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(Science Alert)   Physicists have finally narrowed down the speed of gravity. Read and C for yourself   ( sciencealert.com) divider line
    More: Spiffy, General relativity, neutron star collision, Speed of light, gravitational waves, gravity moves, gravitational wave astronomy, previous ground-breaking thunderclaps, good science demands  
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3366 clicks; posted to Geek » on 04 Nov 2017 at 5:44 PM (28 weeks ago)   |   Favorite    |   share:  Share on Twitter share via Email Share on Facebook   more»



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2017-11-04 02:20:19 PM  
Jesus, subby! Spoiler alerts?
 
2017-11-04 02:25:54 PM  
Slower than I expected. Get in the right lane, asshole!
 
2017-11-04 02:28:08 PM  
I C what you did there.
 
2017-11-04 03:28:10 PM  

themindiswatching: Slower than I expected. Get in the right lane, asshole!


Are pulsars the universe leaving its blinker on?
 
2017-11-04 04:00:32 PM  
Wow... I was gonna guess like 45 mph.
 
2017-11-04 05:08:15 PM  

Eddie Adams from Torrance: Wow... I was gonna guess like 45 mph.


Don't be ridiculous.  That is God speed
 
2017-11-04 05:44:43 PM  
So if the moon suddenly disappeared how long would it be before we noticed?
 
2017-11-04 05:45:29 PM  

fusillade762: So if the moon suddenly disappeared how long would it be before we noticed?


About 12 parsecs.
 
2017-11-04 05:48:18 PM  
So gravity works at the speed of light? Okay, that makes sense.
 
2017-11-04 05:51:41 PM  
Now does the speed of gravity vary depending on the medium?
 
2017-11-04 05:53:46 PM  

bingethinker: So gravity works at the speed of light? Okay, that makes sense.


I was thinking the same thing. It just kind of fits.

Not that the physics of the universe gives two shiats what I think "fits," but it just doesn't surprise me.
 
2017-11-04 06:00:53 PM  

sxacho: Now does the speed of gravity vary depending on the medium?


Well, the medium would be spacetime, much as it is for c.

Light can be slowed to a crawling pace through Bose Einstein condensates, light can exceed the speed of light in media (cf Cherenkov radiation).

299,792,458 ms-1.

It's not just a good idea, it's the law.
 
2017-11-04 06:03:34 PM  

iron de havilland: sxacho: Now does the speed of gravity vary depending on the medium?

Well, the medium would be spacetime, much as it is for c.

Light can be slowed to a crawling pace through Bose Einstein condensates, light can exceed the speed of light in media (cf Cherenkov radiation).

299,792,458 ms-1.

It's not just a good idea, it's the law.


But can it reflect?
 
2017-11-04 06:04:07 PM  

bingethinker: So gravity works at the speed of light? Okay, that makes sense.


I know this is what we expect, but it doesn't make inherent sense to me... I don't see any reason that gravitational fields should consistently propagate at the maximum speed that a photon can travel.

It seems to me more likely that all fields propagate at the same speed, and that's really what C is, and the easiest way for us to attempt to measure that is to measure the speed of a massless particle in as close to a vaccuum as we can get, and light is conveniently massless and readily available.
 
2017-11-04 06:19:48 PM  

sxacho: iron de havilland: sxacho: Now does the speed of gravity vary depending on the medium?

Well, the medium would be spacetime, much as it is for c.

Light can be slowed to a crawling pace through Bose Einstein condensates, light can exceed the speed of light in media (cf Cherenkov radiation).

299,792,458 ms-1.

It's not just a good idea, it's the law.

But can it reflect?


Sure.

Why not?

/This is my thesis defence for my GED in cosmology.
 
2017-11-04 06:23:18 PM  

SomeAmerican: bingethinker: So gravity works at the speed of light? Okay, that makes sense.

I know this is what we expect, but it doesn't make inherent sense to me... I don't see any reason that gravitational fields should consistently propagate at the maximum speed that a photon can travel.

It seems to me more likely that all fields propagate at the same speed, and that's really what C is, and the easiest way for us to attempt to measure that is to measure the speed of a massless particle in as close to a vaccuum as we can get, and light is conveniently massless and readily available.


"Speed of light" has become kind of a shorthand; the whole electromagnetic spectrum travels at the same speed. If we had been able to measure the speed of gravity first, we'd probably use that as our baseline conversational reference instead of the speed of light. Bottom line, it's still humans putting labels on things in a sometimes haphazard fashion. The things themselves do what they do without needing us to measure or name them.
 
2017-11-04 06:23:44 PM  
Can these waves be used to surf?
 
2017-11-04 06:45:24 PM  

2wolves: Can these waves be used to surf?


img.fark.netView Full Size


/not mine.
//incredibly old photoshop that I've had for decades, though. Thought it was relevant.
 
2017-11-04 06:46:35 PM  

sxacho: Now does the speed of gravity vary depending on the medium?


Ask several mediums and compare the answers.
 
2017-11-04 06:57:56 PM  
Cornish's team of researchers combined the timings of the first three detections to narrow down the speed of the waves to between 55 and 142 percent of c.

Well way to nail it there.
 
2017-11-04 07:00:42 PM  

iron de havilland: fusillade762: So if the moon suddenly disappeared how long would it be before we noticed?

About 12 parsecs.


That's no moon.
 
2017-11-04 07:01:08 PM  
i have found that the folks here that have a greater gravitational pull move slower.
this is until they get in a small car, then they go zipping around.
 
2017-11-04 07:04:38 PM  

jaggspb: iron de havilland: fusillade762: So if the moon suddenly disappeared how long would it be before we noticed?

About 12 parsecs.

That's no moon.


img.fark.netView Full Size
 
2017-11-04 07:05:44 PM  

SomeAmerican: bingethinker: So gravity works at the speed of light? Okay, that makes sense.

I know this is what we expect, but it doesn't make inherent sense to me... I don't see any reason that gravitational fields should consistently propagate at the maximum speed that a photon can travel.

It seems to me more likely that all fields propagate at the same speed, and that's really what C is, and the easiest way for us to attempt to measure that is to measure the speed of a massless particle in as close to a vaccuum as we can get, and light is conveniently massless and readily available.


The "speed of light" is not the speed of light, per se. It's the speed of causality.

The Speed of Light is NOT About Light | Space Time | PBS Digital Studios
Youtube msVuCEs8Ydo
 
2017-11-04 07:11:42 PM  
Hmmmmm.
So instead of the speed of light being 299,792,458 m/s, wouldn't it be better to state that speed of the propagation of energy. any energy (or information change), in a vacuum is 299,792,458 m/s and that light itself doesn't have a speed but is dependent on the medium it is in. This make me wonder if gravity would act on an object slower if it was in a denser medium (for example water)
 
2017-11-04 07:33:43 PM  
Neutrinos from Supernova 1987A showed that the speed of neutrinos are VERY close to the speed of light, but we now know that they must travel slower than c because they have a tiny mass. Sadly the recently detected event was to far to detect neutrinos as we could have gotten an estimate how much slower their speed is from light. I would love for their to be a supernova in our own galaxy so we could get light, gravity, and neutrino observations from the same event.
 
2017-11-04 07:38:27 PM  
Of course you'd be a fool to bet against Mr. General Relativity himself, but good science demands that even geniuses need to be checked against reality.

This is a good recommendation; otherwise, they tend to blow up large-scale objects when left to their own devices.  Like, say, a solar system.

img.fark.netView Full Size


And then Neil DeGrasse Tyson steals their research data.
Being a genius is rough.

img.fark.netView Full Size
 
2017-11-04 07:39:10 PM  
imgflip.comView Full Size
 
2017-11-04 07:50:46 PM  

PleaseHamletDon'tHurtEm: Of course you'd be a fool to bet against Mr. General Relativity himself, but good science demands that even geniuses need to be checked against reality.

This is a good recommendation; otherwise, they tend to blow up large-scale objects when left to their own devices.  Like, say, a solar system.

[img.fark.net image 245x201]

And then Neil DeGrasse Tyson steals their research data.
Being a genius is rough.

[img.fark.net image 402x268]


Please, it was 5/6 of a solar system.
 
2017-11-04 07:58:07 PM  

SomeAmerican: It seems to me more likely that all fields propagate at the same speed, and that's really what C is, and the easiest way for us to attempt to measure that is to measure the speed of a massless particle in as close to a vaccuum as we can get, and light is conveniently massless and readily available.


Bingo.  Relativity (both special and general) treats time as another dimension of space, with the constant c serving as a "unit conversion" when comparing distances along the time axis with distances in the three spatial dimensions.  As a result, c is the speed of cause and effect.
 
2017-11-04 08:00:32 PM  
The question I have wanted to ask someone who understands this stuff is, does the existence of gravity waves prove that moving masses and changing gravity fields produce an effect analogous to the way moving electrical charges and changing electrical fields produce magnetic effects?
 
2017-11-04 08:05:29 PM  

Bondith: PleaseHamletDon'tHurtEm: Of course you'd be a fool to bet against Mr. General Relativity himself, but good science demands that even geniuses need to be checked against reality.

This is a good recommendation; otherwise, they tend to blow up large-scale objects when left to their own devices.  Like, say, a solar system.

[img.fark.net image 245x201]

And then Neil DeGrasse Tyson steals their research data.
Being a genius is rough.

[img.fark.net image 402x268]

Please, it was 5/6 of a solar system.


And (probably) uninhabited, but can a genius catch a break?  Nooooo.
 
2017-11-04 08:10:21 PM  

flondrix: The question I have wanted to ask someone who understands this stuff is, does the existence of gravity waves prove that moving masses and changing gravity fields produce an effect analogous to the way moving electrical charges and changing electrical fields produce magnetic effects?


No. It's more like detecting magnetic field changes alone. No hints yet of cross-type influences.
 
2017-11-04 08:22:26 PM  

flondrix: The question I have wanted to ask someone who understands this stuff is, does the existence of gravity waves prove that moving masses and changing gravity fields produce an effect analogous to the way moving electrical charges and changing electrical fields produce magnetic effects?


No.

I think you are asking the wrong questions.

No matter how fast something is traveling, distance can be measured.

Light gets to places before it gets to places further away than the place it reaches first.

We can measure it like we can measure gravity.

As light dissipates over distance, so does gravity.
 
2017-11-04 08:23:56 PM  

mongbiohazard: SomeAmerican: bingethinker: So gravity works at the speed of light? Okay, that makes sense.
The "speed of light" is not the speed of light, per se. It's the speed of causality.


TFA is dated Nov, 2017 but confirmation of the speed of gravity was Feb 2016.

Oddly enough, gravity waves travel faster than light.  This was recently discovered when the source of gravity waves were observed (those colliding neutron stars a ways back, presumably what TFA's data is from).  Just in case you are wondering, the light that reached was going ever-so-slower than the "speed of light".  c is just "the speed of light in vacuum", and while space is a pretty hard vacuum, that's still a lot of hydrogen and helium before light gets from there to here so the gravity waves got a few minutes earlier.
 
2017-11-04 08:46:40 PM  

mrlewish: Hmmmmm.
So instead of the speed of light being 299,792,458 m/s, wouldn't it be better to state that speed of the propagation of energy. any energy (or information change), in a vacuum is 299,792,458 m/s and that light itself doesn't have a speed but is dependent on the medium it is in. This make me wonder if gravity would act on an object slower if it was in a denser medium (for example water)


My thought is that any medium inherently has mass, and therefore would have a gravitational field. So if you have objects A and B, yes, the effect of gravitational force between them would be different in a vacuum than if they were in water, as the water itself would have its own gravitational pull that would dilute the effect on A and B. But the actual force itself would remain constant.
 
2017-11-04 08:51:54 PM  

yet_another_wumpus: mongbiohazard: SomeAmerican: bingethinker: So gravity works at the speed of light? Okay, that makes sense.
The "speed of light" is not the speed of light, per se. It's the speed of causality.

TFA is dated Nov, 2017 but confirmation of the speed of gravity was Feb 2016.

Oddly enough, gravity waves travel faster than light.  This was recently discovered when the source of gravity waves were observed (those colliding neutron stars a ways back, presumably what TFA's data is from).  Just in case you are wondering, the light that reached was going ever-so-slower than the "speed of light".  c is just "the speed of light in vacuum", and while space is a pretty hard vacuum, that's still a lot of hydrogen and helium before light gets from there to here so the gravity waves got a few minutes earlier.


The extremely precise comparison of speed of gravity and light was announced only a few weeks ago. The prior evidence was crude at best.  The gravity wave came in two seconds before the light did from a distance of many millions of light years. That is indeed news.  Well it was news a few weeks ago.  Anyone interested in astronomy probably realized it as soon as they heard that the gravity wave and light came only two seconds apart. It was certainly mentioned at the time.  But that the issue gets a formal write up in a paper means the old news is news again.
 
2017-11-04 08:53:18 PM  

Shaggy_C: mrlewish: Hmmmmm.
So instead of the speed of light being 299,792,458 m/s, wouldn't it be better to state that speed of the propagation of energy. any energy (or information change), in a vacuum is 299,792,458 m/s and that light itself doesn't have a speed but is dependent on the medium it is in. This make me wonder if gravity would act on an object slower if it was in a denser medium (for example water)

My thought is that any medium inherently has mass, and therefore would have a gravitational field. So if you have objects A and B, yes, the effect of gravitational force between them would be different in a vacuum than if they were in water, as the water itself would have its own gravitational pull that would dilute the effect on A and B. But the actual force itself would remain constant.


This is correct.
 
2017-11-04 08:53:26 PM  

mongbiohazard: The "speed of light" is not the speed of light, per se. It's the speed of causality.
[Youtube msVuCEs8Ydo image 480x270][Youtube-video https://www.youtube.com/embed/msVuCEs8​Ydo]


That was a really well done video and actually not impossible to understand. Good stuff!
 
2017-11-04 08:57:10 PM  
iron de havilland: Bose Einstein condensates

Those are good speakers ...
 
2017-11-04 08:58:33 PM  
Distance is the medium that dilutes the effects of light and gravity but does not slow down its speed.
 
2017-11-04 09:15:48 PM  

fusillade762: So if the moon suddenly disappeared how long would it be before we noticed?


It would be detectable from earth in 1.28 seconds

(Average distance from earth to the moon is 238,900 miles, speed of light is 186,282 miles/sec.)
 
2017-11-04 09:20:00 PM  

HawgWild: iron de havilland: Bose Einstein condensates

Those are good speakers ...


Aye well the last money I spent on musical things was on a JBL Flip Bluetooth speaker thing.

And it's aight. I mean, for the money, it could be better, but every nation on the planet has the sexy right to spank the pound for its insolence.

Just such a shame that nativists can't see the inherent contradiction in thinking that the Canadian English deserve such a voice in parliament.

smh
 
2017-11-04 09:36:14 PM  

fusillade762: So if the moon suddenly disappeared how long would it be before we noticed?


Well first we'd have to wait till night time.
 
2017-11-04 09:38:12 PM  

fusillade762: So if the moon suddenly disappeared how long would it be before we noticed?


3 seconds
 
2017-11-04 09:41:36 PM  

mrlewish: Hmmmmm.
So instead of the speed of light being 299,792,458 m/s, wouldn't it be better to state that speed of the propagation of energy. any energy (or information change), in a vacuum is 299,792,458 m/s and that light itself doesn't have a speed but is dependent on the medium it is in. This make me wonder if gravity would act on an object slower if it was in a denser medium (for example water)


I'll go too far and say gravity is a force and light is a wave. They have nothing in common.
 
2017-11-04 09:50:28 PM  

lxixem: mrlewish: Hmmmmm.
So instead of the speed of light being 299,792,458 m/s, wouldn't it be better to state that speed of the propagation of energy. any energy (or information change), in a vacuum is 299,792,458 m/s and that light itself doesn't have a speed but is dependent on the medium it is in. This make me wonder if gravity would act on an object slower if it was in a denser medium (for example water)

I'll go too far and say gravity is a force and light is a wave. They have nothing in common.


Some radio waves can pass clean through earth. Gravity can affect the way they pose and it's calculable. I suggest studying gravity drives for FTL travel since mass surely has an unprecedented affect on radio waves.
 
2017-11-04 09:54:10 PM  
i.imgur.comView Full Size
 
2017-11-04 09:55:13 PM  

lxixem: lxixem: mrlewish: Hmmmmm.
So instead of the speed of light being 299,792,458 m/s, wouldn't it be better to state that speed of the propagation of energy. any energy (or information change), in a vacuum is 299,792,458 m/s and that light itself doesn't have a speed but is dependent on the medium it is in. This make me wonder if gravity would act on an object slower if it was in a denser medium (for example water)

I'll go too far and say gravity is a force and light is a wave. They have nothing in common.

Some radio waves can pass clean through earth. Gravity can affect the way they pose and it's calculable. I suggest studying gravity drives for FTL travel since mass surely has an unprecedented affect on radio waves.


We should be able to study the sun. With receptors on Mars in its aphelion. Shoot all kinds of radiation at it an see what emerges.
 
2017-11-04 10:14:30 PM  
FTA:  Or, to be more precise, gravity moves at 299,792,458 metres per second, a rate we can just call c.

It is exactly what I expected it to be.

Yes, I did memorize it to nine places. Why do you ask?

It does continue a bit after the decimal point, though.
 
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