PDA

View Full Version : Yet another Speed Limit...


joy ride
23rd Jan 2015, 14:45
BBC News - Scientists slow the speed of light (http://www.bbc.co.uk/news/uk-scotland-glasgow-west-30944584)

ORAC
23rd Jan 2015, 16:22
The speed of light is the speed of light....... But it varies according to the medium, it's different in water to in a vacuum, and scientists have previously slowed it to 38mph. (http://abcnews.go.com/Technology/story?id=99111)

joy ride
23rd Jan 2015, 16:33
The difference with this experiment is that once the light is back in free space (e.g. after slowing down as it passes through water) then it carries on at the same slower speed rather than going back to c.

Kelly Hopper
23rd Jan 2015, 17:58
Begs to ask the question that if light is not a constant and the universe is measured in light years, is it possible that the universe could be much much smaller or bigger than we think?

Loose rivets
23rd Jan 2015, 18:11
Everything I say here is based on unrefreshed memories.

I seem to recall every colour telly in the old days had a delay line made of a lump of glass. The thing is, the photon coming out of the glass is not the same one that went in. However, when the new one came out, it would accelerate to the limit in the local medium a bit sharpish like. In fact, it seems as though a photon is born at the speed of light.

It was for this very reason that Richard Feinman dared to look at the first atomic explosion with only a lorry's windscreen to protect his eyes. As it happens, he threw himself to the floor with a huge mauve blotch on his vision.

So, changing it's shape? Mmmm . . . new thoughts for my next yarn.


"The experiment is likely to alter how science looks at light." :ooh:







.


..

onetrack
24th Jan 2015, 04:59
Ah, LR .. that would be Richard Phillips Feynman, as the scientist of which you speak?

Hempy
24th Jan 2015, 07:11
Speaking of this 'astronomical', if this doesn't make you feel insignificant you must have a powerful ego

udAL48P5NJU

Pinky the pilot
24th Jan 2015, 07:24
Hempy; Thanks for posting that.:ok::ok:

Simply breathtaking and awe inspiring!

And Andromeda is but one of possibly billions of galaxies. And amongst all of them, in our galaxy of the Milky Way our planet is the only one with so-called Intelligent Life, and all of this was formed from nothing, purely by chance! No 'Intelligent design' or created by a God.:ooh:

Yeah, right!:rolleyes:

ORAC
24th Jan 2015, 08:02
Hempy; Thanks for posting that.

Simply breathtaking and awe inspiring!

And Andromeda is but one of possibly billions of galaxies. And amongst all of them, in our galaxy of the Milky Way our planet is the only one with so-called Intelligent Life, and all of this was formed from nothing, purely by chance! No 'Intelligent design' or created by a God.

Yeah, right!

If it makes you feel better to believe in an invisible loving being is responsible, fell free, it appeals to something atavistic in human nature. For myself, it's the sheer hard cold scale and indifference of the universe which fills me with awe.

Nightfall (https://www.uni.edu/morgans/astro/course/nightfall.pdf) by Isaac Asimov

...........With the slow fascination of fear, he ifted himself on one arm and turned his eyes toward the blood-curdling blackness of the window.

Through it shone the Stars!

Not Earth's feeble thirty-six hundred stars visible to the eye; Lagash was in the center of a giant cluster. Thirty thousand mighty suns shone down in a soul-searing splendor that was more frighteningly col in its awful indifference than the bitter wind that shivered across the cold, horribly bleak world.

Theremon staggered to his feet, his throat, constricting him to breathlessness, all the muscles of his body writhing in an intensity of terror and sheer fear beyond bearing. He was going mad and knew it,and somewhere deep inside a bit of sanity was screaming, struggling to fight off the hopeless flood of black terror.

It was very horrible to go mad and know that you were going mad -- to know that in a little minute you would be here physically and yet all the real essence would be dead and drowned in the black madness. For this was the Dark -- the Dark and the Cold and the Doom. The bright walls of the universe were shattered and their awful black fragments were falling own to crush and squeeze and obliterate him.

He jostled someone crawling on hands and knees, but stumbled somehow over him. Hands groping at his tortured throat, he limped toward the flame of the torches that filled all his mad vision. 'Light!' he screamed.

Aton, somewhere, was crying, whimpering horribly like a terribly frightened child. 'Stars -- all the Stars -- we didn't know at all. We didn't know anything. We thought six stars in a universe is something the Stars didn't notice is Darkness forever and ever and ever and the walls are breaking in and we didn't know we couldn't know and anything -- '

Someone clawed at the torch, and it fell and snuffed out. In the instant, the awful splendor of the indifferent Stars leaped nearer to them.

On the horizon outside the window, in the direction of Saro City, a crimson glow began growing, strengthening in brightness, that was not the glow of a sun. The long night had come again.

joy ride
24th Jan 2015, 09:10
The cold godless universe is indeed a bleak concept, but it is the version I accept.

If only someone could write down a lot of key facts about it in an easy to understand form. If put to music this would be great, and if it was made funny how much better the universe would be!

Oh wait a mo, Eric Idle has done it!


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

it's worth googling the lyrics, IMO you have to be pretty clever to write a song like this, big respect Mr Idle!

onetrack
24th Jan 2015, 09:33
When a smart scientist produces the exact formula for eternal life, I'll cease believing in a vastly more intelligent God, who made the Universe and all that is in it.
The more scientists look, the more they find out, and they haven't even touched on .0000000000000000001% of Gods knowledge.
The scientists still can't even find the edge of the Universe - surely that should be a piece of cake for these superior beings? :suspect:

A bloke pointed out a simple rationale to me the other day.
Earth is the rotten jail of the Universe. Our planet is a general No-Go area for anyone but Earthlings born here. A kind of Compton (CA), or Preston (Lancs), or Lakemba (NSW) of the universe.
Mankind did wrong from the Word Go - and ever since, mankind and his/her offspring have had to languish in this lousy, crime and hatred-filled prison, until Death takes us, and we have served our Time.

As with all jails, this place has some good things - and a lot of bad things. One of the bad things is the number of intelligent people who are so arrogant they think they alone have all the knowledge that exists, and that their study of science and physics will provide all the answers.
In that much-touted belief, they could not be more wrong.

Loose rivets
24th Jan 2015, 12:18
ORAC, is that a direct cut and paste of Asimov?



Re this creation of the Universe thing. It often sounds as though people imagine God carefully creating each planet, moon and star. Also, giving thought to every species, with us 'just one grain in a desert of species.' (to quote myself) I don't think this is the case at all.

I imagine life and (oh, go on, let me say it one more time) The Perfect Code that made us is just one piece of creative design. That's it. One piece of code, but one that's fighting its way back to perfection . . . despite everything mankind seems to do to stop it.

As for the universe we happen to find ourselves in. Well, that may, or may not, have been intentional. My guess would be it may have been designed to be rather smaller, in fact, minute by comparison, but the algorithm just ran and ran until it became 'inconveniently large.' After all, it does seem that spacetime was self fueling - at least until the end of the Inflationary Period.

My notions are not important in their specific content. What is important is that we seek out modern interpretations of what can be sensed, with whatever tools we can build - and this includes an in depth study of ancient knowledge.

My guess would be that we are in for a lot more surprises.

G-CPTN
24th Jan 2015, 13:11
I heard a 'scientist' describing how particles drifting in space collected and formed comets.
She suggested that these were the beginnings of planets like Earth (something that I could believe), but what is the origin of the stars (ie the multitude of suns which are active nuclear reactions)?

Oh, and, as mentioned above, if Earth is, perhaps, the only inhabited planet, why was it chosen?

Why didn't the Creator equip all similar planets with beings?

Just asking . . .

Hempy
24th Jan 2015, 15:31
All this 'creation' thing makes me laugh. I have a question..

Why does there have to be a 'beginning'?



That's just a human limitation. EVERYTHING needs to be 'created' right?

Why?

There is a theory that suggests that the 'big bang' wasn't a one-off event. The Universe expands until its own gravity slows it down to the point that it starts contracting again. Then we all get sucked back to a single origin point - when BANG, it all starts over again.

Infinitely.

(I like this theory. Theoretically, when the Universe contracts time goes backwards. It might also explain déjà vu :} )

Even if there was only one 'bang', the question asked is 'so what was there before the big bang?'

Tell my why there has to be a 'before'?

Loose rivets
24th Jan 2015, 16:16
Because it would be very difficult to structure any pre-big bang theory without the concept of absolute time. Such a 'Time Absolute', would let us analyze Relativistic time with greater accuracy . . . if only God would let us borrow his clock.

Loose rivets
24th Jan 2015, 16:28
How do you pronounce proselytising? I thought it was pros lee tizing.

Smudger
24th Jan 2015, 18:53
There is no God.... seemples

OFSO
24th Jan 2015, 19:03
if this doesn't make you feel insignificant you must have a powerful ego

Thanks Hempy. However, no it doesn't make me feel insignificant since I'm the centre of the universe, at least as I'm concerned. How else could it be ? My sensory devices (such as they are) are implanted in my head which is on top of my body, therefore to me I'm in the centre of a sphere with everything external to me on the inner surface of that ball.

One day, I'll be dead and it won't be; until then, it is.

Hempy
25th Jan 2015, 02:07
Yeah, but that's just you speaking for you. My original assertion still stands.

joy ride
25th Jan 2015, 09:22
It is my opinion that no matter how much we ever learn about energy, light, matter etc., we will always find deep or smaller levels of mystery, and have to develop ever-more complex devices to extend our knowledge. The LHC has answered some questions but more new ones have sprung up!

I doubt we will ever be able to prove or disprove that some form of divine intervention was involved in creating the universe/multiverse/omniverse.

Even if science ever proves that the universe created itself spontaneously without any divine force being needed, perhaps a god was created as part of big bang! From what we know I feel it is equally possible to argue for or against god, because neither case is proven and probably never will be. For myself, I stopped believing in god at 8, long before I got interested in the science!

ruddman
25th Jan 2015, 09:44
Who said there was a Big Bang? They've been plenty of 'big bangs' here on earth which has already has the needed things for life. Result? No order. No laws put into place. No structure or life. Just destruction.



Man is foolish thinking he knows anything about the universe, life and it's beginning. Somebody mentioned ego. Hard to see facts when you're blinded by 'scientific' ego.

joy ride
25th Jan 2015, 10:34
I reckon that scientific ego has an exact equivalent in religion; I don't fully trust or believe either!

ruddman
25th Jan 2015, 10:38
Same. But I believe what the Bible says. Big difference. :)

oldchina
25th Jan 2015, 10:59
"Same. But I believe what the Bible says. Big difference"

Wow, do you really, honestly, believe that bible stuff? I thought folks like that went out with the Dodo.

joy ride
25th Jan 2015, 10:59
I respect people's opinion even if I don't agree with it.
"To each his/her/its own!"

ruddman
25th Jan 2015, 13:46
Yeah. I studied evolution and found you needed more faith to believe in that idea.
The Bible is amazingly accurate.


But whatever floats your oragami boat.

ehwatezedoing
25th Jan 2015, 14:39
Yeah. I studied evolution and found you needed more faith to believe in that idea.
The Bible is amazingly accurate.


Faith:

http://www.sunnyskyz.com/uploads/2014/04/vonzh-how-planes-fly.jpg

Smudger
26th Jan 2015, 14:55
I'll have a pint of whatever OFSO is drinking lol

Carry0nLuggage
26th Jan 2015, 18:15
Man is foolish thinking he knows anything about the universe, life and it's beginning. Somebody mentioned ego. Hard to see facts when you're blinded by 'scientific' ego.

Wait a minute! Doesn't the Bible tell us everything we know about the universe? It is after all amazingly accurate :confused:

KenV
26th Jan 2015, 18:36
There is a theory that suggests that the 'big bang' wasn't a one-off event. The Universe expands until its own gravity slows it down to the point that it starts contracting again. Then we all get sucked back to a single origin point - when BANG, it all starts over again.

Infinitely.


You do realize that the above is a totally obsolete theory for the final fate of our universe? First of all, there is no mechanism to produce the hot dense singularity that lead to the Big Bang. The expansion of the Big Bang was extremely uniform. There is no way to contract uniformly the way the universe expanded uniformly. Entropy would cause the universe to clump as it contracted, forming countless black holes that would eventually coalesce to form one big black hole.

Second, way back in 1998 lots of careful measurements were taken to determine which of the two possible fates our universe would experience:
1. Is there sufficient mass in the universe to slow its its current expansion quickly enough (in other wards, is the escape velocity of the universe greater than its expansion velocity) to lead to a contraction and ultimately a "big crunch" back to the primordial singularity?
2. Is there insufficient mass in the universe to cause a contraction (in other words, is the escape velocity of the universe less than its expansion velocity) and thus result in our universe continuing to expand into a diffuse nothingness of infinite entropy. Also called the big freeze.

As it turns out BOTH outcomes were totally wrong. The universe's expansion is ACCELERATING. Somewhere out there is the equivalent of "anti-gravity" (more correctly, dark energy with negative pressure is spread uniformly throughout the universe) that is overcoming the gravitational attraction of ALL the mass in the universe, which is about 5% ordinary matter and 27% dark matter (which we cannot detect by any means we know of).

KenV
26th Jan 2015, 18:43
Ruddman: Same. But I believe what the Bible says. Big difference. :)


Interesting. I'm a preson of faith also, who believes in the Bible AND the Big Bang. In my opinion, it takes huge religious ego/arrogance to believe your interpretation of the Bible is the only correct one.

Loose rivets
27th Jan 2015, 02:13
KenV The thing about a collapse is that at some stage - if it is to be the reverse of the Big Bang - all the rules of the Standard Model will become invalid. Having said this, I've never been impressed with the Big Crunch models.

In one of my fits of enthusiasm, I mistook the Great Attractor for the overall reason for the acceleration of the fabric of space. A very qualified person put me right. Despite that moment of confusion, I think spacetime is a self-fueling three-dimensional matrix of something and it's not really surprising it is springing apart with a seemingly greater rate. Okay, now I've got to explain, 'seemingly'.

Stop groaning, you lot.:*

I fear it needs another of my rambles about gravity, but anyway, this variable speed photon has just entered stage left and thickened the plot.

Next time you’re riding a bike down a hill, consider the smoothness of the force that’s carrying you faster and faster, the inescapability from its clutches, and the one-wayness of this something we’re told we should not refer to as a force at all. It’s a bewildering mystery that causes us to expend unholy amounts of money on rocket power and making it necessary to buy expensive mattresses.

A few weeks ago I spotted an article by an astrophysics professor in the US. It was about fluid spacetime. I was somewhat excited about it and asked his permission to send him a 40 year old idea of mine along with how it might be germane to his hypothesis. I didn't think it wise to pen more than an outline, and frankly it's not going to impress a professional with twice my number of brain cells, but the notion of spacetime being perfectly fluid is a total requirement to my model of how gravity works.

BTW, I was introduced to a wonderful diagrammatic image of the fabric of space by someone here on JB. From plumbing to astrophysics all on one forum! Never cease to be amazed, but whatever, the Higgs' field, fluid spacetime or gravitational lensing, all seems to make it clear that quite a few folk see space as a very malleable something - a something that at first seems to be distorted by mass, but on reflection could be flowing into matter to allow the existence of particles in the first place.

Only one other person on this planet, at least that I know of, has suggested such a fluid structure is flowing into matter. A peer review of that paper was not very encouraging and one rebuttal was ‘I’m not sure where all this spacetime is going.’ I wrote to that reviewer - another American PhD - with what I thought might be the answer.* The reply was the rudest e-response I’d ever received, and that’s including JB.:ooh: It was obvious he’d only read the first few words before going into hyper-spuffle. It was my fault perhaps, I had started by listing my early thoughts, building to the present model. Three lines at the most, but enough to send him into a fit and not read the developed thought at all. Lesson must be: an accurate hook with the first few lines or die.

Now, with this latest news, we seem to have a photon following a different set of rules because it has been changed in some way? It seems it becomes unable to tune to the Universe in a way that will allow optimum speed? Optimum? Now we have to question that. It might be that even the photons we know and love are not in the ultimate state of tune. Perhaps we could modify them in some way that would see them going faster than . . . than . . . now what the heck are we going to say? Faster than common-or-garden light? Faster than Bog-standard light? I suppose c will have to do, and c+ for fast light. Mmmm, Microsoft will never allow that.

So, is a photon somehow locked, or better still, tuned, to some sort of fabric of spacetime? Given we accept some of the photons passing our planet have traveled 41 billion light-years in a sub 14 billion year-old universe, it makes it even harder to understand how their energy is maintained. Perhaps they feed on the Universe, a finely balanced input and energy expenditure. Perhaps . . . buggah, I've run out of words.:rolleyes:


* My answer to where all this spacetime might be going is simply that space, and every particle in it, is changing scale – spacetime feeding this change of ‘scale absolute’ in particles.

Hempy
27th Jan 2015, 02:39
As it turns out BOTH outcomes were totally wrong. The universe's expansion is ACCELERATING.

...at the moment...

Unless someone has decided the ultimate potential age of the universe and has plotted our present position on the timeline?

In fact the fact that the universe is still accelerating is the basis for the 'My Pretty Pony' 'theory'..the more time passes the faster time passes, i.e time acclerates with the universe (and theoretically vice versa :E)

Which sucks, but explains why I had heaps of time as a kid but now wonder where the days go :}

AnAussieNut
27th Jan 2015, 03:10
"So remember, when you're feeling very small and insecure,
How amazingly unlikely is your birth,
And pray that there's intelligent life somewhere up in space,
'Cause there's bugger all down here on Earth."

Hehehehe,brilliantly funny I reckon.

As for the speed of light? well I know bugger all really..apart from the fact that I'm glad it's pretty constant when I have a go in the flying school's PA-38 'cause at this point I still need lots of it to know where I'm going!:)

Interesting thread.

Cheers
Paul

Oh and apparently I should say sorry for posting aviation content on JB:E

Choxolate
27th Jan 2015, 12:41
Ruddman > The Bible is amazingly accurate.

How do you know? Can you give an example of something the Bible says that is "amazingly" accurate?

KenV
28th Jan 2015, 16:29
Ken: As it turns out BOTH outcomes were totally wrong. The universe's expansion is ACCELERATING.

Hempy: Unless someone has decided the ultimate potential age of the universe and has plotted our present position on the timeline?



Assuming that space itself is the source of the negative pressure that is resulting in the acceleration, then as the universe expands the acceleration accelerates resulting in an exponential expansion. Theoretically the expansion of the universe will reach the speed of light and the universe will literally cease to exist. The very particles that make up matter will no longer be able to interact and everything will sort of wink out. This theory (called the "Big Rip") calculates that would happen about 22 billion years from now.

rgbrock1
28th Jan 2015, 16:30
KenV wrote:

will reach the speed of light and the universe will literally cease to exist

The Universe we know of, yes. (The Visible Universe or what have you.)

There are others, I'm sure.

KenV
29th Jan 2015, 14:34
The Universe we know of, yes. (The Visible Universe or what have you.)

There are others, I'm sure.


Seems to me we've got more evidence of the existence of god than of the existence of parallel universes. And we all know what a hamsterwheel any discussion of god is.

Hempy
29th Jan 2015, 16:20
Perhaps he just has faith in parallel universes?

KenV
29th Jan 2015, 18:15
Perhaps he just has faith in parallel universes?

Clearly.

And as an aside, it takes a whole heap of faith to believe in the conjectures/assumptions in Hawking's latest book that purports to prove that god(s) are not required to explain the existence of our universe.

Loose rivets
30th Jan 2015, 01:24
My guardian angel and I are going to have a jolly good laugh about that tonight.

Hempy
30th Jan 2015, 09:21
Pretty sure some ppruners contributed to some of these.

gW7607YiBso

nsfw