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Author Topic: Does gravity attract masses in space, or does it curve space between them?  (Read 4992 times)

Offline Alan McDougall

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Does gravity attract masses in an existing space, or does it curve the space between them?

The answer to this question is much more complex than meets the eye?


 

Online jeffreyH

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Since we know that time dilation exists then at least one of the components of spacetime is affected. If we are to assume the validity of Lorentz transformations then space must also be affected. If somehow the Lorentz transformations are incorrect as regards the spacial component then a reassment of general relativity would be necessary. Although I don't see how this can be.
 

Offline IAMREALITY

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Be honest... Do you just search quora for topics to post? Lol

The answer is b. It's due to the curvature of spacetime. Like occams razor dictates... The simplest explanation usually is the right one...  Far easier an explanation to say an object is just continuing in a straight path around a curved surface than the mechanisms necessary for the attraction explanation...
 

Offline agyejy

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Be honest... Do you just search quora for topics to post? Lol

There was a day awhile back that I noticed at least 3 of Alan's topics were straight copy pastes from quora. I don't visit quora enough to know for sure but if I noticed that many the actual number must be significant. Other question and answer sites could also be providing material.
 

Offline JohnDuffield

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Does gravity attract masses in an existing space, or does it curve the space between them?
A concentration of energy in the guise of a massive star "conditions" the surrounding space, altering its properties. This effect diminishes with distance in a non-linear fashion, and is modelled as curved spacetime. Note though that curved spacetime is not curved space and curved time. Instead it's space that is "neither homogeneous not isotropic". When you plot this inhomogeneity, your plot is curved. And you plot it with measuring devices such as clocks at different altitudes, so your metric is curved. But space isn't. 
 

Online jeffreyH

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Does gravity attract masses in an existing space, or does it curve the space between them?
A concentration of energy in the guise of a massive star "conditions" the surrounding space, altering its properties. This effect diminishes with distance in a non-linear fashion, and is modelled as curved spacetime. Note though that curved spacetime is not curved space and curved time. Instead it's space that is "neither homogeneous not isotropic". When you plot this inhomogeneity, your plot is curved. And you plot it with measuring devices such as clocks at different altitudes, so your metric is curved. But space isn't.

You could actually learn this properly and be able to use the correct terms. Once you do this you might actually be able to start helping others by properly answering their questions. Give it a try John.
 

Online jeffreyH

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I have  a question for you John. It is not difficult and I don't mind if you look the answer up. What is the definition of a metric?
 

Offline puppypower

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Wouldn't a curved path create centrifugal force thereby cancelling out some of the gravity vector? One can see this affect with satellites orbiting the earth so they never are able to meet. The moon and earth attract by gravity yet they can never close the deal, due to a curved path.

Although, asteroids which hit have hit the earth, originally follow their own curved paths as they orbit the sun. These collide more out of being in the right place at the right time, compared to direct gravity affect between earth and asteroid. 

If we assume curved path, as the two objects gets closer and closer and therefore gravity gets stronger, does the path curve more and more as the space-time well gets deeper? If this was true, to be logically consistent, does this mean that things falling into a black hole take forever to reach the core, due to tighter and tighter orbits, until it becomes a centrifugal based satellite? It may never reach the core if it orbits, therefore the ideal of the singularity may take forever.



 
 

Offline Thebox

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Well I do not think Einstein actually said space was curved in anyway but rather space-time was curved, so I suppose the answer to your question depends on how we interpret space-time.

If we considered that space-time only exists between masses  then orbital motion would suggest that in some way the space-time was ''spiralling'' and a torque was produced between masses that curved the forces between the masses.



Mass attracts mass, gravity is what we call the force,


Does the space curve? there is no evidence of this

Does the ''invisible'' forces between masses curve?  probably but we can't ''see'' it.

 
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Offline IAMREALITY

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Be honest... Do you just search quora for topics to post? Lol
There was a day awhile back that I noticed at least 3 of Alan's topics were straight copy pastes from quora. I don't visit quora enough to know for sure but if I noticed that many the actual number must be significant. Other question and answer sites could also be providing material.
It was just an observation I couldn't avoid.  I really was just being lighthearted though.  But his reply. Wow. Lol.

On Edit:  Might as well reply here instead of disrupting the conversation that has since taken place downthread...

So what! "This was the result of  IAMREALITY who is on my ignore list trying to make trouble by proxy, because he cannot get at me directly with his insults"
Ummm, no.  This was simply a lighthearted observation, which turned out to actually be true.  It wasn't an insult at all.  You really need to lighten up dude. 

And the main part of my post was actually replying to your thread.  Why?  Cause it's a thread.  And the whole point is to have replies in them. 
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Although I no longer look at anything IAMREALITY posts, he continues to follow everything I post, and invade all of my threads and makes comments "in all of them" in an ongoing effort to demean me in anyway he can.

Don't flatter yourself.  I do not 'follow' you at all.  But when half of the threads are started by you, it kinda makes it impossible to not reply to some of them; especially when there are only so many new threads generated on this site each day to begin with.  Do I reply to all of them?  Ummmm nope!  And I don't 'invade' your threads.  I reply within them, like anyone else does.  Why?  Because I don't suffer from this irrational and nonsensical vendetta that you have.  Instead, you're a poster like anyone else.  If I see a thread and feel the need to reply, I reply, period.  That's like, ya know, what people do here and stuff.
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He has proved a disruptive influence on the forum since the sad day he joined and almost never starts a thread of his own or asks anything of interest himself.
There ya go with the personal attacks again.  And all this because of a lighthearted comment.  I'd wager your attacks and constant replies to me outside of the context of my posts is what has been disruptive.  Otherwise I'm the same as any other poster here, and I've disrupted nothing.  In fact, in the last few days I've seen you attack many other posters as well, with direct personal attack.  I've seen you post religious mumbo jumbo and a bunch of other spam like nonsense.  Do you think people came to a scientific forum to be preached religion?  Do you think they came here for your lengthy poetry?  No, they didn't.  And I have posted threads and will do more when I see fit.  I've also asked several things of interest within threads.  Just because you choose to cherry pick what you see is your problem not mine.
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He was simply using you to get at me, who he despises! 
First of all, how could I use someone to get to you, when I replied directly to you, and it was the other poster who replied to me?  How does that even remotely make sense?  Second of all, I despise no one.  Again, you're projecting.  Your constant irrational personal attacks on me have shown you to be the one who despises.  As far as my perspective, I literally couldn't care less.  You're an anonymous poster on a forum.  If you reply to me I'll reply back with logical rebuttal.  Same as any other poster.  The reason things get derailed with our interaction is directly related to your inability to reply to the context of my replies but instead choosing the path of irrational personal attacks instead.  But again, as far as I'm concerned, you're nothing more than a poster just like anyone else.  You're trying to insinuate that I have this vendetta against you, that I seek you out, that I'm focused on you.  But that's utter nonsense.  There's only one here with an irrational vendetta, and it ain't me...  I ask you yet again, for the umpteeth time, please avoid personal attacks and stick to the context of my posts only.  Thanks.

And I'm sorry to those in this thread that need to read all this nonsense.  I know it's not what you came here for.  But when I'm personally attacked like that I can't avoid defending myself.  But I'll limit saying what I need to say in one post only (in this case, this one) and give my word I will not go back and forth if there are additional attacking replies.  Carry on...

« Last Edit: 29/06/2016 16:26:23 by IAMREALITY »
 

Online jeffreyH

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Well I do not think Einstein actually said space was curved in anyway but rather space-time was curved, so I suppose the answer to your question depends on how we interpret space-time.

If we considered that space-time only exists between masses  then orbital motion would suggest that in some way the space-time was ''spiralling'' and a torque was produced between masses that curved the forces between the masses.



Mass attracts mass, gravity is what we call the force,


Does the space curve? there is no evidence of this

Does the ''invisible'' forces between masses curve?  probably but we can't ''see'' it.

Sometimes you actually impress me and this is one of those times.
 
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Offline Thebox

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Well I do not think Einstein actually said space was curved in anyway but rather space-time was curved, so I suppose the answer to your question depends on how we interpret space-time.

If we considered that space-time only exists between masses  then orbital motion would suggest that in some way the space-time was ''spiralling'' and a torque was produced between masses that curved the forces between the masses.



Mass attracts mass, gravity is what we call the force,


Does the space curve? there is no evidence of this

Does the ''invisible'' forces between masses curve?  probably but we can't ''see'' it.

Sometimes you actually impress me and this is one of those times.

Congrats on becoming a moderator Jeff, I noticed yesterday .


If we take a look at an equilibrium of forces and describe this as an absolute linearity, then applied centripetal force by both masses at each ''end'' of the linearity on each other, then the linearity of the equilibrium force would surely curve under the gravitational pressure?


A sort of stress curvature of the ''invisible'' linearity of forces.



 

Offline Alan McDougall

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Well I do not think Einstein actually said space was curved in anyway but rather space-time was curved, so I suppose the answer to your question depends on how we interpret space-time.

If we considered that space-time only exists between masses  then orbital motion would suggest that in some way the space-time was ''spiralling'' and a torque was produced between masses that curved the forces between the masses.

Mass attracts mass, gravity is what we call the force,


Does the space curve? there is no evidence of this

Does the ''invisible'' forces between masses curve?  probably but we can't ''see'' it.

Sometimes you actually impress me and this is one of those times.

I fail to see how that impressed you?

https://www.thestar.com/news/insight/2012/08/18/einstein_discovered_that_gravity_is_not_a_force_but_a_curvature.html

Excerpt

Max Planck, himself a leading German physicist, advised Einstein to abandon his quest for this grander theory of relativity, for he was bound to fail.

But by 1916, Einstein had succeeded.

The resulting depiction of gravity was stunningly different from the orthodox view that had prevailed since the time of Sir Isaac Newton, who first devised a coherent explanation of the phenomenon, one that accounted for the behaviour of familiar objects on Earth as well as the interaction of planets and stars.

Up to a point.

The classical theory of gravity had been a huge breakthrough in its time, and it still provides a good means of predicting the motion of objects. But it is wrong, in part because Newton misunderstood what gravity is.

He considered gravity to be a force that objects exert upon each other.

But?

'But, in a burst of brilliance, Einstein realized that no such force is required and in fact no such force exists.'

We “feel” the force of gravity only because we are perched upon a surface that gives us weight. Remove that surface and gravity would no longer feel like anything at all.

We would be weightless.

By this way of reckoning, the Earth only seems to be turning in circles around the sun. In fact, it is going straight, but straight along a space-time surface that is itself curved — warped by the mass of the sun.

If this seems to make no sense, imagine driving “straight” from Toronto to Montreal. The truth is, you can’t do it, not even on the 401. The “straightest” route between the two cities — in fact, any route between the two cities — is curved by the surface of the Earth. In fact, if it goes on long enough, any “straight-line” journey along the surface of the Earth will eventually describe a circle.
The same goes for any “straight-line” journey in the vicinity of the sun.

“Newton would have said that an apple fell to Earth because there was a mutual force of gravitational attraction,” writes Simon Singh in his book Big Bang . “But Einstein now felt that he had a deeper understanding of what was driving this attraction: the apple fell to Earth because it was falling into the deep hollow in space-time caused by the mass of the Earth.”

Although it might not seem like it, the Earth is right now falling into the even deeper hollow in space-time caused by the mass of the sun. The only thing preventing a collision is the Earth’s velocity, which is about 107,000 km/h relative to the sun, or just enough to ensure that, in its never-ending downward spiral toward the fiery centre of the planetary system, our fine blue orb keeps missing its target — fortunately for us.

This constant state of free fall, coupled with an appropriate velocity, is what constitutes an orbit.
Astronauts aboard the orbiting International Space Station appear to be weightless — in fact, they are weightless — but not because they have escaped the reach of the Earth’s gravity. Instead, they and their space station are in a state of free fall toward the Earth.

They avoid striking the planet for the same reason the Earth doesn’t crash into the sun — because they are going pretty fast. The space station travels at about 19,000 km/h relative to the Earth, or just enough to prevent a collision.

But the important point for relativity theory is that space-time is curved by mass.

“A star or a planet or any hunk of mass warps space and time,” says Robert Mann, a physicist at the University of Waterloo.

This may sound bizarre, but it is true


« Last Edit: 29/06/2016 15:13:19 by Alan McDougall »
 

Offline Thebox

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The problem with saying that objects displace space is that we would then have to prove space is made of substance.


A while back I came up with a balloon situation and in this situation we start off with a deflated balloon and create an imaginary line of two points, A and B,

cdca247f7994f232db1fb4da88755518.gif

Within this line is the deflated balloon ''sitting'' at the half way point.


A...............Balloon.................B


We then inflate the balloon to reveal the points end up inside the balloon

Balloon...A...........................................B........Balloon.


The question was does the space pass through the balloon or does the balloon displace the space.


We know the Balloon displaces the air around it but we do not know the question asked .


However we do know that objects attract objects by something that is in the object being a mechanism for gravity.

The Cavendish experiment showing this and the obviousness of that things are held together by something.
« Last Edit: 29/06/2016 15:30:28 by Thebox »
 

Offline IAMREALITY

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Well I do not think Einstein actually said space was curved in anyway but rather space-time was curved, so I suppose the answer to your question depends on how we interpret space-time.

If we considered that space-time only exists between masses  then orbital motion would suggest that in some way the space-time was ''spiralling'' and a torque was produced between masses that curved the forces between the masses.

Mass attracts mass, gravity is what we call the force,


Does the space curve? there is no evidence of this

Does the ''invisible'' forces between masses curve?  probably but we can't ''see'' it.

Sometimes you actually impress me and this is one of those times.

I fail to see how that impressed you?

https://www.thestar.com/news/insight/2012/08/18/einstein_discovered_that_gravity_is_not_a_force_but_a_curvature.html



You misunderstood the context possibly.

The original poster was not saying einstein didn't say spacetime wasn't curved.  In fact, the poster directly stated that he did.

Instead, the poster was referring to merely space, as space.  Because you had asked if the space between the objects is curved instead of using the proper terminology of spacetime.  So it was a good pickup by the poster and good reply.
« Last Edit: 29/06/2016 16:29:47 by IAMREALITY »
 
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Offline IAMREALITY

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The problem with saying that objects displace space is that we would then have to prove space is made of substance.


A while back I came up with a balloon situation and in this situation we start off with a deflated balloon and create an imaginary line of two points, A and B,

cdca247f7994f232db1fb4da88755518.gif

Within this line is the deflated balloon ''sitting'' at the half way point.


A...............Balloon.................B


We then inflate the balloon to reveal the points end up inside the balloon

Balloon...A...........................................B........Balloon.


The question was does the space pass through the balloon or does the balloon displace the space.


We know the Balloon displaces the air around it but we do not know the question asked .


However we do know that objects attract objects by something that is in the object being a mechanism for gravity.

The Cavendish experiment showing this and the obviousness of that things are held together by something.

How can spacetime be displaced by anything, since technically if it was displaced time would cease for all the particles in the object (suspend your disbelief in time for a moment) if that were true?   Wouldn't spacetime, though curved, still need to be present within any given mass?
« Last Edit: 29/06/2016 15:47:16 by IAMREALITY »
 

Offline IAMREALITY

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Sometimes you actually impress me and this is one of those times.

Congrats on becoming a moderator Jeff, I noticed yesterday .

Oh wow I just noticed too!  Congrats man!  And best of luck to you in that role!  Moderators are the most unappreciated folk on the entire web hahaha
 

Offline Thebox

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The problem with saying that objects displace space is that we would then have to prove space is made of substance.


A while back I came up with a balloon situation and in this situation we start off with a deflated balloon and create an imaginary line of two points, A and B,

cdca247f7994f232db1fb4da88755518.gif

Within this line is the deflated balloon ''sitting'' at the half way point.


A...............Balloon.................B


We then inflate the balloon to reveal the points end up inside the balloon

Balloon...A...........................................B........Balloon.


The question was does the space pass through the balloon or does the balloon displace the space.


We know the Balloon displaces the air around it but we do not know the question asked .


However we do know that objects attract objects by something that is in the object being a mechanism for gravity.

The Cavendish experiment showing this and the obviousness of that things are held together by something.

How can spacetime be displaced by anything, since technically if it was displaced time would cease for all the particles in the object (suspend your disbelief in time for a moment) if that were true?   Wouldn't spacetime, though curved, still need to be present within any given mass?


Yes space-time is present in all mass if we consider that mass if the summation of all energies and forces within an objects volume .  Without space-time you would be a dense dormant ''rock'' with no ''life''(energy).  I consider space-time on a deeper understanding could be ''light'', because if it were not for ''light'' I am sure an objects entropy would soon dissipate it's energy into space and be a ''dead'' object.
 

Offline PmbPhy

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Quote from: Alan McDougall
Does gravity attract masses in an existing space, or does it curve the space between them?

It depends. If you have to point masses then the spacetime is curved and the space between the two objects is also curved. However the presence of spacetime curvature or spatial curvature is not necessary to exist for there to be a gravitational force acting on an object. was that more complicated than met your eyes? :)

Quote from: Alan McDougall
The answer to this question is much more complex than meets the eye?
You're asking a question that you already know the answer to? That makes it more of a rhetorical question, does it not?
 

Offline puppypower

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Gravity is an acceleration, with acceleration d/t/t. If you do a dimensional analysis, acceleration due to gravity is one part distance, d, and two parts time, t. Or the acceleration due to gravity is space-time, plus time. What is bending or curving space-time d-t, is connected to time; t.

With special relativity, space-time does not curve, since SR is due to velocity, which is d/t. This does not contain the extra time dimension associated with acceleration.

There is evidence of this which has existed since the 1820's. In photography there is an affect called motion blur. Motion blur occurs when the shutter speed is slower than the action speed. Since a still picture stops time, the difference in speed appears as uncertainty in distance; motion blur. If you look at the picture below, one gets the impression of motion, even with time stopped. The brain interprets the uncertainty in distance, as motion; d/t*, even though time has stopped. Time is conserved in the motion blur.

If we go back to gravity and acceleration, it is space-time plus time, (d-t, t). If we add the motion blur, where the time potential is converted to distance potential, acceleration can also become two layers of space-time; space-time plus (t=space-time)* .

The motion blur analogy of space-time or (space-time)* is an artifact of our quantum universe. Time is not continuous in a quantum universe but needs to follow quantum steps. When time jumps between quanta, time has stopped and uncertainty in distance appears.  When time is in focus, then time creates acceleration in space-time. 



 
« Last Edit: 29/06/2016 16:47:06 by puppypower »
 

Offline Alan McDougall

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Quote from: Alan McDougall
Does gravity attract masses in an existing space, or does it curve the space between them?

It depends. If you have to point masses then the spacetime is curved and the space between the two objects is also curved. However the presence of spacetime curvature or spatial curvature is not necessary to exist for there to be a gravitational force acting on an object. was that more complicated than met your eyes? :)

Quote from: Alan McDougall
The answer to this question is much more complex than meets the eye?
You're asking a question that you already know the answer to? That makes it more of a rhetorical question, does it not?

Was my saying it was more complex than means the eye true or false, don't read into my statements something that is not there??

"I do not know the answer", but "what I do know"from reading about this topic "is that this issue that it is complex" and that the answer is complex and has been widely debated by better minds than mine and I am curious and would like to be informed and learn from people like you, who are much more knowledgeable than I am.

You should not just assume things I did not mean. I have emphasized on more than one occasion that I am not a physicist or a mathematician, I am a humble very curious Engineer, trying to broaden my understanding in the sciences of which I have a basic comprehension. However, in Engineer we have to use math and physics as tools in our jobs.

"You know this Pete and your comment was uncalled for"!

Edited and unnecessary underlining removed by me (Alan)

Alan
« Last Edit: 30/06/2016 00:14:08 by Alan McDougall »
 

Online jeffreyH

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Can we have a little decorum please. Challenge the ideas not the personalities.
 

Offline Alan McDougall

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Can we have a little decorum please. Challenge the ideas not the personalities.

I see nothing wrong with my response to Pete, it was a polite and attempt to put right a misconception that I knew the answer because, I said it the answer was complex.?

In no way could the question I posed in this tread of mine be taken as a personal rhetorical question of which I knew the answer!
 

Offline IAMREALITY

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Can we have a little decorum please. Challenge the ideas not the personalities.

I see nothing wrong with my response to Pete, it was a polite and attempt to put right a misconception that I knew the answer because, I said it the answer was complex.?

In no way could the question I posed in this tread of mine be taken as a personal rhetorical question of which I knew the answer!

For sake of being up front, he was referring to our war, and triggered by my objection to your calling out Pete by saying what he said was uncalled for when it was benign and perfectly fine.  Though there was more, and it was written matter of factly, I won't get into it cause that's not the point of this post. The point was for sake of defending the mod and setting it straight, since I didn't consider at the time that deleting my post since the back and forth wasn't worth it, would end up causing Jeffrey's message to lose context.  So I figured I'd come forward. Anyway, let this thread move on now.  Thanks
 

Offline Alan McDougall

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Can we have a little decorum please. Challenge the ideas not the personalities.

I see nothing wrong with my response to Pete, it was a polite and attempt to put right a misconception that I knew the answer because, I said it the answer was complex.?

In no way could the question I posed in this tread of mine be taken as a personal rhetorical question of which I knew the answer!

For sake of being up front, he was referring to our war, and triggered by my objection to your calling out Pete by saying what he said was uncalled for when it was benign and perfectly fine.  Though there was more, and it was written matter of factly, I won't get into it cause that's not the point of this post. The point was for sake of defending the mod and setting it straight, since I didn't consider at the time that deleting my post since the back and forth wasn't worth it, would end up causing Jeffrey's message to lose context.  So I figured I'd come forward. Anyway, let this thread move on now.  Thanks

It takes at least two to engage in a war and two to make peace, this is my attempt to make peace and move on!

Best Regards

Alan
 

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