The earth is round

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Go to the beach.
« Reply #120 on: October 19, 2006, 03:38:11 PM »
Go to a port. Any port. You can PICK the port. But it's gotta be a port. Find a ship going in a straight line. Watch it go out into the ocean.

After a while, the boat will shrink and vanish from the bottom up as it goes over the horizon.

I dare you to tell me that that's because the boat sailed THROUGH THE ICE WALL and off the edge of the damn planet.

If the earth was flat, we would be able to look across the ocean and see the other continents. We would be able to look south from wherever we are, and SEE the ice wall. I would be able to stand on top of a tall building in Seattle, and see Japan, no matter how small it was off in the distance. People in japan would be able to see Everest as a lot larger than Fuji.

This is not a "discovered" theory. This is something constructed slowly with an archaic thought that then had epindicycles tacked on to defend it. (Sometimes more literally than when that phrase is usually applied)

I know damn well that I'm not going to convince you wierdos. I don't expect to. But god damnit, I've got to at least say that this is bullcrap. Your theory has been very well thought out, your epindicycles are in all the right places. But honestly, I could use the same logic to argue that I impregnated your mom with you.

DNA tests are a conspiracy.

I brainwashed her afterwards.

Time machine.

What do you have to say now? I just "proved" that I am your father.

Why did I use the time machine just to have sex with your mom? Why would the goverment make up that the world is round? Also: I was bored.

Why are DNA tests bogus? Why would NASA lie? Also: It's a conspiracy backed by Maury Pauvich and other daytime "talk" shows. There is no definite way to compare DNA with that degree of accuracy. They just look at the data and take an educated guess. (Most often, whatever will get the better ratings for that week)

So, I know you will never listen to your parents, but PLEASE at least know that this idea is about as sound as the idea that I'm your father.

The earth is round
« Reply #121 on: October 19, 2006, 03:40:44 PM »
That Horizon arguement is really good.


*Waits for the BS FE answer*
he earth is a cube!

The earth is round
« Reply #122 on: October 19, 2006, 03:41:49 PM »
-sigh- I just wish I had stayed around to raise them better...

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GeoGuy

The earth is round
« Reply #123 on: October 19, 2006, 03:50:15 PM »
Quote from: "tycoonius"
Are sure about that? I've been out on a lake on a sunny day, and you can see pretty damn far. What do you mean by "obstructions" exactly?


I'm very sure. You can see about twenty-five to thirty miles before the atmosphere blocks your view. And Earth only curves one degree every sixty five miles or so, which means you can't even see half as far as you'd need to.

The earth is round
« Reply #124 on: October 19, 2006, 03:59:34 PM »
The atmosphere is translucent.

Otherwise, we wouldn't be able to see SPACE.

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tycoonius

The earth is round
« Reply #125 on: October 19, 2006, 03:59:49 PM »
Quote from: "GeoGuy"
Quote from: "tycoonius"
Are sure about that? I've been out on a lake on a sunny day, and you can see pretty damn far. What do you mean by "obstructions" exactly?


I'm very sure. You can see about twenty-five to thirty miles before the atmosphere blocks your view. And Earth only curves one degree every sixty five miles or so, which means you can't even see half as far as you'd need to.


I still don't follow how the atmosphere would block your view. If light from the sun reaches my eye with no difficulty, why would light reflecting off a distant object be unable to make the journey?

The earth is round
« Reply #126 on: October 19, 2006, 04:01:30 PM »
Maybe we can see Mount Everest from anywhere, but perspective makes it microscopically tiny.
 believe the Earth is round.
That doesn't mean the Earth is round.

"If you're going to yell at me every time I do something stupid, then I guess I'm just going to have to stop doing stupid things!" --Homer Simpson

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GeoGuy

The earth is round
« Reply #127 on: October 19, 2006, 04:01:45 PM »
Clicky. Those mountains were about fifteen miles way from me.

The earth is round
« Reply #128 on: October 19, 2006, 04:04:44 PM »
That, specifically right there, is a conspiracy by the FEs to confuse us. Clearly photoshopped. Hipocrates.

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tycoonius

The earth is round
« Reply #129 on: October 19, 2006, 04:13:46 PM »
Quote from: "GeoGuy"
Clicky. Those mountains were about fifteen miles way from me.


That looks like a pretty cloudy day. Also, you don't happen to live in one of those high-smog cities, do you? I'm pretty far from the big city, and it's not hard to see off into the distance. Also, why is the bottom cut off?

The REAL proof that the world is round:
« Reply #130 on: October 19, 2006, 04:24:41 PM »
Pendulum.

Go get a pendulum. Make sure it's a large, heavy one in order to ensure that it moves independantly for a long, long time. (Ideally, all day with relatively little slowing)

Now, set up a bunch of dominos or things around it so that the pendulum will knock them down as it swings.

Now, watch and be amazed as on a flat planet, the pendulum would only knock over the first few. The earth rotates, and thus, the pendulum slowly knocks over the rest of them.

On a flat earth, with the sun and moon "orbiting" overhead, the pendulum would not rotate. But it does.

If a flat earth rotated, then centripital force (centrifugal? I forget the word.) would hurl us south, into the ice wall, where we would all be killed by the conspiritors. On a round earth, there's this nice little thing called gravity.

Now do you get it, son?

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tycoonius

Re: The REAL proof that the world is round:
« Reply #131 on: October 19, 2006, 04:29:33 PM »
Quote from: "IneptOne"
Pendulum.

Go get a pendulum. Make sure it's a large, heavy one in order to ensure that it moves independantly for a long, long time. (Ideally, all day with relatively little slowing)

Now, set up a bunch of dominos or things around it so that the pendulum will knock them down as it swings.

Now, watch and be amazed as on a flat planet, the pendulum would only knock over the first few. The earth rotates, and thus, the pendulum slowly knocks over the rest of them.

On a flat earth, with the sun and moon "orbiting" overhead, the pendulum would not rotate. But it does.

If a flat earth rotated, then centripital force (centrifugal? I forget the word.) would hurl us south, into the ice wall, where we would all be killed by the conspiritors. On a round earth, there's this nice little thing called gravity.

Now do you get it, son?


That pendulum thing is actually a pretty sound argument. I remember my physics teacher talking about that once. Of course, I've never really tried it, so I guess that could be part of the whole conspiracy.

Re: The REAL proof that the world is round:
« Reply #132 on: October 19, 2006, 04:37:20 PM »
Quote from: "IneptOne"
Pendulum.

Go get a pendulum. Make sure it's a large, heavy one in order to ensure that it moves independantly for a long, long time. (Ideally, all day with relatively little slowing)

Now, set up a bunch of dominos or things around it so that the pendulum will knock them down as it swings.

Now, watch and be amazed as on a flat planet, the pendulum would only knock over the first few. The earth rotates, and thus, the pendulum slowly knocks over the rest of them.

On a flat earth, with the sun and moon "orbiting" overhead, the pendulum would not rotate. But it does.

If a flat earth rotated, then centripital force (centrifugal? I forget the word.) would hurl us south, into the ice wall, where we would all be killed by the conspiritors. On a round earth, there's this nice little thing called gravity.

Now do you get it, son?


I like how the conspirators wouldn't be affected by gravity, and would be waiting for us at the wall :)
atttttttup was right when he said joseph bloom is right, The Engineer is a douchebag.

The earth is round
« Reply #133 on: October 19, 2006, 04:49:41 PM »
Of course they wouldn't. If they have technologies that cloud the atmosphere, and are in on every level of government, and can apparantly fake all of the laws of physics, you think a little thing like centripital force wou-

-is headshot-

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GeoGuy

The earth is round
« Reply #134 on: October 19, 2006, 04:56:12 PM »
Quote from: "tycoonius"
That looks like a pretty cloudy day. Also, you don't happen to live in one of those high-smog cities, do you? I'm pretty far from the big city, and it's not hard to see off into the distance. Also, why is the bottom cut off?


No, the city didn't have much smog, and the picture was taken later in the afternoon, but the view is the same no matter the time of day. The bottom is cut off because the picture was taking too long to upload, so I just stopped it.
And even from my house out in the middle of nowhere I can't see any further than that, even on the clearest days.

The earth is round
« Reply #135 on: October 19, 2006, 11:33:23 PM »
Quote from: "TheEngineer"
Quote from: "bibicul"

TheEngineer, please read the vector argument that I made and think of what you learned in middle-school. I never said that you cannot calculate a total acceleration using g as one of the two vectors, but I also said that you can break it into 2, with g being PART of the total acceleration (given by adding up the 2 vectors, and therefore AN acceleration, not TOTAL acceleration and not a force, as was previously believed).

Why are you resolving the acceleration vector into components? One of them is not g.




The acceleration due to gravity is, as the name suggests, an acceleration. Any acceleration is defined as the rate of change (or derivative with respect to time) of velocity. It is thus a vector quantity with dimension length/time².

The following is taken from wikipedia: "The total acceleration of a body is found by vector addition of the opposite of the actual acceleration (in the sense of rate of change of velocity) and a vector of 1 g downward for the ordinary gravity (or in space, the gravity there)."

I stated this before and I think it is the best explanation for what I want to say. It clearly states that total acceleration is resolved into components and that g is one of them.

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beast

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The earth is round
« Reply #136 on: October 19, 2006, 11:40:08 PM »
Dude your posts will be much easier to read if you click on the "disable BBCode in this post" button again so that it isn't checked.

Just a tip.

The earth is round
« Reply #137 on: October 19, 2006, 11:51:48 PM »
Biblical your posts make no sense. The earth is a cube.
he earth is a cube!

The earth is round
« Reply #138 on: October 20, 2006, 12:50:30 AM »
Thanks beast. I am new to forums in general so any tips about their use would be appreciated.

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TheEngineer

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The earth is round
« Reply #139 on: October 20, 2006, 12:53:03 AM »
Quote from: "bibicul"

I stated this before and I think it is the best explanation for what I want to say. It clearly states that total acceleration is resolved into components and that g is one of them.

Now I see what you are trying to do.  I was trying to make it simple for you and use a one dimensional acceleration.  But if you want to complicate things, that's fine.  
Those resolved components can be combined into a single equivalent vector and by choosing a suitable coodinate system, that single vector is one dimensional again.  
Let's go back to the car example.  The car sits on the ground (for the sake of argument, let's ignore gravity for now) subject only to acceleration in the forward direction.  Let's say this is 20m/s^2.  Without referencing the outside world, I have no way to distinguish between the car accelerating forward, and a gravitational field of 20m/s^2 pulling me into the seat.  Now, if you want to include the gravity of the earth, then I have no way of distinguishing if the car is accelerating forwards and off the road, (however that would happen) or if a gravitational field is pulling me into the floor of the trunk.

I hope this clears it up for you.  But you don't have to take my word for it, listen to a theoretical physisist:
Quote from: "Alan Lightman"
The key idea of general relativity, called the equivalence principle, is that gravity pulling in one direction is completely equivalent to an acceleration in the opposite direction. A car accelerating forwards feels just like sideways gravity pushing you back against your seat.

http://www.pbs.org/wgbh/nova/einstein/relativity/


"I haven't been wrong since 1961, when I thought I made a mistake."
        -- Bob Hudson

The earth is round
« Reply #140 on: October 20, 2006, 12:59:31 AM »
Quote from: "bibicul"
Thanks beast. I am new to forums in general so any tips about their use would be appreciated.


don't be so polite  :wink:  get stuck into some of the buggers!  :P

The earth is round
« Reply #141 on: October 20, 2006, 01:02:52 AM »
After so many posts, I think these is the main differences between what we are saying:

1. I break total acceleration in two parts:
 
    a) the acceleration of gravity
    b) the acceleration known as the "rate of change of velocity"
These are 2 different things, which is why to me the statement "gravity=acceleration" and vice-versa" is false.

while you only take into account "total acceleration", as the vector addition of the two. I guess you could say that I "complicate" things, but I still see the two as distinguishable from each other in physics.

2.
Quote
Alan Lightman wrote:
The key idea of general relativity, called the equivalence principle, is that gravity pulling in one direction is completely equivalent to an acceleration in the opposite direction. A car accelerating forwards feels just like sideways gravity pushing you back against your seat.


I agree - "gravity pulling in one direction is completely equivalent to an acceleration in the opposite direction". I also agree that gravity is an acceleration, not a force like it was thought of before. But I also uphold (and I don't think that this contradicts the Theory of relativity - which I read myself and hope that I understand) that acceleration due to gravity and the rate of change of velocity have different causes and therefore are different things, even though they "feel the same".

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TheEngineer

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The earth is round
« Reply #142 on: October 20, 2006, 01:06:28 AM »
Quote
even though they "feel the same".

EXACTLY!!!!  They are indistinguishable from eachother and are equivalent!


"I haven't been wrong since 1961, when I thought I made a mistake."
        -- Bob Hudson

The earth is round
« Reply #143 on: October 20, 2006, 01:40:57 AM »
No, they are not equivalent.

Gravity (and its acceleration) specifically refers to a force which all massive objects are theorized to exert on each other to cause gravitation.

The acceleration of an object (for example a car on the surface of the earth) is the rate of change of its velocity.

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turbofis

The earth is round
« Reply #144 on: October 20, 2006, 09:39:07 AM »
Quote from FAQ: Q: Why does the hull of a ship disappear over the horizon before the mast does?

This is about the hardest proof you can get, and you still havent got an answer.

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Erasmus

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The earth is round
« Reply #145 on: October 20, 2006, 11:35:40 AM »
Perhaps I can be of some assistance here.

Quote from: "bibicul"
Gravity (and its acceleration) specifically refers to a force which all massive objects are theorized to exert on each other to cause gravitation.


You are correct in that gravity, when it refers to a force, does refer to this force.  There are some theories of physics which include this force; there are others that do not.  One that does is Newtonian mechanics; one that does not is General Relativity, and since General Relativity is more accurate on a wider range of scales than Newtonian Mechanics, I will assume it to be true for the remainder of this post.

Thus, gravity is not a force of any kind.  Instead, it is a property that nearby straight lines tend to get closer to one another over time; in GR this is formally called "convergence of nearby geodesics".

Quote
The acceleration of an object (for example a car on the surface of the earth) is the rate of change of its velocity.


This is almost correct; you did not specify the frame of reference in which the car's (or other object's... but I'll stick with the car example) velocity is being measured.  Sure, you could put lines on the road and measure how quickly the lines go by; or you could measure the circumference of the wheels and measure how fast they are turning.  These would be measuring velocity with respect to the road.

However, you could also measure the car's velocity by bouncing a laser off of the moon.  You would get a different number for your velocity now, since you are using a different reference frame.  You would also get a different number for acceleration (you might be moving at a constant velocity w.r.t. the road, but a variable velocity w.r.t. the moon, which is moving in a circle).  You could again measure velocity w.r.t. the fixed stars by assuming a certain shape of the Earth and looking at the visible sky; this would be different from both the moon-measurements and the road measurements.  You could even measure velocity by looking at how quickly the cars on the road are moving past you... for each car, you would get a different measurement.  In particular, you could measure your velocity and your acceleration relative to yourself, and you would get zero!

So, which is correct?  Well, the whole point of theories with the word "relativity" in the name is that it is not meaningful to ask which is correct; they are all correct in the reference frame in which they are measured.  Special Relativity is the promise that you are allowed to measure your velocity with respect to any reference frame you want (i.e. that velocity is relative) -- in particular, you get to declare yourself to be at rest.  It gets around the weird side effects by assuming that time and distance are not defined globally.

General Relativity is the promise that you are allowed to measure your acceleration in any reference frame you want (i.e. that acceleration is relative) -- in particular, you get to declare yourself to be not accelerating.

How does General Relativity make this promise?  Well, it says, spacetime is curved; objects moving in straight lines might appear to be moving in curved lines from the perspective of other objects.  Thus, if you think you are accelerating but want to claim that you are not, you can instead just blame the apparent change in velocity on the curvature of spacetime.

To restate: you are permitted to believe either that you are accelerating, or that spacetime is curved in such a way as to make it look like you are.     It doesn't matter what "force" is causing you to accelerate: your car's engine, a rocket, a magnet, an elevator cable, whatever; doesn't matter.  No acceleration is happening to you; it's only happening to other things, and it's happening, (you are allowed to believe, and be correct) because spacetime is curved.  Since "spacetime is curved" is what GR means by "gravity", then GR is saying that from your perspective, every acceleration is gravity.
Why did the chicken cross the Möbius strip?

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TheEngineer

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The earth is round
« Reply #146 on: October 20, 2006, 12:48:42 PM »
As always Erasmus, nicely put.


"I haven't been wrong since 1961, when I thought I made a mistake."
        -- Bob Hudson

The earth is round
« Reply #147 on: October 23, 2006, 12:01:24 AM »
Erasmus, I believe you are referring to gravitation, not gravity. Wikipedia states the following:

"It is important to note that gravitation is not gravity. Gravitation is the attractive influence that all objects exert on each other, while "gravity" specifically refers to a force which all massive objects are theorized to exert on each other to cause gravitation. Although these terms are used interchangably in everyday use, it is important to note that in theories other than Newton's, gravitation is caused by factors other than gravity. For example, in general relativity, gravitation is due to spacetime curvatures which causes inertially moving object to tend to accelerate towards each other."

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TheEngineer

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The earth is round
« Reply #148 on: October 23, 2006, 12:02:54 AM »
As long as it helps your understanding.


"I haven't been wrong since 1961, when I thought I made a mistake."
        -- Bob Hudson

The earth is round
« Reply #149 on: October 23, 2006, 12:27:15 AM »
No, it helps the argument that "gravity=acceleration" is a false statement, while "gravitation=acceleration" is the right choice of words.