# Don't Mess with the Little Guy (small particle traveling fast)

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According to gamma= (1/(1-V^2/C^2)^(1/2)), It is understood that as a particle reaches the speed of light, it will approach infinite mass, infinite density (length contraction), and time for the particle will be viewed as by an observer as approaching no change in time (infinite time dilation). Thus from my understanding (that of a biologist) this would mean that the smallest possible particle that as it approaches the speed of light would become the largest in terms of mass, but yet it would have no volume. Also, it would seem as if time is not passing for the particle. Yet, if time does not seem to passing for the particle, wouldn't this mean it would appear to not be moving? Thus, this particle traveling really really close to the speed of light, but be observed as not moving. Also it would have tremendous gravitational pull due to its infinite density. So it would be a black hole...

Thoughts please! I'm not a physicist, but I like to play with it... so please tell me why I'm a crack-pot!

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According to gamma= (1/(1-V^2/C^2)^(1/2)), It is understood that as a particle reaches the speed of light, it will approach infinite mass, infinite density (length contraction), and time for the particle will be viewed as by an observer as approaching no change in time (infinite time dilation). Thus from my understanding (that of a biologist) this would mean that the smallest possible particle that as it approaches the speed of light would become the largest in terms of mass, but yet it would have no volume. Also, it would seem as if time is not passing for the particle. Yet, if time does not seem to passing for the particle, wouldn't this mean it would appear to not be moving?

How time passes for the particle (according to us) has no effect on the particles velocity with respect to us. One way to look at it is that while from our viewpoint, the particle travels, say, 1 light year as it ages 1 sec, From its viewpoint, we are the ones that are moving and as a result are length contracted(along with the distance that we measure as being 1 light year. So according to it, it just travels a much smaller distance in that one sec.

Thus, this particle traveling really really close to the speed of light, but be observed as not moving. Also it would have tremendous gravitational pull due to its infinite density. So it would be a black hole...

One of the principles of Relativity is that there is no preferred frame of reference. There is no experiment that you can perform that can tell you if you were "really" moving. IOW, there is no way that the particle can tell that it is moving, thus for it, its mass does not increase, nor does it length contract, so it cannot form a black hole. If it doesn't form a black hole in its own rest frame, it doesn't form one according to someone that it is moving relative to.

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According to gamma= (1/(1-V^2/C^2)^(1/2)), It is understood that as a particle reaches the speed of light, it will approach infinite mass, infinite density (length contraction), and time for the particle will be viewed as by an observer as approaching no change in time (infinite time dilation). Thus from my understanding (that of a biologist) this would mean that the smallest possible particle that as it approaches the speed of light would become the largest in terms of mass, but yet it would have no volume. Also, it would seem as if time is not passing for the particle. Yet, if time does not seem to passing for the particle, wouldn't this mean it would appear to not be moving? Thus, this particle traveling really really close to the speed of light, but be observed as not moving. Also it would have tremendous gravitational pull due to its infinite density. So it would be a black hole...

Thoughts please! I'm not a physicist, but I like to play with it... so please tell me why I'm a crack-pot!

For starters that is generally not accepted as a definition of mass... as it leads to thoughts like "tremendous gravitational pull due to its infinite density" and "black hole"...

and it cannot reach the speed of light in any case.

Edited by J.C.MacSwell
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For starters that is generally not accepted as a definition of mass... as it leads to thoughts like "tremendous gravitational pull due to its infinite density" and "black hole"...

and it cannot reach the speed of light in any case.

That depends on who is doing the accepting. There is no universal definition of "mass". Tolman argued for relativistic mass. Rest mass occurs naturally in many applications. Invariant mass is convenient in considering systems of particles. Mass,. though a common term, is really not a cut-and-dried concept. (BTW aftewr a recent thread on this topic I had a discussion on this very topic with a local, and well known, high-energy physicist. There is no single definition within the community.)

You are right that "gravitational pull" does not increase with relativistic mass. Spacetime curvature is invariant -- it is a tensor -- and that is what determines "gravitational pull".

If gravity increased with speed, everything would look like a black hole to a photon, and it would be awfully dark around here.

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How time passes for the particle (according to us) has no effect on the particles velocity with respect to us. One way to look at it is that while from our viewpoint, the particle travels, say, 1 light year as it ages 1 sec, From its viewpoint, we are the ones that are moving and as a result are length contracted(along with the distance that we measure as being 1 light year. So according to it, it just travels a much smaller distance in that one sec.

One of the principles of Relativity is that there is no preferred frame of reference. There is no experiment that you can perform that can tell you if you were "really" moving. IOW, there is no way that the particle can tell that it is moving, thus for it, its mass does not increase, nor does it length contract, so it cannot form a black hole. If it doesn't form a black hole in its own rest frame, it doesn't form one according to someone that it is moving relative to.

Thank you for this very clear explanation.

Then why do scientists argue that time dilation and space contraction do truly happen?

As I read your explanation, it appears to me that both effects are the result of observation and measurements from another Frame Of Reference, nothing else.

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Then why do scientists argue that time dilation and space contraction do truly happen?

As I read your explanation, it appears to me that both effects are the result of observation and measurements from another Frame Of Reference, nothing else.

Because they do happen. As Janus mentioned, in the frame of reference of the particle, distances in the direction of travel are length-contracted. In any other frame you have time dilation. So no matter which frame you choose, there is a relativistic effect that truly happens. Since there is no preferred frame of reference, the "other frame of reference" is just as valid.

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One of the principles of Relativity is that there is no preferred frame of reference. There is no experiment that you can perform that can tell you if you were "really" moving. IOW, there is no way that the particle can tell that it is moving, thus for it, its mass does not increase, nor does it length contract, so it cannot form a black hole. If it doesn't form a black hole in its own rest frame, it doesn't form one according to someone that it is moving relative to.

Yes, but we are not observing it from its reference frame, are we? We are observing it from our reference point, granted yours and mine might vary slightly depending on our seperate locations. So from our reference point it has infinite mass and is not moving. No reference point is more correct than others, but its still what the one reference point precieves it as. So yes the particle in its reference frame is no different, but in ours it is.

Because they do happen. As Janus mentioned, in the frame of reference of the particle, distances in the direction of travel are length-contracted. In any other frame you have time dilation. So no matter which frame you choose, there is a relativistic effect that truly happens. Since there is no preferred frame of reference, the "other frame of reference" is just as valid.

so so true!

For starters that is generally not accepted as a definition of mass... as it leads to thoughts like "tremendous gravitational pull due to its infinite density" and "black hole"...

and it cannot reach the speed of light in any case.

You are a mathematician aren't you? Yeah... you are... If you were told that you could go halfway to your favorite candy bar and continue going halfway, youd just leave because youd never reach that candy bar. But really for all intensive purposes you could get close enough to eat it. Thats what I was inferring.

If you noticed I kept mentioning as it approaches the speed of light, so for all intensive purposes it is at the speed of light!

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Yes, but we are not observing it from its reference frame, are we? We are observing it from our reference point, granted yours and mine might vary slightly depending on our seperate locations. So from our reference point it has infinite mass and is not moving. No reference point is more correct than others, but its still what the one reference point precieves it as. So yes the particle in its reference frame is no different, but in ours it is.

so so true!

You are a mathematician aren't you? Yeah... you are... If you were told that you could go halfway to your favorite candy bar and continue going halfway, youd just leave because youd never reach that candy bar. But really for all intensive purposes you could get close enough to eat it. Thats what I was inferring.

If you noticed I kept mentioning as it approaches the speed of light, so for all intensive purposes it is at the speed of light!

No. You cannot get any closer to the candy bar. You can run around the candy bar as much as you like, but you cannot get any closer at all.

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Because they do happen. As Janus mentioned, in the frame of reference of the particle, distances in the direction of travel are length-contracted. In any other frame you have time dilation. So no matter which frame you choose, there is a relativistic effect that truly happens. Since there is no preferred frame of reference, the "other frame of reference" is just as valid.

That is too far over my head.

I understand that multiple observations of the one and same phenomena can be valid, but I cannot accept the concept of a multiple phenomena happening.

IOW, when you state "Since there is no preferred frame of reference, the "other frame of reference" is just as valid."

I say Yes.

When you state

As Janus mentioned, in the frame of reference of the particle, distances in the direction of travel are length-contracted. In any other frame you have time dilation. So no matter which frame you choose, there is a relativistic effect that truly happens.

I say Yes.

but when you state "Because they do happen.", I say ?????????

There is a huge step between those statements.

Edited by michel123456
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That is too far over my head.

I understand that multiple observations of the one and same phenomena can be valid, but I cannot accept the concept of a multiple phenomena happening.

IOW, when you state "Since there is no preferred frame of reference, the "other frame of reference" is just as valid."

I say Yes.

When you state

I say Yes.

but when you state "Because they do happen.", I say ?????????

There is a huge step between those statements.

The particle sees length contraction. Other observers see time dilation for the particle. There is no physics that can say one of the observers is correct while the others are wrong. But they ALL see a relativistic effect. IOW, relativity actually happens.

It's not a matter of multiple phenomena happening, it's a matter of multiple observations of one phenomenon.

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It's not a matter of multiple phenomena happening, it's a matter of multiple observations of one phenomenon.

cough cough. it is multiple phenomena. the particle event in question is a phenomenon, and every viewer of it the event is also experiencing phenomena. it is relativity because of the fact that each entity has a distinct experiential perception of it. unless you somehow posit that witnessing the event is excused from the laws of physics.

Edited by foszae
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cough cough. it is multiple phenomena. the particle event in question is a phenomenon, and every viewer of it the event is also experiencing phenomena. it is relativity because of the fact that each entity has a distinct experiential perception of it. unless you somehow posit that witnessing the event is excused from the laws of physics.

Semantics.

Everyone observes the same phenomenon, e.g. an object moving relative to something else, but each observation is frame-dependent. They disagree on the measurements of time and distance if they are in different frames of reference.

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The particle sees length contraction. Other observers see time dilation for the particle. There is no physics that can say one of the observers is correct while the others are wrong. But they ALL see a relativistic effect. IOW, relativity actually happens.

It's not a matter of multiple phenomena happening, it's a matter of multiple observations of one phenomenon.

Yes.

But then, what is this one phenomenon on which all are correct but on which all disagree?

Edited by michel123456
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Yes.

But then, what is this one phenomenon on which all are correct but on which all disagree?

I answered that in my previous post.

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an object moving relative to something else,

Is that it?

Edited by michel123456
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Yes.

But then, what is this one phenomenon on which all are correct but on which all disagree?

Nobody technically disagrees. They can all measure certain aspects of the same phenomena differently (time, distance, etc -- while other aspects which are invariant would be measured the same by anyone).

But all the different measurements are consistent with each other. They do not fail to correspond; by definition they don't disagree.

You can say they disagree on the values of 2 measurements made from different frames if you want. Another way of saying that is "the measurements are relative."

Also... while everyone may see things slightly differently, they all agree on what each other should see.

Edited by md65536

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