h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

So that's anti-gravity machines, teleporters and asteroids crashing into earth - all in the space of a month.

What about next month Time Travel? Faster than Light Travel? Fluff Resistant Velcro?

an anti-gravity asteroid would be nice

or it could be evidence of the waning power of multi-nationals who have discovered all these devices years ago, along with the 200mpg water engine, ever lasting light bulbs and the cure for the cold but kept it hidden.

OR....the same multinationals are panicing at the downturn in the worlds economy and releasing some of these hiden inventions one at a time to restart the economy before they all have to admit to false accounting



CH - me paranoid?

There's cosmological evidence that there may a natrually occurring anti-gravity force, that acts like gravity put repels instead of attracting.

Wait (I hear you cry) wouldn't they just cancel out, leaving the stronger?

Well, when observing distant supernovae (only supernovae were bright enough to be seen over these distances), a team of scientists discovered that they were further away than gravity alone predicted. It was outside the bounds of experimental error, and seemed significant. It could be that there is an anti-gravity force, but it is not inverse square with distance but some other relationship, because it is proprotionally more powerful over long distances. However, the evidence was far from conclusive because there was no theoretic framework to account for it, and the observed supernovae were so far away (in space and thus in time) that it may be another effect of the novel behaviour of the early universe.

I mention this only because while blocking gravitons may not be possible, it may be possible to generate gravitinos (anti-gravitons which may exist if Grand Unified Theory is to be believed).

That was way more technical than I intended. I'm sorry I can't be any more definite about my source (it was a TV documentary, Horizon or something).

You can get these toys where you have a flat surface. Then you have a top with a magnet in it. The surface and the top have different magnetic poles. If you hold the top over the surface it will just flip over and fall down. But if you spin the top, it will stabilize itself and hover in the air. Looks pretty cool. I wonder if it could be something similar with this antigravity device. Though then you'd expect they'd have found out quite fast.

OK, firstly, Podkletnov's results were first published in "Physica C", a respected peer-reviewed journal, but not Physical Review. He lost his job at the university of Tampere in Finland shortly after.

According to the abstract of the paper by Podkletnov and Modanese: "Discharges originating from a superconducting ceramic electrode are accompanied by the emission of radiation which propagates in a focused beam without noticeable attenuation through different materials and exerts a short repulsive force on small movable objects along the propagation axis. Within the measurement error (5 to 7 %) the impulse is proportional to the mass of the objects and independent on their composition. It therefore resembles a gravitational impulse."

This would seem to rule out comparison with electromagnetic effects.

The full abstract, and a link to the original (very technical) paper in PDF and other formats can be found here: http://xxx.lanl.gov/abs/physics/0108005

H.

Very technical indeed.
It looks like the scientific community accepts the anomalies as facts.
Now for someone to create a good theory around it and a way to make it really usefull instead of just a curiosity.

http://www.uni-bonn.de/~uzs4y4/makingof/making%20of.htm

Groovy.

H.

Groovy indeed. Show this to a certain Dubya and he may proclaim a holy war on bad or even evil gravity!

Just for the record... Newton's laws aren't correct, and any physicist with a PhD who thinks they are obviously hasn't been paying attention

Relativity and all that, y'know...

Hmm. And the fact that the theory of relativity is now widely accepted is good evidence that revolutionary new ideas *can* become accepted... it's at least as bizarre as anti-gravity... time dilation, anyone?

One of the things about relativity, though, is that it has been repeatedly verified by experiments and observations...

(oh, and how about quantum mechanics? Another idea that is complete crazy and widely accepted... because it explains observable phenomena)

So if I have questions about relativity, can somebody here answer them for me?

Absolutely, only the answers may be relatively usefull

Or they could be relatively unusefull

Okay then, According to Einstein the faster you move the slower time gets right? So you have two spaceships, one of them speeds up and after a while comes back again. If you compared the clocks in those two ships you should find a difference. But which one would be behind? If we say there were no outside points of reference how would we know which one was moving?

The clock of the ship that was moving would be behind and that's all you'd need to check, assuming the clocks were known to be accurate.

The way to distinguish between them without an objective frame of reference is to see which is under acceleration (I think - I'm no physicist).

But does it have to be under acceleration to have time slowed down? As far as I understood it just had to be moving.

I don't know. Perhaps if you look at the history of acceleration that will give you some kind of reference for 'speed', and thus time dilation.

It's definitely speed (well, it's technically velocity as direction's irrelevant) rather than acceleration that matters.

But acceleration matters as well I think. It is indistinguishable from gravity, and time slows down in a heavy g-field. But from what I remember speed alone should be enough to slow down time as well.

Then there is also centrifugal force, we wouldn't have that without some sort of reference point I think.