, which is where the gravity comes from).

We have done this over and over. The combination of oxygen and hydrogen creates EM energy, we call it rocket fuel, and this heat and light can move a space ship or probe all the way out of the solar system, using nothing more than EM energy. Or you could use your own EM energy, and jump up and negate the entire planets gravity, with nothing more than the EM generated by your muscles and nerves.

See? The small amount of energy in your own body can counter (however brief) the entire planets gravity. In fact, we do it all the time, by standing or walking.

And while we are very close to the center of gravity of our planet, it isn't hard to resist or counter all that energy, with a very small amount of EM energy. If gravity was anywhere close to the strength of EM, we couldn't do much of anything.

Gravity seems more powerful, because of the huge amount of mass that creates the effect. But in small masses, gravity is almost non existent, in a practical sense.

Yes it is hard to compare EM with gravity, but somehow those really smart physics dudes seem to be able to do it. We should ask one of them about this. :D
 
robinson said:
Yes it is hard to compare EM with gravity, but somehow those really smart physics dudes seem to be able to do it. We should ask one of them about this. :D
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I already tried to explain it to you, but evidently I failed.

It is impossible to compare the forces without specifying what the objects are that are being acted on. However we do have theories of elementary particles, and those elementary particles interact much more strongly electromagnetically than they do gravitationally, roughly speaking because their charge is much bigger than their mass. For an elementary particle, gravity is almost totally irrelevant. As you move up in length scales, it gets more and more important (because the universe is electrically neutral, but has lots of mass in it). For an insect, gravity is still pretty weak compared to many other forces we don't notice much (surface tension of water for example). For a bird, it's still weaker than air resistance, so birds can fly - but only smallish ones. For us, it's getting pretty important. For planetary orbits, it's the only force that matters.

That's what it means to compare them.
 
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Dancing David said:
Much of what BAC is saying is foolish,

However i don't suppose that the 'solar wind' is ions in the vacum of space, is it?

Not that this demonstrates the 'large scale currents' which BAC is beloved of.
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The average solar wind has 5- 10 protons per cubic centimeter. The high seems to a high of a few hundred particles per cubic centermeter.
 
Davidlpf said:
BAC, if you cannot have a magnetic field witout a current explain a bar magnet, without links, or the words Gnome, magic, or bogus.
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As I said, I will respond to no questions on this thread until I get a ruling from the Admin (Darat) as to the permissability of my series of posts provided they are modified to eliminate hotlinks and with each quote reduced to but a small fraction of any given source. Doing that would comply with the rules of the forum. But I'm still waiting for that ruling.
 
robinson said:
Yes it is hard to compare EM with gravity, but somehow those really smart physics dudes seem to be able to do it. We should ask one of them about this. :D
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I've already answered it. As have other really smart physics dudes. Amazingly, some of us actually know what we're talking about. What I said, and what others have clarified, is entirely correct. You cannot compare fundamental forces with each other because they have different sources. Gravity is caused by mass, electormagentism by electric charge. If you have something with small mass but large charge, the EM force is bigger. If you have something with small, or zero, charge but large mass, gravity is bigger.

As I pointed out ealier, trying to compare them is exactly the same as asking whether a piece of string of a plank of wood is longer. It depends entirely on which piece of string and which plank of wood.

When textbooks say things like EM is stronger than gravity, all they mean is that the electric constant (k) is larger than the gravitational constant (G). Which doesn't really mean anything because this ignores all the other factors in the equation. It is what Terry Pratchett calls "lies to children". Not everything you are told is true, and even the things that are technically true are usually not the whole story. This is because it is impossible to learn everything all at once, and so things must be simplified to begin with. What you are basically trying to argue is that the simplified ideas told to the layperson are more accurate than the better understanding of professional physicists. Rather than simply arguing for the sake of it, why not try to actually think about it and learn something for once?
 
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