Not only that, but because of the expansion of the universe, some celestial objects are moving away from us faster than the speed of light, so we cannot perceive them. And some objects we can see now will be invisible to us in the future, for the same reason.
Cosmology is a never ending quest.
Expansion theory is demonstrated indirectly through mathematics. It's a theory that so far has satisfied all testable predictions and not contradicted any known evidence.
Correct, but the important parameter relevant to the relativistic mass change isn't absolute velocity, which we can agree doesn't exist or at least can't be determined, rather it is velocity change or acceleration of the object in question. An object's inertial velocity doesn't change nor does energy need to be input to it simply because it is viewed from another object which is moving relative to it. Einstein postulated the inertial frame of reference to constrain the energy balance of relativistic velocities to actual changes in an objects velocity which require actual inputs of energy.
It's handy to 'tidy up' this relationship by introducing the Lorentz factor (see attachment) and representing it by the Greek letter γ (gamma).
Hence m = m0 γ
Where m is the velocity dependent (relativistic) mass and m0 is the rest mass.
The closer the velocity v of an object to the velocity of light c, the bigger the Lorentz factor γ and the bigger the relativistic mass m.
An observer moving at a velocity v relative to an object of rest mass m0 will observe its mass to be m.
I'm not introducing anything new here, just attempting to make the concept of relativistic mass more approachable!
Attachments
So are you implying that objects moving through the cosmos don't follow paths as defined by their proper motion and the local curvature of spacetime? No that can't be or the galaxy wouldn't be the coherent rotating structure that it is. It is true that the apparent velocity of an object depends on the motion of the object from which it is viewed, but that doesn't mean that it isn't following a definitive and particular path through spacetime, nor that it's energy state changes every time it is viewed from a different moving object.
In the spacetime way of thinking, a moving clock uses up some of its fixed quota of spacetime speed because of its motion through space and that leaves less for its motion through time. This is why a moving clock doesn't travel so fast through time as a stationary one. In other words, a moving clock runs slow.
No that was not my intention. Merely that there is no "universal" reference point to which a "norm" speed can relate to. When we say that a car can do 100 km/h the reference is implied. When we think something moves in cosmos it may stand still from a point of view that we haven't discovered yet - thats what I ment.
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Spacetime is really weird!
Even an object which is stationary in space would progress through time at a speed equal to c.
When an object starts to move through 3 dimensional space it starts to lose speed in the 4th dimension which is time.
If I ever I manage to finish my reference book, I may be able to explain it better!
While that's essentially true we can still see an object like Oumaumau and pretty quickly identify it's velocity and path to enough precision to call it as an extra-Solar system object and backtrack it's path over millennia. So it's important not to overplay the lack of a measured 100 meter grid in space. We understand the path and speed of the Solar system through the Milky Way, the path and speed of the Milky Way through the Local Group, etc. etc.
I hope this clears up the confusion about relative velocities. A mass in motion possesses momentum and kinetic energy, even regardless of relativistic considerations. It's classical Newtonian physics.
If two vehicles are traveling 100 kilometers per hour, they do not have zero momentum and zero kinetic energy relative to each other. If these vehicles collide, then this will become very apparent.
Very important point. You have to look at the inertial frame of reference to know its momentum and kinetic energy.
The kinetic energy possessed by an object having a non-zero mass, depends heavily on its velocity. If this velocity is measured with respect to different frames of reference, different values for velocity are inevitable. This would suggest, a moving object has a multitude of kinetic energy values, which to say the least, is beyond weird.
This is also why an absolute frame of reference should exist, otherwise, there must be something wrong with these (established) scientific theories. A mess of relative frames without an absolute flies in the face of reality.
This is also why an absolute frame of reference should exist, otherwise, there must be something wrong with these (established) scientific theories. A mess of relative frames without an absolute flies in the face of reality.
Ridicule is the lowest form of wit. When there are no arguments to present, use ridicule.
Thank you for proving you have no arguments. Yes, reality flies in the face of having no absolute frame of reference.
To the poster who implied I am seeking some form of personal gratification, may I remind you, this is my style, this is the English I was thought at school, and I have every right to continue using it. I was never thought slang English at school, and since the English I learnt can be used in academic literature, there is no need to learn slang English.
The impression I am someone seeking personal gratification, or someone with an inflated ego is wrong. I am the opposite. Maybe, the fact I modified a large public amplifier, gives the wrong impression I am a narcissistic person after undue personal gratification. In that case, I could not do otherwise, as the amplifier was a large one and it failed. I did not choose a large amplifier to impress. If I want to impress there are other convincing ways to do it, like doing university courses, but I did not choose that, and at my age, I am not interested.
Please, stop this: I am not after personal gratification, far from it. That would be narcissistic and delusional, something worthy of embarrassment, and I dare also write, psychiatric treatment.
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Absolutely!
The purpose of this thread, as I see it, is to shine some light on the physics behind black holes with the objective of increasing our own understanding and that of others.
And a little lightheartedness along the way is a bonus!
I don't think anyone here is trying to show off, we simply share the same sense of wonderment of the universe around us.
Being freed from the millstone of absolute space (i.e. there's no special grid that defines 'at rest') played a crucial role in allowing Einstein to develop his theory of space and time.
Einstein realised that if there is no absolute space then there is no reason why two observers have to agree on, say, the length of a pencil.
The theory of relativity encompass two interrelated theories.
Special relativity and General relativity. This is how they are named in English, these names can be confusing, because translations differ in other languages.
In French, the used names literally mean Restricted relativity and Generalized relativity.
The first theory applies to all physical phenomena in absence of gravity. Basically, Lorentz laws and beyond.
The second theory explains the law of gravitation. Basically, Newton revisited.
Special relativity and General relativity. This is how they are named in English, these names can be confusing, because translations differ in other languages.
In French, the used names literally mean Restricted relativity and Generalized relativity.
The first theory applies to all physical phenomena in absence of gravity. Basically, Lorentz laws and beyond.
The second theory explains the law of gravitation. Basically, Newton revisited.
There is little importance to the relative velocity between masses in both classical and relativistic physics, an example may help to illustrate. Let's take two vehicles travelling in the same direction, a lead vehicle and a following vehicle. Say in the first instance the lead vehicle is travelling 0m/s and the following 1m/s and the following vehicle impacts the leading. In the second instance everything is the same except the lead vehicle is travelling 10m/s and the following 11m/s. A third case has the lead vehicle travelling 100m/s and the following vehicle 101m/s. In all three cases the relative velocity between the following and lead vehicles is exactly the same at 1m/s, but the collision energy in the second example is 21 times as large as the first and in the third example it's 201 times as large as the first and 9.6 times as large as the second. The actual kinetic energy of a mass is always a function of its actual velocity and a particular relative velocity reveals nothing about its energy state.
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