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(Medium)   Speed of light needs correcting after photons outpaced by neutrinos. Speed of dark unchanged   (medium.com ) divider line
    More: Interesting, neutrinos, supernovas, Einstein, speed of light, fine structures, weak forces, astronomers, virtual particles  
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3341 clicks; posted to Geek » on 25 Jun 2014 at 3:53 PM (2 years ago)   |   Favorite    |   share:  Share on Twitter share via Email Share on Facebook   more»



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2014-06-25 02:23:39 PM  
That was a thoroughly interesting read.  Thank you for applying the right tag to it. Given the (unstated in TFA) distance of 168000 light years to SN1987a, the 4.7 hour differential represents a 3.2E-7% difference in the predicted versus observed light arrival time.

Significant for astrophysicists, certainly, and would represent an error of 41 years in the estimated 13B year age of the universe.
 
2014-06-25 02:45:23 PM  

factoryconnection: That was a thoroughly interesting read.  Thank you for applying the right tag to it. Given the (unstated in TFA) distance of 168000 light years to SN1987a, the 4.7 hour differential represents a 3.2E-7% difference in the predicted versus observed light arrival time.

Significant for astrophysicists, certainly, and would represent an error of 41 years in the estimated 13B year age of the universe.


Here we go again, revising history.
 
2014-06-25 02:47:22 PM  
The "Speed of Neutrinos" doesn't have the same zing, though.

/seriously, way cool article
 
2014-06-25 03:06:51 PM  

This About That: factoryconnection: That was a thoroughly interesting read.  Thank you for applying the right tag to it. Given the (unstated in TFA) distance of 168000 light years to SN1987a, the 4.7 hour differential represents a 3.2E-7% difference in the predicted versus observed light arrival time.

Significant for astrophysicists, certainly, and would represent an error of 41 years in the estimated 13B year age of the universe.

Here we go again, revising history.


"Science" got it wrong again.  You know what never changes?  The Bible.
 
2014-06-25 03:18:22 PM  

factoryconnection: That was a thoroughly interesting read.  Thank you for applying the right tag to it. Given the (unstated in TFA) distance of 168000 light years to SN1987a, the 4.7 hour differential represents a 3.2E-7% difference in the predicted versus observed light arrival time.

Significant for astrophysicists, certainly, and would represent an error of 41 years in the estimated 13B year age of the universe.


Or about 10 minutes in the 6000 year Biblical age. ;)
 
2014-06-25 03:55:56 PM  
We finally discovered that bad news is made out of neutrino particles.
 
2014-06-25 03:56:13 PM  
Didn't professor Farnsworth talk about this?
 
2014-06-25 03:56:58 PM  
Um....

Considering that the 'speed of light' (IE, the speed of photons) slows down inside a physical medium like,
say, interstellar dust clouds, whereas neutrinos can zip through almost all intervening matter, I don't see
why the theory of relativity needs to be revised in any way.

But I'm not a scientist.
 
2014-06-25 04:00:22 PM  

DjangoStonereaver: Um....

Considering that the 'speed of light' (IE, the speed of photons) slows down inside a physical medium like,
say, interstellar dust clouds, whereas neutrinos can zip through almost all intervening matter, I don't see
why the theory of relativity needs to be revised in any way.

But I'm not a scientist.


Plus, if it's a supernova, if I Remember right, the neutrino burst occurs *BEFORE* the visible light from the explosion, *because* while the photons are working through all the other gunk that's going to explode (The plasma), the neutrinos, well, don't.

Perhaps the revising isn't "Relativity was wrong!", though, and more "The 8th digit of the speed of light neds to be turned from a 5 to a 6" or something.

/Note: I am not a cosmologist, my field of physics is nano-phsicys/engineering/synthesis.
//Goddamnit nanorods, STICK TO THE GODDAMN SUBSTRATE, I AM FOLLOWING THE PROCEDURE.
 
2014-06-25 04:03:05 PM  
"Speed of Dark" sounds like a biatchin' title for a metal album.


timujin: This About That: factoryconnection: That was a thoroughly interesting read.  Thank you for applying the right tag to it. Given the (unstated in TFA) distance of 168000 light years to SN1987a, the 4.7 hour differential represents a 3.2E-7% difference in the predicted versus observed light arrival time.

Significant for astrophysicists, certainly, and would represent an error of 41 years in the estimated 13B year age of the universe.

Here we go again, revising history.

"Science" got it wrong again.  You know what never changes?  The Bible.


What about the New Revised Standard Version?
 
2014-06-25 04:05:52 PM  
But the speed of love is still the same right?
 
2014-06-25 04:07:04 PM  
Also, submitter: Huzzah for the pratchett reference (Or, at least, so I assume)
 
2014-06-25 04:07:14 PM  

ghall3: But the speed of love is still the same right?


I don't know what the speed is, but the time hasn't changed: About 2 minutes.
 
2014-06-25 04:10:28 PM  

Felgraf: Plus, if it's a supernova, if I Remember right, the neutrino burst occurs *BEFORE* the visible light from the explosion, *because* while the photons are working through all the other gunk that's going to explode (The plasma), the neutrinos, well, don't.


^

This was even covered on an episode of Cosmos.
 
2014-06-25 04:14:09 PM  

skozlaw: Felgraf: Plus, if it's a supernova, if I Remember right, the neutrino burst occurs *BEFORE* the visible light from the explosion, *because* while the photons are working through all the other gunk that's going to explode (The plasma), the neutrinos, well, don't.

^

This was even covered on an episode of Cosmos.


The article does account for that. Based solely on the supernova the neutrinos should have arrived 3hrs earlier not 4.7.

But I didn't see anything about other matter slowing the photons down on the way to us which seems more likely to me, but I am only a failed astrophysicist.
 
2014-06-25 04:15:13 PM  

Felgraf: DjangoStonereaver: Um....

Considering that the 'speed of light' (IE, the speed of photons) slows down inside a physical medium like,
say, interstellar dust clouds, whereas neutrinos can zip through almost all intervening matter, I don't see
why the theory of relativity needs to be revised in any way.

But I'm not a scientist.

Plus, if it's a supernova, if I Remember right, the neutrino burst occurs *BEFORE* the visible light from the explosion, *because* while the photons are working through all the other gunk that's going to explode (The plasma), the neutrinos, well, don't.


Know how I know you didn't read the article?
Neutrinos and photons both travel at the speed of light and should therefore arrive simultaneously, all else being equal. The mystery is what caused this huge delay of 7.7 hours between the first burst of neutrinos and the arrival of the optical photons...
First, some background about the mechanism behind the supernova. A supernova begins with the collapse of a star's core, generating both neutrinos and optical photons. However, the density of the core delays the emergence of the photons by about 3 hours. By contrast, the neutrinos interact less strongly with matter and so emerge unscathed more or less immediately...
But the timing is still a puzzle. The optical photons should have arrived about 3 hours after the first burst of neutrinos rather than 4.7 hours after the second burst.
 
2014-06-25 04:17:36 PM  
In the absence of any explanation, astrophysicists have simply ignored this burst, saying that it cannot have been associated with the supernova and must have been a flukish coincidence. That's despite the chances of such a coincidence being something like 1 in 10,000.

Not to piss on anyone's parade, but given that there are 300 billion stars in our galaxy, a 1 in 10,000 chance would happen 30 million times.

I don't know what that translates to in this case, but you know how they talk about long odds as "astronomical"? Because shiat that "doesn't happen often" happens all the damned time somewhere in the universe.

// the quantums are probably to blame
 
2014-06-25 04:18:58 PM  

Felgraf: DjangoStonereaver: Um....

Considering that the 'speed of light' (IE, the speed of photons) slows down inside a physical medium like,
say, interstellar dust clouds, whereas neutrinos can zip through almost all intervening matter, I don't see
why the theory of relativity needs to be revised in any way.

But I'm not a scientist.

Plus, if it's a supernova, if I Remember right, the neutrino burst occurs *BEFORE* the visible light from the explosion, *because* while the photons are working through all the other gunk that's going to explode (The plasma), the neutrinos, well, don't.

Perhaps the revising isn't "Relativity was wrong!", though, and more "The 8th digit of the speed of light neds to be turned from a 5 to a 6" or something.

/Note: I am not a cosmologist, my field of physics is nano-phsicys/engineering/synthesis.
//Goddamnit nanorods, STICK TO THE GODDAMN SUBSTRATE, I AM FOLLOWING THE PROCEDURE.


That was mentioned in the article. The problem was that the expected photon burst didn't arrive at the predicted time.
 
2014-06-25 04:19:40 PM  
"Neutrinos and photons both travel at the speed of light, "

um, no...
 
2014-06-25 04:20:31 PM  
So if we were ever in the path of an energy jet from a supernova, which would fry the solar system to a crisp in seconds, then we would have a small warning from neutrino detectors.   No one would bother to tell us though.   They would be trying to analyze the data.
 
2014-06-25 04:21:10 PM  

wjllope: "Neutrinos and photons both travel at the speed of light, "

um, no...


explain?
 
2014-06-25 04:21:16 PM  

Dr Dreidel: Not to piss on anyone's parade, but given that there are 300 billion stars in our galaxy, a 1 in 10,000 chance would happen 30 million times.


That's pretty much exactly what I thought when I read that.
 
2014-06-25 04:21:30 PM  
Check out pages 14 and 15 of the actual paper. It's a bit clearer than TFA... cheers
 
2014-06-25 04:23:04 PM  

BafflerMeal: wjllope: "Neutrinos and photons both travel at the speed of light, "

um, no...

explain?


neutrinos have mass. A very small mass, but non-zero. (Just pointing out the usual science-reporting-fail)...cheere
 
2014-06-25 04:25:04 PM  

wjllope: BafflerMeal: wjllope: "Neutrinos and photons both travel at the speed of light, "

um, no...

explain?

neutrinos have mass. A very small mass, but non-zero. (Just pointing out the usual science-reporting-fail)...cheere



Ah.  Ok.  Was not aware of that.  I assumed by their general almost zero interaction with matter that they did not.
 
2014-06-25 04:27:38 PM  
The speed limit is just a suggestion anyway.
 
2014-06-25 04:30:24 PM  
Both still slower that the speed at which bad news travels.
 
2014-06-25 04:31:32 PM  

BowtoMogul: Didn't professor Farnsworth talk about this?


Cubert J. Farnsworth: That's impossible. You can't go faster than the speed of light.
Professor Hubert Farnsworth: Of course not. That's why scientists increased the speed of light in 2208.

2208? We're 194 years ahead of schedule. God damn we're good!
 
2014-06-25 04:35:36 PM  

Theaetetus: Felgraf: DjangoStonereaver: Um....

Considering that the 'speed of light' (IE, the speed of photons) slows down inside a physical medium like,
say, interstellar dust clouds, whereas neutrinos can zip through almost all intervening matter, I don't see
why the theory of relativity needs to be revised in any way.

But I'm not a scientist.

Plus, if it's a supernova, if I Remember right, the neutrino burst occurs *BEFORE* the visible light from the explosion, *because* while the photons are working through all the other gunk that's going to explode (The plasma), the neutrinos, well, don't.

Know how I know you didn't read the article?
Neutrinos and photons both travel at the speed of light and should therefore arrive simultaneously, all else being equal. The mystery is what caused this huge delay of 7.7 hours between the first burst of neutrinos and the arrival of the optical photons...
First, some background about the mechanism behind the supernova. A supernova begins with the collapse of a star's core, generating both neutrinos and optical photons. However, the density of the core delays the emergence of the photons by about 3 hours. By contrast, the neutrinos interact less strongly with matter and so emerge unscathed more or less immediately...
But the timing is still a puzzle. The optical photons should have arrived about 3 hours after the first burst of neutrinos rather than 4.7 hours after the second burst.


You are correct, I have not yet had time to read it.

Trying to get a nanorod deposition to work, can only brain so much.

I would think, though, it might be more likely that the neutrino burst comse 'earlier' than expected? Maybe not.

Tobin_Lam: That was mentioned in the article. The problem was that the expected photon burst didn't arrive at the predicted time.


Understood. I suppose just after the whole "POSSIBLY FASTER THAN LIGHT NEUTRINOS!" (that the media was shouting about, while the people reporting it were going ".. someone please figure out WTF we're doing wrong over here, we can't find it"),that turned out to be... I think one of their timing cables was farked up?

My brain went ".. Are we doing this again?".

I am perhaps just overly frustrated at my own work at the moment. I swear to god nano sometimes feels more like voodoo than science.
 
2014-06-25 04:39:12 PM  
Man, God is having some fun with scientists, lately.

"Farking N00bz" - God.
 
2014-06-25 04:42:34 PM  

DjangoStonereaver: Um....

Considering that the 'speed of light' (IE, the speed of photons) slows down inside a physical medium like,
say, interstellar dust clouds, whereas neutrinos can zip through almost all intervening matter, I don't see
why the theory of relativity needs to be revised in any way.

But I'm not a scientist.


As I read it, it doesn't sound like a revision to relativity or quantum mechanics at all; it's just another mechanism for velocity change (loss, in this case) that would have been overlooked before. The speed of a photon outside of a gravity well should still be the same. Making assumptions and approximations when calculating solutions are often necessary evils; and it's often as much of an art as it is a science choosing what needs to be considered and what can be disregarded. Things like this SN1987a are often nature's way of slapping us in the face and telling us to pay more careful attention to our calculations because something's likely been left out. Often by choice, but usually by ignorance or accident. In this case, the hypothesis appears to be that we're dealing with a relatively well known effect that just hadn't been considered over very long distances.

More importantly, this hypothesis should eventually be testable without waiting for another supernova to blow
 
2014-06-25 04:44:49 PM  

Arkanaut: "Speed of Dark" sounds like a biatchin' title for a metal album.


timujin: This About That: factoryconnection: That was a thoroughly interesting read.  Thank you for applying the right tag to it. Given the (unstated in TFA) distance of 168000 light years to SN1987a, the 4.7 hour differential represents a 3.2E-7% difference in the predicted versus observed light arrival time.

Significant for astrophysicists, certainly, and would represent an error of 41 years in the estimated 13B year age of the universe.

Here we go again, revising history.

"Science" got it wrong again.  You know what never changes?  The Bible.

What about the New Revised Standard Version?


I said NEVER CHANGES!!
 
2014-06-25 04:45:08 PM  

wjllope: "Neutrinos and photons both travel at the speed of light, "

um, no...


You are technically correct. Realistically, neutrons do travel at practically the speed of light. Experimental measurements show that neutrons travel at the speed of light or at least close enough that we can't measure the difference yet.
 
2014-06-25 04:51:55 PM  
Ehh, space is only a pretty good vacuum, not perfect. Figure an atom of hydrogen per cubic meter, 9.46 *10^15 meters per light year, and 1.68*10^5 light years to the star. Just ballpark, but there's 1.5 *10^21 atoms of hydrogen per square meter between you and that star.
 
2014-06-25 04:52:38 PM  

Tobin_Lam: You are technically correct.


That's the best kind of correct!
 
2014-06-25 04:52:39 PM  
The important takeaway is that light doesn't actually move at the speed of light in practice. Neutrinos are moving at the speed of light.   Which should throw off quite a few calculations about the universe.

/A few hours after a million light years doesn't seem like a big deal, but it probably adds up.
 
2014-06-25 04:54:04 PM  

BafflerMeal: wjllope: BafflerMeal: wjllope: "Neutrinos and photons both travel at the speed of light, "

um, no...

explain?

neutrinos have mass. A very small mass, but non-zero. (Just pointing out the usual science-reporting-fail)...cheere


Ah.  Ok.  Was not aware of that.  I assumed by their general almost zero interaction with matter that they did not.


You're in good company. Physicists long believed that neutrinos were probably massless, and this was consistent with the Standard Model. The discovery (in the late 1990s) that neutrinos apparently oscillated from one flavor to another was the first clue that they must have mass. It remains an interesting problem to explain why the neutrino mass is so small, yet not actually zero.
 
2014-06-25 04:56:15 PM  

Felgraf: You are correct, I have not yet had time to read it.

Trying to get a nanorod deposition to work, can only brain so much.

I would think, though, it might be more likely that the neutrino burst comse 'earlier' than expected? Maybe not


That's pretty cool.  You're cool.  And I'm jealous.

/not even snarking
 
2014-06-25 04:57:02 PM  

ghall3: But the speed of love is still the same right?


About 30 seconds, according to your mom.
 
2014-06-25 05:07:52 PM  
Maybe it's an after-effect of a Halo detonation?

img1.wikia.nocookie.net
 
2014-06-25 05:09:32 PM  

BafflerMeal: wjllope: BafflerMeal: wjllope: "Neutrinos and photons both travel at the speed of light, "

um, no...

explain?

neutrinos have mass. A very small mass, but non-zero. (Just pointing out the usual science-reporting-fail)...cheere


Ah.  Ok.  Was not aware of that.  I assumed by their general almost zero interaction with matter that they did not.


Though the mass of a neutrino hasn't been measured, neutrino mass is required in order to explain the solar neutrino problem, which is why we were initially only detecting 1/3 of the expected amount of neutrinos streaming from the Sun.

As it turns out, there are three flavors of neutrinos, and neutrinos can change flavor as they travel through space. In order for them to change over time, they have to experience time. In order to experience time, they have to move slower than light, and in order for that, they need mass.

These other flavors of neutrinos were later detected experimentally, confirming neutrino mass (And, thus, slower-than-light movement) The flavors seem to be oscillations in how much of the total energy is represented as mass vs. momentum. (or something like that)
 
2014-06-25 05:11:05 PM  
Now one physicist says the speed of light must be slower than Einstein predicted and has developed a theory that explains why


I'm pretty sure the speed of light had been calculated before Einstein had anything to say on the matter...
 
2014-06-25 05:15:56 PM  
imgs.xkcd.com
 
2014-06-25 05:18:48 PM  

Mikey1969: Now one physicist says the speed of light must be slower than Einstein predicted and has developed a theory that explains why


I'm pretty sure the speed of light had been calculated before Einstein had anything to say on the matter...


Tell me Morley.
 
2014-06-25 05:22:44 PM  

czetie: BafflerMeal: wjllope: BafflerMeal: wjllope: "Neutrinos and photons both travel at the speed of light, "

um, no...

explain?

neutrinos have mass. A very small mass, but non-zero. (Just pointing out the usual science-reporting-fail)...cheere


Ah.  Ok.  Was not aware of that.  I assumed by their general almost zero interaction with matter that they did not.

You're in good company. Physicists long believed that neutrinos were probably massless, and this was consistent with the Standard Model. The discovery (in the late 1990s) that neutrinos apparently oscillated from one flavor to another was the first clue that they must have mass. It remains an interesting problem to explain why the neutrino mass is so small, yet not actually zero.


Don't photons have to have _some_ mass in order to transmit/transfer energy?
 
2014-06-25 05:27:12 PM  

Felgraf: DjangoStonereaver: Um....

Considering that the 'speed of light' (IE, the speed of photons) slows down inside a physical medium like,
say, interstellar dust clouds, whereas neutrinos can zip through almost all intervening matter, I don't see
why the theory of relativity needs to be revised in any way.

But I'm not a scientist.

Plus, if it's a supernova, if I Remember right, the neutrino burst occurs *BEFORE* the visible light from the explosion, *because* while the photons are working through all the other gunk that's going to explode (The plasma), the neutrinos, well, don't.

Perhaps the revising isn't "Relativity was wrong!", though, and more "The 8th digit of the speed of light neds to be turned from a 5 to a 6" or something.

/Note: I am not a cosmologist, my field of physics is nano-phsicys/engineering/synthesis.
//Goddamnit nanorods, STICK TO THE GODDAMN SUBSTRATE, I AM FOLLOWING THE PROCEDURE.


That's actually what I was wondering. Seems like the obvious answer.
 
2014-06-25 05:30:23 PM  

OceanVortex: [imgs.xkcd.com image 740x232]


LOL, liked that bit about the "Thought Police". That's an awesome comic. And yeah, it's a great point. Either this is going to turn out to be a mistake/error(or have a perfectly rational explanation) or it's gonna be a cool new thing to talk about. Either way, we're still gonna be able to hurt each other's feelings  daily on Fark...
 
2014-06-25 05:33:32 PM  
My ex wife used to say our household emergency flashlight which had a "regular" and "bright" setting had two speeds.
 
2014-06-25 05:38:54 PM  

Theaetetus: Felgraf: DjangoStonereaver: Um....

Considering that the 'speed of light' (IE, the speed of photons) slows down inside a physical medium like,
say, interstellar dust clouds, whereas neutrinos can zip through almost all intervening matter, I don't see
why the theory of relativity needs to be revised in any way.

But I'm not a scientist.

Plus, if it's a supernova, if I Remember right, the neutrino burst occurs *BEFORE* the visible light from the explosion, *because* while the photons are working through all the other gunk that's going to explode (The plasma), the neutrinos, well, don't.

Know how I know you didn't read the article?
Neutrinos and photons both travel at the speed of light and should therefore arrive simultaneously, all else being equal. The mystery is what caused this huge delay of 7.7 hours between the first burst of neutrinos and the arrival of the optical photons...
First, some background about the mechanism behind the supernova. A supernova begins with the collapse of a star's core, generating both neutrinos and optical photons. However, the density of the core delays the emergence of the photons by about 3 hours. By contrast, the neutrinos interact less strongly with matter and so emerge unscathed more or less immediately...
But the timing is still a puzzle. The optical photons should have arrived about 3 hours after the first burst of neutrinos rather than 4.7 hours after the second burst.


I did read the article (mostly), and while it accounts for the delay in the emission of photos vs that of neutrinos at the source, it doesn't account for any intervening gas clouds or nebulae or other cosmic stuff on the path of the photons'
travel that could slow them.
 
2014-06-25 05:48:53 PM  

dryknife: My ex wife used to say our household emergency flashlight which had a "regular" and "bright" setting had two speeds.


Yeah, and?  I've been known to complain about a really loud odor.

/ made a cashier fall down laughing - ex-wife had sent me to the pink aisle to grab a box of plugs, and I grabbed 'the wrong flavor.'
 
ZAZ [TotalFark]
2014-06-25 05:52:05 PM  
He waved the renormalization wand to make the effect independent of photon energy, but a more complex calculation might predict energy dependence. Possibly we could imagine a test of that prediction.
 
2014-06-25 06:03:32 PM  

DjangoStonereaver: Theaetetus: Felgraf: DjangoStonereaver: Um....

Considering that the 'speed of light' (IE, the speed of photons) slows down inside a physical medium like,
say, interstellar dust clouds, whereas neutrinos can zip through almost all intervening matter, I don't see
why the theory of relativity needs to be revised in any way.

But I'm not a scientist.

Plus, if it's a supernova, if I Remember right, the neutrino burst occurs *BEFORE* the visible light from the explosion, *because* while the photons are working through all the other gunk that's going to explode (The plasma), the neutrinos, well, don't.

Know how I know you didn't read the article?
Neutrinos and photons both travel at the speed of light and should therefore arrive simultaneously, all else being equal. The mystery is what caused this huge delay of 7.7 hours between the first burst of neutrinos and the arrival of the optical photons...
First, some background about the mechanism behind the supernova. A supernova begins with the collapse of a star's core, generating both neutrinos and optical photons. However, the density of the core delays the emergence of the photons by about 3 hours. By contrast, the neutrinos interact less strongly with matter and so emerge unscathed more or less immediately...
But the timing is still a puzzle. The optical photons should have arrived about 3 hours after the first burst of neutrinos rather than 4.7 hours after the second burst.

I did read the article (mostly), and while it accounts for the delay in the emission of photos vs that of neutrinos at the source, it doesn't account for any intervening gas clouds or nebulae or other cosmic stuff on the path of the photons'
travel that could slow them.


Your examples of objects that would reduce speed is not correct. They would simply reduce the volume of photons when observed. Our planet reflected some of the aforementioned photons that were recorded. But the others kept on trucking.
 
2014-06-25 06:05:37 PM  

dionysusaur: czetie: BafflerMeal: wjllope: BafflerMeal: wjllope: "Neutrinos and photons both travel at the speed of light, "

um, no...

explain?

neutrinos have mass. A very small mass, but non-zero. (Just pointing out the usual science-reporting-fail)...cheere


Ah.  Ok.  Was not aware of that.  I assumed by their general almost zero interaction with matter that they did not.

You're in good company. Physicists long believed that neutrinos were probably massless, and this was consistent with the Standard Model. The discovery (in the late 1990s) that neutrinos apparently oscillated from one flavor to another was the first clue that they must have mass. It remains an interesting problem to explain why the neutrino mass is so small, yet not actually zero.

Don't photons have to have _some_ mass in order to transmit/transfer energy?


No. Photons are massless. Yet that carry momentum. Freaky, huh?

The equation p=m*v applies when m!=0. For photons, p=h*nu/c, where h is Planck's constant, nu is the frequency, and c is the speed of light.

Dr Dreidel: Tell me Morley.


FIrst measurement related to the speed of light was in the 1600's by Rømer. Huygens estimated c from that data and it was correct to 30%.
In 1809, Delambre estimated the speed of light from the sun to the earth as 8 min 12 sec - within ~1.5% the present value of 8 min 19 sec.
cheers
 
2014-06-25 06:06:30 PM  
Example not examples
 
2014-06-25 06:06:31 PM  
Yet they carry momentum

/sorry
 
2014-06-25 06:08:27 PM  
But the speed of dim is still slow.
 
2014-06-25 06:10:54 PM  
This guy never mentions obscuration in the interstellar medium.

However, assuming he's right, the neutrinos never went faster than c. Physics doesn't really change... Just how c is defined.
 
2014-06-25 06:11:28 PM  
The speed of dim sum is close to the speed of shi... I mean light.
 
2014-06-25 06:16:50 PM  
The most interesting part to me is that if what is posited is correct. Every photo reaching earth experienced vacuum polarisation. So it's not finite...it's inevitable.
 
2014-06-25 06:17:29 PM  
Photon
 
2014-06-25 06:17:50 PM  

skozlaw: Felgraf: Plus, if it's a supernova, if I Remember right, the neutrino burst occurs *BEFORE* the visible light from the explosion, *because* while the photons are working through all the other gunk that's going to explode (The plasma), the neutrinos, well, don't.

^

This was even covered on an episode of Cosmos.


It was even covered in the goddamn article, if anyone cares to read it.
 
2014-06-25 06:18:42 PM  

wjllope: "Neutrinos and photons both travel at the speed of light, "

um, no...


Yeah, stopped reading right about there.
 
2014-06-25 06:22:04 PM  

StrangeQ: wjllope: "Neutrinos and photons both travel at the speed of light, "

um, no...

Yeah, stopped reading right about there.


No. Read it. Just skip that part. The researcher didn't write the article.
 
ZAZ [TotalFark]
2014-06-25 06:32:10 PM  
factoryconnection

The effect is essentially zero in deep space far from galaxies. It's based on gravitational potential relative to the universe as a whole. Most of the universe today is well outside the gravity well of galaxies. (At really high redshift, maybe not, and not if the universe is not flat.)
 
2014-06-25 06:33:32 PM  

dionysusaur: made a cashier fall down laughing - ex-wife had sent me to the pink aisle to grab a box of plugs, and I grabbed 'the wrong flavor.'


img.fark.net

/no, the w doesn't stand for "weight"
 
2014-06-25 06:57:24 PM  

dionysusaur: Don't photons have to have _some_ mass in order to transmit/transfer energy


Nope. The photon is the energy that is being transferred. Specifically, energy being transferred via the electromagnetic force is transferred as photons. This includes the virtual photons that are exchanged between like charges, repulsing them.
 
2014-06-25 07:01:19 PM  
Funny how the big guy keeps changing universal constants. Where's your science now biatches?
 
2014-06-25 07:04:39 PM  
img.fark.net
 
2014-06-25 07:09:19 PM  

Catlenfell: [img.fark.net image 500x500]


Is it just my imagination or are her eyes pointing in slightly different directions?
 
2014-06-25 07:19:37 PM  
light is not slower than before, time is. when we first discovered the speed of light about 150 years ago, time was just a bit quicker. it's really the the same reason that causes us to age slightly more slowly than before as well, elongating lifespans. this is clearly just another attempt to distract us from knowing that the earth is slowing down, and that someday, time will stop altogether, and then we will never die, and live like gods.
 
2014-06-25 07:35:03 PM  

BigLuca: Felgraf: You are correct, I have not yet had time to read it.

Trying to get a nanorod deposition to work, can only brain so much.

I would think, though, it might be more likely that the neutrino burst comse 'earlier' than expected? Maybe not

That's pretty cool.  You're cool.  And I'm jealous.

/not even snarking


It is seriously not as cool or glamorous as it sounds, but thanks!

(I swear to god I need to sacrifice a chicken to moloch to get it to work).
 
2014-06-25 07:50:04 PM  

Felgraf: BigLuca: Felgraf: You are correct, I have not yet had time to read it.

Trying to get a nanorod deposition to work, can only brain so much.

I would think, though, it might be more likely that the neutrino burst comse 'earlier' than expected? Maybe not

That's pretty cool.  You're cool.  And I'm jealous.

/not even snarking

It is seriously not as cool or glamorous as it sounds, but thanks!

(I swear to god I need to sacrifice a chicken to moloch to get it to work).


My best friend was all over the board in physics for a while, he ended up as a materials guy in Morgantown WV trying to build the Beanstalk.  I can keep up with him for about five minutes when he does a brain dump my way then things get fuzzy. Yes, we're living in the future.
 
2014-06-25 07:55:23 PM  

dionysusaur: Don't photons have to have _some_ mass in order to transmit/transfer energy?


Surprisingly, no. Well, surprising if you were taught physics the way it's usually taught in school, which is to start with the mechanics of macroscopic objects and everyday experience and appeals to intuition, and to speak of energy as a property of moving bodies.

It turns out, though, that in order to properly grok physics, you have to unlearn that idea and discover that energy can exist and be transferred in lots of ways, of which massive particles moving through space is just one special case. It turns out that fields are what are truly fundamental. One way to think about it is to imagine a field (electromagnetic, gravitational, or otherwise) as a stretched wall-to-wall carpet -- there is energy "stored" in the tension in the carpet. And you can move that energy around by stretching the carpet in one place or another. You can also think of a particle as a bump in the carpet -- a highly localized bit of tension that you can move around, but if you push it down it just pops up elsewhere. Now, if you can imagine that same thing but without the carpet -- like the Cheshire cat disappearing and leaving only its smile, the carpet disappears leaving only the tension -- you are 90% of the way to a good mental picture. (By the way, this analogy is completely wrong in every conceivable physical way, but it gives the right sense).

Perhaps even more counterintuitive is that photons (and other massless particles) also have momentum. This is how a solar sail works: the photons "bounce off" the sail, which rebounds in the opposite direction. Even less intuitively, perhaps, the fields themselves have momentum. Again, this is because momentum is the more fundamental property; the fact that for a macroscopic object with mass, moving at low speed, (momentum = mass x velocity) is just a special case of momentum. A fuller discussion is probably TL;DR for this thread, though.
 
2014-06-25 08:06:09 PM  

2wolves: My best friend was all over the board in physics for a while, he ended up as a materials guy in Morgantown WV trying to build the Beanstalk.  I can keep up with him for about five minutes when he does a brain dump my way then things get fuzzy. Yes, we're living in the future.


What's the Beanstalk?  You're not talking a space elevator are you?
 
2014-06-25 08:16:02 PM  
Think of it this way: When you're on a long trip of x miles going 60 miles/hr., you should go a mile a minute and take x minutes, BUT this doesn't take into account lunch, rest stops, etc., so the trip should take slightly longer than x minutes.

Similarly, here, the photons occasionally have to stop, so they get to their destination slightly later than the nutrinos, who didn't have to stop to go to the bathroom. This doesn't change the fact that they travel at the speed of light as long as they're in the car, however.
 
2014-06-25 08:18:31 PM  
I thought I recalled the results of the 1987A neutrino/light differential was important because it put an upper limit on the mass of the neutrino at no more than 15 eV (which is not zero but compare to an electron at 511,000 eV).  This is quite a different interpretation, but it seems plausible to me.  Thanks, subby!
 
2014-06-25 08:24:59 PM  

ThreadSinger: Maybe it's an after-effect of a Halo detonation?

[img1.wikia.nocookie.net image 850x637]


If only one blew, then there has been a premature detonation.

(I don't blame 343 Guilty Spark for that one, if I saw Cortana in person, I might have a premature detonation myself.)

/In my pants.
//Also, this is a Joke, nerds.
///And dorks.
 
2014-06-25 08:26:34 PM  
Just my two cents, but as a physicist who worked on the Neutrino projects (ICECUBE and AMANDA), the article takes a lot of the right things into account.  The first blind leap of faith I saw was estimating the mass of the galaxy through which they are passing.  That alone puts a big question mark on the resulting calculations.  Another little tweak might come from inflation and expansion.  But I am glad to see the questions are being asked.

Some additional items:  Photon packets may have no mass.  They may not interact with the Higgs field.  However, they do seem to have momentum and are affected by gravity wells.  Momentum and linearity may be more associated with space-time than with mass.  But that is something for someone else to address.

Lastly: There are three types of Neutrinos.  The most interesting ones are WIMPS (weak interactive massive particles).  These are being studied to see if they are responsible for some of the proposed dark matter in the universe.  When one of these massive Tau Neutrinos smacked into our detector, it lit the thing up like a Christmas Tree.  The ones shot out by the sun are relatively small Electron Neutrinos.

I enjoyed the article and all of your comments!
 
2014-06-25 08:37:48 PM  
I don't recall Einstein predicting the speed of light.  He declared it the universal speed limit, but he didn't predict it.
 
2014-06-25 08:39:56 PM  

syrynxx: I thought I recalled the results of the 1987A neutrino/light differential was important because it put an upper limit on the mass of the neutrino at no more than 15 eV (which is not zero but compare to an electron at 511,000 eV).  This is quite a different interpretation, but it seems plausible to me.  Thanks, subby!


Yeah - i think the present limit is .le.2.something eV for the electron neutrino...

CSB (an tl;dr) time. I was an undergraduate at the University of Michigan in 1987, and a physics major making beer money by working with a couple of professors who were principles in the "IMB" experiment. I basically came in ~10-20 hours a week to keep tapes processing, starting simple analysis jobs, doing simple Cerenkov cone fits, etc... IMB was a large cubic hole underground filled with very clean water and surrounded on all 6 sides by very big PMTs to look for the light produced if any of the protons in that clean water happened to decay. Throughout that experiment, and including some upgrades,  no protons were ever seen to have decayed. But on one particularly cool morning, I went in there (probably hung over) and everyone was loosing their minds.

Professors were actually down in the lab, postdocs and staff scientists were all over the place hunching over displays and pointing and giggling and arguing. As a dumbass undergraduate, I did not know exactly what was going on, but I knew it was exciting to them. Later that day, I accosted one of the staff scientists and said "what the hell?". He showed me a scatter plot (an old school VT100-like lineprinter scatterplot if you can picture that), and in the lower left corner there were 6 or 7 little X's.

Those were neutrinos from SN1987A that underwent charged-current interactions producing leptons which produced light in the water which the PMTs saw.

It was at exactly this point that I realized how truly exciting science can be. As a result, a year or so later, I applied to a summer science program at Brookhaven National Laboratory, and was selected to attend by a new experiment at the Alternating Gradient Synchotron. That was so much fun that I applied to graduate school at Stony Brook a year later (collaborating institution on that same experiment), and to this day (some 25 years later) I am still doing physics at BNL, now at the RHIC collider. So, SN1987A was quite undoubtedly part of the reason why my day job is as a physicist. I love it. Sometimes exciting stuff sneaks up and bites you on the tookus.
Sorry for the tolstoy. I've never typed this out before... cheers
 
2014-06-25 08:43:55 PM  
No further research on the speed of lint?
 
2014-06-25 08:44:40 PM  

vharshyde: (I don't blame 343 Guilty Spark for that one, if I saw Cortana in person, I might have a premature detonation myself.)


upload.wikimedia.org

Happy fapping!
 
2014-06-25 09:51:46 PM  

wjllope: syrynxx: I thought I recalled the results of the 1987A neutrino/light differential was important because it put an upper limit on the mass of the neutrino at no more than 15 eV (which is not zero but compare to an electron at 511,000 eV).  This is quite a different interpretation, but it seems plausible to me.  Thanks, subby!

Yeah - i think the present limit is .le.2.something eV for the electron neutrino...

CSB (an tl;dr) time. I was an undergraduate at the University of Michigan in 1987, and a physics major making beer money by working with a couple of professors who were principles in the "IMB" experiment. I basically came in ~10-20 hours a week to keep tapes processing, starting simple analysis jobs, doing simple Cerenkov cone fits, etc... IMB was a large cubic hole underground filled with very clean water and surrounded on all 6 sides by very big PMTs to look for the light produced if any of the protons in that clean water happened to decay. Throughout that experiment, and including some upgrades,  no protons were ever seen to have decayed. But on one particularly cool morning, I went in there (probably hung over) and everyone was loosing their minds.

Professors were actually down in the lab, postdocs and staff scientists were all over the place hunching over displays and pointing and giggling and arguing. As a dumbass undergraduate, I did not know exactly what was going on, but I knew it was exciting to them. Later that day, I accosted one of the staff scientists and said "what the hell?". He showed me a scatter plot (an old school VT100-like lineprinter scatterplot if you can picture that), and in the lower left corner there were 6 or 7 little X's.

Those were neutrinos from SN1987A that underwent charged-current interactions producing leptons which produced light in the water which the PMTs saw.

It was at exactly this point that I realized how truly exciting science can be. As a result, a year or so later, I applied to a summer science program at Brookha ...


Holy shiat that is an awesome story, and I mean this sincerely.

There's not a lot that compares to that giddy "YES! I farkING HAVE DATA AND THIS GODDAMN THING WORKED" feeling, does it?

/Still in grad school.
//~ half a year left.
///OH GOD I HAVE TO LEAVE THE COCOON OF ACADEMIA.
 
2014-06-25 10:13:27 PM  

BigLuca: 2wolves: My best friend was all over the board in physics for a while, he ended up as a materials guy in Morgantown WV trying to build the Beanstalk.  I can keep up with him for about five minutes when he does a brain dump my way then things get fuzzy. Yes, we're living in the future.

What's the Beanstalk?  You're not talking a space elevator are you?


Exactly what I'm talking about.
 
2014-06-25 11:01:29 PM  

czetie: BafflerMeal: wjllope: BafflerMeal: wjllope: "Neutrinos and photons both travel at the speed of light, "

um, no...

explain?

neutrinos have mass. A very small mass, but non-zero. (Just pointing out the usual science-reporting-fail)...cheere


Ah.  Ok.  Was not aware of that.  I assumed by their general almost zero interaction with matter that they did not.

You're in good company. Physicists long believed that neutrinos were probably massless, and this was consistent with the Standard Model. The discovery (in the late 1990s) that neutrinos apparently oscillated from one flavor to another was the first clue that they must have mass. It remains an interesting problem to explain why the neutrino mass is so small, yet not actually zero.


Is there, then, anything that -does- travel at "The Speed of Light"? Since Neutrinos apparently have really small mass (from what you said), and light occasionally takes a "break" and turns into electrons and positrons before going back to "photons" (according to my reading of the article?)
 
2014-06-25 11:05:27 PM  

2wolves: BigLuca: 2wolves: My best friend was all over the board in physics for a while, he ended up as a materials guy in Morgantown WV trying to build the Beanstalk.  I can keep up with him for about five minutes when he does a brain dump my way then things get fuzzy. Yes, we're living in the future.

What's the Beanstalk?  You're not talking a space elevator are you?

Exactly what I'm talking about.


Oh man that is so cool.  If he is in materials and working on space elevator stuff, he probably was developing nanotube tech, either carbon or boron nitride.  News on that front was all over the place 5-6 years ago but I can hardly dig up in any new info in the last couple years, and I've been paying attention.  I think the Strong Tether Competition has ended, but they need to start it up again - it was great motivation.  Exciting stuff.
 
2014-06-25 11:21:15 PM  

Theaetetus: Felgraf: DjangoStonereaver: Um....

Considering that the 'speed of light' (IE, the speed of photons) slows down inside a physical medium like,
say, interstellar dust clouds, whereas neutrinos can zip through almost all intervening matter, I don't see
why the theory of relativity needs to be revised in any way.

But I'm not a scientist.

Plus, if it's a supernova, if I Remember right, the neutrino burst occurs *BEFORE* the visible light from the explosion, *because* while the photons are working through all the other gunk that's going to explode (The plasma), the neutrinos, well, don't.

Know how I know you didn't read the article?
Neutrinos and photons both travel at the speed of light and should therefore arrive simultaneously, all else being equal. The mystery is what caused this huge delay of 7.7 hours between the first burst of neutrinos and the arrival of the optical photons...
First, some background about the mechanism behind the supernova. A supernova begins with the collapse of a star's core, generating both neutrinos and optical photons. However, the density of the core delays the emergence of the photons by about 3 hours. By contrast, the neutrinos interact less strongly with matter and so emerge unscathed more or less immediately...
But the timing is still a puzzle. The optical photons should have arrived about 3 hours after the first burst of neutrinos rather than 4.7 hours after the second burst.


What I read is a fairly simple reason for the added delay from 3 hours to 4.7 (1.7 hours over 168000 light years). The high energy gamma rays, the only ones we are paying attention to, have enough energy each to split from a photon into an electron-positron virtual particle pair and almost instantly change back. This normally only happens very rarely, and I can't find a quote on the statistical chance of it (nor can I solve the Schrodinger equation to figure it out), but over those many thousands of years (not 168000, see "expansion of space") it happened often enough that the chance that every photon got delayed by about 1.7 hours was statistically close enough to 100%. Those above mentioned virtual particles (see quantum electrodynamics and Feynman diagrams) have mass, and are affected by gravity. So instead of taking a slightly curved path (light is affected by gravity) the gamma rays get bent even further each time they turn into virtual particles. This makes the path that the light took longer than what we previously thought, and explains the delay. According to the article author (who's previous abstract on the same research tried to explain the delay as extra proof of superluminal neutrinos, so grain of salt.)

The media makes this into "OMG, c needs to be changed!" The truth is, c is stable, and the rest of our knowledge about how photons travel long distances and times might change. If it does (seeapropos XKCD) then that will eventually be a big deal for cosmology and astronomy.
 
2014-06-25 11:24:35 PM  

RuneSaint: czetie: BafflerMeal: wjllope: BafflerMeal: wjllope: "Neutrinos and photons both travel at the speed of light, "

um, no...

explain?

neutrinos have mass. A very small mass, but non-zero. (Just pointing out the usual science-reporting-fail)...cheere


Ah.  Ok.  Was not aware of that.  I assumed by their general almost zero interaction with matter that they did not.

You're in good company. Physicists long believed that neutrinos were probably massless, and this was consistent with the Standard Model. The discovery (in the late 1990s) that neutrinos apparently oscillated from one flavor to another was the first clue that they must have mass. It remains an interesting problem to explain why the neutrino mass is so small, yet not actually zero.

Is there, then, anything that -does- travel at "The Speed of Light"? Since Neutrinos apparently have really small mass (from what you said), and light occasionally takes a "break" and turns into electrons and positrons before going back to "photons" (according to my reading of the article?)


lower energy photons (it takes gamma rays of either 511keV or 1022keV, i forget which; while visible light has between 1.something and 3.2 eV (electron volts)), radio waves, gravity (as we currently understand it), anything that doesn't have the energy to turn into mass according to E=mc^2
 
2014-06-25 11:37:46 PM  

ghall3: But the speed of love is still the same right?


Nothing changes faster than the speed of love.

/ A radiance that travels
 
2014-06-25 11:38:01 PM  
Huh.  So if I get this guy right, he is saying that there is a small but non-zero chance that a photon would degrade into two particles.  Since the particles have mass, they would be briefly slowed by gravity until they collapse and reform back into a photon that continues on its way.  Over astronomical distances, this would happen frequently enough to any given photon that it would result in a very slightly slower speed.

OK but invert that.  The galaxy is full of light, some percent of which would spontaneously be particles at any given moment.  Particles with mass, that impact the galaxy in the same way that the galaxy is impacting the particles.

How much extra mass, exactly?
 
2014-06-25 11:39:09 PM  
I'm confused.
 
2014-06-25 11:59:59 PM  
so this proves it, i am older than i look...
 
2014-06-26 12:36:56 AM  

Felgraf: Trying to get a nanorod deposition to work, can only brain so much.


.

Felgraf: I am perhaps just overly frustrated at my own work at the moment. I swear to god nano sometimes feels more like voodoo than science.


Use more scotch tape.
 
2014-06-26 12:40:12 AM  

SomeAmerican: Huh.  So if I get this guy right, he is saying that there is a small but non-zero chance that a photon would degrade into two particles.  Since the particles have mass, they would be briefly slowed by gravity until they collapse and reform back into a photon that continues on its way.  Over astronomical distances, this would happen frequently enough to any given photon that it would result in a very slightly slower speed.

OK but invert that.  The galaxy is full of light, some percent of which would spontaneously be particles at any given moment.  Particles with mass, that impact the galaxy in the same way that the galaxy is impacting the particles.

How much extra mass, exactly?


Not much extra mass from the electron-positron pair. Literally the mass of 2 electrons for a time scale that may not even be measurable. And it only applies to very high energy photons, so supposing there is a fair dispersal of those photons spread over the galaxy, then the mass would statistically even out over any measurable time span; as far as I can figure out. Not even the mass of a grain of sand, or a stray hydrogen atom.

From another perspective, any light emitting source that throws out those high energy photons should, over time, experience the pull of the mass of 2 electrons from the virtual particles along each and every (θφ) as the photons travel outward, with only the radius being effected. Since the effect of gravity is decreased by distance or the short time that the mass exists, and these virtual particles don't exist for any measurable time, the distance should not be a factor over time. So, the light emitting source experiences a very minor pull in every direction; and that source should be the star, or the galaxy, or anything else; making the effect (if it exists as the author proposes) something that shouldn't affect the way galaxies move, but may change the way we 'see' them move.
 
2014-06-26 01:10:37 AM  

Mikey1969: OceanVortex: [imgs.xkcd.com image 740x232]

LOL, liked that bit about the "Thought Police". That's an awesome comic. And yeah, it's a great point. Either this is going to turn out to be a mistake/error(or have a perfectly rational explanation) or it's gonna be a cool new thing to talk about. Either way, we're still gonna be able to hurt each other's feelings  daily on Fark...


The article writer, doing what article writers do, made the implications of this out to be more than they were.  The "speed of light in a vacum" is really a theoretical limit that is never reached.   We already know that light doesn't ever travel at the speed of light (even in the greatest voids of space there is still a very, very, very thin gas, but it can still be enough to slow down light a noticeable amount over a few billion years).  This theory just adds another factor that can slow down light slightly.

It may or may not be true but it is not at all controversial.  It doesn't "disprove relativity" (apart from taking into account effects for which scientists already knew relativity doesn't hold) any more than light moving slower through a gas disproves it.
 
2014-06-26 01:54:42 AM  

ghall3: But I didn't see anything about other matter slowing the photons down on the way to us which seems more likely to me, but I am only a failed astrophysicist.


That's the "Tired Light" hypothesis.

So far, no supporting data.
 
2014-06-26 02:17:12 AM  

lohphat: ghall3: But I didn't see anything about other matter slowing the photons down on the way to us which seems more likely to me, but I am only a failed astrophysicist.

That's the "Tired Light" hypothesis.

So far, no supporting data.


According the Wikipedia article, "tired light" means the light's frequency gets lower over long distances (red-shifting), not slowing down.

That light slows down when traveling through a medium is a known fact.  But I'm pretty sure that effect was already accounted for in the calculations for SN 1987a, and there was still a discrepancy.
 
2014-06-26 02:29:29 AM  

cgraves67: We finally discovered that bad news is made out of neutrino particles.


Actually it's the lies that are made of neutrinos. 
The speed of light is the truth in physics. Lies travel faster than truth. 
So all findings in this article are clearly lies. 
Speed of light is correct, but we can never know.
 
2014-06-26 03:05:38 AM  
So, nothing exceeds the speed of light in a vacuum, photons travel slower than neutrinos due to interactions in less than vacuumy interstellar space? Is that about right?

My question is this: if the sun were to "disappear", would the Earth fly off instantly, or would there be a delay equivalent to the speed of light? In other words, does the gravitational force act instantly, or at the speed of light?

My daughter's physics teacher asked the class that question, and argued that it is an instantaneous effect. We disagree, but there isn't much out there on the topic.
 
2014-06-26 03:22:36 AM  

powhound: My daughter's physics teacher asked the class that question, and argued that it is an instantaneous effect. We disagree, but there isn't much out there on the topic.


Wat?

The speed of gravitational waves in the general theory of relativity is equal to the speed of light in vacuum, c.[1]
 
2014-06-26 03:39:36 AM  
Photons do indeed have mass, as do the orthopositronium. Suck it deniers. Therefore, light has weight and can be bent by gravity as evidenced at the accretion disk.


I just totally faced you into next week.
 
2014-06-26 05:50:00 AM  
As has been mentioned several times, neutrinos are bound to hit us before the actual light from the event because of occlusionof photons by the mass itself.
And as I gather..
The puzzlement is that 1.7 hour difference in the expected reception of the photons after the neutrinos.

Maybe I'm a bit foggy because it's 4:40 am or because I'm partially sick at the moment but that doesn't seem like a big deal.

I've seen many simulations of things blowing up or colliding at scale(planets / suns) and it's not a fast process(in the classical view of "explosion" ie as we see them in tiny scale on earth[ie firecrackers or dynamite]).  Is it so inconceivable that the photons would be occluded for a different amount of time depending on variability in the mass/materials between objects of varying events?
 
2014-06-26 06:51:46 AM  

powhound: So, nothing exceeds the speed of light in a vacuum, photons travel slower than neutrinos due to interactions in less than vacuumy interstellar space? Is that about right?

My question is this: if the sun were to "disappear", would the Earth fly off instantly, or would there be a delay equivalent to the speed of light? In other words, does the gravitational force act instantly, or at the speed of light?

My daughter's physics teacher asked the class that question, and argued that it is an instantaneous effect. We disagree, but there isn't much out there on the topic.


Your daughter's physics teacher needs to go teach something he/she is actually qualified for, like woodshop, or gym.

As an aside, if gravitational effects didn't propagate at the speed of light, advanced civilizations would be routinely blowing up stars as a form of instantaneous interstellar communication.
 
2014-06-26 09:12:53 AM  

aerojockey: Mikey1969: OceanVortex: [imgs.xkcd.com image 740x232]

LOL, liked that bit about the "Thought Police". That's an awesome comic. And yeah, it's a great point. Either this is going to turn out to be a mistake/error(or have a perfectly rational explanation) or it's gonna be a cool new thing to talk about. Either way, we're still gonna be able to hurt each other's feelings  daily on Fark...

The article writer, doing what article writers do, made the implications of this out to be more than they were.  The "speed of light in a vacum" is really a theoretical limit that is never reached.   We already know that light doesn't ever travel at the speed of light (even in the greatest voids of space there is still a very, very, very thin gas, but it can still be enough to slow down light a noticeable amount over a few billion years).  This theory just adds another factor that can slow down light slightly.

It may or may not be true but it is not at all controversial.  It doesn't "disprove relativity" (apart from taking into account effects for which scientists already knew relativity doesn't hold) any more than light moving slower through a gas disproves it.


Lind of like it's pretty hard to find a place on the planet where water freezes at 'exactly' 32 degrees F...

powhound: So, nothing exceeds the speed of light in a vacuum, photons travel slower than neutrinos due to interactions in less than vacuumy interstellar space? Is that about right?

My question is this: if the sun were to "disappear", would the Earth fly off instantly, or would there be a delay equivalent to the speed of light? In other words, does the gravitational force act instantly, or at the speed of light?

My daughter's physics teacher asked the class that question, and argued that it is an instantaneous effect. We disagree, but there isn't much out there on the topic.


Um, the Earth would still be under the effect of the gravitational pull of every other object in our solar system.
 
2014-06-26 09:42:25 AM  
If he's right-that the speed of light is slower than Einstein predicted-that is hugely significant.

Actually, to me it means one of two things... either

a. Speed of Light isn't a constant. or
b. "Speed of Light" isn't the right term, so much as "Speed of Photon" which is still constant, but while a photon isn't a photon but a positron electron pair, it quite reasonably doesn't move at 100% Speed of Photon.

However, if true it means the distances of many objects and due to that, both size and age of the universe need some minor corrections.

Cool
 
2014-06-26 09:48:37 AM  
So, science DOESN"T have all the answers like they always claim! Therefore Mitt Romney is president, Stephen Hawking gets unplugged, all science books are burned, and Pat Robertson gets lifetime-appointment as head of the U.N.
 
2014-06-26 11:20:21 AM  
This reminds me of freshman physics. Astronomers are obviously still at the freshman physics level, where we pretend that strings are massless and pulleys are frictionless. So long as strings are massless, pulleys are frictionless, and instruments are sufficiently crude, you can have nice, simple equations. However, if your instrument is no longer sufficiently crude, then you have to start accounting for the masses of strings and friction of pulleys, which is a hassle.
 
2014-06-26 12:43:33 PM  

Silly_Sot: However, if your instrument is no longer sufficiently crude, then you have to start accounting for the masses of strings and friction of pulleys, which is a hassle.


Or as scientists like to call it, "engineering".
 
2014-06-26 01:58:03 PM  

czetie: Silly_Sot: However, if your instrument is no longer sufficiently crude, then you have to start accounting for the masses of strings and friction of pulleys, which is a hassle.

Or as scientists like to call it, "engineering".


As an engineer, I can assure you that all you have to do is carry out calculations to two significant figures.  Boom, massless strings hold.
 
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