What is Gravity?

If NASA faked the moon landings, does the agency have any credibility at all? Was the Space Shuttle program also a hoax? Is the International Space Station another one? Do not dismiss these hypotheses offhand. Check out our wider NASA research and make up your own mind about it all.
hoi.polloi
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Re: The MOON HOAX

Unread post by hoi.polloi » Tue Jun 02, 2015 2:51 am

roastrunner wrote:*If* you are willing to accept that a large object exerting a gravitational force exists (such as the Earth), then orbital velocity follows logically.

The force of gravity towards the center of mass of the large object is one leg of a right triangle; the force propelling the "spacecraft" at a constant speed (orbital velocity) away from the planet is another leg, and the hypotenuse is the tangent line to the large object. As the spacecraft accelerates at 9.8 m/s^2 towards the Earth (or whatever) it also remains moving away from the Earth along the other leg's vector and maintains equal distance from the planet. This continues for eternity. No work is being done so it's a system at rest.
I am not so sure it is very logical to assume there is a perfect "orbital velocity" that requires no course corrections.

Since we do not know what gravity is, we cannot presume that it behaves in a mathematically perfect circle contrary to the physical elevations. We also cannot be sure gravity fluctuates less in the hypothetical space above the atmosphere. Indeed, to me, it is more logical to assume that gravity would be less uniform as its power diminishes due to it being a large (fluctuating) "object".

While it may be part of dogmatic science to project a single measurement into infinite directions and dimensions, it is not clever or intelligent science.

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Re: What is Gravity?

Unread post by hoi.polloi » Tue Jun 02, 2015 3:11 am

Please allow me to politely critique your post in the "Gravity" thread, here. Although this thread does not have as much of the centripetal calculations or 'Earth curvature' points made in the other thread (which you somewhat fairly ignore for the sake of pure speculation on a specific point) it does have to do with all of those things.
simonshack wrote: [...] anyone is free to believe that it is actually the stars that are circling around us, clockwise over one side of the earth - and counter-clockwise over the other! Good Heavens... and good luck with that one, you flat/concave / pyramidal earthers ! ^_^
Simon, I appreciate your post. You know that I can only be honest with you and that even so I haven't found any issue to quarrel with you yet. So I hope that you can accept some friendly criticism about your writing style in this last paragraph of yours. I think it's unfair to lump "flat" and "concave" theories together just because you haven't allowed their unanswered questions to exist as openly as the ones you imply in your model speculations. Concave Earth theory would just invert the situation, for which we have no reasonable arguments except that we prefer it to be the other way. Flat Earth is something you are just cross with for the time being because you feel it's an old insult being leveraged against freethinkers and critical thinkers lately. The different spins are indeed a strange mystery that "Flat Earth" would have to explain well, but you know that if someone were attached to a shape, they would find an explanation they preferred.

You should have just left this little "jab" at other theories besides Flat Earth out of the end of your piece, and formatted the critique of Flat Earth more formally, and it would make your own post stand stronger, in my opinion.

Furthermore, I think passengers in a 1000mph train might indeed feel bumps and valleys of any given rails on the landscape they were running across. If they made a mostly flat surface for that train (which they typically do) it would be very flat, so having people recollect typical train travel is a bit of a mistake, in my opinion. It's almost just an argument for Flat Earth, if someone couldn't pick out what you were trying to say in your complex post above.

Having said that, I am not sure that being "in a bubble" of any kind (invisible and physical "top" to the sky, or lack thereof, notwithstanding) should reduce the centripetal force that I already calculated many posts back in the "The Cold of Space and Our Universe That Isn't" thread. There, I pointed out (hopefully clearly enough) that even scientific instruments pick up nothing — not even a ripple or mathematical average of ripples in the atmosphere — indicating any rotations to the Earth.

All we have are the stars and other cosmic things we speculated about in various models so far — Sun, Moon, "planets" — and some electromagnetic readings. So to imply to us that your explanation simply makes more sense is playing a bit of limbo with our normal standards. I have still not seen any indication you have processed or addressed the points by scud and others regarding all the problems with "just believing" your model of choice.

If you are worried about the fact that these questions have made us a target in some way (which I still have not seen any evidence of) I suggest you simply ignore this thread as usual.

But since this is the thread for "Gravity" questions, I see and recognize and respect your point that gravity has everything to do with atmospheric pressure of some kind.

I just don't think that's the final answer to everything; nor does it really answer many questions about the so-called "shape" of our "planet" (though personally some of that kind of language is increasingly becoming worthless to me for describing the world we inhabit; I am not sure why we need so badly to choose a physical "shape" to our world since the spherical map is good enough for navigation).

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Re: What is Gravity?

Unread post by simonshack » Tue Jun 02, 2015 3:56 pm

hoi.polloi wrote:
Furthermore, I think passengers in a 1000mph train might indeed feel bumps and valleys of any given rails on the landscape they were running across. If they made a mostly flat surface for that train (which they typically do) it would be very flat, so having people recollect typical train travel is a bit of a mistake, in my opinion. It's almost just an argument for Flat Earth, if someone couldn't pick out what you were trying to say in your complex post above.
Hoi, I usually strive (or at least I think I do) to express my thoughts in simple, easily-processable / unambiguous manner and writing. Evidently, I miserably failed on this occasion! :P

My point about the speedy train was simply meant to say: " it would be nigh impossible for our bodies to perceive any centrifugal force if you were to travel at 1000mph around a railtrack with a 40.000km circumference."

We experience strong centrifugal forces, for instance, when taking a roller-coaster ride. This is due to the rapid direction-changes our bodies get subjected to. The larger the circumference of any given trajectory (within a given time frame) that our bodies take, the less centrifugal forces we will feel. This is why I find it quite plausible that we do not feel any centrifugal forces while we stand on earth - as it leisurely completes a 360° loop in as many as 24hours - or 1440 - or 86400 seconds - whereas when your body makes a 360° circle in a rollercoaster "death loop" - this lasts for only one / two seconds or so.

If I were a newbie on this forum, you would rightly ask me: "Do you have any evidence to submit regarding your (rotating-around-own-axis ONLY) spherical earth theory?" And I would reply: "Yes indeed, I do. Give me a few days to present my evidence". And that is just what I will do in the next few days. :)

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Re: What is Gravity?

Unread post by arc300 » Tue Jun 02, 2015 10:09 pm

Hi Simon,

As a complete layman I don't find it strange that your ants would not be flung off the orange at the centre of the Earth because, even though the angular momentum of both the surface of the orange and the surface of the Earth are the same, the linear momentum at the surface of the Earth would be orders of magnitude(?) greater, at least at the equator.




*********
ADMIN COMMENT: (simon)
Exactly my point, dear arc300, exactly my point.
:)

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Re: What is Gravity?

Unread post by pov603 » Wed Jun 03, 2015 6:43 am

If one considered a ball bearing, let's say 7.850kg in weight, which would equal one thousandth of a cubic metre of steel; 100x00x100mm if cubed, [not that the ball bearing has to be of steel], how much of its surface area would be in touch with the surface?

Assuming this is a perfectly [at least as much as can be in a spherical world!] flat surface/plane and has minimal or zero friction as presumably could be measured with some sort of electro-magnetic meter [?] to determine any static build up caused by the said friction, surely this ball bearing would be perceptible to the effects of rotation/coriolis of the planet?

As the ball bearing would be finely balanced, with only a minimal part of its surface in touch with the surface, it would be free to move in any direction should even a small force be applied to it.

if, therefore, an equal 'force' was applied to the ball bearing in one direction, say North, and then this exercise repeated for other directions; South, East & West, would its distance travelled be different depending upon its movement against or with or along the supposed movement of the planet?

Presumably a large conglomeration of ants resting upon one point of the ball bearing would offset its 'balanced' weight and it would move in the direction of the eccentric loading to balance out this anomaly.

This then raises the question of the planet itself and the constant movement of huge amounts of mass such as air [through wind], the motion of the seas/tides [supposedly of another gravitational device known as the Moon, huge torrents of rivers of water and, last but not least, the massive movement of humans and their machines which should be constantly impacting on the fine balancing of the planet.

One only has to use Google Earth to realize that [allegedly] one aspect of the planet, the Pacific side, is almost totally covered in water, which would mean that it should be theoretically at 0.00 datum/level.

The other aspect of the planet [through 180 degrees] is not completely covered in water and is therefore at X+0.00 datum/level, also made up of substances in excess of 1.00Tonne/CubM which is the weight of water, in effect making the planet lob-sided.

This in turn should [?] impact on any items finely balanced in turn, such as the ball bearing [with or without the ants...] and possibly have some perceptible effect?

Does it seem strange that a supposedly 'homogenous force' can accommodate all of these fluctuations without any indication of over/under compensation to accommodate such things as say the Tsunami on Boxing Day in 2004 and the trillions of tonnes moved in such a relatively short space of time?

If there is some simple high school explanation, please let me down, gently...

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Re: What is Gravity?

Unread post by scud » Wed Jun 03, 2015 9:13 am

Hi pov

At last, complete proof that there is indeed an aether! For I was having the exact and I mean exact same thought experiment over the last few days.

That’s your super sensitive ‘scientific instrument’ right there. Wowing the Smithsonian audience by visibly demonstrating that the Heliocentric ‘super waltzer’ ride through space is entirely correct. The ball moves around in a predictable manner about its fixed, perfectly flat, perfectly smooth and perfectly level table in response to all those inertial and ‘gravitational’ changes, caused by rotation, an elliptical orbit around the Sun and ‘galactic’ orbit about the milky way.

Err...except it doesn’t seem to work and the audience (now bored to death with staring at a completely static ball bearing) wonder off to look at the lunar landing module or some dinosaurs or something.

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Re: What is Gravity?

Unread post by hoi.polloi » Wed Jun 03, 2015 8:22 pm

Okay, thanks for the clarity, Simon. Hate to interrupt a project or thought of yours, but I have to admit people are posting some compelling thoughts against the notion of a "perfect sphere" rotating evenly.

And sorry, but, how again does this cause gravity?

If the rotation itself doesn't cause gravity, why are we discussing it in the gravity thread? Let's start a 'rotation' thread or put rotation subjects in the 'Universe' thread.

Regarding the train, I guess the difference in view for me is that whether people consciously notice a force doesn't determine its measurement by scientific instruments. (Well, actually, on some level, it does. But for large aspects of the human scale physical habits we "know" about now, it doesn't.)

Also, the question of whether people feel a change in gravity due to a "spinning" motion of the Earth doesn't seem to relate to the mystery of what gravity is, exactly. However, if gravity isn't a majickal etheric "glue" (as it occasionally, in our explorations, does indeed seem to be) and we are talking purely physical "accelerations", we should discuss it in the other thread, where we've already talked about the lack of equatorial-leaning items regardless.

If we are talking "gravity is air pressure", are we suggesting that climbing a tall mountain should make us feel lighter or heavier? Being deep in underground caves doesn't seem to make us lighter or heavier. Being underwater puts us in the position of being 'buoyant' while still feeling gravity's effects on a diminished scale. There may be something more to working out your gravity-pressure speculations, but it's very interesting.

There are definitely wacky stories about gravity's behavior, and I would argue until we design some tests, gravity is just as well explained as an energetic effect of some kind.

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Re: What is Gravity?

Unread post by mnew9 » Thu Jun 04, 2015 1:33 pm

Image

The Flat Earth Society believes - Earth's gravity is an illusion. Objects do not accelerate downward; instead, the disc of Earth accelerates upward at 32 feet per second squared (9.8 meters per second squared), driven up by a mysterious force called dark energy. Currently, there is disagreement among flat-earthers about whether or not Einstein's theory of relativity permits Earth to accelerate upward indefinitely without the planet eventually surpassing the speed of light. (Einstein's laws apparently still hold in this alternate version of reality.)

http://www.huffingtonpost.com/2012/10/2 ... 38198.html

Yes, their theories are completely out of left field but it does make you think. :blink:

hoi.polloi
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Re: What is Gravity?

Unread post by hoi.polloi » Thu Jun 04, 2015 3:44 pm

It definitely does. Though, I think crediting the entire confused pseudo-society of FE theorists with a single belief is a mistake too. That's almost as bad as starting a statement with, "Scientists say ..."

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Re: What is Gravity?

Unread post by anonjedi2 » Thu Jun 04, 2015 3:49 pm

I'm convinced the Flat Earth Society is controlled opposition and this is one of many arguments put forth to make real flat earthers look crazy. Real flat earth earthers don't believe in this nonsense.

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Re: What is Gravity?

Unread post by hoi.polloi » Thu Jun 04, 2015 8:53 pm

I am not so sure. Acceleration, to me, makes about as much "sense" as an "explanation" for gravity as does an energetic property of matter or air pressure.

Whether it means we are on a cosmic pizza dough flying faster and faster through the restaurant at the end of the universe is another matter. I am content simply imagining an exponentially expanding dimension as the explanation, without a need to belittle it.

I agree, however, that Flat Earth Society forum could easily be run by controlled opposition in order to trash or dumb down all sound arguments as quickly as possible.

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Re: What is Gravity?

Unread post by Thinktwice » Fri Jun 05, 2015 4:52 am

Yes that is indeed the simplest model of a mechanical "gravity force"... as I alluded to in my previous lengthy post, where I jokingly called it a "UN-flag-earth mounted on a rocket". This model's biggest advantage is it really demonstrates a simple, mechanical explanation for gravity--something that Newtonian/relativistic science has never provided. Other than that, it's hard to argue for this model...

I had the chance to take a commercial airline flight yesterday--and I couldn't help but keep this thread in mind as I rode. I had a few observations, which I'd like to summarize:

When the plane accelerates on the runway, there is a great force pushing my back to the seat behind me.

When the plane lifts off the ground and is rapidly rising, there is a large force that appears to smash my body down into the seat below me. When I try to lift my leg (my best experimental test at the time), it is very much harder to lift my leg than normal.

When the plane gets higher up, but is still rising, the gravity seems to balance out back to normal. Once at cruising altitude, gravity is seemingly normal.

When we hit a bump in air turbulence, gravity's apparent effect can fluctuate between greater-than-normal, and weaker-than-normal.

When the plane tilts downward as it begins to descend, you feel a moment of "weightlessness" as the seat fails to push on your body. When the plane is descending quickly, it becomes very much easier to lift my leg--it almost floats up by itself, it is so easy.

When the plane is in a sharp, banking turn, so that I am looking directly at the ground through the window--so apparently something between 45-90 degrees rotated relative to the ground - gravity seemed to push straight down into my seat--i.e. straight down, perpendicular to the wings. I picked up one of the safety pamphlets and dropped it a few times, as we were banking. It fell straight to my lap every time--not towards the ground, which was directly sideways outside the window.

OK, so from what I experienced on this flight, it seems clear that the "vomit comet" type anti-gravity plane would work in principle -- that, as the plane ascends, its floor pushes against anything inside the plane, and hence the objects experience a "gravity force" from the floor-- and that, as the plane descends, the floor literally drops out, so that the objects experience a weakened or absent "gravity force".

The plane is pushing against the AIR. This itself does suggest that air has something to do with gravity!

However, I would like to run a thought experiment. Let's say the back of the plane was completely opened to the air. Would that change my experiences at all? I do not think so! Even if the pressure in the plane were ambient pressure or even 0 psi, I would still experience forces from the floor of the plane as it rises or falls. Therefore, I do not buy the argument that we experience gravity on planes simply due to the pressurized chamber.

Another simple thought experiment is this. Say you have a very small room or closet, with just a door and no windows, and you walk inside and close the door very tightly. There is a certain amount of air inside the room with you, including a little bit of air above your head. Now, you take a coin out of your pocket, hold it out, and release it. The coin will fall to the ground, of course. But there is only a tiny amount of air actually weighing down upon it. The air in the atmosphere above us is not connected to us in any way--we are sealed off. Therefore, the air pressure above us cannot be weighing us down, when we are in this room. Or is the "atmospheric pressure" in the room enough to create the gravity effect?

Let's leave the room, now we are standing in a hallway. There are windows on each end, so that the wind is blowing through the hallway. Now, we take out our coin, release it. It falls directly to the ground again. If there is any air movement or air flow in this room at all, it is certainly horizontal. But the horizontal movement of the coin will be negligible, while we all know that the coin will fall directly to the ground. So again, it can't be the air above it, it can't be the air moving sideways--what is making the coin fall?

The main question is, if air pressure creates the force of gravity, then why is gravity always "DOWN"? And what makes the air want to move down, so that it pushes so hard?

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Re: What is Gravity?

Unread post by anonjedi2 » Fri Jun 05, 2015 5:44 am

The weight and mass of the object make it fall down. Since the object's weight and mass will be greater than any air molecules around it, it'll go through the air until it hits an object (the ground, a wooden table, etc) with greater mass. This is why we know that aluminum airplanes can't penetrate steel and concrete towers. Gravity, as far as I understand it is just another one of pscience's magical invisible forces designed to be complex enough to explain away a number of things that we observe for ourselves.

For example:

How is it possible for a human being standing in Australia to not fall off the spherical Earth? Gravity.

How does all the water stay on all sides of the sphere? Gravity.

How does the moon stay fixed in orbit around the Earth? Gravity of course!

Gravity and Relativity are the answers to many of the questions they field that they can't explain. They just chalk it up to good ole' gravity or relativity or any other number of magical, invisible forces, knowing full well that nobody can verify it for themselves and that the majority of people will believe it without a moment's hesitation.

Also, remember that we are told that this magical force of gravity is applied to any spacecraft in orbit around the Earth, but it's somehow not strong enough to pull the craft back down into the atmosphere. In other words (as seen in the Gemini 4 spacewalk), a spacecraft can just "hover" right outside of the atmosphere without falling back down to Earth. I mentioned it in another thread but how is it that gravity can suck something towards the Earth but then stop just shy of the imaginary line where the vacuum stops and the atmosphere begins? To me, none of this makes any sense at all.

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Re: What is Gravity?

Unread post by hoi.polloi » Fri Jun 05, 2015 6:53 pm

Gravity as NASA explains it doesn't make sense. They would say there are no significant fluctuations at orbit distances, but 90% of the force still present in deep space. Whaaa!?

So the necessarily wavy behavior of gravity "smooths" to a perfect oval as the Earth hurtles through the solar system, colliding with Musk-knows-what space debris and radiation, and these miraculously sturdy satellites and ships are not affected by any of it — not the fluctuations in gravity, not debris, not radiation, not the Moon (which is said to be moving entire tides by the way) and not each other?

And they "mostly" require no course corrections? And when course corrections are admitted to be necessary, a little air spritzer jet of gas, escaping the satellite with no work being done on the object releasing the gas into the massive void of space, is supposed to be all that's needed to move the object more effectively than physical meteorites, collisions, waves of radiation, fluctuations in gravity above the massive object of the planet, the Moon, the Sun, etc.

No.

It's nonsense. Malarkey. Horse palaver. I don't care who you work for, how much money you oversee or how hard you've thought about paychecks for your tin-foil, plastic wheel bedecked, circuit board of gyros, micro-engines, chips and solar panels; we are not capable of sending physical contraptions like this to a magic realm where physics suddenly stop applying.

I think Simon is closer to the truth; some rotation of something (Earth? Star field? Light from the stars, twisting into our dimension?) occurs. But not the way they claim. And homemade model kit sa-TallTale-lites do not enter the equation of what "Gravity" is. We'd be better off studying actual objects here on Earth, or barring that the behaviors of heavenly objects: Moon, Sun, stars, planets, NEOs.

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Re: What is Gravity?

Unread post by simonshack » Fri Jun 05, 2015 10:46 pm

*

I am really enjoying & appreciating the various contributions to this thread - yet I suggest that, due to the undeniable, almost mind-numbing complexity of the subject (and to the sheer 'weight' of hundreds of years of conditioning by official psyence), we all try to avoid (so as not to distract our thought processes) even mentioning any "NEWTON-and-NASA-type-information". NASA is a shameless fraud - period. NEWTON never explained /nor proved the idea of "gravity" - period.

Also, before we tackle the concept of "gravity" (an obscure, almost "magickal" term coined by an overly-hailed alchemist who saw an apple fall to the ground) - and try to somehow 'explain it to ourselves', shouldn't we first - more humbly and rationally - try and define some more basic / mundane things which we ALL have direct / firsthand / empirical experience of - here on Mother Earth - such as : air / water / pressure / weight / mass / volume / density / heat / buoyancy ? Hey, perhaps we should re-name this thread:

WHAT IS BUOYANCY?

Well, let me just have a brief go at it. Here's a few things we know about buoyancy: a TITANIC-size megaton ship will neatly float on top of the water surface - and will NOT be falling down towards the center of the Earth. This is because the air volume it contains keeps it afloat. A hot-air (or helium / hydrogen-filled) 500kg balloon full of fat people will neatly take off and soar up, up, in the skies - regardless of 'gravity'. As it reaches a certain altitude, it will stop ascending - due to the density of the molecules in the balloon equalizing with the surrounding atmosphere.

On the strenght of only these two examples, we may rightly say that "gravity" is NOT an absolute force which affects ALL things on this Earth equally. Here's what our 'favorite' online encyclopedia has to say about buoyancy:
BUOYANCY OF AIR:
"Similar to objects at the bottom of its ocean of water looking upward at objects floating above it, humans live at the bottom of an "ocean" of air and look upward at balloons drifting above us. A balloon is suspended in air, and a jellyfish is suspended in water for the same reason: each is buoyed upward by a force equal to the weight of fluid that would occupy its volume; when that buoyant force equals its own weight, it neither rises nor falls. In one case, the displaced fluid is air; and in the other case, the fluid is water. Objects in water are buoyed up because the pressure acting up against the bottom of the object exceeds the pressure acting down against the top. Likewise, air pressure acting up against an object in air is greater than the pressure above pushing down. The buoyancy, in both cases, is equal to the weight of fluid displaced - Archimedes' principle holds for air just as it does for water."

http://en.wikipedia.org/wiki/Buoyancy
So, I think Archimedes was probably onto something... 'Weight', as it turns out, is an abstract concept which is entirely determined by the surrounding system/ atmosphere / density in which ANY object finds itself in. There really isn't any absolute definition of 'weight' - hence - there is no absolute definition of any 'downward-pulling-force' such as "gravity".

Now, what exactly is "air / atmospheric pressure"? Well, as Torricelli found out (as he invented the barometer) it is the force of the air above us affecting ALL earthly objects - such as you and me. As it is, not even that (in)famous Galileo genius had figured out this obvious fact at the time! Again, from our 'favorite' encyclopedia:
"It was traditionally thought (especially by the Aristotelians) that the air did not have lateral weight: that is, that the kilometers of air above the surface did not exert any weight on the bodies below it. Even Galileo had accepted the weightlessness of air as a simple truth. Torricelli questioned that assumption, and instead proposed that air had weight and that it was the latter (not the attracting force of the vacuum) which held (or rather, pushed) up the column of water."
http://en.wikipedia.org/wiki/Barometer
I will stop here for now - although I have a fair amount of other 'gravity thoughts' to share with you all.
That will be for another day.

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