Confusing Scientific Thought experiment of mine?

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Hi,

So when I woke up, I had a thought experiment. Imagine taking Earth and shoot it at near C (Speed of Light) and we know as objects moves faster the mass increases proportionate to the velocity. As speed approaches to that of light the length will look more and more "squashed up". After a certain time in the frame of reference passes the Earth will start to look like a black hole for the observer.

But, this is where confusion starts.Now imagine as we gain mass (due to velocity) we also emit light in correct way that the rest mass will be the same even as we increase in velocity. However for observer even though we reduce mass via emitting light proportional to velocity earth will still look like a black hole after some-time and people on earth will still feel normal gravity and will be oblivious to their velocity due to us dropping mass. But for observer they we would seem like a blackhole.

So where did this relativistic gravity come from even though we are dropping mass proportionate to velocity. Then next, of all if Earth then looked like a black hole then would the gravity also be relative to observer if so anything that gets near it it would get sucked it yet in the other frame of reference the earth is not a black hole so what would happen to things that get sucked in? Would it fall from space onto earth or what?

the rest mass will be the same even we increase in velocity.


The rest mass is always the same, no matter what the velocity. That is why it is called the rest mass. ;)

In your experiment, as the velocity (mass) of the Earth increases, we are at the same rate radiating out mass as electromagnetic radiation. Since these are at the same rate and the electromagnetic radiation emitted is moving away from us at the speed of light at the same rate the energy we are putting in is added, the relativistic mass of the system does not change and nor does its gravity.

However, how exactly that gravitational field would look like when the speed gets very close to c is (so far as I know) not defined.

As for the Earth becoming a black hole... The system's gravity will not be changing and so no observer will see light not able to escape from its gravity.
Yea, I actually even got the same conclusion but the thing is that surely as the planet will become more and more "squashed" up, the observer should in theory be observing it become a black hole because the size of the Earth will start looking denser and denser until it looks like a black hole thus in theory the gravity also must be incresed for the observer.

As even you and me can become a black hole if compressed enough to a small enough point. Therefore even earth will start becoming a blackhole (for the observer) but for the people on earth they will not feel as though any gravity is increasing as the mass will always be equal to its rest mass as we are radiating out mass in symmetrical light beam proportionate to its velocity.

Nevertheless, with this question raises other question such as:

1. Is Gravity Relative? Like Time & space.

2. Does Earth become a black hole or not?

3. What happens to matter that is sucked in? Where does it go?

4. Why are people on earth not experiencing the gravity of an black hole?
1. Is Gravity Relative? Like Time & space.


Gravity is a description of time and space, so I'm not sure exactly what you mean by this question?


2. Does Earth become a black hole or not?


No. It will not become a black hole (I'm 100% sure of this) and I'm fairly sure the reason is that you cannot put in enough energy for things to become that 'relativistic', if that makes sense? I mean, the entire Earth would have to be the size of like a tennis ball or something to be a black hole. I'm sure long before this point you will be creating other problems.


3. What happens to matter that is sucked in? Where does it go?


To a black hole, or an extremely high velocity Earth?


4. Why are people on earth not experiencing the gravity of an black hole?


Because Earth is not a black hole.
1.When I mean relative I mean they are relative to an observer and it differs from the observer and a other obersver.

2.But you tell me what types of problems will be created before that point.

3. But if the matter is going to an black-hole why are people on earth not feeling gravity ? If its falling on earth surely its not a black hole but for observer it should be but its not?

4. N/A

Anyway, Could it be due to doppler effect may be that the light is simply being redshifted to a point that we assume its a black but its not ? Yet creates problems such as even if it were an illusion later in the time frame it will become a actual black hole.
2) Explain by what method you are accelerating the Earth?

3) People on Earth are experiencing gravity, just the same as always and Earth is not and will not become a black hole, nor will it be to the observer.
2) I am not quite sure as I was think more of what happens during it but I would say somewhat like a Gun so Earth will be increasing in velocity exponentially. Besides its not really important because I'm talking about what happens when it reaches that stage but if you want to know its fine.

3) Why not because as it starts becoming smaller and smaller due to relativistic "shrinking" the observer will think it should become a black hole as the mass is being compressed in smaller and smaller amount of space.
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Besides its not really important because I'm talking about what happens when it reaches that stage but if you want to know its fine.


Actually, it is of the utmost importance. If you propose something in physics, you have to say how you're going to do it and if you can't actually do it, you can't propose the question (unless you want a sci-fi question with a sci-fi answer).
If you proposal is to propel the Earth using chemical explosive means, there are all kinds of difficulties you will face to achieve your goal, the first of which would be, how to have the fuel keep up with the Earth in order to continually accelerate it (hint: The answer cannot be "with more fuel.")?

Why not because as it starts becoming smaller and smaller due to relativistic "shrinking" the observer will think it should become a black hole as the mass is being compressed in smaller and smaller amount of space.


My point is, I don't think you can accelerate something to such a speed that it would appear to outside observers to compress that much; the energies required to do this are simply unattainable through any physical means.

Edit: The grammar was just too horrible.
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That being said even Einsteins experiments were impossible such as being able accelerate a train to speed of light and look out side at clocks. With that in mind it does not have to be possible and for more proof it says so in wikipedia:

Given the structure of the experiment, it may or may not be possible to actually perform it


http://en.wikipedia.org/wiki/Thought_experiment (2nd Line OR 2nd Sentence) thus I called it a Thought Experiment, nothing serious.

That in mind, imagine we did somehow accelerate it to that speed. Would Earth turn into a black hole work? but what will happen to things on earth?

(I AM NOT COMPARING MYSELF TO EINSTEIN (I'M NOT THAT GREAT, LOL) ITS JUST A EXAMPLE)
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What is "that speed" ? I mean, the LHC is accelerating things to 99.9999996% the speed of light and that is clearly nowhere near fast enough to cause the scale or relativity you are looking for.

Also, you must be able to achieve the experiment in the real world, no matter what Wiki says. For instance, Einstein imagined that if you were on an object that accelerated to near the speed of light (something which is perfectly possible), what would you see? He didn't imagine a train going AT the speed of light, because that would not be possible (or perhaps tried to think of a train reaching the speed of light and saw it would require infinite momentum).

Anyway, no matter what happens, you will not get a black hole. The object's gravity will always be the same and so no observer from any frame of reference will see light unable to escape.
In fact if you are saying einstein did not imagine a train then I strongly recommend you view: https://www.youtube.com/watch?v=KcXxHZssCh4

Somewhere there its talks about train reaching the speed of light, so theres my proof. Anyway, you cannot simply throw a source out like that, unless you are suggesting Wiki is wrong and is not credible in the current article. Hawking radiation for example requires a black hole for his theory to be proven yet there hasn't because currently its cannot be performed due to legal and other safety issues but its widely excepted. Similarly, it may not be able to be performed now but it does not mean its a bad thought experiment.

Thanks for answering the question, but then a quick query what would happen if the relativistic "shrinking" is that great maybe at 99.9999999999999999999999. followed by 100, 99s would it start to increase in gravity or what would happen will it still not be a blackhole?
I think you have to consider what happens to time in that case as well. I think that on earth the outside observer would have stopped in tiime, and for the outside observer time on earth would have stopped.
Earth has rest mass. That fact alone makes it impossible for earth to accelerate to the speed of light. You cant emit something with zero rest mass like light to reduce earths mass. This is too confusing because of all the ifs added to the theory are violating laws of quantum physics..
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First I said, near speed of light as shown here:
at 99.9999999999999999999999


Next, E=MC2 (Mass Energy Equivalence theory) says mass can be converted in energy and vice versa in our case electromagnetic radiation. Therefore we are reducing mass via emitting electromagnetic radiation thus reducing mass. As rearranging the equation to:

M= E/C2

then as we periodically reduce mass via release of energy to counteract the increasing mass due to velocity. Thus remaining mass at the rest mass.
Next, where did you get quantum physics from we are talking about relativity and quantum physics laws pertaining about light or similar speeds to light are almost all from General Relativity.

@htirwin

But we will still be increasing in speed regardless of time of movement to take place but the relativistic "compression" begin also happens relative to that therefore time is really not a option here unless travelling at light speed which will breach laws of physics as we know it as earth has mass.
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But we will still be increasing in speed regardless of time of movement to take place but the relativistic "compression" begin also happens relative to that therefore time is really not a option here unless travelling at light speed which will breach laws of physics as we know it as earth has mass.


A few things. First it is not correct to think of it as compression. From the outside observer, earth will appear flat like a 2d circle surface facing it's direction of relative movement.

You cannot ignore time dilation. I think the key to understanding the result of thought experiment is factoring in time dilation.

What do you think the effects of time dilation will be and how do they factor into the scenario?
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Hawking radiation for example requires a black hole for his theory to be proven yet there hasn't because currently its cannot be performed due to legal and other safety issues but its widely excepted.


Not because of legal or other safety issues. We are just waaaaaay off the energy to create a black hole, also, if we did manage to create a black hole on plank scale, it would evaporate in a time so short (I think the figure is ~10-40 seconds) that it could not even be measured, you would find only residual evidence that the black hole was there at all.

maybe at 99.9999999999999999999999. followed by 100, 99s would it start to increase in gravity or what would happen will it still not be a blackhole?


It still won't be a black hole.

Similarly, it may not be able to be performed now but it does not mean its a bad thought experiment.


It's bad if you violate known laws of physics.

You cant emit something with zero rest mass like light to reduce earths mass


Actually, you can. This is after all how nuclear fission and fusion are working (converting energy from the atomic nucleus into (mostly) other particles with mass, but also EM radiation (and neutrinos)).

First it is not correct to think of it as compression.


It is compression though. Granted, the compression is only in the direction of momentum, but compression is exactly what it is.

What do you think the effects of time dilation will be and how do they factor into the scenario?


The effects of time dilation will obviously mean for an outside observer traveling relatively much slower, time on Earth will be much slower, but it will not be stopped. I don't really see how this effects this situation though? All events will still take place in that reference frame, it's just we will have to watch for a long time to see them happen.
Actually thanks Cody, So I see it will mimic a black hole so my hypothesis was right. But I agree Mats, that this would require energy of a entire galaxy or more for this to happen but regardless its still fun to think about it.

In fact, similarly my experiment also is
waaaaaay off the energy to create
the situation but I'm not violating laws of physics as far as I'm aware.

Anyway, so if it does mimic the black hole then where did the gravity come from even though we would be keeping the mass the same as the rest mass, so mass cannot be held responsible for this so does this mean that there is something else creating this gravity - Velocity, "Compression" and if this is the case the people on earth would also become black holes due to everything compressing but then the question is now if we stop or slow down would we return to our usual self or would be never return from that trip.

Or what happens if I throw something on the planet like a small rock or anything where would it go.

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Nice find Cody0023! Some of the comments on that article are very interesting.
Well time dilation is a crucial aspect of a black hole.

Event horizon
Main article: Event horizon
BH-no-escape-1.svg
Far away from the black hole, a particle can move in any direction, as illustrated by the set of arrows. It is only restricted by the speed of light.
BH-no-escape-2.svg
Closer to the black hole, spacetime starts to deform. There are more paths going towards the black hole than paths moving away.[Note 1]
BH-no-escape-3.svg
Inside of the event horizon, all paths bring the particle closer to the center of the black hole. It is no longer possible for the particle to escape.

The defining feature of a black hole is the appearance of an event horizon—a boundary in spacetime through which matter and light can only pass inward towards the mass of the black hole. Nothing, not even light, can escape from inside the event horizon. The event horizon is referred to as such because if an event occurs within the boundary, information from that event cannot reach an outside observer, making it impossible to determine if such an event occurred.[45]

As predicted by general relativity, the presence of a mass deforms spacetime in such a way that the paths taken by particles bend towards the mass.[46] At the event horizon of a black hole, this deformation becomes so strong that there are no paths that lead away from the black hole.

To a distant observer, clocks near a black hole appear to tick more slowly than those further away from the black hole.[47] Due to this effect, known as gravitational time dilation, an object falling into a black hole appears to slow down as it approaches the event horizon, taking an infinite time to reach it.[48] At the same time, all processes on this object slow down, for a fixed outside observer, causing emitted light to appear redder and dimmer, an effect known as gravitational redshift.[49] Eventually, at a point just before it reaches the event horizon, the falling object becomes so dim that it can no longer be seen.

On the other hand, an indestructible observer falling into a black hole does not notice any of these effects as he crosses the event horizon. According to his own clock, which appears to him to tick normally, he crosses the event horizon after a finite time without noting any singular behaviour. In particular, he is unable to determine exactly when he crosses it, as it is impossible to determine the location of the event horizon from local observations.[50]

The shape of the event horizon of a black hole is always approximately spherical.[Note 2][53] For non-rotating (static) black holes the geometry is precisely spherical, while for rotating black holes the sphere is somewhat oblate.


http://en.wikipedia.org/wiki/Black_hole

It sort of seams that if something is moving close enough to the speed of light, then your observations of it would be similar to that of a black hole even if it were not so in it's own frame of reference. And even it seams that in the reference frame of the black hole itself, it is not a black hole (as we consider it), and this is mostly due to time dilation. But the main difference is that a black hole actually has so much rest mass that when objects are sucked into it, they are actually destroyed by the immense gravitational fields, where as for the one that only appears like a black hole this will not be the case.

What my thoughts are is that something such as earth may look and behave similar to a black hole from the view of an outside observer while maintaining normal earth behavior in it's own reference frame.
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