Faster than the speed of light?

Where I was going was really that all our observations - until recently - have used light or waves travelling at light speed. I think i get how they have done this, distance over time and all that but what I was thinking was that if something is going faster than c, these waves will never reach the thing we are looking at.

All this stuff about it breaking causality? Surely it doesn't because its not like the effect happened before the cause, just that it happened before cause + distance / c. The effect could have been caused by something else going faster than c. Now if you start seeing effects before the cause (negative time) that would break causality, but surely this doesnt? What's your take on where this could lead us? Do you have to believe in folding space time to justify all this?
 
I haven't studied general relativity, which is where bending space time etc. comes from, at all so it's dodgy ground for me really. Frankly relativity just messes with my head, so please forgive me if I just speak a load of rubbish.

If I cheat and ignore the causality question, if you look at special relativity you have terms like gamma = 1/sqrt(1 - v^2/c^2) appearing (v being the speed of the particle and c the speed of light). If v is greater than c then you have a square root of a negative number to deal with - which is fine in Maths (imaginary numbers*) but not so much fun when you end up with masses, energies etc. that have imaginary components (i.e. not Physical or not really consistent with 'real life' experiences). For example E = gamma*m*c^2 (not just E = m*c^2).

Now, I'll try and give a quick attempt to explain why travelling faster than the speed of light can break causality. Light has the strange property that it always travels at the same speed. For example, if you can throw a ball at 10mph when stood still, if you then throw that ball in a car moving at 40mph the ball will be moving at 10+40 = 50mph. Strangely, the light coming out of a stationary torch and a moving one travels at the same speed, 3x10^8 metres per second. But this means if you put a torch in a car moving faster than the speed of light, the torch would arrive before the light. In fact, to someone in that car it would look like the light is moving backwards, or I guess you could say that the torch is coming out of the light?! This doesn't make sense and breaks causality.

There are ways that the difference could be explained without the neutrinos actually travelling faster than light, for example extra dimensions as mentioned by Brian Cox in the link posted before. Neutrinos themselves are not particularly well understood as they travel through basically everything unaffected so are hard to detect. As you are reading this loads of little neutrinos from the sun will be passing through you. I am not going to pretend to have any idea where the new Physics to explain this result would eventually come from if it is proved to be correct though.

There's a mix of ramblings for you, hopefully something will be useful in there?!

* For those that don't know, imaginary numbers are written like 2 + 3i, where i is the square root of minus 1 (something that doesn't really 'exist' but nevertheless appears everywhere in Maths and Physics and is used to calculate real life quantities). So, for example, the square root of -4 is 2i.
 
As you were...

Those clocks are receiving a signal from an orbiting satellite, which is moving in reference to the Earth. This creates two frames of reference for the experiment, and not one, says van Elburg.

When it comes to relativity, frame of reference is everything. The satellite in this experiment was moving from West to East, tilted 55º in reference to the equator. Taken from this vantage point, the distance between the source of the neutrinos at CERN and the detector in Italy are actually changing. The excellent Physics arXiv blog at MIT’s Technology Review quotes van Elburg as saying, “From the perspective of the clock, the detector is moving towards the source and consequently the distance travelled by the particles as observed from the clock is shorter.”

Van Elburg says that this would throw off the experiment’s timing by 32 nanoseconds on each end of the experiment, for a total of roughly 64 nanoseconds of error in the experiment overall. This would mean that neutrino speed is quite similar to that of light, but not faster.
Click to expand
http://idealab.talkingpointsmemo.co...nation-for-cerns-faster-than-light-claims.php
 
From the original report, it certainly seems that great care was taken to synchronise the clocks.

Page 9

A key feature of the neutrino velocity measurement is the accuracy of the relative time
tagging at CERN and at the OPERA detector. The standard GPS receivers formerly installed at
CERN and LNGS would feature an insufficient ~100 ns accuracy for the TOFν measurement.
Thus, in 2008, two identical systems, composed of a GPS receiver for time-transfer applications
Septentrio PolaRx2e [16] operating in “common-view” mode [17] and a Cs atomic clock
Symmetricom Cs4000 [18], were installed at CERN and LNGS (see Figs. 3, 5 and 6).
The Cs4000 oscillator provides the reference frequency to the PolaRx2e receiver, which is
able to time-tag its “One Pulse Per Second” output (1PPS) with respect to the individual GPS
satellite observations. The latter are processed offline by using the CGGTTS format [19]. The
two systems feature a technology commonly used for high-accuracy time transfer applications
[20]. They were calibrated by the Swiss Metrology Institute (METAS) [21] and established a
permanent time link between two reference points (tCERN and tLNGS) of the timing chains of
CERN and OPERA at the nanosecond level. This time link between CERN and OPERA was
independently verified by the German Metrology Institute PTB (Physikalisch-Technische
Bundesanstalt) [22] by taking data at CERN and LNGS with a portable time-transfer device [23].
The difference between the time base of the CERN and OPERA PolaRx2e receivers was
measured to be (2.3 ± 0.9) ns [22]. This correction was taken into account in the application of
the time link.
Click to expand

My guess is that right now there is a conversation going on between CERN and those Mereology Institutes about the sums they did in 2008. We will find out soon enough, either they did or they didn't.
 
One of the things I love* about science (and which probably keeps most scientists going) is the way you never get to a simple clear explains-it-all answer. Inevitably every new discovery opens up a whole new bunch of interesting and exciting questions to explore. Judging by the way previous discoveries have panned out, it seems to me that the Higg's Boson is far too perfect a solution, and it'll no doubt end up being something far more mysterious and complex than anyone ever predicted. God/mother nature/the cosmos always has another trick up his/her/its sleeve!

*Although, I do remember that this was the very thing I hated about physics lessons as a teenager: "why can't it just have an answer?!"
 
Around 1990 the astronomers said that they had basically uncovered how the universe works, all they had to do was find more matter to stop it flying apart.

Around 2000 they still had not found enough matter, so to stop the universe flying to pieces they were seaching for dark matter. Also everything was a lot too light anyway, what they needed was the Higgs boson.

Around 2010 they still had not found the dark matter but they did know that it was associated with dark energy. Higgs boson had not yet been found but the new, more powerful particle accelerator should nail it. Oh, by the way, the speed at which the universe is expanding is increasing, there must be some cause but we're not sure what.

2011 there is still no sign of the dark matter. Higgs boson has gone into hiding, and we're not going to say anything more about the increase of the rate of expansion of the universe. By the way, the possibility of neutrinos going faster than the speed of light has could blow away Einstein and totally change our (lack of) knowledge of how the universe works.

Such is progress and could we have some more money, please.
 
sushifiesta said:
This is the key really. You won't find many people rewriting the laws of Physics before at least one/two independent experiments get the same result. There has been a couple of previous experiments (in particular one by MINOS and one based on neutrinos from a Supernova) that did not find neutrinos travelling faster than light, or at least couldn't claim that when the error in their experiments is taken into account (I think MINOS found a neutrino speed above the speed of light but the error in their result meant it still could be less).
Click to expand

Hi, I know I'm a bit slow to this party, but I really do find this stuff interesting. When the news of this first broke I firstly simply brushed it off as I thought there was certaintly some form of calculational error. However, I have since seen the documentary on BBC2 and am thinking quite differently now!

Thank you for your contributions sushifiesta, very helpful and I am sooo jealous of you being at CERN!

What excites me most about this potential discovery is the fact that it has the potential to 'turn theories on their head', but it is not neccessarily going to prove Einstein to be wrong either.

With regards to the potential error in the calculation of the speed, it is clear that there was going to be some margin for error. However, the evidence suggests so far that even with all these errors accounted for the neutrinos are still travelling faster than light. Of course there may be something which has not yet been picked up on.

Nevertheless, this "phenomenom" is not actually the first of its kind. As sushi points out above, neutrinos were discovered to be going faster than light in America (MINOS), although, as he also points out, their instruments were not refined as those at OPERA and therefore the potential margin for error allowed for the fact that the could be travelling less than the speed of light. However, even more surprising is that neutrinos travelling faster than light were discovered 10 years ago in China by a scientist called Guang-Jiong Ni (a muon neutrino in a vacuum). In light of this, there is certaintly more weight behind OPERA's claim!

From a mathetical point of view (having studied maths myself) it is actually possible for particles to travel faster than the speed of light. In order for this to happen the particles must already be travelling at faster than c when they are created. These undiscovered/imaginary particles are called Tachyons and I believe, although not entirely sure, that these particles have imaginary/complex masses. Having not studied these in any detail, I am unsure of how exactly there might work, but perhaps Sushi may know more?

This clearly shows that particles travelling at the speed of light does not neccessarily disprove relativity, but such a discovery may help shed light on the relationship between relativity and quantum theory. As I understand it scientists are having a difficult time to marry these two theories together and maybe this could be the catalyst. There are some theories such as string theory, albeit these are extremely abstract and would be difficult to prove.

I hope that this is the beginning of something new and exciting and not just a miscalculation. With any luck we should know more in a few months time. I think they are planning to fire more neutrons out of CERN to OPERA with the sole intention of calculating their speed whilst reducing the pulse time, which should increase the accuracy of any readings.

Let's wait and see :)
 
Bill Boddy said:
Around 2010 they still had not found the dark matter but they did know that it was associated with dark energy. Higgs boson had not yet been found but the new, more powerful particle accelerator should nail it. Oh, by the way, the speed at which the universe is expanding is increasing, there must be some cause but we're not sure what.
Click to expand

The problem with Dark matter is that it is the exact opposite of matter (us). So like 1 and -1 when they meet it become zero. Both cease to exist. And out matter eyes can't see them, except occasionally when they bump into our matter. It is feasable that entire dark matter galaxies exist, if they haven't been interfered with by our matter.

Also does anyone know if strings and quantum foam weigh anything? That might count up for the missing 70% of the universe weight, as they are everywhere, whereas matter is only 0.01% of all places.

More insight by Prof Tooncheese dPH iTs LI eS
 
tooncheese said:
The problem with Dark matter is that it is the exact opposite of matter (us). So like 1 and -1 when they meet it become zero. Both cease to exist. And out matter eyes can't see them, except occasionally when they bump into our matter. It is feasable that entire dark matter galaxies exist, if they haven't been interfered with by our matter.
Click to expand

Tooncheese, I'm a little confused here. Are you talking about Anti-Matter? I thought dark matter was purely a part of a theory to explain gravitational forces keeping the universe from flying apart, whereas anti matter is the complete opposite of matter.
 
Found this: http://csep10.phys.utk.edu/astr162/lect/cosmology/antimatter.html

It is conceivable that the dark matter (or at least part of it) could be antimatter, but there are very strong experimental reasons to doubt this. For example, if the dark matter out there were antimatter, we would expect it to annihilate with matter whenever it meets up with it, releasing bursts of energy primarily in the form of light. We see no evidence in careful observations for that, which leads most scientists to believe that whatever the dark matter is, it is not antimatter.
Click to expand
 
:embarrassed: Oops, there's me using big words and I get it wrong. Yes I meant Anti-Matter that had a bit of a war with Matter. In the second paragraph I spoke about Dark energy which what speeds up the universes expansion I believe.
 
tooncheese said:
:embarrassed: Oops, there's me using big words and I get it wrong. Yes I meant Anti-Matter that had a bit of a war with Matter. In the second paragraph I spoke about Dark energy which what speeds up the universes expansion I believe.
Click to expand
Hehe, that all makes sense now! Although I still don't really understand Dark Matter and Energy, they seem like randomly created stuff (for want of a better word) to explain the universe's behaviour.
 
Chasz said:
Hehe, that all makes sense now! Although I still don't really understand Dark Matter and Energy, they seem like randomly created stuff (for want of a better word) to explain the universe's behaviour.
Click to expand
They probably said the same about oxygen when that was first thought of?
 
Chasz said:
Hehe, that all makes sense now! Although I still don't really understand Dark Matter and Energy, they seem like randomly created stuff (for want of a better word) to explain the universe's behaviour.
Click to expand

That's exactly what they are, well not randomly created but this is how science works. The same can be said for the Higgs Boson etc. They are things that we need in theories to make them match experimental results but haven't found yet. Science is basically a big loop of refine experiment, refine theory, refine experiment, refine theory etc. etc.
As for the mention of tachyons I can't really comment as they're not something I've ever really come across but I guess we have to remember that these are meant to be neutrinos, which are fairly well understood, not some as yet undiscovered, hypothetical particles.

tooncheese said:
Also does anyone know if strings and quantum foam weigh anything? That might count up for the missing 70% of the universe weight, as they are everywhere, whereas matter is only 0.01% of all places.
Click to expand

Again, string theory is something I definitely don't understand, but strings, if they exist, would be the microscopic building blocks of everything. The mass measurements are macroscopic based on things that contain strings so I'm thinking the 'mass' of the strings would already be included. Sorry for such a vague, sketchy and probably inaccurate explanation.
 

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