another one

http://arxiv.org/ftp/physics/papers/0112/0112081.pdf

Is a Bat the only flying mammal ??

For Johnny Guinness--

For your research--Look up "Quantum Loop Gravity" many think that it is the path to a Grand Unified Theory (GUT). It might unify gravity with the other forces which are unified only at extremely high temperatures --which did occur in the putative Big Bang.

regards,

Bill

AKA DADDIO

Thanks enzed!!!

;)

;)

another one

http://arxiv.org/ftp/physics/papers/0112/0112081.pdf

Is a Bat the only flying mammal ??

Is a Bat the only flying mammal ??
-- If you discount the "gliding" tree bound critters... then I think so

-- Or perhaps if we "enlarge" the definition ... then things may get a bit more interesting.

-- Or perhaps if we "enlarge" the definition ... then things may get a bit more interesting.

Oh my!

---

me@rescam.org

-- Or perhaps if we "enlarge" the definition ... then things may get a bit more interesting.

Oh my!

..laugh.. I think William is pulling a swift double meaning... the other mammals that fly... is humans ...(with external power)

-- Or perhaps if we "enlarge" the definition ... then things may get a bit more interesting.

Oh my!

..laugh.. I think William is pulling a swift double meaning... the other mammals that fly... is humans ...(with external power)

There's at least one example of human powered flight (no external power)...

Cheers,
Martin

---

See new freedom: Mageia Linux
Take a look for yourself: Linux Format
The Future is what We all make IT (GPLv3)

-- Or perhaps if we "enlarge" the definition ... then things may get a bit more interesting.

Oh my!

..laugh.. I think William is pulling a swift double meaning... the other mammals that fly... is humans ...(with external power)

There's at least one example of human powered flight (no external power)...

Cheers,
Martin

Yes, I saw a documentary a few years ago on a guy with a large plastic covered wing and a frame enclosing him on a bicycle type hookup to a large windmill shaped plastic propeller. I seem to recall he managed to get it off the ground and flew something like 200 meters or so.

cheers

A Gossamer Albatross has crossed the British Channel in 1979 on a human powered flight and has completed a 8 figure in 1980 winning the Kremer prize. Two different models are now in a NASA museum and the Smithsonian Institution. See this:
Gossamer
Tullio

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Thank you Tullio!


.

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"Be who you are and say what you feel, because those who mind don't matter and those who matter don't mind." - Dr. Seuss

A Gossamer Albatross has crossed the British Channel in 1979 on a human powered flight and has completed a 8 figure in 1980 winning the Kremer prize. Two different models are now in a NASA museum and the Smithsonian Institution. See this:
Gossamer
Tullio

Yes the guy who did it was a bicycle racer and could sustain 1/3 horsepower for long enough to cross the Channel from France to England. He had an aborted try or two, I think, because of unfavorable winds.

Yes the guy who did it was a bicycle racer and could sustain 1/3 horsepower for long enough to cross the Channel from France to England. He had an aborted try or two, I think, because of unfavorable winds.

1 HP equals 735 watt. But a professional racer can reach 700 watt for a short time and hold 500 watt a longer time. They race at 50 km/hour in the Giro d'Italia, Tour de France and Vuelta de Espana and reach 70 km/hour in the final sprints. God only knows how.
Tullio

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I just watched the History Channel's "Universe" episode on gravity. Nice series, but I still like Sagan's "Cosmos" series better. Anyway, "Gravity" was good even though they stuck with Newton for the first 40 minutes before Einstein. Those two massive G-Wave detector projects got me thinking: phase modulation of intelligence using a G-Wave carrier?

There are presently a number of serious studies being conducted in gravity-modification. Eugene Podkletnov has created what appears to be gravity waves in the lab, large enough to knock over furniture and still be measurable 10 miles away. The chinese have the high frequency gravity wave experiments and apparently are having some rather quiet but definite success as they are investigating its usage for communications. and good ole BOEING who seem to want to keep a low profile on this issue (but the cats already out of the bag) have some studies in it as well.... can anyone say -gravity shielding-.


regards


Hello Johnney, how paddys

OOps, sorry about the possible blank reply, mouse hiccups. Gravity shielding would be extremely profitable technology one would think. However, such an advance in technology could cause those in power some considerable trouble.

I mean imagine if you could "Float" an oil tanker in air instead of water, use far less propulsion to get something into orbit, eventually making lots of current technologies redundant. Worse still, from the Governments' point of view, the fuel saved would hit their tax revenue. Effectively you give the oil companies and the puppet masters both a serious cut in their pay.

So it is definitely not just about science.

Has progress been made that we do not know about? There are certainly a number of things which although inherently good just might result in a form of anarchy. Anyone know a politician smart enough to be able to deal with sudden and dramatic loss of revenue?

In the past (several thousand years) numerous recognised "Scientists" came up with explanations for the observed movements of planets etc, shall we say the structure of what they might have called "The Heavens". Each of these theories represented the best knowledge "Of the day" and each has had to be scrapped or modified extensively to better fit what we think we now know. Some were just plain wrong, though at that time they were supported by observation and possibly experiment. Each theory became a dead end, and we look back at them (not disrespectfully because we know they could not have known what they were missing) but nevertheless one could say "Duh!" and they probably would themselves.

We have (I think) to accept the fact that we could be simply heading for the next dead end because we can't see the next "Duh!".

... Gravity shielding would be extremely profitable technology one would think. However, such an advance in technology could cause those in power some considerable trouble...

Of far far greater concern, any such "gravity shielding" would cause the whole world of physics utter consternation!

"Anti-gravity" and "gravity shielding" may well be impossible in our present universe...

And then also, there is a lot that is still unknown about various aspects of gravity.

Keep searchin',
Martin

---

See new freedom: Mageia Linux
Take a look for yourself: Linux Format
The Future is what We all make IT (GPLv3)

Maybe this is a "duh" but when I first read about the Einstein project's interferometer, I couldn't help thinking of the Michelson-Morley experiment to detect the ether.

See: http://en.wikipedia.org/wiki/Michelson-Morley_experiment

In fact, the following quote appears at the end of the Wikipedia entry:

"Amongst the predictions of Einstein’s later general theory of relativity is that there exist gravitational waves, but as of 2006, these waves have only been indirectly observed. Enormously sensitive, kilometer-scale Michelson interferometers (coupled with Fabry-Perot interferometers) are used in current projects attempting to directly detect gravitational waves, such as LIGO and VIRGO. LISA is a planned joint NASA-ESA mission to put three 5 million kilometer Michelson interferometers in space, with the intent of observing significantly lower-frequency gravitational waves than terrestrial predecessors."

What's interesting, I think, is that the failure of M&M to detect evidence of the ether revealed a basic flaw in our undertanding of the universe that required Einstein to answer. Deja vu all over again, perhaps?

---

"Good against remotes is one thing. Good against the living, that's something else." (Han Solo)

... the failure of M&M to detect evidence of the ether revealed a basic flaw in our undertanding of the universe that required Einstein to answer. Deja vu all over again, perhaps?

... And all over again, and all over again... Such is the nature of science.

That 'failure to detect' eliminated one of various theories of that day. Thereafter, other theories were developed or developed further and 'evolved' so that science advanced further.

We'll get a lot of such 'deja vu'.


Meanwhile, I'm slowly working my way through various papers on gravity and one aspect is very clear: There is a lot of confusion on what the phrase 'speed of gravity' represents... There's the one aspect of the propagation of changes in a gravitational field that can be viewed like ripples on a pond - "gravity waves".

Then separately, there is the change in direction/force of acceleration due to gravity due to the change in location of the centre of mass responsible for that gravity. This is then referred to as taking a "retarded" position or alternatively an "instantaneous" position for that centre of mass depending on your viewpoint.

If you use the "retarded" position for orbiting bodies, then the sort of orbits that we see in our universe just don't work. Worse still, those bodies magically GAIN momentum! Yet, that view is what you get when you assume that 'the action of gravity' operates at the speed of light.

To make orbits work correctly, you must assume a gravitationally instantaneous position for all the bodies and so take the view that gravity acts at any (including infinite) distance infinitely quickly (instantaneously in fact).

A 'killer' example is that looking from the Earth, we visually see the sun as it was and where it was a few minutes ago (it's "retarded position"). However, the gravity from the sun is acting upon the Earth for where the sun is exactly now, instantaneously. That is, the light rays (propagating at the speed of light) from the sun are at an angle AWAY from the line of acceleration towards the "instantaneous position" of the sun.


So... What is the 'speed' of what aspect of gravity?

Einstein himself was unhappy about some of the assumptions made and has been quoted as not accepting anything that included "spooky action at a distance". Our view of physics insists on there always being a defined direct connectedness for everything.


Keep searchin'!
Martin

---

See new freedom: Mageia Linux
Take a look for yourself: Linux Format
The Future is what We all make IT (GPLv3)

Martin, a cordial tip of the hat to you. I find your posts illuminating and instructive. Thank you. Way back in April you wrote:

"I'm strongly in 'belief' of causality and of there NOT being a 'spooky and magic' non-mediated 'action at a distance'. I have a strong faith in the connectedness of everything. Our present understanding of gravity stretches that belief somewhat..."

I share your faith in that connectedness. If we see "spooky action at a distance" it's only our lack of understanding that makes it look spooky, and it's only that adjective that's getting in our way. We see "action at a distance" all the time and take it for granted. I punch your number and your cell phone rings. A century ago that would have seemed pretty spooky to most people.

Wasn't it Einstein who gave that great explanation of radio to a reporter? Something like: Imagine a giant cat. You tweak his tail in New York and he meows in Los Angeles. Radio is just like that, except there is no cat.

LOL. Analogies have their limits.

Dr. E also said he didn't believe God plays dice, and God answered with quantum physics. Go figure!

---

"Good against remotes is one thing. Good against the living, that's something else." (Han Solo)

Meanwhile, I'm slowly working my way through various papers on gravity and one aspect is very clear: There is a lot of confusion on what the phrase 'speed of gravity' represents... There's the one aspect of the propagation of changes in a gravitational field that can be viewed like ripples on a pond - "gravity waves".

Then separately, there is the change in direction/force of acceleration due to gravity due to the change in location of the centre of mass responsible for that gravity. This is then referred to as taking a "retarded" position or alternatively an "instantaneous" position for that centre of mass depending on your viewpoint.

If you use the "retarded" position for orbiting bodies, then the sort of orbits that we see in our universe just don't work. Worse still, those bodies magically GAIN momentum! Yet, that view is what you get when you assume that 'the action of gravity' operates at the speed of light.

To make orbits work correctly, you must assume a gravitationally instantaneous position for all the bodies and so take the view that gravity acts at any (including infinite) distance infinitely quickly (instantaneously in fact).

A 'killer' example is that looking from the Earth, we visually see the sun as it was and where it was a few minutes ago (it's "retarded position"). However, the gravity from the sun is acting upon the Earth for where the sun is exactly now, instantaneously. That is, the light rays (propagating at the speed of light) from the sun are at an angle AWAY from the line of acceleration towards the "instantaneous position" of the sun.


So... What is the 'speed' of what aspect of gravity?

Einstein himself was unhappy about some of the assumptions made and has been quoted as not accepting anything that included "spooky action at a distance". Our view of physics insists on there always being a defined direct connectedness for everything.


Keep searchin'!
Martin

Thanks for the info. Funny thing is that photons have mass, gravity seems to have no mass, but is an effect of mass (warping of timespace). It would seem to me that the 'speed' of gravity is tied in with how fast the warping of timespace changes when a mass moves from point A to point B. Which would give insight of an aspect of timespace itself. Knowing that a body of a given mass moves through timespace at a given constant velocity with no resistance (hence no retardation) then it would seem reasonable to assume the same is true on a macro scale (star and galaxy size).

That in itself doesn't seem to help, or apply to gravitational waves. But what would apply more is the rate of change of gravitational waves at specific oscillation frequencies. I dare to guess that that might not be a constant with all frequencies. Hence confusion. But whether constant or not, if it is not instantaneous then it should be measurable.

My guess is that its not instantaneous. Because instantaneous is up there with infinity, unobtainable. And timespace seems to be real, and therefore should have a resistance to frequency (gravitational wave frequency). But that's just a guess.

Or timespace could have a resistance to the change of gravitational frequencies. Which is consistent with an orbiting body. An orbiting planet around a star outside our solar system has a certain gravitational frequency from our point of view. If that planet doesn't experience any outside force, then its orbiting speed and its gravitational frequency is constant. You have to apply work (energy, force etc) to change the orbital speed and hence the gravitational frequency.

If there is a resistance there should be a rate of change, hence 'speed'.

***

Your analogy of the earth and sun might not be the best since earth experiences roughly the same gravity force for the sun year around. Perhaps Pluto would be better since it comes in close then very far away in an elliptical orbit. From Pluto's point of view it would experience a gravitational wave with the wave length the length of the circumference of its orbit, measured in astronomical units (AU). But I agree with your point. I think its because gravitational waves do not have mass as a property.

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Comments:

Photons have no rest mass they are pure energy. from e=mc^2 they can be assigned a "mass".

Earth based gravity detectors are not sensitive enough and are prone to vibrations caused by traffic, people walking etc.

When we get to put up the long baseline interferometers in space I feel that we will quickly find gravity waves.

I don't think that we are critical enough of Quantum Theory even though it makes accurate projections. Some of the supposed consequences I don't fully embrace.