The Dark Matter hunt continues

[xelasnave]

I suspect there are others who enjoy the news about the dark matter hunt and although a press or news release here it a link for those who care.


http://www.sciencedaily.com/releases/2008/02/080214144535.htm


alex:):):)

[xelasnave]

Oh I had to add this..simply because I find it amusing as so much of this stuff is really..er and very interesting may I say:D....check the last paragraph :lol::lol::lol:

http://www.sciencedaily.com/releases/2006/09/060930094827.htm

alex:):):)

[xelasnave]

And this is for those who cant put this stuff down and want more

http://www.sciencedaily.com/releases/2007/11/071130075008.htm

I think that the refernce to particles popping into and out of existence and the premise is flawed:shrug:... from what I have read this is the development of a math fiction ..shortly the way I read this stuff behind this notion is the particles are there all the time but until observaed treated as they do not exist and hence the corruption of the reality...

and I may have it wrong and will not be upset if anyone says so...what would I know anyways:P

but as a side issue on that point I think it was this approach that gave the inflation idea some momentum... mmm thats not a pun is it..is not meant to be anyways.

alex:):):)

[xelasnave]

I had in mind this section of the text.......

The most conventional explanation is that dark energy is some kind of "cosmological constant" that arises from empty space not being empty, but having an energy as elementary particles pop in and out of existence.

alex

[coldspace]

Thanks for that Alex,

I too am very much into the science side of our hobby, it just keeps my mind thinking. I like the bit about how fast dark matter falls, sounds like testing out the old apple falling out of the tree as done by Newton to discover gravity, maybe the inhabitants of the dark matter planet could see if the toast that they cooked for breakfast and then falls off the side of the kitchen table would land butter side up,only problem on the dark matter planet both sides of the toast would be burnt black.:rofl: on a more serious note thanks for the link to these sites.

Matt.

[xelasnave]

Hi Matt out of respect for the real scientists here and elsewhere I call any of my thoughts mere philosophy:whistle:... maybe less arguements with philosophy than with science;)..if you keep the religion out of the philosophy that is:lol::lol::lol:

alex:):):)

[coldspace]

Sorry if I offended you Alex or any other real scientists or should I say career scientists. Just trying to have a bit of fun after you pointed out the dark matter falling of the table. I was just refering to the Myth busters show experiment with the toast and table. Anyway all good.

Matt.;)

[xelasnave]

Mate you did not offend me:):):) I havent read what I said but dont take me seriously ..when I sound my most serious it is usaully my weird sence of humour...

If you cant have a joke whats left:).... and it is not easy to offend me ..hit me in the head with a brick and I will be worried about what is upseting you..a very thick hide to match the thick skull.;)

I have some different ideas that has a real scientist puling their hair... it is my respect for them that I dont pretend to be a scientist...for I am not ... I am a Morosophicist:eyepop:... ask me if you dont get the joke.

thanks for your concern but all is cool always is:thumbsup:.
alex:):):)

[coldspace]

Great to here mate, yeah I took it the wrong way just thought when you said the real scientists it was a crack at me, anyway how thick is your head must be thicker than mine.:)

Cheers Matt.

P.S. I found some more links on the hubble latest discoveries I will post them for all to view.

[xelasnave]

Also I dont really buy the Dark Matter thing I reckon they are wrong:eyepop:..dead wrong, so wrong it hurts:whistle:...but I love to read about it so I can go off about it:P...weird eh:screwy:...

I think it is a mtyh to be honest but that is my philosophy... I cant argue the toss scientifically on anything and it is not fair to annoy people trying to understand stuff and they know you miss a simple point:)... its like someone trying to tell me how to sell real estate and they are off the street green as...
How do you tell them there is more to it than just riding is a flash car selling each house you visit...it is not really like that..it is hard work for a start.

and I can be a little impertinant as well...

So there you go
alex:):):)

[DARKMATTER]

Ahem!

Ahhh? Present?


lol

[xelasnave]

I have been cruel really... because these folk trying to work out the problems are alone... they have a problem before them..they have come up with one answer..dark stuff from start to finish...

and the rest of us sit back and say fair enough...

rather than trying to contribute...

I mean when we get to a situation where we have to invent matter that can not be seen does not that tell us these folk need help....

I bet they were surprised no one stepped forward and said ..no I have a more reasonable idea than your dark matter.. but no one has come up with anything better...so dark matter is the best we have...how sadly tragic...

the Universe can only be understood by resort to what one would call magic and mystery... most of what is real we can not see...yes indeed... it sounds unbelievable because it is unbelievable..

so as we can see those trying to understand are really out of ideas it is up to us to come up with something that is reasonable... who will rise to the occasion and provide a better view..

there is no one capable of doing the job so now is the time to step up folks.

help those who need help in finding direction..for humanity..for humanity lift us from the dark ages ...dark matter dark energy and black holes... lets move past the mystery... if nothing else stop calling stuff not understood scientifically ..dark or black..such degrades those involved....and hints of times in our history we can not be proud of.........it is a good day when you can end with a preposition

alex:):):)

[Zuts]

Would it make you happier if we called it fairy matter. Like in we cant see it but it would be great if it was actually there :)


When I was in first year uni, someone did a geometric illustration (not proof) of special relativity time dilation. The only assumption was that the speed of light was a constant. I was stunned, there in clear understandable view was an illustration of how time passes at different rates for bodies (including people) in relative motion.

When Einstein thought of this, the understanding of anyone who cared to listen would have been as clear. However it could not be proved. These days of course there are many ways of proving it and the dilation can actually be easily measured.

Things which seem impossible at one stage of history have a habit of becoming commonplace in another and I think the same will happen with dark matter. Another example is antimatter, once a theoretical substance and these days manufactured by the milligram.

Paul

[xelasnave]

Yes Paul we know not what the future holds for us...

I have no problem with that at all...

but honestly dark matter... why not go back to the drawing board and consider why we are inventing such stuff... there is a determination that our current belief in general relativity will not lead us astray..yet the longer we entertain the universe and all it sets out for us the more we are forced to entertain stuff that is in the region of mystery...

I dont care what the sums say ..it does not add up...

As to time dialation it is not proved as one would prove the acceptability of a new drug..in so far as there are not many experiments ..repeated so as to relieve the sceptical person that a quick fix has been enlisted...or simply put I dont buy it when a lot of sums are followed by only a few experiments ...

and of course that may not be my real position on the matter just pointing out an inadequacy in the proof offerred;).
alex:):):)

[xelasnave]

If my reply seems out of context ..if it is that way.. can I confess this.. I have not been on the job..rushing past the lap top .. reading this reading that..and jumping in with little time to think thru the issues.. so If I am all over the place that is why...but I am polishing my eq 6 gears... that is where my mind it...sorry for that lack of application to discussion

alex

[bojan]

Alex,
Every time you use your GPS, you have time dilatation experiment conducted and a proof is on the screen that Dr A. was right.

[bojan]

As far as dark matter is concerned..
What is bugging you probably is that everybody says it can not be seen... I agree, the whole thing is a bit mystified...
Would it help if we accept that it is only not seen yet, but its gravity effects which are measured definitely show it really exist?

[xelasnave]

Thanks Bojan..that has been put to me before and I forgot about it being offerred as hard evidence... I forgot to follow up, simply forgot, but I will try and work out how it fits in in a GPS......... I expect the speed of light when working out positions needs to be taken into account for position fixing because of the lag in transmissions... is that what they mean... anywyas I will try and track that down so I can see a working example of the theory..a practical application helps me understnad things better.

I imagine positioning would be a 4d estimate because of the time it takes for the sat to say where it is by the time the ground gets that the sat has moved on...anywyas I dont know and will look it up.

The dark matter thing frustrates me for sure.. I think it is a cop out really... and the attemps to infer its existence get to me... I just think there must be a better explaination ... and I know one can show it exists by "its" influence on sourounding matter... that is why it is there in the first place ..to explain the apparent gravitational influence of matter which must be there because if it wasnt we would not have the gravitational effects we observe... because we need matter in our sums.

The sums demand that it (dark matter)must be there because gravity is vieved as a relationship between mass..an attraction thing..

And we need the dark matter outside the galaxy so it beats me why they thought brown dwarfs or any other galactic body was relevent...the more matter you find in the galaxy only means you have to add 50 /60 % more matter outside... anyways any help you can give is always appreciated... my mind is never made up notwithsatnding I have definite views on some things.

BUt how unfortunate that I am so interested in this stuff and not foot ball say...

AND as to Dr A it must never sound like it but he is one of my heros..a role model...he is where I get my humility from;)...I never though it was a good trait in a human until I met him...and I reckon he is right..his cosmological constant is what got me first thinking of push gravity.. I worked it up from that really..I never knew it was an old idea going back to Newton's times...

alex:):):)

[xelasnave]

Re time dilation and GPS this is a site which explains it simply for any who are in the darklike me...

http://www.astronomy.ohio-state.edu/~pogge/Ast162/Unit5/gps.html

This just a snip from the page ....

Because an observer on the ground sees the satellites in motion relative to them, Special Relativity predicts that we should see their clocks ticking more slowly (see the Special Relativity lecture). Special Relativity predicts that the on-board atomic clocks on the satellites should fall behind clocks on the ground by about 7 microseconds per day because of the slower ticking rate due to the time dilation effect of their relative motion.

Further, the satellites are in orbits high above the Earth, where the curvature of spacetime due to the Earth's mass is less than it is at the Earth's surface. A prediction of General Relativity is that clocks closer to a massive object will seem to tick more slowly than those located further away (see the Black Holes lecture). As such, when viewed from the surface of the Earth, the clocks on the satellites appear to be ticking faster than identical clocks on the ground. A calculation using General Relativity predicts that the clocks in each GPS satellite should get ahead of ground-based clocks by 45 microseconds per day.

...............

So the first prediction of special realativity from above.........
we should see the sat clocks ticking slower than those on the ground.
and the second....
the on board clocks should fall behind those on the ground...
The General Relativity predicts...
the clocks on the satellites appear to be ticking faster than identical clocks on the ground...and that the clocks in each GPS satellite should get ahead of ground-based clocks by 45 microseconds per day...

What am I missing which theory do we believe or is special relativity dealing with one thing and General relativity dealing with another... one says slower and the other says faster... I am confused.

alex

[xelasnave]

So is it this..the speed of the craft makes the clocks "appear" slower (special relativity) and the bend of space time being lesser the further out you go has them actually appearing faster (general relativity)...

I can not figure it so far seems like an each way bet????

alex

[xelasnave]

I think this clears it up

The combination of these two relativitic effects means that the clocks on-board each satellite should tick faster than identical clocks on the ground by about 38 microseconds per day (45-7=38)!

alex

[Zuts]

A microsecond is an eternity (just ask my 3 gigahertz cpu) and easily measured which is why Bojan says the proof is on your gps...

Paul

[xelasnave]

I was not trying to be cute:)...

what I was saying was.. I think I am seeing how they arrive at the math overview of the situation..that there are two theories to be considered, one adds a bit and one takes away..please believe me when I say that I believe differences in time no matter how insignificant from a human experience view of the Universe are absolutely important..

and given my recognition that I am probably hard to understand at times due to verbosity I am trying to state the position in my way hoping that if I am getting it wrong someone will be good enough to point out what I am missing:D...which happens from time to time when some kind person like Bojan overlooks their frustration with my ignorance and helps me out showing me something that I need to know… and so I upgrade my ideas to fit a new understanding of a concept.

I lay awake for about three hours last night thinking this through... and it is not the first time... firstly I am never really sure what any theory really says sometimes and what it does not say.. folk express things differently and each expression of the same Idea can sound different... and at the end of every thought a little voice at the back asks me …” yes but what does that really mean...”

So is there a Doctor in the house... a condition where there is no delusion about the prospect of any reality being a delusion…it is not easy not to believe in anything and question everything.

The time dilation thing I think that is probably where I get the difficulty in understanding is the "twin paradox" ..

there is something there that seems "wrong" and I can not put my finger on it ..and until I settle whatever it is confusing me I will go around and around until I accept the idea or can overthrow it... not for any reason other than for my own understanding...

and ask that I not be grouped with all the crackpots out on the net... Once I though I was like them but they are usually just trying something to get recognition... I may have been similar once in appearance and direction but I finally realize that all I want is to understand personally and that is for me not others...so there will never be a book as they say…

I have an obsession with all this stuff..gravity mainly.. and it shows I know that.. but I find physics and particularly General relativity and Special relativity not easy to understand...its like that 3 shell game with the ball under one of the shells. every time I think I have it really worked out. and look under the shell the ball is under another... I don’t care so much where the ball is but I sure want to know how the guy moving the shell can make that ball appear under any shell he likes .......

alex:):):)

[xelasnave]

look at this:D... someone has become obsessed and written a book I dont know that it has got him or science any further ahead:shrug:..

http://home.alphalink.com.au/~jdx/muller.htm

anyways still reading other stuff about it and probably more confussed..but this was a little off track and humerous given my earlier coments about crack pot approaches ... :whistle:
alex:):):)

[xelasnave]

Is this a fair coment??? from the above site.....

In search for a causal reason of Time Dilation the author is wasting his time. Regardless of what our century believes, Einstein never gave a causal explanation of anything. The plea for a "why" concerning Time Dilation is, therefore, a futile one.
An authoritative relativist like Nobel laureate Max Born clearly expressed this when he wrote: the (length) contraction, (and time dilation), are "only a way of our way of regarding things and is not a change of a physical reality. Hence (they) do not come within the scope of the concepts of cause and effect". They are "circumstantial companions of motion", (1). No wonder John Doan could never find a rational explanation. There is none! Relativity Theory must be "swallowed" as an entire package.


alex

[xelasnave]

Is this a reasonable statement?

Thus, relativity theory, as established by Einstein can never be experimentally proven. Einstein himself admitted this. But a single experiment against it would totally disprove it. Based on this Popper created his entire philosophy of scientific falsification: theories can only be disproven, not proven

alex

[Zuts]

Hi Alex

I think time dilation is a proven fact, there are countless illustrations. Another example is the decay rate of cosmic rays (mesons). In the labratory they decay at a certain rate, however when they measure the number of particles above the earths atmosphere with those actually arriving at a detector on the surface there is a discrepancy. The 'extra' particles arriving can be accounted for by time dilation. That is in the frame of reference of the particle it is 'living' slower and has not had time to decay.

Max Born died at 88 in 1970. Well before all these 'proofs' became readily apparent. I think had he been alive today he would tell a different story.

The whole point of my mention of time dilation is simply to point out that things which appear far fetched can be absolutely true. Also, unfortunately as our knowledge of things increases and regarding many things in science, quantum mechanics, black holes etc our 'common law' understanding of what the average man thinks is reasonable no longer holds water.

What possible experience can a man have of the interactions of electrons for example, or things acting on plank scale. When dealing with the realities of these types of things our common sense cannot possibly guide us. What was possible to the Greeks regards their simple armchair philosophy of understanding everything through thought experiments alone, these days is sadly impossible.

Whether Einstein is right or wrong is moot. The fact is that time dilation is readily apparent and observable, it wont go away if Eintein is proved wrong. People in the 19th century thought the Sun gave out heat because it was a gigantic lump of Coal. Of course they were incorrect; but not about the Sun giving out heat.

Please feel free to come up with some other explanation for time dilation, however since it is completely outside the realm of everyday human sensation i dont see how you could find one that average humans would say 'oh thats obvious i see that everyday, why didnt i think of that'. Unfortunately to understand certain things these days you need a grounding in maths and physics. Once you have this grounding, exceptional individuals amongst us move on from there and conceive of things like 'dark matter'.

Paul

[xelasnave]

Dam I lost one of those long replies Paul.
I thank you for a well thought out reply.
I cant come up with a specific as to the twin thing I tried once in this forum actually but no one bought it..
Dark matter maybe there no doubt we cant "see" air yet it is there so the fact we cant see it does not by logic exclude it... however could there be alternatives to it ... the search has not been encouraging and ceratinly Hubble has some shots showing why they think it is there...

If there is a real force behind the notion of a cosmological constant maybe that produces an effect we can not yet understand... anyway a situation that we have an alternative to dark matter..

I have been reading as much as I could to day still none the wiser but a nice way to past the day nevertheless
alex

[xelasnave]

Here we go heaps of the stuff ..still cant see it however
http://www.sciencedaily.com/releases/2008/02/080221121109.htm
alex

[Karls48]

Few people stated previously that time dilation is a proven fact. It certainly is not. What is proven is that physical forces can slow or speed up clocks (and physical processes). It was known long before Einstein that rises in the temperature will lengthen pendulum and therefore slow the clock. Is it time dilation? And how does it differ from the clock on board of spaceship travelling at high speed. If I stand close to the pendulum clock that I heated up, is the time for me flowing slower? I don’t think so. That does not prove that the time itself actually slows down. No one knows what time is and if it actually exists. It may be just our invention to describe sequences of events happening.
As for GPS being practical example of GR, not really as it is using the Earth-centred inertial frame (universal frame) of reference to synchronise clock on the satellites. This is more in agreement with Lorentz relativity then GR

[bojan]

Karl,
we were not talking about temperature or whatever dependency of time base. This is an effect easily accounted for within classical physics.
We should not confuse those two totally different effects.

Here we are talking about time dilatation, the relativistic effects.
BTW, Lorenz or GR, this is the same thing, the same formulas apply, if I remember correctly my grammar school classes (maybe I do not? :P)

[Karls48]

Quote: In SR, the Lorentz transformations apply to time, space, and mass. By contrast, in LR, they apply only to clocks, meter sticks, and momentum. This is a subtle but important distinction. For example, increasing the temperature slows a pendulum clock and increases its length, yet this does not mean that something happens to time or space. Only the attempted measures of time and space using the pendulum clock, but not time and space themselves, are affected by temperature. In a similar way, in Lorentzian relativity, only the attempted measures of the dimensions time, space, and mass are affected by speed, but not the dimensions themselves. (In general relativity we find that measures of time by clocks are also affected by gravitational potential.) So in LR, equation set relates clocks and meter sticks in the preferred frame (X,Y,Z;T) to those in any relatively moving inertial frame (x,y,z;t). Time and space themselves are simply dimensions (concepts), and cannot be changed by motion, by potential, or by any material entity.
Because time is never affected, LR recognizes a “universal time” applicable to all frames, and a universal instant of “now”. In SR, all inertial frames are equivalent, so the Lorentz transformations apply reciprocally (both ways between two frames); whereas in LR, the local gravitational potential field constitutes a preferred frame, and the Lorentz transformations work just one way from the preferred frame to any inertial frame with a relative motion, but not reciprocally.


To me this theory of relativity is more logical then SR. As far I can find out it has been experimentally proved as much as GR has been. The GPS network uses preferred frame to synchronise satellites clocks, so there is some practical example of its validity.

[bojan]

As I said, both use the same mathematical expressions to calculate the effects.
BTW, this is where Einstein started from, and build his GR which is complete theory, which LR is not.
Temperature has absolutely nothing to do with this.

[Zuts]

So LR applies only to clocks and not time? Well the human body can be considered to be a clock as can many other things. Thats the point, frames in relative motion as viewed from each other appear to be living at different rates by their clocks. Of course in there own frame of reference this affect is not visible.

The pendulum is a bad example, as with respect to other objects it is different from say an unheated pendulum next to it. In an intertial frame the clock is accurate in all parts of the frame however when viewed from other inertial frames it is different.

My heart beats at 70 beats a minute so i choose that as my clock. If I measure the heartrate of someone who normally has my heartrate right next to me and it is the same then if they move (somehow) to another inertial frame and now the heartrate is different then to me that is time dilation.

There are no forces involved here to account for the difference (unless you wish to invent one) simply bodies in relative motion.

Paul

[bojan]

This is well said..
BTW, Lorentz just tried with his transformations to explain the Michaelson-Morley's experiment result (the measured speed of light turned to be equal in all directions), while still retaining the "ether".
That is why the math is the same.... but the philosophy behind it was definitely not.

[bojan]

More on this..
It certainly is the case.
As it was mentioned before, the relativistic mesons that are reaching the surface of the Earth, they would not be here if not for time dilatation, which (from our point of view) prolongs their half-life and enables them to penetrate deeper int our atmosphere before they decay.
Also, time dilatation it is the routine for people working with particle accelerators, in the same sense as is the mesons presence.