Gravity and Magnetism the same?

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ramparts

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dryson":2pgaprxr said:
I am only open minded to what I can read and learn for myself based on science and not what someone else wants me to believe.

But you have yet to show me a single thing you've read and learned :) Everything here you seem to have come up with completely on your own. I can show you lots of support for what I'm saying... perhaps an introductory physics textbook?

It doesn't take a genius to figure that the circulatory system is controlled by the core's rotation and the gravity that is generated.

Then surely you'll have plenty of articles by geniuses and non-geniuses alike that say this very thing, right? Please show me these.

If gravity was not the same as magnetism then why do astronaughts have problems in space with their muscles and other body parts? The farther that you get away from a planet the less gravity is present or magentism, why else do you think that astronaughts seem to float the farther that they get away from Earth? It is because there is less magnetic fields of force to effect the iron in the humans blood, thus allowing them to float. It's not that there is less gravity it is because there is lesser amount of magnetism generating from the Earth which is gravity.

Right. So I (along with the rest of the scientific community) have this idea that astronauts float in space because there is less gravity pulling on their entire bodies. You have this idea that it has only to do with the iron in astronauts' blood. My question to you (as I've asked plenty, and you seem to ignore) is why it is that objects without magnetic properties feel gravity the same way. Non-magnetic objects float in space the same way people do. As a matter of fact, if gravity were the same as magnetism, non-magnetic objects would float on Earth, too!

http://en.wikipedia.org/wiki/Gravitation

Please read that article and find me one place where it says that gravity is the same as magnetism :) Otherwise why are you linking to it?
 
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yevaud

Guest
Questions, Dryson:

If Gravity is Magnetism, then how do non-magnetic large masses still possess gravitational fields?

If Gravity is caused by an active planetary core, then why does Mars - with a dead core - still possess Gravity?

As pointed out (I will express it slightly differently), how is it that gravitation still attracts masses that do not have ferromagnetic properties equally as much as masses that do?

Why doesn't a Horseshoe Crab - who's blood chemistry is based on Copper, IIRC, act differently in the presence (or absence) of a magnetic field?

Why does an MRI - which generates a magnetic field of several thousands of Gauss greater than the Earth itself - not equally attract objects with no ferromagnetic properties?

Game, set, match.
 
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Mars_Unit

Guest
No, Gravity can warp Space and even Time. Magnetism, as far as I know, cannot slow down an Atomic Clock.

Gravity can slow down an Atomic Clock!

Whoever said Gravity does not repel, I refer you to Saturn's Moons which can repel each other into swapping orbits.

An article in an early National Geographic magazine tells of Gravitational repulsion of Moons in Saturn's orbits.

I spoke with the late Robert Lull Forward and he agreed that Gravity could repel.

Faller invented the Laser Lunar Ranger and it found the Moon is drifting away from Earth due to tidal actions.

http://en.wikipedia.org/wiki/James_E._Faller

An article in 1977 Science News called Moon June Gone Balloon said we could lose the Moon into Solar orbit any day now!

I'm still waiting for the Moon to break free. It wont ever happen in my life.
 
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MeteorWayne

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Mars_Unit":o9xya9r3 said:
Whoever said Gravity does not repel, I refer you to Saturn's Moons which can repel each other into swapping orbits.

An article in an early National Geographic magazine tells of Gravitational repulsion of Moons in Saturn's orbits.

I spoke with the late Robert Lull Forward and he agreed that Gravity could repel.

Faller invented the Laser Lunar Ranger and it found the Moon is drifting away from Earth due to tidal actions.

http://en.wikipedia.org/wiki/James_E._Faller

An article in 1977 Science News called Moon June Gone Balloon said we could lose the Moon into Solar orbit any day now!

I'm still waiting for the Moon to break free. It wont ever happen in my life.

You are completely misinterpreting the cause and effect here. The changes in the Saturnian moon's orbits are caused by the interaction of the ATTRACTION of gravity causing the change in momentum between the moons. The same as the change in momentum is causing the moon to move away from the earth an inch or so every year. If gravity was repulsive, the effects would be completely different.

Please provide a link showing that a National Geographic article says gravity repulsion causes this. I have my problems with NG, but they keep basic physics straight, so I find that very unlikely.

Faller, yes, the moon is drifting away from the earth . That is caused by gravitational attraction, not repulsion! That's what causes tides.

Please show a link to the Science News article (I'll check my archives, since I have 30 or 40 years of Science News in my basement) where it indicates that is due to gravitational repulsion. I find your assertion ludicrous, silly, goofy, etc :)
 
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ramparts

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Do the schools really never teach that gravity is an attractive force, or that it's different from magnetism? I think sometimes we assume people have been taught the most basic of scientific concepts, but as anyone who has seen this: http://verizonmath.blogspot.com/2007/08 ... tomer.html knows, even basic math seems to elude a good segment of our population!
 
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Skibo1219

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Wow. Just Wow! To think that the difference between Gravity and Magnetism was learned in 9th grade physics class. The thing that gets me is why can't we build a simple elevator using magnetism(electro ;) ) to get from the ground to the space station. :twisted: {The space shuttle ain't simple ;p }
what is the equation(theory?) for mass vs gravity vs distance from source ?
 
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cpumasterwv

Guest
There are words, and I really want to say them. I know that they will get me kicked off of SDC forever though so I shall refrain.

While I will agree that SOME of the VERY GENERALY observed effect of gravity and magnetism are SOMEWHAT similar, in no way, shape, or form is gravity and magnetism the same thing. I would go into a very simple explanation for you, but I know that you wouldn't even begin to listen because you already have it set into your mind that they are. But I have an experiment for you.

Go buy a magnet. Please. Buy one, and place it next to a tree. There will be no magnetic attraction between the magnet and the tree. The only force that will act on them is GRAVITY, and it ONLY does this because both the Magnet and the Tree have MASS!

If what you are saying is correct, I should be able to go into the field next to my house and literally slap together another house and have 2. The gaping hole in the magnetism theory is that not everything is magnetic.

WATER! Water is not magetic and yet they only way it can rise of the ground is to evaporate and become slightly less dense then the air around it. Then it condenses, and its MASS increases, not its iron content, and it falls to the ground because of GRAVITY!


Ok, I think I got that out of my system for the most part.
 
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Skibo1219

Guest
Skibo1219":21td6ugs said:
Wow. Just Wow! To think that the difference between Gravity and Magnetism was learned in 9th grade physics class. The thing that gets me is why can't we build a simple elevator using magnetism(electro ;) ) to get from the ground to the space station. :twisted: {The space shuttle ain't simple ;p }
what is the equation(theory?) for mass vs gravity vs distance from source ?
Taken from the Wiki:
"The force of gravity is proportional to the mass of an object and inversely proportional to the square of the distance between the objects"
Think-time.
Ok this seems to apply to planetary mass mainly
 
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cpumasterwv

Guest
You know its funny, I used that equation at Tech School to explain a question we were working out, and I almost came up with a singularity at the center of the Earth. We were trying to figure out how many time an object would pendulum (sp?) barring survivability and what not, the math never wanted to go to 0. Someone was like "Its a black hole!!!!" I had to throw something at him. Then we poked at it for a few more minuted and realized that there couldn't be a zero point because there is what I've been referring to as variable mass. The core spins and gravity is generated from a grouping of "zero points" that are constantly in motion. Center, but no Zero.
 
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emperor_of_localgroup

Guest
ramparts":2mn33vlj said:
Do the schools really never teach that gravity is an attractive force, or that it's different from magnetism? I think sometimes we assume people have been taught the most basic of scientific concepts, but as anyone who has seen this: http://verizonmath.blogspot.com/2007/08 ... tomer.html knows, even basic math seems to elude a good segment of our population!

This statement is so misguided or misplaced. There are many on this swho have gone through high levels of physics and learned what college/Univ textbooks taught us. But when we are out of school and don't use physics as profession, we start rethinking about physics and trying to find an alternative explanation of nature. Our minds are now 'what - if....'.

I don't think 1000 years from now physics textbooks will have the same contents as we have today, even in high schools.
 
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emperor_of_localgroup

Guest
cpumasterwv":23f9lb6e said:
You know its funny, I used that equation at Tech School to explain a question we were working out, and I almost came up with a singularity at the center of the Earth. We were trying to figure out how many time an object would pendulum (sp?) barring survivability and what not, the math never wanted to go to 0. Someone was like "Its a black hole!!!!" I had to throw something at him. Then we poked at it for a few more minuted and realized that there couldn't be a zero point because there is what I've been referring to as variable mass. The core spins and gravity is generated from a grouping of "zero points" that are constantly in motion. Center, but no Zero.

Ha ha ha ha. Interesting. I just saw a video online which claims there is a blackhole at the center of everything, earth, planets, sun, even atoms. He says center of the earth is hollow because of event horizon, just as an atom is basically hollow inside except the center. According to him, gravity is pull of the blackhole at the center of earth.

Please don't think I'm buying this theory....'yet'. ha ha ha.
Anyway, anyone knows how far deep inside earth we have sent probes to explore? The center is only 4000 miles deep.
 
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cpumasterwv

Guest
As per Wikipedia:

The Kola Superdeep Borehole (Russian: Кольская сверхглубокая скважина) is the result of a scientific drilling project of the former USSR. The project attempted to drill as deep as possible into the Earth's crust. Drilling began on 24 May 1970 on the Kola Peninsula, using the Uralmash-4E, and later the Uralmash-15000 series drilling rig. A number of boreholes were drilled by branching from a central hole. The deepest, SG-3, reached 12,261 metres (40,230 ft) in 1989, and remains the deepest hole ever drilled.

Honestly, they should have just started at the bottom of Challenger Deep, after 5000 feet, they would have this beat.
 
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ramparts

Guest
emperor_of_localgroup":217k5k7v said:
ramparts":217k5k7v said:
Do the schools really never teach that gravity is an attractive force, or that it's different from magnetism? I think sometimes we assume people have been taught the most basic of scientific concepts, but as anyone who has seen this: http://verizonmath.blogspot.com/2007/08 ... tomer.html knows, even basic math seems to elude a good segment of our population!

This statement is so misguided or misplaced. There are many on this swho have gone through high levels of physics and learned what college/Univ textbooks taught us. But when we are out of school and don't use physics as profession, we start rethinking about physics and trying to find an alternative explanation of nature. Our minds are now 'what - if....'.

I don't think 1000 years from now physics textbooks will have the same contents as we have today, even in high schools.

No, but that doesn't mean you can go make up your own physics :p Really, now.

Listen, having your own opinion is nice and all, and it's great to be interested in physics when not in class, but it doesn't mean that opinion is right, just like if I had the opinion that the sky is hot pink. If you're going around saying that gravity and magnetism are the same, you're wrong.

All new physics since Newton's time has come about by taking what was established and building upon it, rather than throwing it out the window. And especially none of new physics of the last four centuries has come from people making hand-wavy, non-technical arguments who put their "theories" out to laymen rather than scientists ;)
 
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ramparts

Guest
Skibo1219":30btht6s said:
Skibo1219":30btht6s said:
Wow. Just Wow! To think that the difference between Gravity and Magnetism was learned in 9th grade physics class. The thing that gets me is why can't we build a simple elevator using magnetism(electro ;) ) to get from the ground to the space station. :twisted: {The space shuttle ain't simple ;p }
what is the equation(theory?) for mass vs gravity vs distance from source ?
Taken from the Wiki:
"The force of gravity is proportional to the mass of an object and inversely proportional to the square of the distance between the objects"
Think-time.
Ok this seems to apply to planetary mass mainly

Indeed! Well, this applies to any mass, actually, not just planetary mass :) The gravitational force is given by:

F = G m M / r^2

Where G is the gravitational constant, m is your mass, M is the mass of the planet you're on, and r is your distance "above" the planet's center. In order to break above the Earth's surface, this force (which attracts you towards the Earth) has to be less than the electric force, which looks very similar, but has a different constant and is proportional to the charges (and also goes as 1/r^2). (The equation for magnetism is a bit more complicated.) Unfortunately, as you may have noticed if you've seen those toy floating magnets, the electric and magnetic forces are stronger than gravity, but only over very small scales. To create a magnet that could actually propel people to the moon - well, that would be a VERY strong magnet ;)
 
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dangineer

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One of my cowrokers has one at his desk. There's lots of different ones. This one is a globe entirely suspended by magnets, with nothing touching it. The globe sits in a magnetic well which is at the equilibrium point between two magnets (one on top and one on the bottom).
 
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ramparts

Guest
cpumasterwv":qhzad0rw said:
You know its funny, I used that equation at Tech School to explain a question we were working out, and I almost came up with a singularity at the center of the Earth. We were trying to figure out how many time an object would pendulum (sp?) barring survivability and what not, the math never wanted to go to 0. Someone was like "Its a black hole!!!!" I had to throw something at him. Then we poked at it for a few more minuted and realized that there couldn't be a zero point because there is what I've been referring to as variable mass. The core spins and gravity is generated from a grouping of "zero points" that are constantly in motion. Center, but no Zero.

Hmm, I can assure you that if you're running through Newton's 1/r^2 equation (see my last post) and finding a singularity at the center of the Earth, it's your math that's off, not physics ;) So rather than invent a new theory, perhaps check one's math?

I'm not sure what calculation you did, but I'll take a guess: did you look at the 1/r^2 equation, and find that at the center (when r=0), the force is infinite, since you can't divide by 0? That's a pretty common problem (and an interesting one even if it's not the one you ran into!), so maybe I can digress to explain it? This doesn't show the Earth has a central singularity - it assumes it! Newton proved a lovely little theorem showing that when you're inside a massive sphere, only the mass that's closer to the center than you are (no matter where in the sphere it is) will have a gravitational pull on you - all of the matter at a radius greater than you cancels out. So when you're inside the Earth's surface, you need to change the M term (Earth's mass) in the equation to reflect whatever the interior mass is - as a function of the radius. When you reach the center, there's obviously no interior mass to pull on you, so the M term becomes zero - and so does the force! The issue of dividing by zero doesn't even come into play.

Not sure if that's what you ran into, but I've always found that nifty :)
 
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ramparts

Guest
dangineer":2sqdrxqu said:
One of my cowrokers has one at his desk. There's lots of different ones. This one is a globe entirely suspended by magnets, with nothing touching it. The globe sits in a magnetic well which is at the equilibrium point between two magnets (one on top and one on the bottom).

Yeah, they're fun :) The one's I've seen have a magnetic floor, and then the object is sort of an elongated magnetic spinning top that floats about an inch off the floor, and makes contact with a vertical glass surface that allows it to spin around.
 
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cpumasterwv

Guest
ramparts":1gfh9uih said:
cpumasterwv":1gfh9uih said:
You know its funny, I used that equation at Tech School to explain a question we were working out, and I almost came up with a singularity at the center of the Earth. We were trying to figure out how many time an object would pendulum (sp?) barring survivability and what not, the math never wanted to go to 0. Someone was like "Its a black hole!!!!" I had to throw something at him. Then we poked at it for a few more minuted and realized that there couldn't be a zero point because there is what I've been referring to as variable mass. The core spins and gravity is generated from a grouping of "zero points" that are constantly in motion. Center, but no Zero.

Hmm, I can assure you that if you're running through Newton's 1/r^2 equation (see my last post) and finding a singularity at the center of the Earth, it's your math that's off, not physics ;) So rather than invent a new theory, perhaps check one's math?

I'm not sure what calculation you did, but I'll take a guess: did you look at the 1/r^2 equation, and find that at the center (when r=0), the force is infinite, since you can't divide by 0? That's a pretty common problem (and an interesting one even if it's not the one you ran into!), so maybe I can digress to explain it? This doesn't show the Earth has a central singularity - it assumes it! Newton proved a lovely little theorem showing that when you're inside a massive sphere, only the mass that's closer to the center than you are (no matter where in the sphere it is) will have a gravitational pull on you - all of the matter at a radius greater than you cancels out. So when you're inside the Earth's surface, you need to change the M term (Earth's mass) in the equation to reflect whatever the interior mass is - as a function of the radius. When you reach the center, there's obviously no interior mass to pull on you, so the M term becomes zero - and so does the force! The issue of dividing by zero doesn't even come into play.

Not sure if that's what you ran into, but I've always found that nifty :)


EUREKA! I wasted an entire weekend trying to work out the whole variable mass theory. So then help me out with this. If you were working out the amount of time it would take to reach the center, then said object would actually decelerate as you approched the center due to a lower amount of gravity? (Were assuming air resistance equal to sea level)

And if this is the case you get into longer and longer decimals to the point of would you ever reach the true center? I guess thats all up to scale. .000000625 in doesn't really figure into anything when the person... I mean... object is 6 ft tall.
 
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dangineer

Guest
Not quite. First of all, I would neglect air resistance entirely - that just makes things more complicated.

Second, you're acceleration will decrease, but will still have positive acceleration (hence positive velocity) until you reach the center of the Earth, where your velocity is at a maximum. Then you will begin to deccelerate until you reach the surface on the opposite side of the Earth. This would result in undamped oscillatory motion. If you add air resistance, then you get damped oscillatory motion, which becomes more difficult to calculate (not substantially more difficult, but more difficult none-the-less). Actually, air resistance is non-linear (proportional to velocity squared), thus you would get a second order, non-linear, ordinary differential equation. Fun stuff!

It would also help to assume that the Earth is of uniform density and perfectly spherical.
 
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ramparts

Guest
cpumasterwv":9ywszni9 said:
EUREKA! I wasted an entire weekend trying to work out the whole variable mass theory. So then help me out with this. If you were working out the amount of time it would take to reach the center, then said object would actually decelerate as you approched the center due to a lower amount of gravity? (Were assuming air resistance equal to sea level)

And if this is the case you get into longer and longer decimals to the point of would you ever reach the true center? I guess thats all up to scale. .000000625 in doesn't really figure into anything when the person... I mean... object is 6 ft tall.

WARNING: Math ahead! :)

This is actually in general a very non-trivial problem, since it's essentially a fairly difficult second-order differential equation (acceleration, the second time derivative of distance, as a function of distance^-2), although adding in the fact that it's not a point source can make things more or less difficult, depending on your assumptions. So let's look at the problem:

Newton's second law: F = ma, relates force to acceleration

Newton's gravity law: F = -GmM/r^2, relates distance, mass of planet, etc., to force.

Put them together and cancel out m (your mass), you have:

a = r'' = GM/r^2 (equation 1)

Where ' denotes a time derivative. This problem is rather subtle even assuming that M is constant (as you did - a point source). But we're doing a different problem, where (assuming we're already beneath the Earth's surface), M is a function of r - call it M(r). That's the mathematical difference. Let's rewrite the equation in terms of the density of the Earth, since that makes life easier - density ρ is equal to mass divided by volume, or M/V=M/(4/3 pi r^3) = 3/4pi M/r^3 (assuming the Earth is spherically symmetric, or that a thin shell of Earth at any given radius looks uniform). Let's absorb the 3/4pi into our constants (so far there's just -G), call our constants -k^2 (the reason will be clear in a moment), and we can rewrite equation 1 as:

r'' = -k^2 ρ(r) r

So the solution of our equation depends on our choice of ρ(r), the density of the Earth as a function of distance from the center. I have no idea what this is in real life, though I'm sure it's not pretty, but let's (for fun) assume that ρ(r) is constant - in other words, every point inside the Earth has the same density as any other point. If that were the case, then we absorb ρ into our constants and we have a familiar equation:

r'' = -k^2 r

This is the equation for simple harmonic motion. Now you see why we called our constants -k^2 (instead of k) - we need to make it clear that the constants are negative (due to the minus sign in Newton's gravity law), because if they were positive, we'd have exponential behavior - clearly wrong! So the general solution to this is:

r(t) = A sin(kt) + B cos(kt)

Where k is some combination of positive constants. So the motion is harmonic, nice periodic trig motion. With initial conditions we can knock this down a bit further. Let's assume we start from rest at the surface of the Earth (call it capital R). Then we have:

r(t=0) = R = A sin(0) + B cos(0) = B
r'(t=0) = 0 = k A cos(0) + k B sin(0) = k A

So A is equal to 0, and B is equal to R. The final equation of motion is:

r(t) = R cos(kt)

I just saw dangineer's post - he's entirely right, of course :) Air resistance is a schlep, and I won't bother; not to mention we're dealing with the inside of the Earth's surface, where air resistance is hardly a concern!

Apologies for thread drift, MeteorWayne.
 
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MeteorWayne

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As a moderator, this thread is REALLY frustrating. Every time it runs off the rails and crashes into a ravine of gibberish and fantasy physics worthy of exile to The Unexplained, someone comes along and makes an intelligent post.

:) :)
 
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ramparts

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Sorry!! If you'd like I can edit the last post to reflect my personal theory of math, which states that the solution to the differential equation r''(t) = -k^2 r(t) is clearly r(t) = 11. Then dangineer would be the only sane one in the building ;)
 
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cpumasterwv

Guest
Eh, we live to annoy, and besides, I'm learning from all of this. Doesn't matter what I want to think, I need to learn calculus. Lots and lots of calculus. CCAF, here I come.
 
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dangineer

Guest
I think everyone should have a basic understanding of calculus. The government needs to make it a requirement to pass high school, although that discussion probably should go in another forum.

Back to physics...

If anyone's interested in tackling the air resistance problem, here's a start:

Aerodynamic drag is given by Cd*(1/2)*density*A*V^2. 'A' is the cross sectional area. Cd is the drag coefficient and depends on the geometry. Using 1 is a decent assumption. Density refers to the density of the air. Now, drag is a force that ALWAYS opposes motion, so this force changes when you pass the center of the Earth. It is subtracted from the gravitational force on the way down and added to the force on the way up. It thus becomes a damping force, causing the object to lose energy during the whole process. The problem is that it is a non-linear damping force and that adds a whole load of fun to the problem.

Eventually, the object should come to rest at the center of the Earth. Technically, it will continue to oscillate at ever decreasing amplitudes, but you can see how many times it oscillates before it reaches a very small amplitude.
 
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