Due to curvature, wouldn’t another detector in-line have to be tunneled pretty deep? Or could it just be in the same room but just in front of the existing detector?
Ideally, you’d want it to be in the same room as the source. The idea is that if you’re comparing times from one detector to another detector, you don’t have to worry about any effects from the source at all, and as long as the detectors are identical, the effects from the detectors will cancel out, so you don’t have to worry about those, either. But measuring from one detector to the other means you want the two detectors to be far apart.
I wonder how long the pulse is. Since the neutrino detector, I assume, detects only a handful of neutrinos out of billions emitted, could it be that one detector would, randomly, detect some from beginning of pulse, and the other from the end of it, or vice versa? I guess if you do enough runs it will all cancel out.
I would be absolutely gobsmacked if that weren’t one of the first things they considered and ruled out.
10 microseconds.
This is a single-detector experiment, however the issue remains even there. In this case, they accumulated several thousand neutrino interactions in the detector to construct a time profile that has a generally square-pulse shape (but with some features). They also measured the proton beam profile at CERN, which has an equivalent shape (although I have reservations about what they have shown so far on this point). They then aligned those distributions, finding that they line up best if they introduce this 60 ns shift relative to what is expected.
Since neutrinos pass through matter like this and travel faster than light (possibly), wouldn’t our worldwide telecommunications be improved by setting up neutrino emitters/detectors that shoot through the ground to the other side of the planet instead of bouncing data from satellite to satellite?
It would also cut down on space debris.
That’s very true. It would be a practical application of this. Round-the-world is not quite realtime , whereas straight through is realtime for a lot more practical purposes (1/7th of a second versus 1/20th IIRC), so it would improve playability of games and two-way global conversations.
You underestimate how hard it is to make and detect neutrinos. Also, the Earth is big. Going right through the middle would reduce the neutrino flux relative to the OPERA experiment by a factor of 300, and OPERA only got one neutrino interaction every couple of hours. So, you’d be talking about a month or so between single interactions. Not exactly broadband-ready.
Also, note that the last stage of the neutrino production line is a 1-km-long evacuated decay channel inside of which the neutrinos are born. This structure doesn’t lend itself to arbitrary aiming. If you only wanted point-to-point communication, you could make a kilometer (or so) deep hole in the ground. But you’d still be many orders of magnitude away from useful communication.
(One way to help the numbers, at least, is to put the detector in a natural body of water. You can instrument a very large volume of water for not too much money, and more volume means a higher interaction rate. But, you will still be tied to point-to-point communication, and you will still need to amp up your beamline by several orders of magnitude beyond what we know how to do right now just to become competitive with a 2400 baud modem.)
So you’re saying that in ten years I’ll be wearing an accurate neutrino transmitter on my wrist watch.
The factors which limit miniaturization of neutrino instruments are unrelated to the factors which limit miniaturization of electronics, and are much more fundamental. We can make electronics smaller just by figuring out ways to arrange atoms on finer and finer scales. But neutrino detectors aren’t limited by arrangement of atoms, but by sheer number of them. It’s conceivable, of course, that someone will come up with such a huge revolution in how we understand neutrinos that we could figure out how to detect them far more efficiently. But such a revolution would take at least a decade (and probably two or three) just to make its way through science, before anyone even started implementing technologies based on it.
And the then they’ll send the directions back to us here in the past. Duh. Really, should only take a year or two to hit the market.
All this talk of tachyons that don’t interact, and have uniformly greater than c velocity leaves me with a mind image that puzzles me.
Throughout time, from the big Bang to the end of the epoch of proton decay, it seems to me that some rather large number, or zero are the only possible answers to how many tachyons get produced in the universe. Since they cannot interact, without really pissing Chronos off, and they move backwards in time, and through space at greater that c, don’t they all have to arrive at the singularity, at Universal Time 0?
Sorry to stick my foot in this, but I have been imagining it all day.
Tris
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Can someone post the link where I can dload the article, for free if possible. I read the concluding paragraph and it is magnificent, science at it’s best (plus it will be famous one day…). But I lost the damn URL for that paragraph.
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Thats the beauty of it. All those particles from the future arriving at the exact same place at time 0 is what CAUSED the Big Bang. Its ALL that future time/space stuff that created the beginning.
Nice.
Naw, its more a “whoah dude” puff puff “thats deep man” puff puff.
But its vodka induced in this case not stuff you inhale. But it does sound scarily plausible doesn’t it?
One of my points still remains: any object with mass, no matter how small, by Einstein can never reach the"cosmic speed limit" as it would have to reach infinite mass to do so. How then can either photons or neutrinos be said to do that?
And if someone wouldn’t mind, a brief explanation of *relativistic mass *might be nice. I understood this to be the reason (a reason that I don’t understand) why sometimes photons are said to be massless, and sometimes not.
Well if the universe in all its time just “is” … then yeah. The end of time for a tachyon that cannot interact with normal matter would be the start of time for us. And the end of time for normal matter would be the start of time from a tachyon POV. Causation being infinitely recursive, no more problematic than infinity and no “first cause” (or having a “first cause” too) always is, really.
In other words, Dr McCoy’s gift glasses emerged intact from the Big Bang, to eventually land on Earth intact and be gifted to Jim Kirk? 
As probable as a mother in law visiting detector… ]