I felt sad after this video .

[Bobbyoutback]

After you watch this you may also .

https://www.youtube.com/watch?v=55pcpTjd3BY

Nobel laureate Brian P Schmidt ~ The accelerating Universe .

Hope you are humbled & thrilled like I was '''' !


Bobby

[billdan (Bill)]

Thanks for posting this video Bobby, I have seen similar videos showing the future of the Universe.
This is the first time I have seen the speculation that eventually Dark Energy will rip all the atoms apart leaving a Universe filled with just Dark Energy, Quarks and Neutrinos.

[xelasnave]

If we were to accept that gravity is not attractive but acts as a pressure system, in other words manifests from the various particles and radiation out there "pushing" we perhaps would not need dark energy or dark matter...a clue may be that dark energy is seen as a form of gravity that is pushing and it is recognised as the major force .....drop the idea that a force of attraction exists and I suggest such an approach will explain the observations..particularly the perplexing rotation curves of stars that suggest the presence of additional matter that is required to get a model that essentially relies upon the notion that attraction exists to work..if one could construct a model that assumes gravity is essentially a "pushing" of particles and radiation I bet the need for dark matter would disappear.
It just seems unacceptably counter intuitive that there could exist so much matter that is hidden from us.
Alex

[bojan]

Alex...
You know what I think of this pushi-trons :-)
This idea was debunked long time ago..

[bojan]

Originally Posted by Bobbyoutback

After you watch this you may also .

https://www.youtube.com/watch?v=55pcpTjd3BY

Nobel laureate Brian P Schmidt ~ The accelerating Universe .

Hope you are humbled & thrilled like I was '''' !


Bobby

Why sad? It is just what things are.. or what we think/know at the moment what things are.

Fascinating, nevertheless.

[xelasnave]

Originally Posted by bojan

Alex...
You know what I think of this pushi-trons :-)
This idea was debunked long time ago..

I know Bojan.
But I feel it is no more strange than the notion of unseen matter that has mass in my humble view.
Think of the many popular concepts that have been shown to be incorrect, ulcers being caused by stress for example...the folk invested in the notion of stress as a cause could offer many reasons why ulcers were not caused by bacteria and yet there came a point where the stress cause was debunked.
I can only wish that I could build a computer model where I could replicate the model I can hold in my mind. IF one could construct a 3d model (on a 2d screen) with near infinite trajectories passing thru every point I have no doubt the effect on a model galaxy would behave as observed in reality.
I could be wrong but I see it so clearly.
Why can my use of hypothetical as yet undiscovered particles be any more fanciful that believing there are particles (I use this term to describe what ever it is that makes my hypothetical push) that constitute a dark matter.
Dark matter is required on the assumption that GR applies..it may not perhaps...why can we nominate dark energy , which is I feel no more than a manifestation of pushing gravity, ..And then ignore that in that case gravity appeared to be pushing.
Anyways don't think I reject GR as it does not see gravity as a force and when it all boils down is a co ordinate system and really does not offer a mechanical explanation of how space is bent etc. All I try do do is understand what may go on at a particle level.
I suppose I am trapped in that place where facts will not change my belief.
Think of the rotation curves for example..if driven by an external force I am sure we would find why the outter stars would behave as observed..
A push gravity would have close bodies being "pushed" together and distant bodies moving away from each other...
I will leave it there as I don't think about it much these days.
Alex

[bojan]

One problem with push*trons is you require infinite flux (IMO) of them at any point of space to explain black hole concept (which is not concept any more as they were (almost) directly observed)...

You are tied too much to conventional thinking of "force", which is based on observation of the world by our existing senses (which were evolved as good-enough solution to ensure our survival as species) but are totally inadequate to grasp the other levels of reality (think of quantum mechanics.. how THAT fits to your understanding? And then think about everyday techology that we are using, development of which would have been TOTALLY impossible without accepting completely counter-intuitive concepts of QED..)
As to GR.. GPS wouldn't work without it.

[xelasnave]

Well think of a single point. The number of trajectories thru a point would seem geometrically infinite...then the particles or waves that travel along each trajectory even if a single particle each minute I expect would give a near infinite flux,
I wonder how many nutrinos travel along each and every tradjectory...

A black hole is where all the pu****rons stop

I am indeed tied to the force notion or at least to a vague expectation that at some level things fly about that carry information and my view is that without something along those lines we can only be left with magic.

GR doesn't like a mechanical explanation that much is clear but surely there must be something physical that passes information...And at a basic level bumping into something passes information.

Well I must be good at quantum mechanics as it is said that if you think you understand it than you are mistaken...And I don't understand it

I think the mystery attactched to quantum mechanics reflects nothing more than we just don't know some things..however it seems that with uncountable particles flying about we get to resort to probability.. sure we may not be able to tell much about a specific particle and many may do the unexpected but it can be expected based on assessment of the probability that not withstanding an suggested confusion a result can be determined ..I expect that even with the flow of electrons in a simple circuit, if we could follow them all it would show some outside the circuit going somewhere that a strick interpretation of a circuit would suggest does not happen but the probability is most follow the expected path such that strays are irrelevant.
And of course our technology is reliable because all of it is built on tested scientific models.. I could have a scientific model that says super nova are produced by goblins and it would be acceptable so long as I could predict the next super nova...extreme example but the point is the understanding of reality could be different to the reality if the model makes correct predictions.

GR and GPS...sure thing but does that eliminate a different approach?

I have seen various claims that positioning can be done by other methods and given that GR is a co ordinate system I would expect there is perhaps other co ordinate systems that can deliver GPS...I don't know however.

All I attempt to do is look for how mass tells space how to bend ...what information travels from the mass to tell space what to do...there must be something and I merely speculate on how such may happen.

But I know the difference between speculation and science models.
I have no illusions.
Thanks for the chat.
Alex

Bojan what do you think about this?
There is another part that is easy to miss notes at the end .
Alex http://www.alternativephysics.org/book/GPSmythology.htm

[bojan]

Alex,
I need to read what's there carefully, it will take some time for me to devise the accurate reply (because it will have to involve some more complicated math... ).

For the start, we can say the following:
In mobile phone, signal processing block does something called "derotation" of the received signal before de-coding into useful data.
Basically this is frequency sync with base-band signal, so the decoding could become possible.


I suppose the similar technique is used at GPS receiver-- so there is no need for atomic clock in mobile phone, and yet it is still possible to have the same timing accuracy as there was one present.
As you know, atomic clock uses electron orbitals energy level diferences as time base for its operation.
Due to GR, it runs faster in orbit compared to the one running on Earth surface (this is the fact, confirmed independently from GPS).

Also, Doppler effect plays the most significant role in positional accuracy.

I think the correction needed for all the above to achieve the required GPS accuracy of the position is not so simplistic as suggested by the website you linked.

[bojan]

Also, have a look here:
http://www.astronomy.ohio-state.edu/...Unit5/gps.html


The article also mentiones time dilation due to relative speed of the GPS satelites..



All depends on how accurate you need to know your position.

[xelasnave]

Thanks Bojan.
I don't like to think about SR and GR as when I do I feel there is something wrong that I can't nail down.
GR not so much but SR...mmm how can I put it...the clock ticks away at whatever rate..but the observer see it differently...it would seem the actual tick rate is one thing ..that is real but the observation is a perversion of the reality..damn it it is like trying to hold an eel...so I feel that any adjustments for SR must be at the observer's end..ie don't touch the clock being observed...whereas for GR the position is probably the reverse..but I am worn out think about SR..I mean thinking about it rather than merely accepting the premises we are told.
There is something I can't put my finger on...the reality...tick rate..And the illusion..the observed tick rate....the observer is seeing a mirage maybe.
The second part of the link I provided makes a claim that the subjected input or lack thereof of SR and GR is nothing like that claimed. I wonder if that claim is valid as I become suspicious of any side that makes exaggerated claims..someone is telling pork pies...how do we work out what nano seconds translate to in terms of error... just be easy math... who is fibbing... the guy who wrote the article or the advocates of SR and GR s importance to GPS.
How do we work out what one nano second error does to position.

Alex

[bojan]

S = t*c...


1 ns equals ~30cm
see here:
https://www.convert-me.com/en/conver...nanosecond&v=1

[Bobbyoutback]

Hello Bill & Bojan ,
Pleased you both found Brian's lecture thought provoking .

I would have preferred a fairy story ending but alas I'll have to except the sad one for now

Have Fun
Bobby .

[leon]

I did read all the comments made, however i am not a movie fan, and would not spend 49-50 minutes watching a video on YouTube in a forum.

Man, i hardly even watch TV, other than the news, and that is all fake news ?? ask Donald, he knows

However when Bojan came up with the math, i was inspired

Leon

[xelasnave]

Thanks Bojan.

And thanks Bobby for posting the link I enjoyed the video a great deal.

Alex

[Bobbyoutback]

Originally Posted by xelasnave

Thanks Bojan.

And thanks Bobby for posting the link I enjoyed the video a great deal.

Alex

Pleased you did Alex , have you ever asked yourself ~ whats the point of existance

Bobby .

[xelasnave]

Originally Posted by Bobbyoutback

Pleased you did Alex , have you ever asked yourself ~ whats the point of existance

Bobby .

I have never asked such a question perhaps because I happily feel there is no point to existence so I guess coming from that position the question would not occur to me.
If I were asked I would answer with the question ..why should there be any point if there is no defined purpose?

I do find it amusing to hear folk asking, with considerable concern bordering upon anxiety, "why am I here?" referring to their historical placement as opposed to their position on the Earth but a question seeking definition of point or purpose.

Presumably their opinion of their significance far out weighs any view I would hold of myself.

Their insignificance escapes them I imagine.

But does escape them most certainly when they are considered as only one in approx seven billion humans alive and most certainly when put umoungst the countless kings, queens , rulers, great men and women, heros and villains through history or the countless millions who have died in war or famine or disaster indeed all humans that have ever lived.

And they can ask their question as if they are some how special.

And often some invent an entity that comes out of eternity to build a presumably finite universe just for them..one must wonder how long this entity spent in eternity before being struck with the idea to pop out to create a universe for his little pets....and if asked these folk can also invent a purpose but as they answer I would love to ask ...so what was the point or purpose of those countless millions who have died in war or famine.....

Alex

[bojan]

Originally Posted by Bobbyoutback

Pleased you did Alex , have you ever asked yourself ~ whats the point of existance

Bobby .

There is no point to existence (of universe and us..) .. but it is consequence of laws of nature.. simple as that.
Lets enjoy this fact and take care of each other, because our time in being in existence is precious to us only.

[billdan (Bill)]

Whats the point of existence? - The pursuit of happiness without upsetting other people.

[Bobbyoutback]

Alex , Bojan & Bill ' I liked all your comments regarding - the point of existence .



So thank you
Bobby.