Antigravity, and the American Journal of Physics

General Questions
#1

I remember reading something in a few places (unfortunately, Omni was one of them) about an experiment in which a couple of scientists were working on a floating superconductive disk, spinning, with current running across it. One of the scientists was smoking a cigar (imagine that, some lab they must have) and noticed the path of his smoke was changed over the disk. Seems that everything placed vertically over the disk had its weight reduced by 2%, and apparently this effect was stackable, so presumably if you stacked 50 in series, you’d have antigravity. Keep in mind, it’s been years since I read this stuff & I’m probably misremembering the details. Anyway, their experiment was published in the Journal of Physics, then apparently all copies of this journal were tracked down & destroyed.

Of course, I don’t believe this story as I’ve recalled it, but I was wondering about what really happened, if anything.

If it IS true, I figure this is a great way to get things into orbit…just put a payload on the disks, turn them on, and let the inertia of the payload hurtle itself into space. Either that, or we could put them under Rush Limbaugh’s chair - it would be the greatest use of technology since duct tape.

#2

Tilt.

#3

Actually the device you mention does exist. You can find details about it here and here. Discussion about it has taken place in this thread. Suffice it to say, no one’s made it work yet.

#4

I don’t think this anti gravity car thing will work that was mentioned in the first article. Lets say you sat in it then turned it on. Now free from earth’s gravitational force, you would go flying off into space at 18,000 mph or so (being roasted by the friction of the atmoshere too).

#5

The rest of what you remember of the Podkletnov story is a pretty accurate version of what he was claiming. This detail is the lurid mutation. He’d submitted a paper to the Journal of Physics D (not emphasis, merely typographical convention), but the story leaked to the Sunday Telegraph newspaper. Podkletnov then retracted the paper before publication. Why remains a matter of some dispute. Pro-Podkletnov websites (and there are plenty out there) tend to claim this was due to sensationalistic publicity destroying his reputation. (Web supporters of his cause tend not to be big on irony.) However, one of the named co-authors had protested that he hadn’t written any of it and complained to the journal before the retraction. But the paper never ever actually appeared in print in the pages of the journal.

There have been no convincing claims of any replications of the experiment.

#6

Incidentally, Journal of Physics D*: Applied Physics* is published by the IOP, the British professional organisation of physicists, and is distinct from the American Journal of Physics. The latter’s an excellent journal, but it’d be a very strange venue for publishing results of the type that Podkletnov was claiming.

#7

Er, wouldn’t you “inherent” the revolutionary velocity of Earth? It sounds like you’re saying you’d spontaneously come to a complete stop relative to the sun if not for the Earth’s gravity - it seems intuitive to me that you’d sort of take your own orbit around the sun at roughly the same spot as earth (which is to say, basically hovering around the earth based on your thrusters).

#8

If you don’t feel the effects of gravity then you do not orbit. Gravity is necessary for orbiting to occur. So you would fly off in a straightline (relative ?) from the moment you turned the machine on.

#9

Well, according to the Popular Mechanics article I read on it (yeah, yeah, I know, not the greatest source), Ning Li claims that it’d be controllable process, so you could have the object hover, or send it off into space at whatever speed you chose. It all depends upon how much power you dump into the device. That’s assuming it can be made to work.

#10

The rotation of the Earth is what is important here… suddenly cut off from gravity, the car or whatever would fly off at a tanjent at the rotational speed of the earth at that latitude-
to a ground based observer, the car would rise upwards almost vertically as the earth dropped away beneath the car-
the inertia of the car would then carry it in a straight line at the same speed as the earth, gradually over the course of a few months moving into the outer solar system and eventually into interstellar space and off out of the galaxy.
Is this wise?

#11

Or if yu took off at dawn, you would be flung into the inner solar system- hey, by switching it on and off you could get practically anywhere-
not such a bad idea-
how much energy is it supposed to consume btw?

#12

I was referring to an orbit around the sun - I figured the device would still be orbiting the sun the same way the earth was, and taking earth’s gravity out of the equation wouldn’t change that. But I realize that the rotational energy imparted on it by the earth would “fling” it off in a straight line - I didn’t factor that in.

But assuming one could counter the starting rotational force of the Earth (firing reverse thrusters or whatever), wouldn’t the craft stay relatively close to the earth in an orbit around the sun?

#13

In his classic books “Fads and Fallacies in the Name of Science,” Martin Gardner devoted a chapter to Roger Babson and the Gravity Research Foundation. Babson’s goal, apparently, was to find a substance or alloy that would block gravity the way a shade blocks sunlight. Apparently he got the idea from Thomas Edison. Babson never got anywhere with it but the Foundation was still in existence in the 1950s, when Gardner wrote the book, and, for all I know, still exists. A cursory Web search turns up several organizations called “Gravity Research Foundation” but it’s not obvious if any of them descends from Babson’s.

Obviously gravity is not the kind of force you could simply “block” – according to modern theory, it’s a kind of space warp – right? Then again, it’s supposed to be transmitted by particles called “gravitons” – if you could identify them, you might, in principle, learn to manipulate them – right? Help me out here – do any dopers out there (1) know a lot about this aspect of physics and (2) have the Asimov-like talent to explain it in layman’s terms?

I always wondered: If you’re in an acceleration-frame that has the same EFFECT as a gravity field (e.g., a really fast elevator such as construction crews use to reach the top of a skyscraper-in-progress), then relativity says it actually IS a gravity field, that is, it has the same time-dilation effect, etc.; there’s no fundamental difference, regardless of whether the field is created by accelerated motion or a large concentration of mass. But if that is true – then what role, if any, do “gravitons” play in an acceleration-frame?

#14

If it worked and each one reduced gravity by 2 percent, then stacking 50 of them would only reduce gravity by about 64 percent (the first one would reduce gravity by 2 percent of full strength, the second would reduce it by 2 percent of the weakened 98 percent and so on).

#15

Ahh, Cavorite.

#16

They don’t appear to have a website, though this article notes that they’re still active. The Wellesley, MA connection is presumably because that’s where Babson College is (some history here). The college’s great claim to fame is that it has one of the world’s best collections of Isaac Newton manuscripts, inherited from their founder.

#17

Relativistic effects are not caused by acceleration but by velocity of the object itself. The Lorentz-Fitzgerald formulae do not have acceleration as an independent variable.

#18

A helium balloon weighs almost nothing and doesn’t almost acquire the earth’s orbital velocity. Something that wieghed nothing would (presumably) do the same. IIRC you’d get a neglibible sideways vel from corialis or something like it.

#19

But if the object trully negated the effect of gravity then it would also be unaffected by the sun’s gravity and thus wouldn’t orbit the sun either. Obviously if you could control so it wasn’t just a no-gravity device then it wouldn’t be such a problem.

Weighing nothing is totally different from not feeling the effects of gravity. A balloon feels all of the effects of gravity, it just happens to have an equal force opposing it.

#20

Aha. Huge brain fart… I was only thinking in terms of negating the Earth’s gravity.