Thursday, October 20, 2011

Good News! Relativity Is Saved! (Probably)


Speedy neutrino mystery likely solved, relativity safe after all
By Evan Ackerman
6:59PM on Oct 14, 2011

Those weird faster-than-light neutrinos that CERN thought they saw last month may have just gotten slowed down to a speed that'll keep them from completely destroying physics as we know it. In an ironic twist, the very theory that these neutrinos would have disproved may explain exactly what happened.

Back in September, physicists ran an experiment where they sent bunches of neutrinos from Switzerland to Italy and measured how long the particles took to make the trip. Over 15,000 experiments, the neutrinos consistently arrived about 60 nanoseconds early, which means 60 nanoseconds faster than the speed of light. Einstein's special theory of relativity says this should be impossible: nothing can travel faster than light.

The fact that the experiment gave the same result so many times suggested that one of two things was true: either the neutrinos really were speeding past light itself and heralding a new era of physics, or there was some fundamental flaw with the experiment, which was much more likely. It's now looking as though the faster-than-light result was a fundamental flaw, and appropriately enough, it's a flaw that actually helps to reinforce relativity rather than question it.

The Experiment

Here's the deal: neutrinos move very very fast (at or close to light speed, at least), and the distance that they traveled in this experiment was (to a neutrino) not that far, only 450 miles. This means that in order to figure out exactly how long it takes a given neutrino to make the trip, you need to know two things very, very precisely: the distance between the two points, and the time the neutrino leaves the first point (the source) and arrives at the second point (the detector).

In the original experiment, the CERN researchers used GPS to make both the distance measurement and the time measurement. They figured out the distance down to about 20 centimeters, which is certainly possible with GPS, and since GPS satellites all broadcast an extremely accurate time signal by radio, they were also used as a way to sync the clocks that measured the neutrino's travel time. The CERN team had to account for a lot of different variables to do this, like the time that it takes for the clock signal to make it from the satellite in orbit to the ground, but they may have forgotten one critical thing: relativity.

It's All Relative

Relativity is really, really weird. It says that things like distance and time can change depending on how you look at them, especially if you're moving very fast relative to something else. In the case of the neutrino experiment, we've got two things to think about: the detectors on the ground that measure where and when the neutrinos depart and arrive, and the GPS satellites up in space that we're using as a basis for these measurements. Since the satellites are orbiting the Earth and moving way faster than the detectors, we say that they're in a different "reference frame," which just means that the motion of the satellites is significantly different than the motion of the Earth.

Part of the deal with relativity is that neither of these reference frames are the "correct" one. From our perspective here on Earth, the satellites are whizzing around in orbit at about 9,000 miles per hour. But the perspective of the satellites, the Earth is whizzing around just as fast, and the difference in velocities between these two reference frames is large enough that some strange things start to happen.

A Satellite's Perspective

To understand how relativity altered the neutrino experiment, it helps to pretend that we're hanging out on one of those GPS satellites, watching the Earth go by underneath you. Remember, from the reference frame of someone on the satellite, we're not moving, but the Earth is. As the neutrino experiment goes by, we start timing one of the neutrinos as it exits the source in Switzerland. Meanwhile, the detector in Italy is moving just as fast as the rest of the Earth, and from our perspective it's moving towards the source. This means that the neutrino will have a slightly shorter distance to travel than it would if the experiment were stationary. We stop timing the neutrino when it arrives in Italy, and calculate that it moves at a speed that's comfortably below the speed of light.

"That makes sense," we say, and send the start time and the stop time down to our colleagues on Earth, who take one look at our numbers and freak out. "That doesn't make sense," they say. "There's no way that a neutrino could have covered the distance we're measuring down here in the time you measured up there without going faster than light!"

And they're totally, 100% correct, because the distance that the neutrinos had to travel in their reference frame is longer than the distance that the neutrinos had to travel in our reference frame, because in our reference frame, the detector was moving towards the source. In other words, the GPS clock is bang on the nose, but since the clock is in a different reference frame, you have to compensate for relativity if you're going to use it to make highly accurate measurements.

Not So Fast

Researchers at the University of Groningen in the Netherlands went and crunched the numbers on how much relativity should have effected the experiment, and found that the correct compensation should be about 32 additional nanoseconds on each end, which neatly takes care of the 60 nanosecond speed boost that the neutrinos originally seemed to have. This all has to be peer-reviewed and confirmed, of course, but at least for now, it seems like the theory of relativity is not only safe, but confirmed once again.

23 Comments:

At 10/20/2011 9:15 AM, Anonymous Anonymous said...

My scientist friends (none of them physicists) all glanced at the original article and immediatedly assumed some kind of experimental error.

"It's all relative"

Except that the point of the theory of relativity is that it all isn't. Most things are relative, but the speed of light is constant regardless of frame of reference. This is why things get so weird as soon as they get fast.

And why the theory gets so badly abused when we humanities types use it as a metaphor ... we tend to ignore the most important part.

Paul

 
At 10/20/2011 5:58 PM, Blogger Gary B. Fitzgerald said...

.

Time


“When I was a boy, time didn’t seem so fast.
You could savor the moment. Things seemed to last.
School days never ended but summer took forever,
playing games or lazy fishing, waiting for dinner.
But now that I’m older it seems like time’s passed
before I even spent it, and now that I consider it,
I think it’s going even faster.”

I believe this is true, I replied.
I think Einstein even proved it. Consider this:
if the gravity at a black hole slows time,
then it’s lack must surely speed it.
So if gravity weakens as the Universe expands,
then wouldn’t time be going faster?

Likewise, Einstein’s identical twins:
if one travels for an hour near the speed of light
when he returns in an hour he’ll find his brother
is now twenty years older.
So if high velocity shrinks time,
then its decrease must surely stretch it.
If the expansion of the Universe is slowing,
and gravity decreasing, if velocity is waning,
then wouldn’t time be going ever faster?

But don’t take it from me…take it from you.
Reconsider your time when you’re seventy-two.

Copyright 2010 - Ponds and Lawns-New and Corrected Poems, Gary B. Fitzgerald

 
At 10/20/2011 6:45 PM, Blogger Gary B. Fitzgerald said...

.

A Flower

Such a simple thing,
just a flower;
petals and pistil and stamen,
a scent and a color,
a bloom and some seeds.
Just a stem and some leaves,
growing, absorbing, reflecting
the light, some roots taking
water from soil.
Just xylem and phloem, some
membranes and tissue and cells,
a nucleus, some organelles,
green chloroplasts transforming
the sun into starches and sugars,
just chlorophyll, molecules
of elements and atoms built
of protons and electrons,
muons and quarks, made of waves
and strings and fields of time
and space and energy and chance.
It’s really quite simple.
Just a flower.


Copyright 2008, HARDWOOD-77 Poems, Gary B. Fitzgerald

 
At 10/20/2011 6:55 PM, Anonymous Anonymous said...

Ok, so there's another absolute in the universe. I won't state the obvious.

Paul

 
At 10/20/2011 7:04 PM, Blogger John Gallaher said...

Paul,

Absolutely.

 
At 10/20/2011 8:13 PM, Blogger Gary B. Fitzgerald said...

Ouch!

Absolutely glad that you enjoyed the poetry, though.

 
At 10/21/2011 3:57 AM, Anonymous Scary Be DeLuna said...

A Penis

Moments of some simple elevators,
muons, cenotaphs, stashes, elixirs and
moments of some memsahibs elixirs
fluke; pews a fluke. Such provinces,
some simple xylem, a fluke; such
numerals, A from a and timpanist
and timpanist and some memsahibs
and stashes and some transforming
the fights channel. It’s pistil quarks;
provinces blow and some memsahibs
are sultans into transforming the waysides
into rostrums and schemer strolls channel.
It’s attacks, schemer of moments of leaves,
growing cenotaphs, a solecism.
Just stepdaughter toad, engraver
taking waterproof A engraver.

 
At 10/21/2011 5:12 PM, Blogger Gary B. Fitzgerald said...

.

Evil or stupid…
you can’t tell the difference.

The stupid act evil
and the evil play dumb.


Copyright 2010 - Ponds and Lawns-New and Corrected Poems, Gary B. Fitzgerald

 
At 10/21/2011 5:54 PM, Blogger Gary B. Fitzgerald said...

.


Evil

Of sunlight and moonlight what can I say?
One shines in the night, one brings us the day.
One reflects in the darkness but the one
in the deeper dark brings the light.

Of protons and electrons, what said of their way?
One positive, one not, one shall follow, one stay.
One spins toward the yes but that spun
towards the no brings the balance.

A strange symmetry here on the planet of life,
for easily, if no moon, only dark in the night.
But if no night and no moon to rise in the sky,
then no day to divide the when from the why.

If no danger, no struggle, no reason to fight.
If no equal opposing, no wrong to make right.


Copyright 2009 - Tall Grass & High Waves, Gary B. Fitzgerald

 
At 10/22/2011 4:31 AM, Anonymous Anonymous said...

"His vanity requires no response, And makes a welcome of indifference."

 
At 10/22/2011 6:09 PM, Blogger Gary B. Fitzgerald said...

Anonymous said:

"His vanity requires no response, And makes a welcome of indifference."

T.S. Eliot


(You should attribute the quotes you offer to those you quoted).


“Vanity is so secure in the heart of man that everyone wants to be admired: even I who write this, and you who read this”

Blaise Pascal

 
At 10/22/2011 6:19 PM, Blogger Gary B. Fitzgerald said...

This comment has been removed by the author.

 
At 10/22/2011 7:04 PM, Anonymous Anonymous said...

When the man in the urine-soaked trench coat on the subway interrupts my conversation and flashes me, this too is an example of sharing with others.

I guess my point is that some kinds of sharing are more welcome than others.

Paul

 
At 10/22/2011 7:15 PM, Blogger Gary B. Fitzgerald said...

And, by the way, who the hell would even bother to write a poem, or a novel, or a short story or a book of any kind if they didn't want to share it with others?

I guess, by your measure, this puts me in good company: with every poet or writer who ever lived.

 
At 10/22/2011 7:31 PM, Blogger Gary B. Fitzgerald said...

.

Anonymous said:


"When the man in the urine-soaked trench coat on the subway interrupts my conversation and flashes me, this too is an example of sharing with others.

I guess my point is that some kinds of sharing are more welcome than others.

Paul"

I suppose that this would make more sense if this was actually YOUR blog, Paul, rather than Mr. Gallaher's.

If I threw a party and one of my guests told another one that they weren't welcome, not only would I throw him out but I'd kick his ass too.

Who the hell are you to say who is or isn't welcome here, you megalomaniacal nincompoop?

And, by the way, If you don't like my poems, all you have to do is not respond. I'll get the message. Your aggression is unbecoming and unnecessary. It serves nobody's purpose.

If you don't like my poetry then

A) Don't buy the books,

B) scroll past my comments, and

C) Just STFU.

 
At 10/22/2011 8:02 PM, Blogger Gary B. Fitzgerald said...

And one further thing, Paul. There are many people, maybe hundreds, who read Gallaher's blog (although you may comment the most), but I get a lot of feedback from other places and there are a lot of people out there who like my poetry.

You might consider a little more consideration.

GBF

 
At 10/22/2011 9:06 PM, Anonymous Anonymous said...

Wow. Gary, you really seem to think my example was unfair to the man in the urine-soaked trench coat. I formally extend my apologies to him.

Paul

 
At 10/23/2011 12:28 PM, Blogger John Gallaher said...

Gary,


Please don't bring me into this. I’m grateful for Paul’s presence on this blog. He’s contributed many things of value.

 
At 10/23/2011 5:25 PM, Blogger Gary B. Fitzgerald said...

John said:

"Gary,

Please don't bring me into this. I’m grateful for Paul’s presence on this blog. He’s contributed many things of value."

Then tell him to stop being a bully and picking on me. He shouldn't beat up your customers.

If my poetry isn't welcome here there are at least twenty blogs where it is. I just happen to prefer this one.

It is not my intention to be a nuisance, but I never thought of poetry as a nuisance.

And, FYI, one of these days I'm going to comment here when I'm sober and THEN you'll be sorry!

Gary

(WV: Garien. Now is that weird or what?)

 
At 10/23/2011 5:37 PM, Blogger John Gallaher said...

Gary,

You obviously want to share your poetry. It sounds like, if there are 20 other websites that would welcome your poems, you should certainly share them there.

Another alternative would be to start a blog. It's as easy as commenting on a blog. You can be up and posting in a few minutes.

As for this blog, maybe we can come to a compromise. How about you limit yourself to posting one poem a week? Maybe every Friday. That way you could start the weekend off some verse.

As it is, I see no way in which Paul was/is acting like a bully.

 
At 10/23/2011 6:00 PM, Blogger Gary B. Fitzgerald said...

"He's not a bad man, just ambitious."

- Jeff Beck

 
At 10/23/2011 6:05 PM, Blogger Gary B. Fitzgerald said...

John:

You may have noticed (hopefully) that I only post poems that are relevant to the subjects of your posts. Since I write a lot of Science related poetry and this was a Science related post, it was a natural.

I will try to refrain in the future.

Gary

 
At 10/23/2011 6:38 PM, Blogger Gary B. Fitzgerald said...

I do want to say, though, that I find it regrettable to learn, based on your comments above, that you are not a big fan of my poetry. I’m sorry.

 

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