## Flat Earth Discussion

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tomokun
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### Flat Earth Discussion

So... I used this video as an example of how "water can cling to a spinning ball:
https://www.youtube.com/watch?v=7ctaA2mERzI

It didn't fly. The response was, "Dude that's totally cool however it's not sticking to a spinning ball in a vacuum."

Anyone have any videos that have experiments anyone can do that would qualify?

rowan
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### Re: Flat Earth Discussion

Is your goal to convince a flat-earther that the Earth is a sphere? Or that water will stick to the Earth? Or something else?
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Sonic#
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### Re: Flat Earth Discussion

"Dude that's totally cool however it's not sticking to a spinning ball in a vacuum."
What are the factors that make Earth have water but Mars have little/no surface water? Temperature? Atmospheric pressure?

SimpleMan
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### Re: Flat Earth Discussion

I don't think that trick in the OP video is actually possible... you know... because Gravity...

Anyway, I like this other experiment on this other video:

https://www.youtube.com/watch?v=KFPvdNbftOY

tomokun
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### Re: Flat Earth Discussion

rowan wrote:
Fri Jan 5, 17:02 2018
Is your goal to convince a flat-earther that the Earth is a sphere? Or that water will stick to the Earth? Or something else?
My goal is to provide an experiment they can do themself that demonstrates how water stays on the planet. I'm guessing that if you have something which spins and rotates fast enough that the water will "stay on the ball" so to speak. Similar to swinging an open bucket of water by a rope.
Sonic# wrote:
Fri Jan 5, 22:04 2018
"Dude that's totally cool however it's not sticking to a spinning ball in a vacuum."
What are the factors that make Earth have water but Mars have little/no surface water? Temperature? Atmospheric pressure?
I believe it's temperature, atmospheric pressure... and the fact that we have a LOT of water, right? I mean, most of Mars's water is beneath the surface, right?
SimpleMan wrote:
Fri Jan 5, 23:39 2018
I don't think that trick in the OP video is actually possible... you know... because Gravity...

Anyway, I like this other experiment on this other video:

https://www.youtube.com/watch?v=KFPvdNbftOY
Oh, it's totally possible, but you have to have the right surface to make it spin, and it makes a terrible mess. :p That other experiment is great, and I did offer an example of the Zero G plane, showing that water becomes spherical in zero-g... but that doesn't quite demonstrate why water stays on the Earth as it spins and rotates around the sun.

I mean... the biggest hurdle I think is that the Earth's gravity makes such an experiment almost impossible without going into Zero G...

Taurwen
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### Re: Flat Earth Discussion

Isn't gravity the primary reason water stays on the surface? Centripetal force (what keeps the water in the bucket) pushes push outward, not inward which is what you'd need for water to stay on a sphere.

Pikachu
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### Re: Flat Earth Discussion

Taurwen wrote:
Sat Jan 6, 13:20 2018
Isn't gravity the primary reason water stays on the surface? Centripetal force (what keeps the water in the bucket) pushes push outward, not inward which is what you'd need for water to stay on a sphere.
This. Water flying off the Earth when it stops spinning presumes a sudden stop, causing the water to exceed escape velocity.

MFS
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### Re: Flat Earth Discussion

it doesn't push outward - it is the movement forward. If you spin something around and let it go, it doesn't go flying out in the direction your arm is pointing, it goes flying forward, otherwise throwing would be a really strange looking movement.
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Taurwen
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### Re: Flat Earth Discussion

I knew my physics was off. Forward is better.

tomokun
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### Re: Flat Earth Discussion

Gotcha, so it iS the combination of spinning and rotation along with gravity that keeps all the water "on the ball" of Earth, yes?

So the main question is, what's an experiment she could do to experience this for herself?

DarkOne
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### Re: Flat Earth Discussion

The way I understand it: Gravity pulls water (and everything else) toward the Earth's center. A combination of the geography of the landmasses, the volume of water, and the earth's rotation determines the distribution of the water on the Earth's surface, and therefore, the shape of the land/water boundary (e.g. Africa's skull shape or Italy's boot shape.) The Earth's axial rotation is mostly responsible for the Earth's oblate-ish shape, wide at the equator and squatter at the poles. If the Earth slowly stopped rotating, theory is it would change shapes towards spherical, which would affect mass distribution, which would affect gravity at any given spot on the surface, which would affect how the water sits. But the water would still sit at the surface without rotation.

Problem with trying to reason with flat-earth believers is that, by default they are also massive conspiracy theorists. Otherwise, they would have to accept pictures and footage from space as evidence of flat-earth being monumentally wrong. But all those pictures from space are a hoax. They also tend to have, at best, a fleeting grasp of science. So using scientific concepts to explain why water stays on the surface of a spheroidal body is like explaining it in cuneiform. Exactly.

Have you tried these?: https://www.popsci.com/10-ways-you-can- ... h-is-round
"Winston Churchill once said 'The eyes are the windows of your face.' " -A man who's very scared of plants.

rowan
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### Re: Flat Earth Discussion

I'm going to come back to this thread in a bit, since there are some interesting questions here, but I just wanted to point out that the Earth's rotation speed (460 meters/second at the Equator, where it's fastest) is not above escape velocity (11,200 meters/second) so if the Earth were to suddenly stop all the water wouldn't fly off. Also it's not speed relative to the surface that's the issue but speed relative to the center so if it were fast enough to fly off, it would have already done so.
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rowan
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### Re: Flat Earth Discussion

Sonic# wrote:
Fri Jan 5, 22:04 2018
What are the factors that make Earth have water but Mars have little/no surface water? Temperature? Atmospheric pressure?
Primarily this is because Mars' gravity is only about 1/3 of Earth's. Because of this, Mars wasn't able to hold onto as much atmosphere (thus less pressure) and liquid water becomes unstable (there is water ice at the poles under the CO2 ice). Water ice (potentially liquid) remains underground because it's shielded down there. Much of Mars' water was lost to space because it just can't be retained (water is lighter than CO2 - but even a lot of CO2 has been lost. Mars' atmosphere is only 6 millibars at the surface). So Tomokun is mostly right here (quantity of water doesn't matter so much in terms of being able to retain water, apart from water is a super great greenhouse gas - which makes it hotter and harder to retain atmospheric gases if you're already having trouble).
Taurwen wrote:
Sat Jan 6, 13:20 2018
Isn't gravity the primary reason water stays on the surface? Centripetal force (what keeps the water in the bucket) pushes push outward, not inward which is what you'd need for water to stay on a sphere.
DarkOne is pretty much spot on here so skip if you don't want mega details here.

Ok let's talk the water in the bucket. At the top of the swing you have gravity pulling the water down, and the bucket's normal force pushing the water down (in order to keep it moving in a circle since it wants to go in a straight line as MFS points out). These forces are both directed toward the center of the circle, thus fall into a category called centripetal forces. Which basically means "center-directed forces" and aren't a force themselves, just forces that happen to be in the direction of the center of the circle. Any force can be centripetal.

Aside: "centrifugal forces" are fictious forces and don't exist but can occasionally be useful in certain reference frames. I hate using them because they confuse people tremendously. It's really just the tendency for things to move in straight lines being re-branded as a "force" that doesn't exist. So just kick that term to the curb.

The water in the bucket isn't as useful to help with your flat earther because the problem is that on the Earth the normal force of the surface pushes toward space (holding things up from falling down due to gravity) and the inertia (moving in a straight line) is what would fling the water off into space. Gravity >> that inertia so it really is only gravity keeping the water on. You could maybe talk about the bucket itself (which has tension and gravity) at the top of the circle where if you go slow enough you don't need tension to make the circle (just at the top) because gravity is enough to keep it falling at just the right amount to be a circle. But TBH this is probably too subtle for a flat earther's reasoning.
DarkOne wrote:
Mon Jan 8, 12:24 2018
Have you tried these?: https://www.popsci.com/10-ways-you-can- ... h-is-round
These are all pretty good, though again, as DarkOne says the conspiracy theory tinfoil hat set that flat earthers tend to be have all kinds of silly explanations that "fix" these things, that generally involve amazing conpiracies. Good luck.

Another possibility is try to get them to explain - by drawing - how plane travel times can be the same. You have to lead into it though. First ask them to sketch a rough map of the earth. A typical flat earther will draw the Earth such that the north pole is at the center and the southern hemisphere is along the edge with Antarctica around the edge. Now, check out the distances between two places such as idk Atlanta and Rome, vs. Perth AUS and Auckland NZ. Problem: time zones. So I imagine they'll just use time zones to "fudge" things. But nontheless, unless there is a huge conspiracy between all the airlines, all the governments AND ALL THE TRAVELERS that might work. But I suspect not; they think we are all the sheeple and that somehow they are Special and In The Know. (another challenge is that there is more land mass in the northern hemisphere than the southern so can be hard to find nonstop flights at similar latitudes and distances).

I haven't tried the airplane flights on a real flat earther, but you could google it and see what conspiracy theory they have to deny it before trying to talk to your person. I know I've tried to talk about time zones and gotten some whack "explanation" of them. Anyway good luck.
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tomokun
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### Re: Flat Earth Discussion

rowan wrote:
Thu Jan 11, 12:49 2018
Another possibility is try to get them to explain - by drawing - how plane travel times can be the same. You have to lead into it though. First ask them to sketch a rough map of the earth. A typical flat earther will draw the Earth such that the north pole is at the center and the southern hemisphere is along the edge with Antarctica around the edge. Now, check out the distances between two places such as idk Atlanta and Rome, vs. Perth AUS and Auckland NZ. Problem: time zones. So I imagine they'll just use time zones to "fudge" things. But nontheless, unless there is a huge conspiracy between all the airlines, all the governments AND ALL THE TRAVELERS that might work. But I suspect not; they think we are all the sheeple and that somehow they are Special and In The Know. (another challenge is that there is more land mass in the northern hemisphere than the southern so can be hard to find nonstop flights at similar latitudes and distances).
This is brilliant.

Not to short-change anyone's responses, all have been helpful, but I might have to play around with this myself because from what I understand, it really makes sense!

tomokun
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### Re: Flat Earth Discussion

So... here's the latest in my delving into Flat Earth - there explanation for gravity. I'm... just going to cut and paste this in here. Would really appreciate help navigating some of this because I am not competent in terms of static electricity beyond that I don't think its strong enough to hold anything heavier than paper to a balloon.

Them:
" so electromagnetism has the same inverse square law as gravity but can be measured and observed ( coloumbs law )
Yet gravity is only good for distances of solar system size hence the search for dark matter or an interplanetary medium which is needed to hold galaxies together due to there defiance of Newtons laws of motion , if you think in electrical terms as all is electromagnetism , the earth acts like a capacitor with two opposing plates which hold opposite and equal charges ( one negative one positive ) and these two charges are seperated by dielectric material ( air ) at there closest point the charges are separated by another great dielectric called ice ,"
Me:
"here's the contradiction I see that electromagnetism has that gravity does not.

Gravity affects all things equally based on the object's mass.

Electromagnetism varies based on the net electromagnetic field that an object puts out. So for example, certain metals and magnets themselves will generate stronger or weaker fields, irrespective of their mass. Human beings would have a different net-field that they put out because while our brains put out EM fields, human tissue is a poor medium for putting up pictures on refrigerator doors. :p

So, if electromagnetism is the reason up is up and down is down, how is it possible for people to pick up magnets and metals? These things should be "heavier", but they aren't. Also, if they are dropped, they should fall faster than say... a piece of wood of roughly the same weight and size, right?

In fact, if you were to weigh a nail with a wire wrapped around it, and then apply a current while you were weighing it, those electromagnetic forces should increase the attraction of the nail to the electromagnetic field of the Earth and make it "heavier".

Instead what we find is that if we take a scale, and we adjust for the pull of gravity, we can accurately read its mass, whether or not it is made of a material that is more "magnetic" than others.

I, of course, do not have a need to explain this contradiction, as it is sufficiently explained by what we currently know about gravity.

However, this does strike me as an interesting contradiction that should be explained if you are suggesting that electromagnetism is a better explanation than gravity, right? I could be wrong, so if I'm missing something, just let me know what it is so I can adjust my point accordingly."
Them:
how would we be able to pick up metal if gravity is an electrostatic effect , the earth is not a magnet as such but carries a potential static charge of around 5 million volts or 100/150 volts per meter and the voltage capacitance drops with altitude due to the positive charge in the air molecules being attracted to the negative surface of earth , the same can be said for metals , as metals carry neither positive or negative charge the earth will pull them towards the ground so the ionised surface of earth can try and get rid of its negative potential , potential static electric fields do not interact with magnetic fields as far as I know so a magnet will not be effected when in one , weight is determined by mass density and charge potential between the nuetral and the negative .

https://www.thenakedscientists.com/foru ... ic=51511.0

When I say electromagnetic I mean all is a byproduct of this phenomena , the convecting magma field creates the electric current that powers the magnetosphere , thus inturn ionises the surface of earth
Giving it a neg charge and static electric field

, but if you go up into a high building where the potential charge is higher ie 100/150 v/m and touch a conducting material one may get zapped quite easily ,
http://www.ittc.ku.edu/.../ener.../Feyn ... 1to9-3.pdf
How much of any of this makes sense?

Sonic#
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### Re: Flat Earth Discussion

if you think in electrical terms as all is electromagnetism

There's the bullshit (12 year old me would say: what about the three other fundamental forces?), followed closely by initiating an analogy ("acts like") and then insisting it be taken entirely literally.

I won't really go further down that road. It's a zealot's maneuver.

tomokun
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### Re: Flat Earth Discussion

LOL, I appreciate that Sonic.

I DO want to break this down a bit more for him though.

So would it be correct to say that static electricity is a product of electromagnetism, and that if what he was saying was true, then it would plausible for human being to be propelled AWAY from Earth due to any sort of disruption in the "static field"? Like, if you happne to be walking through Vegas, because its so dry, and you walk into a Casino with those carpeting and lights, it would be possible to be drawn to the ceiling or a wall because of the static field?

Basically, I'm looking for things that would HAVE to be true if what he is saying is true, that clearly aren't true. I think that by inviting them to think about those things, and come up with explanations, they'll be forced to confront the holes in their "theories".

rowan
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### Re: Flat Earth Discussion

I'm sorry I am laughing too hard to be able to make a coherent argument against that person at this time of night.

I will try tomorrow though.

I will add this though, the electric field within a capacitor is constant, not 1/r^2
(so then it isn't behaving like gravity, is it.)

But oh... oh there is so much more there hahahahahahaha.
spacefem wrote:All your logical argue are belong to us!

Mordak

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### Re: Flat Earth Discussion

rowan. omg rowan.
people still think the earth is flat?
like, for real?

what the fuck have I missed while I've been off adulting?

did they put a few billion doses of stupid in the water supply?

Storage and Disposal
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### Re: Flat Earth Discussion

This thread is great, but I wouldn't be surprised if the flat earth movement is made up of trolls.
"He weeps for he has but one small tongue with which to taste an entire world." - Dr. Mungmung

rowan
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### Re: Flat Earth Discussion

Some of them are trolls, but there are actual real people who actually believe it.

Ok so, I am going to do this in a couple of stages. Stage 1 here is where I explain a bit about how electromagnetism works for real. I will make a couple of references to gravity in here so we can see the parallels and differences. Then in a separate post which will take longer to write I'll try to deconstruct the inconsistencies and misconceptions in their statements.

Electromagnetism

So, we have a few things here:
Static electricity (static in this sense means stationary, charges which are not moving, to clarify from the usual use of it)
Magnetism
and their combined force/fields electromagnetism

Static electric forces/fields:
The Coulomb force, which is the fancy named-after-a dead-white-dude name that we give the electric force, does indeed have a similar form to gravity. This form in equations (don't panic! it's not too bad!):

Electric Force = k * q1 * q2 / r^2
where q1 is charge 1 and q2 is charge 2, and r is the distance between the two charges. This gives the force that charge 1 exerts on charge 2 (or vice versa, via Newton's third law of reaction). This is only valid for a point charge. This is important.

You can use it for, say, a proton and an electron. Or for two protons. Or for two electrons. Or, if you have two larger atomic nuclei, as long as they are sufficiently far enough away from each other you could use it (for nuclei on atomic scales this is probably not of concern for us on macro scales). If you get too close though then you have to do something else, and that's not even counting the strong nuclear force.

compare to gravity:

Gravitational Force = G * m1 * m2 / r^2
where m1 and m2 are the two respective masses and r is the distance between their centers of mass (I will come back to this).

Note: Mass is only positive and gravity is only attractive, whereas charges are both positive and negative and can attract (opposite signed charges) or repel (like charges, e.g. + repels + and - repels -). This difference is also important.

Another difference: those constants out front. Gravity is very very very much weaker than the electrostatic force. I think, personally, that this is the crux of why a lot of flat earther and other conspiracy theorists grab onto gravity and try to "fix" it or (gravity is -by far- the topic of most of my Hey Check Out My New Theory emails I get). But it doesn't need fixing.

Here's why:

Let's say you want to calculate the electric force on you due to that table over there and compare it to the gravitational force on that table over there. If you need numbers, put that table at a distance of 1.5 meters and oh, let's give it a mass of idk 35kg. (Always pick weird numbers for thought experiments so that you don't lose factors of 2 or get confused about units) Eh let's use a mass of what, 60kg?

The gravitational force is then: (6.67e-11)(60)(35)/1.5^2 = 6.23e-8 newtons
This is very tiny! oh no! But wait, Americans don't know what newtons are so quick let's think about holding an average sized apple in your hand; its weight will be approximately 1 newton. So this is indeed very tiny. But also it would be weird if the table pulled you over (or, I guess, you would pull the table over). So it's good that it is small.

Compare to the Earth's gravitational force on you (m = 6e24 kg ; r = 6.4e6 m): the earth pulls you with 586 newtons, which is pretty typical weight, 132 pounds. There is a vast difference between 586 newtons, and 0.0000000623 newtons. (Side note: comparing the gravitational force of the earth on you vs Jupiter on you is good for astrology debunking)

Ok but back to the table because we now need to compare the electric force on us by the table. In this case the constant out front is k = 8.99e9

We can see that there are literally 20 orders of magnitude difference. So obviously say the crackpots, the electric force must be way more important on a day to day basis! But wait, they are forgetting something....

What is that table made out of? Mostly, it's made out of neutral atoms. There are about 10^28 positive charges in that puppy, and about 10^28 negative charges. (each individual charge is +/- 1e-19 Coulombs) So when I add all the forces together I get....

zero.

Nada.

Because you have:
Total electric force = (electric force of positives) + (electric force of negatives)
= (8.99e9) (1e9) (your charge) / 1.5^2 + (8.99e9) (NEGATIVE 1e9) (your charge) / 1.5^2

In fact it doesn't matter what the numbers are, because the charges are equal in number the sum is always zero. So the Earth also pulls on you with zero electric force. But 538 newtons of gravitational force.

But what about like sticking balloons to the wall and stuff? Well you can add a small number of charges. Typical excess charges in the world are about 1e-9 to 1e-6 coulombs. Like, a nano- or a micro- coulomb. And that is enough to just barely stick things together like a balloon on the wall.

1 Coulomb by the way is like, a lightning strike. So like, don't go around making 1 Coulomb charge excesses.

I said I'd get back to the thing about point charges and this is where I'm going to: notice I had to add up all the point charge forces to get the total force. You do that literally by adding, or usually using the fancy adding, which is doing an integral (integrals are just fancy adding). But to do so you really must use the distance of each charge. Fortunately for large macroscopic objects, the positives and negatives are generally all mixed together pretty equally so you will always have a positive next to a negative. Atoms are, by nature, pretty neutral.

This has gotten long so I'm going to take a break and maybe come back to capacitors in a bit, and then magnetism in a separate hopefully shorter post.
spacefem wrote:All your logical argue are belong to us!

tomokun
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### Re: Flat Earth Discussion

I am reading this now, but I love you for doing this, thank you.

edited to remove giant quoted post ~mod

rowan
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### Re: Flat Earth Discussion

FYI Everyone: These next posts are seriously TL;DR I am so sorry. If you just want some funny math to make you laugh skip to the last post.

I'm glad. Sorry this is so slow I have been really sick and trying to dig out of the backlog of ignored things.

Capacitors and their electric field:

The electric field inside a capacitor is constant. A dielectric (that your friend mentions) is something not-empty-space that fills in between the two plates that doesn't let charge flow (or the two plates would discharge. The dielectric constant of air is nearly the same as space. I am not sure why friend brings that up. The main thing about capacitors is that no matter where you are in between the two plates the electric field is exactly the same, and therefore the electric force will be exactly the same. Thus you will not have an inverse square law effect.

Magnetism

All right, as I tell my students, understanding the details of your average basic chunk of magnetized metal, such as a compass needle, or a hunk of iron in the Earth, is actually much harder than understanding how electric charges relate to magnetism in general. This is a lot easier with demonstrations, by the way, but I'll do my best and you can try some of these experiments at home if you have a sensitive compass.

One of the first demos I do is showing that putting a compass near a disconnected vertical wire, the compass points North. But then if you connect the circuit, the compass will deflect so that it points perpendicular to the wire. (so, like put the compass on the north side so it points away from the wire, not the East side where it will already be perpendicular)

You can take a coil of wire and show that it also will behave like a magnet when plugged in.

Basically the gist of it is: moving charge creates a magnetic field

With a wire, your + and - charges still are equal so there is no net electric field, but there is a magnetic field. You can of course have an object with excess charge that is moving so you will have both an electric and a magnetic field.

You can also show that a magnet will affect a moving charge, though this is harder to do with things you'll find around the house. You could look for "jumping wire demo" to see if you could find a video.

Anyway moving charges --> magnetic field. This is how people figured out that really the electric field and the magnetic field are tied together. I think it's about a junior-level physics proof to show that they are relativistic expressions of each other, and hence the electromagnetic force. However, on a daily basis, you're usually dealing with one or the other, not both.

To come back to your everyday magnets: on an atomic scale, quantum mechanics dictates how many electrons are in each electron shell, and most atoms have equal numbers of spin-up and spin-down electrons filling their shells, except iron which the quantum mechanics works out differently so you get four spin-up electrons in the last shell, which means you basically have four little current loops. The little teeny magnetic moments therefore do not cancel out and so an iron atom acts basically like a teeny bar magnet. Put a bunch together though, and they are usually randomly oriented so cancel out. But you can force them to all line up, and then you get a magnet. In natural settings this can happen if you have melty iron in lava that all aligns with the Earth's magnetic field at the time, and then cools into a magnetic rock. This kind of thing was one of the huge pieces of evidence for seafloor spreading back in the like, idk 1950s or 60s, I forget.

Similarly in the Earth's core, the outer shell is (at least mostly) liquid metal, which due to the EARTH'S ROTATION has a spin and therefore then proceed to generate the Earth's magnetic field. Which wouldn't happen if the Earth were flat, or at least certainly not in the same way/shape as it does now. I suppose your friend could attempt to draw wtf they think the magnetic field of the Earth looks like but I guarantee it wouldn't work out the way they think.

BTW electricity and magnetism and their mechanisms is a huge part of my astrophysics specialty. Feel free to ask more detailed questions if any of this doesn't make sense.
spacefem wrote:All your logical argue are belong to us!

rowan
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### Re: Flat Earth Discussion

" so electromagnetism has the same inverse square law as gravity but can be measured and observed ( coloumbs law )
I am unsure why he thinks gravity can't be measured and observed here on Earth. But sure, let's pretend that apple falling doesn't count.
Yet gravity is only good for distances of solar system size hence the search for dark matter or an interplanetary medium which is needed to hold galaxies together due to there defiance of Newtons laws of motion
Why does he think it's only good for distances of solar system size?
Dark matter: this doesn't make any sense. The reason we are looking for dark matter is there is *too much* gravitational attraction, not too little.
Even without the dark matter the galaxies would "hold together", why does he think otherwise?
Also: Dark matter is not solar system scale stuff
the earth acts like a capacitor with two opposing plates which hold opposite and equal charges ( one negative one positive ) and these two charges are seperated by dielectric material ( air ) at there closest point the charges are separated by another great dielectric called ice ,"
I'm unclear where his two plates are, but I'm going to assume one of them is in the "heavens" and the other is the earth itself, because if we're on the outside of the capacitor (aka the top part of the earth is one plate and the "underside" of the flat earth is the other side then his 150 volts/meter below doesn't make sense.

So I'm visualizing:

heavens: +++++++++++++++++++++++

air = dielectric = 1 = almost space

people standing on earth
earth: ----------------------

Yes?

People standing on the Earth now will acquire a negative charge through contact. But since we are not attached to the Earth, we will be repelled from the - side, and attracted to the + side and ooops we have just been flung into space. I suppose we will impact the heavens and discharge, then again a + charge and be flung back down again, but eventually all the things (people, animals, loose rocks, etc) will wind up transferring all the charge between your two plates and then they will be neutral.

(You can reverse the + and - with the same results).

Well, crap. That didn't work out did it.

Near the Earth you see a constant acceleration due to gravity (because you are close and distance does not vary much relative to the radius of the earth), and in the case of a capacitor you'd still see a constant acceleration due to the electric force, but as you get further away from the surface, you will find in the case of gravity you've got that 1/r^2 thing going, but your capacitor still is constant, so you will easily see that gravity and capacitor are not equivalent.

By the way the 1/r^2 dependence of gravity is because the Earth is round. If the earth were flat, it would have a different dependence if you are close enough for it not to be a point source of gravity. Oh that pesky calculus showing up again!

Me: "here's the contradiction I see that electromagnetism has that gravity does not.
Acceleration in general is Force/mass so if you have the same force, for different masses you get different accelerations. I find this a much better way of framinng things than F = m * a since it's more cause and effect.

For gravity, the force is related to the two masses (object and the Earth) Hence for earth the acceleration = g = 9.8 m/s^2 near the surface because the object's mass on both sides of the equation cancel out: m * g = m * a
g = G * massEarth/r^2 which you can figure out from the big gravity equation in the gravity post.

For electric force, acceleration is related to the charges.
a = k q1 q2 / r^2 / m
(where m is the mass of the object)
So, if electromagnetism is the reason up is up and down is down, how is it possible for people to pick up magnets and metals? These things should be "heavier", but they aren't. Also, if they are dropped, they should fall faster than say... a piece of wood of roughly the same weight and size, right?
I mean he'd have to come up with a reason that things are charged at all for there to be an electric force.

Anyway you can put an excess charge on anything but I'm concerned about how much you're working with, here (see below).
In fact, if you were to weigh a nail with a wire wrapped around it, and then apply a current while you were weighing it, those electromagnetic forces should increase the attraction of the nail to the electromagnetic field of the Earth and make it "heavier".
But again, this only happens if you have excess charge.

Now, this actually could happen due to magnetic fields. But Earth's magnetic field is very weak (only 1 gauss) and you'd have to orient things appropriately. But you could measure it. And then if you reversed the direction of the current, the scale will go the other way. In other words, if you made it heavier, then reverse the direction of the current, it will then appear lighter. This ... really contradicts everything they're talking about.
Them: how would we be able to pick up metal if gravity is an electrostatic effect , the earth is not a magnet as such but carries a potential static charge of around 5 million volts or 100/150 volts per meter
Slow down there boy, volts is potential, not charge, and volts per meter is an electric field not a charge.

and the voltage capacitance drops with altitude due to the positive charge in the air molecules being attracted to the negative surface of earth
hold up, I thought we were in a capacitor. Also, why are the air molecules charged?
metals carry neither positive or negative charge the earth will pull them towards the ground
If they have no charge, the Earth's charge will have zero effect on them. Electric forces only care about charged objects.
potential static electric fields do not interact with magnetic fields as far as I know so a magnet will not be effected when in one
fields do not affect fields. You can only talk about effects on charges. (By the ending "one" here I assume he means electric fields; obviously magnets are affected by magnetic fields)
weight is determined by mass density and charge potential between the nuetral and the negative
why bother with mass density if you're saying only charges matter?
the convecting magma field creates the electric current that powers the magnetosphere
This is almost true, except it's the outer core, not the magma.
thus inturn ionises the surface of earth
Giving it a neg charge and static electric field
This is false because the magnetosphere is again a field. It will affect charges, yes. But only free, unattached charges get to move around, and we don't have a lot of those. Incoming high energy particles from the sun, yes, but those get stopped by our atmosphere (and make the aurora).
but if you go up into a high building where the potential charge is higher ie 100/150 v/m and touch a conducting material one may get zapped quite easily
Mmmm hhmmm riiiight that's why we hear of this happening in skyscrapers all the time. Yup. Very desirable that extremely zappy top penthouse floor. It's always good when you bring the ladies back to your pad to have static electricity zappin' everything. And, y'know, great for your computers and stuff, those top floors of those businesses.

So let's address your post and questions:
So would it be correct to say that static electricity is a product of electromagnetism
They're really the same thing, not really the product of one or the other, just static electricity is a special case of electromagnetic force.
if what he was saying was true, then it would plausible for human being to be propelled AWAY from Earth due to any sort of disruption in the "static field"?
Indeed from what he says it's what would definitely happen. Oops.
spacefem wrote:All your logical argue are belong to us!

rowan
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### Re: Flat Earth Discussion

Ohhh let's have some more math!

In terms of electric *field* the electric force is given by: F = q * E

Since also F = m * a for any object, we can write:

m * a = q * E

where m is the mass of our object (say, a person at 60 kg) and q is the person's charge. The Earth's charge is wrapped up into E. And we measure everything having an acceleration of 9.8 m/s^2 near the surface, so a constant acceleration. And E is constant. SO THEREFORE by this argument, aka that the acceleration we experience (what we call gravity) is cause instead by the electric force:

q / m = a / E = 9.8 m/s^2 / (150 volts/m)

[the units work out because volts contains other units, it's ok]

so q/m = 0.065333 Coulombs/kg or if you prefere their lower number for E, 0.098 Coulombs/kg

So this means two things:
1) every object with different mass has a different excess charge on it
2) those charges are HUGE. For a 60kg person, we're talking about 3.9 Coulombs -- FOUR TIMES the amount of charge discharged in a lightning strike.

Uh this kind of has Consequences, such as everyone would be zapping the shit out of everyone else in extremely deadly ways.
spacefem wrote:All your logical argue are belong to us!