If neutrinos do travel faster than light..........

[Nillchill]

it may explain why neutrinos are seen ahead of a supernova explosion.

any comments guys?

[PeterW]

Depends how fast the light the light can escape from the bang.... Light does not,always travel at the speed of light... Looknup Cerenkov radiation for starters. Neutrinos seem to be able to escape first, somhave ahead start. I think the result may be a systematic error, time transfer is a tricky business, especially at the nanosecond level..... But i domoove it when spmething crops up and blows away all our existing ideas.... Keeps things exciting and fresh... See the latest ideas on the human migration and dinosaur feathers..... The only certainty in science is that you know nothing and what you think you know is wrong.....

Cheers

PEterW

[kris h]

Just one Question ... whats a neutrino ?

[Nillchill]

i am not assuming that the latest news is scientific fact yet, and yes ensuring clock sources are synchronised at that level of detection is a very difficult process, however, i was discussing this very topic with a friend this evening. it seemed a possible explanation of why they are seen ahead of and be used to detect supernovae. the Cerenkov radiation would still be seen if the neutrino passed through the medium at greater than the speed of light.

[661-pete]

it may explain why neutrinos are seen ahead of a supernova explosion.

any comments guys?

You're probably thinking of SN 1987A in which the neutrinos were detected about 3 hours ahead of the light. This was a type II core collapse supernova in a giant star, and whilst the neutrinos would have emerged from the core at lightspeed without any impediment, the light would have taken several hours to emerge having had to penetrate the dense outer layers of the star. Hence the time discrepancy.

If the early appearance of neutrinos from 1987A were indeed due to the claimed discrepancy in their velocity in vacuo, they would have arrived nearly four years ahead of the light. This is not what actually happened.

[Hypernova]

The reason that neutrinos are observed to arrive earlier than the light from a supernova is because they break out of the star before the visible light. The light takes a couple of hours (2-3) to reach the surface from the core; but because neutrinos interact weakly with matter they just go straight through and get a good head start on the rest of the light and this is reflected in the differing arrival times. This is in accordance to our current understanding neutrinos being limited to the speed of light and the theory of core collapse supernova.

http://zebu.uoregon.edu/~soper/StarDeath/sn1987a.html

*EDIT--661Pete made the same point as me whilst I was composing my message*

[buzzc150]

A neutrino gag.......

And the barman says, 'Sorry, we don't serve neutrinos'. A neutrino walks into a bar.

Sorry if this has posted before (or after). Still funny.

[LeeB]

Hi

To simplify the neutrino does no interact (or should i say is very unlikely to interact) on its way out of the core of a star while electromagnetic radiation takes a long time to reach the surface with interactions likely every 3cm or so, in fact the the emw that end as visible light from the photosphere take approx 200000 years to reach the surface of the sun from the core.

[Ouroboros]

If the early appearance of neutrinos from 1987A were indeed due to the claimed discrepancy in their velocity in vacuo, they would have arrived nearly four years ahead of the light. This is not what actually happened.

Were they looking for it?

[661-pete]

And the barman says, 'Sorry, we don't serve neutrinos'. A neutrino walks into a bar.

The barman says "for you, no charge". "How much is a pint?" A neutrino walks into a bar.

Were they looking for it?

You're right, they probably weren't. In which case it might have been missed, in amongst all those solar neutrinos they couldn't catch either (because they'd transmuted into the wrong sort...).

However, what then would explain the burst that they did catch three hours before the light from the SN arrived?

[ChrisKnipe]

The best thing about this is that even Einstein is actually being questioned and not being taken on blind faith!!!!

[Nillchill]

The best thing about this is that even Einstein is actually being questioned and not being taken on blind faith!!!!

all science, no matter who developed the theory should be questioned, we as a world are educating our children to be members of a scientific community, and not to question, but believe.

A break-through such as this (which indeed i hope this truly is, but suspect it is not), will turn all of science on its head. just imagine the possibilities.

[barkis]

As a physics non entity, I might be way off beam here. (No pun.)

I understood that the restriction on exceeding light speed, was that mass increased ad infinitum. Since Neutrinos are massless particles, that progression can't take place, therefore there is no barrier to exceeding light speed.

I'll be happy to read the replies that shoot this down, because I will then be a little wiser.

Ron.

[oldfruit]

I think that this may show us just how little we truly understand about the Universe.

[Macavity]

Posted link on "Poll" thread too. But a little "light" reading.

The Speed of Light - A Limit on Principle?

[Nillchill]

As a physics non entity, I might be way off beam here. (No pun.)

I understood that the restriction on exceeding light speed, was that mass increased ad infinitum. Since Neutrinos are massless particles, that progression can't take place, therefore there is no barrier to exceeding light speed.

I'll be happy to read the replies that shoot this down, because I will then be a little wiser.

Ron.

actually, neutrinos have a very small amount of mass, and that is why this observation is so surprising. it breaks the rules!

[Ptarmigan]

actually, neutrinos have a very small amount of mass,

Has that been confirmed ? I am a bit out of touch on it, I remember much discussion about the implications ( so many of them that even a tiny non-zero rest mass would have big implications for the expansion etc.)

stands by to be shot at

[Ptarmigan]

and the barman says "is this a joke" .

An electron neutrino, a muon neutrino and a tau neutrino walk into a bar ,

[Nillchill]

Has that been confirmed ? I am a bit out of touch on it, I remember much discussion about the implications ( so many of them that even a tiny non-zero rest mass would have big implications for the expansion etc.)

stands by to be shot at

In May 2010, it was reported that physicists from CERN and the Italian National Institute for Nuclear Physics' Gran Sasso National Laboratory had observed for the first time a transformation in neutrinos; evidence that they have mass.

In July 2010 the 3-D MegaZ experiment reported that they had measured the upper limit of the combined mass of the three neutrino varieties to be less than 0.28 eV.

it's also why the observations are startling if found to be correct

[Ptarmigan]

In May 2010,,,,, a transformation in neutrinos; evidence that they have mass.

Oh yes, I had read about the neutrino oscillations, didnt realise that it was as late as 2010 and that it implied rest mass,,

In July 2010 the 3-D MegaZ experiment reported that they had measured the upper limit of the combined mass of the three neutrino varieties to be less than 0.28 eV.

I see, but "upper limit" dont exclude it being less than to the extent of zero !?

I think I need to do some more reading ,,,

it's also why the observations are startling if found to be correct

Yes, quite so.

Thanks.

[661-pete]

As a physics non entity, I might be way off beam here. (No pun.)

I understood that the restriction on exceeding light speed, was that mass increased ad infinitum. Since Neutrinos are massless particles, that progression can't take place, therefore there is no barrier to exceeding light speed.

I'll be happy to read the replies that shoot this down, because I will then be a little wiser.

Ron.

That's fine, if you don't mind coping with an imaginary number i.e. √(-1) to represent the mass....

Now of course, if mathematicians were to suddenly discover a real number that equals √(-1) .....

[Nillchill]

I'm glad i started this thread, it's been quite a good discussion. thanks to all who have responded so far.

[661-pete]

I should point out that the light-speed limit only applies to matter, or energy, or entities that can carry information, from one point to another. Phase waves in quantum mechanics, which don't convey information, have long been postulated as travelling faster than light, but they are only an artifice.

A simple experiment - if you have a really powerful laser (your typical green laser pointer won't do!). Aim it at the moon and then jerk it quickly sideways. The spot of light will sweep across the moon's surface at a good deal more than the speed of light. That is OK, because there is no causal connection between the successive points that the spot rests on.

[Ptarmigan]

I'm glad i started this thread, it's been quite a good discussion. thanks to all who have responded so far.

Seconded

Yer, I been following in an amateurish way all this elementary particle stuff since ('60s) Gell-Mann, Weinberg and the eightfold way then on to the problems with the resulting "standard model".

Knew it had probs dealing with dark matter and other exotics but missed totally this link between neutrino flavours and mass as being yet another prob for the standard model.

(most likely cos I cant afford to buy New Scientist every week ! it's a lot of dosh to pay for all those adverts )

So, ok, 0.28eV or less is exceeding small ( and tiny compared to what particle physics normally deals in !) it is still big in terms of the mass of the universe, so how come exotic dark energy is enough to avoid a "big crunch" ?

[Ptarmigan]

I should point out that the light-speed limit only applies to matter, or energy, or entities that can carry information, from one point to another. Phase waves in quantum mechanics, which don't convey information, have long been postulated as travelling faster than light, but they are only an artifice.

Yes true for phase, but tell the rest to a quantum entangled pair that carry information about their state to, in the limit, either side of the universe (or beyond? nurse, nurse, help !!)