UFOs

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Originally Posted by prendrelemick

^ The two slit experiment:

Shine a light through two slits onto a screen. you don't get two light bands on the screen, you get several. This is right and proper and predictable because light travels in waves that interfere and collide with each other as they emerge from the slits.

Now adjust your light so that it fires one Photon at a time (that means they can't collide with each other) The result is the same - several light bands on the screen. No one knows why!

So to try and see what is happening, place photon detectors along the route the photons travel. Strangely, they then behave as predicted, two bands of light on the screen. Remove the detectors and they revert back to their many banded odd behavior.

Of course this has spawned many imaginative theories as to what is going on. My favourite is that reality splits in two as the photon approaches the slits, creating a whole new alternative universe.

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Is this just not confusing the particle/wave duality of photons? I think you're also making a mistake that the photon experiment isn't one photon at a time, but one photon wide.

I'm nobody's physicist, but I don't think you've presented the case as it's seen by physicists.

There's a lot more here and here.

Fascinating, but not really a hole in physics.

Nope. it was as I said. one particle at a time, so even if they were acting like a wave they could not interfere with each other.

here is a simple and annoying explanation of the effect I was describing. (with electrons)

http://www.youtube.com/watch?v=DfPeprQ7oGc

The point I was making is that the presence of an observer, or an attempt at measurement, or placing a detector is significant in quantum physics, and not only in this experiment. (It decoheres the probability wave or something)

You might want to look at this too, same annoying bloke on paired particles.

http://www.youtube.com/watch?v=Jh8uZ...eature=related

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Originally Posted by prendrelemick

You might want to look at this too, same annoying bloke on paired particles.

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Do you have something other than a bloke on Youtube?

If there's some science behind his claims, it should be available elsewhere; there will be publications and peer reviews. My understanding - which I'll readily admit is lousy - is that he's wrong, but I could easily be barking up the wrong river.

The thing about individual electrons (or photons, it works in both cases) is mentioned in pretty much every layman's book about modern physics and its interesting implications. I must admit that my personal exposure came from (laymen's) science magazines which I can't recall the name of, science programs on TV (again, probably more than one), and best-selling popularizations. At the moment, I have Brian Greene's "Fabric of the Cosmos" somewhere, but it would take a while to dig it up to find exact page numbers, for example. Roger Penrose and others also describe it in other books for the layman.

Here's another *non-video* discussion. It's lengthy and detailed, but skipping up to the middle section called "The Double Slit Experiment Revisited" will bring you to the part about introducing an observation of the electrons in transit, and thus bringing an end to the interference pattern.
http://www4.ncsu.edu/unity/lockers/u...s/quantum.html

Apparently Feynman's famous lecture on this can be found in the Third volume of his Feynman Lectures On Physics (which Google Books only excerpts). Feynman's idea that the particles are passing through infinite paths is called Sum Over Histories. What it would actually *mean* regarding multiple universes is open to some debate--but I think the basic idea is that the wave travels *each possible path*, and all of the paths cancel each other out except for the one that we finally observe. That's how the math is meant to work, anyhow.


Stephen Hawking describes Feynman's idea about this like so:

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Feynman suggested that particles travel from one location to another along every possible path through spacetime. With each trajectory Feynman associated two numbers, one for the size – the amplitude – of a wave and one for its phase – whether it is a crest or a through. The probability of a particle going from A to B is found by adding the up the waves associated with every possible path that passes through A and B.

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At about 8:40 on this youtube clip (yes, another youtube guy...), you can hear a Fermilab physicist come to the end of a lecture on this famous experiment (and how sending individual electrons produces the same interference pattern that we would get if the electrons were sent in larger numbers, etc.). He goes on to explain the effects of observing which slit the individually-sent electrons happen to actually pass through: in that case, the interference pattern does not appear, you just get two dots, one for each slit as Newtonian physics would predict (a resulting physics similar to what one gets with only one slit).
http://www.youtube.com/watch?v=UXvAl...ayer_embedded#


Here is Stephen Hawking going over the same ground in his book The Grand Design. (see page 81)

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Originally Posted by The Atheist

Do you have something other than a bloke on Youtube?

If there's some science behind his claims, it should be available elsewhere; there will be publications and peer reviews. My understanding - which I'll readily admit is lousy - is that he's wrong, but I could easily be barking up the wrong river.

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There are loads of sites on the interweb about this (see Bill's post above.) This is not some fringe loony Physics, this is fundemental Mainstream stuff. For 90 years scientists have been refining and redoing the experiment, they are still getting the same result, and are still unable to "see" what is happening, though theories abound.

I linked to Dr Quantum because he ignores the Maths (which is all Greek to me) and was a quick and easy explanation. He is the creation of Fred Alan Wolf (you can wiki him)a Theoretical Physicist, who is probably cleverer than me.

My main sources are, as with Billl, magazine articles and popular TV documentries.

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Originally Posted by billl

Here's another *non-video* discussion.

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Thanks!

Here is the nub of it all:

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When you fire your photon emitter, what actually comes out is a Y wave (ie a wavefunction). It is not random: it travels according to the perfectly predictable laws of wave propagation, moving out in all directions and interfering with itself and all that good stuff. According to the Copenhagen interpretation, the Y wave represents the probability of the photon being at any particular place. So at this stage, the question "Where is the photon?" does not have an answer—there is only a wave of probabilities traveling outward. ....

But when we put measuring devices in the slits, we collapse the wavefunction much earlier. We force the photon to choose which slit to go through: one probability becomes "definitely yes" and the other becomes "definitely no" in that instant. Thereafter, there is only one beam, and hence no interference and no interference pattern.

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Which is the problem with wave/particle duality - you can't measure the wavelength of a particle and you can't measure the height or length of a wave with a particle locator.

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Originally Posted by prendrelemick

There are loads of sites on the interweb about this (see Bill's post above.) This is not some fringe loony Physics, this is fundemental Mainstream stuff. For 90 years scientists have been refining and redoing the experiment, they are still getting the same result, and are still unable to "see" what is happening, though theories abound.

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Yep - I should have checked a bit more deeply, but I'm on the right wavelength now!

I think the problem was my reading of your description of what's actually happening.

If you follow the Copenhagen interpretation above, the proton isn't being observed, but located, and to be located, it actually has to be somewhere.

Just think - thanks to CERN, our grandchildren will be learning this stuff at school in a couple of decades' time.

Yes Billl, a very interesting and informative paper. I should've looked harder before linking Dr Quantum. I should just say that Niels Bohr's probability wave, is not the only explanation, there are some weird and wonderful theories out there, like the multi-universe explanation and the idea of conciousness interacting with the physical

Are we ready to do paired particles yet?

When I was a kid I imagined that death was not a reality, but that you inhabited different aspects of yourselves in different universes as and when your body in one universe was killed. It must have been the eternalist in me after reading about the theory somewhere ...

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Originally Posted by prendrelemick

Yes Billl, a very interesting and informative paper. I should've looked harder before linking Dr Quantum. I should just say that Niels Bohr's probability wave, is not the only explanation, there are some weird and wonderful theories out there, like the multi-universe explanation and the idea of conciousness interacting with the physical

Are we ready to do paired particles yet?

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Never mind them, I think we're venturing into infinite improbablity drive!

You're right on theories, and it's difficult to tell the difference between the crazy and the sane, because some of the facts seem more bizarre than the oddest theory. The paired particles are a case in point - it shouldn't happen, but it obviously does, so there might be a dark energy or ............. [/insert theory] cause.

I think the paired particles (as well as discussion of the various "interpretations" that there are for these various weird results) is a bit more difficult than this double-slit business. Maybe another thread, if someone wants to really give it a shot...?

The improbability drive would actually be more relevant to this thread (and I don't mean to be as snarky as I might seem).

Yes we have strayed from UFOs. But as a confirmed skeptic I'm always dissappointed with the believers arguements, they never seem to marshal current Physics theory to their side, relying on "my mates aunty saw a flying saucer once".

I once heard someone explain that, at this point, the most convincing thing that aliens could do would be to parade some enormous hub-cap-looking metal structure slowly overhead as if to say, "Yes, we can even show up in a form you would never believe, that's how powerful and superior we are. Now try to tell your friends, you little being."

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Originally Posted by prendrelemick

Yes we have strayed from UFOs. But as a confirmed skeptic I'm always dissappointed with the believers arguements, they never seem to marshal current Physics theory to their side, relying on "my mates aunty saw a flying saucer once".

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I don't think many of them made the sixth form. ;)

David Icke's mob is a good example. They go a little further than just seeing flying saucers.

(For goodness' sake do NOT try to find out by reading his site - you'll burn your retinas.)

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Originally Posted by prendrelemick

Yes we have strayed from UFOs. But as a confirmed skeptic I'm always dissappointed with the believers arguements, they never seem to marshal current Physics theory to their side, relying on "my mates aunty saw a flying saucer once".

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My mate's auntie saw a flying saucer twice.

Did she see one twice, or two once?

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Originally Posted by prendrelemick

Did she see one twice, or two once?

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I don't remember but she did wear one of these.


http://www.zazzle.co.uk/einstein_ufo...16368051679325

You see that's the problem. Tell your Auntie that E=MC squared greatly limits the chance of interstellar travel. It will have to be done on the back some other more outlandish equation.

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Originally Posted by prendrelemick

You see that's the problem. Tell your Auntie that E=MC squared greatly limits the chance of interstellar travel. It will have to be done on the back some other more outlandish equation.

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There was a thing on the TV a wee while back where some scientist said, as a remark in passing, that actually it isn't necessary to travel faster than light to achieve rapid interstellar travel. His words were something like "as you approach light-speed, the concept of distance becomes unstable and therefore distance actually shrinks once you start moving that fast."

The comment was, as I say, a throwaway one, and only tangential to the matter of the programme, but the offhand nature of the comment would make me assume that it was accepted fact amongst the scientific community. I don't pretend to understand it myself, and I wish the boffin had gone into greater detail, but there you have it!

Ahh, in-ter-esting. Another route for those pesky Aliens.

It's well known that time slows as you speed up, but I haven't heard of distance shrinking.l

But thinking about it. What is a light year, if time is not a constant?




EDIT: Its just been on the News. They've been visiting Jerusalem .


http://www.foxnews.com/scitech/2011/...ffles-experts/.

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Originally Posted by prendrelemick

Ahh, in-ter-esting. Another route for those pesky Aliens.

It's well known that time slows as you speed up, but I haven't heard of distance shrinking.l

But thinking about it. What is a light year, if time is not a constant?

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Suppose you were riding on a light beam, would it take you any time at all to get anywhere? The people at home might think you've been gone forever, but would you? It seems that that extreme case would be all distance and no time.

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Originally Posted by prendrelemick

EDIT: Its just been on the News. They've been visiting Jerusalem .


http://www.foxnews.com/scitech/2011/...ffles-experts/.

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Spooky. :alien:

I doubt that it was a secret Israeli drone, because the last thing they would do would be to let it settle over a major shrine for all to see. One thing I did notice was that there appears to be the sound of thunder right at the start of the video so perhaps the light was ball lightning attracted by the spire of the temple.

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Originally Posted by Lokasenna

There was a thing on the TV a wee while back where some scientist said, as a remark in passing, that actually it isn't necessary to travel faster than light to achieve rapid interstellar travel. His words were something like "as you approach light-speed, the concept of distance becomes unstable and therefore distance actually shrinks once you start moving that fast."

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Yes, all sorts of things apparently happen as you approach the speed of light, but "approaching" means over 200,000 km per second. At the moment, even using sun-gravity escape velocity would only be in the 20 km/sec range. Hitting a piece of dust at 200,000 km/s would be fatal to any kind of craft, so the distance would be a bit secondary.

:D

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Originally Posted by prendrelemick

http://www.foxnews.com/scitech/2011/...ffles-experts/.

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:smilielol5:

Fancy that being on Fox.

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Originally Posted by The Atheist

Hitting a piece of dust at 200,000 km/s would be fatal to any kind of craft, so the distance would be a bit secondary.

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Aye, there'd be a splatter of Higgs-Bosons.:p


The Jeruselem thing was either;

A hoax.
Ball lightning.
Something man made.
Something alien (from Mississippi.)

I like how the ITN announcer closed out their segment on the Dome Of The Rock UFO sighting:

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"We are not alone! OR ARE WE...??"

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Some things are not meant to be 'understood', especially in the case of phase shifting

It is an extremely dangerous pursuit and will bring about itchy palms, Asberger's Syndrome and Night Terrors

I know of at least one person who found his head was able to rotate 360 degrees on its axis

Fortunately all methods so far described are not true phasing in the sense you desire

But if you must 'understand' it make sure you're armed

Things you will need:

A a piece of paper (A4 will do)

B a sharpened HB pencil

C a pencil sharpener (to keep that baby sharp!)

D a box of artist quality Faber-Castille rubber erasers


First, take the paper by two corners and raise it to your lips. Blow over the top

Notice that this causes the sheet to lift in a similar fashion to a Boeing 747 wing at takeoff

While still blowing take the pencil and draw a complete sine phase (one peak one trough) on the underside of the paper

Now while still blowing do the same but opposite (one trough one peak) on the top side of sheet

While still blowing take the first rubber eraser and balance it on the tip of your nose

While still blowing take the sharpener and balance it on the end of the eraser

Still blowing firmly grasp the pencil with your left foot and raise it to the ceiling

While still blowing secure purchase of the box of erasers with you right foot To balance it on the end of the pencil

While still blowing declare 'I am enlightened!'

While still blowing you should now resemble a Danish pretzel

When can I breathe in!

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Originally Posted by billl

I like how the ITN announcer closed out their segment on the Dome Of The Rock UFO sighting:

"We are not alone! OR ARE WE...??"

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I also like what the woman from Mississippi had to say:

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"We've seen 'um in Miss'ssippi like this, but never like this."

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Originally Posted by Lokasenna

There was a thing on the TV a wee while back where some scientist said, as a remark in passing, that actually it isn't necessary to travel faster than light to achieve rapid interstellar travel. His words were something like "as you approach light-speed, the concept of distance becomes unstable and therefore distance actually shrinks once you start moving that fast."

The comment was, as I say, a throwaway one, and only tangential to the matter of the programme, but the offhand nature of the comment would make me assume that it was accepted fact amongst the scientific community. I don't pretend to understand it myself, and I wish the boffin had gone into greater detail, but there you have it!

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This is the Lorentz contraction. Suppose you have a particle that is traveling extremely close to the speed of light. Because of time dilation, it may take the particle 10 seconds from its point of view to cross a distance of 30,000 light-years. Of course, from our POV it took a little longer than 30,000 years. But from the particle's point of view, time is flowing normally for it, it hasn't slowed down, and the reason it completed the trip in 10 seconds is because from its POV, that distance wasn't 30,000 light-years but something way shorter--something it could traverse in 10 seconds. So in a nutshell, from our POV time is flowing really slowly for the particle, but from its POV, space is getting "squished."

Wheras all that is true, were you to pace out the distance travelled, in a traditional earth dweller way, The distance would be the same, only the time taken would be in dispute. (I think) Is it legitimate to measure distance by the time it takes to cover it? It raises an interesting quandry about the relationship of time distance and speed.

Just to get back to UFOs, this one was hanging around outside the other day:

http://i150.photobucket.com/albums/s...heist/ufo1.jpg

Well, if that is not an UFO, I don't know what is...

I hope you avoided the probing.

You were lucky to get such a clear photo - the red ones usually go faster

[QUOTE=The Atheist;1016349]Just to get back to UFOs, this one was hanging around outside the other day :lol:

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Originally Posted by prendrelemick

I hope you avoided the probing.

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Yes, all clear there! I ran back inside quickly.

That picture looks like the red streak I saw outside yesterday. I took a picture of it but it isn't very clear. Hmm...Oh well. I guess I will just have to remain happily ignorant of what that funny light was.

Here's a NASA fact...subject to my memory being up to it.

I would take 100 years worth of the Worlds current energy output to get a 5 tonne spacecraft to the nearest star within 50 years. That's by using the best theoretical propulsion systems. .

and then it probably wouldn't survive the trip.

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Originally Posted by prendrelemick

Here's a NASA fact...subject to my memory being up to it.

I would take 100 years worth of the Worlds current energy output to get a 5 tonne spacecraft to the nearest star within 50 years. That's by using the best theoretical propulsion systems. .

and then it probably wouldn't survive the trip.

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This would of course be using materials and energy sources known to inhabitants of the Earth.

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Originally Posted by prendrelemick

Here's a NASA fact...subject to my memory being up to it.

I would take 100 years worth of the Worlds current energy output to get a 5 tonne spacecraft to the nearest star within 50 years. That's by using the best theoretical propulsion systems. .

and then it probably wouldn't survive the trip.

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I suspect whoever wrote that was fooling with you.

Proxima Centauri is roughly 5 light years, or 47 trillion km distant.

To reach there in 50 years would need a speed of 10% of the speed of light.

Light travels at about a billion km an hour, so we would need to be travelling at 100,000,000 km/h.

Given that current technology only allows us to travel at ~50,000 km/h, we haven't got a clue as to what kind of propulsion might be needed to attain that kind of speed. You can't make rockets go faster by building them bigger, so it's impossible to put an energy value on the question. Whether humans could withstand being propelled 20,000 times faster than ever before is moot.

Even the escape velocity of the sun (sorry to pour cold water on Mr Spock) is a measly 2,000,000 km/h, still only 2% of the speed needed to get to Proxima Centauri in time for the half-century party.

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Originally Posted by The Atheist

David Icke's mob is a good example. They go a little further than just seeing flying saucers.

(For goodness' sake do NOT try to find out by reading his site - you'll burn your retinas.)

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No, no - do! Also read his books. They are absolutely, untouchably fantastic. And I use the adjective in every available sense it carries. As an example of what Vonnegut characterises as slipped-gear thinking, they're unparallelled. Do not for an instant baulk at the thought that, by buying the books, you are funding a dangerous nutter. Nutters of Icke's calibre should be given as much money as they need to keep going. This stuff is so intricately, so unfalsifiably, so comprehensively insane that it beggars the creative imagination.

Honestly - the whole endeavour reaffirms my faith in the impossibility of any human being ever entirely understanding what it must be like to be someone else.