Science: Don't Worry, Physics Is Safe

Earnest Cavalli

New member
Jun 19, 2008
5,352
0
0
Science: Don't Worry, Physics Is Safe



Remember those faster-than-light particles discovered last month? The ones that threatened our notions of how reality functions? Science now has an explanation for that.

Those of you who religiously follow our coverage of science will recall an article from the end of last month [http://www.escapistmagazine.com/news/view/113292-Scientists-Baffled-By-Seemingly-Faster-Than-Light-Particles] in which we relayed the news that scientists had discovered minute particles that were seemingly traveling faster than the speed of light. As I wrote at the time, this is just not supposed to happen and the worldwide scientific community was overcome by a chorus of "harumphs" and monocles falling out of place.

Now it seems the sciencefolk have an explanation for the phenomenon.

Long story, short, relativity is a harsh, confusing mistress that screwed up the scientists' ability to accurately measure the distance between where the particles originated, where they ended up and the amount of time that their trip took.

Long story, long, Dvice reports:

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.

Scientists at the University of Groningen in the Netherlands did the math, and based on this theory, the neutrinos should have picked up an extra 32 nanoseconds of relativity from each of the two "observers." Given that the average amount of unaccounted for time in the 15,000 experiments originally performed at CERN was 64 nanoseconds, that lines up nicely.

And, as a depressing result, ruins any chance we might've had at harnessing the power of superluminal particles. Sorry Billy, looks like you won't be getting that dinosaur for Christmas. Those science jerks had to go and ruin it for you.

Source: Dvice [http://dvice.com/archives/2011/10/speedy-neutrino.php]
(Image [http://www.flickr.com/photos/vincentghyssens/3071053062/])

Permalink
 

Redingold

AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
Mar 28, 2009
1,641
0
0
Wait, that doesn't make sense. GPS satellites are in a geosynchronous orbit. The Earth doesn't appear to move from their perspective. What detail am I missing here?
 

Femaref

New member
May 4, 2008
186
0
0
Redingold said:
Wait, that doesn't make sense. GPS satellites are in a geosynchronous orbit. The Earth doesn't appear to move from their perspective. What detail am I missing here?
geosynchronous != geostationary. There is a difference between those, and while you won't pick that up in normal usage, in that case the difference was measureable. Geosynchronous satellites are at the same spot at the same time, however, they move north and south abit over the day. And that is exactly what was measureable.
 

CrystalShadow

don't upset the insane catgirl
Apr 11, 2009
3,829
0
0
Well, as much as I like to make unfair complaints about science, this was predictable.

And of course, the explanation makes perfect sense. (To me at least. There's a downside to having been a physics student.)

Redingold said:
Wait, that doesn't make sense. GPS satellites are in a geosynchronous orbit. The Earth doesn't appear to move from their perspective. What detail am I missing here?
Well, to quote wikipedia:

"A geosynchronous orbit (sometimes abbreviated GSO) is an orbit around the Earth with an orbital period that matches the Earth's sidereal rotation period.[1] The synchronization of rotation and orbital period means that for an observer on the surface of the Earth, the satellite appears to constantly hover over the same meridian (north-south line) on the surface, moving in a slow oscillation alternately north and south with a period of one day, so it returns to exactly the same place in the sky at exactly the same time each day.

However, the term is often popularly used to refer to the special case of a geosynchronous orbit called a geostationary orbit.[2] This is a geosynchronous orbit that is circular and at zero inclination, that is, directly above the equator. A satellite in a geostationary orbit appears stationary, always at the same point in the sky, to ground observers. Communications satellites are often given geostationary orbits, or close to geostationary, so that the satellite antennas that communicate with them don't have to move, but can be pointed permanently at the fixed location in the sky where the satellite appears."

So, no. A satellite in a geosynchronous orbit is not stationary relative to the earth. It's only stationary relative to a particular meridian.

There's also a secondary issue entirely due to relativity:

Being inside a gravity well (such as the earth's gravitational field) creates relativistic distortions proportionally to the strength of gravity.

Since this follows the inverse square law, the higher above the earth's surface you are, the faster time appears to move relative to someone on the ground.

(This has been demonstrated and measured at the altitude jets fly at. It's effects will be larger in orbit.)

While my knowledge of relativity isn't quite strong enough to say much more on the issue, suffice to say that due to the gravitational effects alone, a satellite is in a different frame of reference compared to anyone measuring on the ground.

Thus, forgetting to correctly account for such relativistic effects will cause measurement errors if one of your sources of data is a satellite, and some of the others are ground-based.
 

Sizzle Montyjing

Pronouns - Slam/Slammed/Slammin'
Apr 5, 2011
2,213
0
0
So... i can't go on about how Physics could actually be completely wrong?
CURSES!!!

I will beat these fancy scientists... one day...
 

Quaxar

New member
Sep 21, 2009
3,949
0
0
See? I told you last month and you called me crazy.
Who's crazy now? I WILL EAT YOUR HEARTS YOU MORTAL FOOLS!

Italian scientists probably were too busy partying with Berlusconi to account for that error. Happens to the best of us.
 

Redingold

AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
Mar 28, 2009
1,641
0
0
Femaref said:
CrystalShadow said:
More words.
Ah, I see. So what you're saying is that the satellite drifts north and south over time and this causes time dilation that affects the distance measurements, yes? I never thought about that, I always assumed that GPS satellites really were perfectly stationary to a ground observer. Well, ya learn something new every day. Danke.
 

ckam

Make America Great For Who?
Oct 8, 2008
1,618
0
0
This is good and somewhat bad. If the laws of physics itself was to be destroyed, that meant there would be a larger possibility than ever before to travel back in time and stop the Japanese from developing into a fundamentalist government that thrives on severely restricting video games, anime, manga, and the internet.

Also, this is called Superluminal phenomena.
 

Woodsey

New member
Aug 9, 2009
14,553
0
0
I guess this is the part where I arbitrarily question how these world-renowned scientists didn't account for factors X and Y beforehand, and pretend to know what the fuck I'm talking about.
 

jurnag12

New member
Nov 9, 2009
460
0
0
So, in short layman's terms, "We forgot to craay the 1 while holding our calculator upside down.".
PHYSICS TRIUMPH ONCE MORE
 

Thaluikhain

Elite Member
Legacy
Jan 16, 2010
19,150
3,891
118
Woodsey said:
I guess this is the part where I arbitrarily question how these world-renowned scientists didn't account for factors X and Y beforehand, and pretend to know what the fuck I'm talking about.
Heh.

But...is anyone surprised? C'mon, they flat out stated an error was the most likely solution to this in the article when this first came out.
 

Femaref

New member
May 4, 2008
186
0
0
Redingold said:
Femaref said:
CrystalShadow said:
More words.
Ah, I see. So what you're saying is that the satellite drifts north and south over time and this causes time dilation that affects the distance measurements, yes? I never thought about that, I always assumed that GPS satellites really were perfectly stationary to a ground observer. Well, ya learn something new every day. Danke.
Kein Problem.

Of course they are perfectly stationary to a ground observer. Unless the ground observer moves at 99% light speed through a space of 700km. That's the point. For the usual use case (fast moving car, boat or airplane), gps satellites are stationary enough.
 

Wieke

Quite Dutch.
Mar 30, 2009
391
0
0
Read about this a couple of days ago. I, however, did not know the paper was from the University Of Groningen, Netherlands ftw!
 

Para199x

New member
Nov 18, 2010
81
0
0
Sizzle Montyjing said:
So... i can't go on about how Physics could actually be completely wrong?
CURSES!!!

I will beat these fancy scientists... one day...
As a physics student I can tell you that you absolutely can say that physics could actually be completely wrong, in fact that's one of the major principles behind scientific method. Also everybody working in physics knows that quantum theory is incredibly incomplete. So yeah physics is "wrong" but it's a damn good approximation of reality
 

Redingold

AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
Mar 28, 2009
1,641
0
0
Femaref said:
Redingold said:
Femaref said:
CrystalShadow said:
More words.
Ah, I see. So what you're saying is that the satellite drifts north and south over time and this causes time dilation that affects the distance measurements, yes? I never thought about that, I always assumed that GPS satellites really were perfectly stationary to a ground observer. Well, ya learn something new every day. Danke.
Kein Problem.

Of course they are perfectly stationary to a ground observer. Unless the ground observer moves at 99% light speed through a space of 700km. That's the point. For the usual use case (fast moving car, boat or airplane), gps satellites are stationary enough.
Stationary enough != perfectly stationary

Perfectly stationary means that they don't appear to move AT ALL to a ground observer. Not even by a googolth (not a real word but you know what I mean) of an arcsecond. The GPS satellites, I presume, move slightly more than that.
 

FFHAuthor

New member
Aug 1, 2010
687
0
0
It seems like a quite simple thing (comparatively speaking) to miss in a calculation. Relativity, cornerstone of the majority of modern Physics, overlooked by physicists. Really?
 

AlexNora

New member
Mar 7, 2011
207
0
0
that's a shame...

I just want know why I should care is there any practical use for this information?
 

McMullen

New member
Mar 9, 2010
1,334
0
0
I seem to remember posting a thread suggesting we not jump the gun and get all excited about this "discovery", and predicting that the cause would be something along these lines (unaccounted-for relativistic effects and unforeseen errors in measurement). I seem to remember a bunch of people replying that I was a little too dismissive of the scientists doing the experiment. This, despite the fact that I was restating the exact thing that the scientists were, that it's exciting if true but that it really needs to be much more thoroughly checked before we start revising physics.

I wonder what those with poor reading comprehension are going to take away from this now. Given the comments made on this thread so far, the emerging consensus among those who don't get it appears to be that it's not that the press and their readers jumped the gun, it's that the scientists "didn't craay (sic) the 1" and don't know what they're doing.

Well done, public. Your skill at projecting your own susceptibility to hype and hysteria onto others remains unparalleled.