Naked Science Forum
Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: Mariana on 12/02/2019 10:37:32
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Shafin wants to know:
Is it possible to achieve relativistic speed? Nearly a speed of light in order to travel the deep space?
What do you think?
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Once you get up to really high speeds CMR photons begin to look like gamma rays and the tiniest dust particle carries megatons of energy.
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I don't really know. My point of view is that 'c', still being a 'constant', is observer dependent. There is no 'golden standard' for it. Why is pretty simple. As long as all uniform motions are equivalent then a acceleration can only be defined from your local frame of reference. Doesn't matter what you define as your 'speed' relative something else if there is no 'golden standard' for the speed you presume yourself to have.
So, it's a balance. And it involves a lot more than just a 'speed'.
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What I mean is that you're free to choose any 'anchor' to define that acceleration from.
doesn't matter, 'c' will be 'c,' and in any uniform motion you will have the same (equivalent) access to 'proper time' and 'proper length'.
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Is it possible to achieve relativistic speed? Nearly a speed of light in order to travel the deep space?
I am already moving at relativistic speed, no acceleration needed. Take a muon born in the upper atmosphere. It is going to decay in only a few μsec and only due to Lorentz contraction is my distance from it so short that I can get there (moving at .995c) to measure it before it decays.
My point of view is that 'c', still being a 'constant', is observer dependent. There is no 'golden standard' for it.
The observed value is the golden standard. It is the same for all observers, hence a constant.
Doesn't matter what you define as your 'speed' relative something else if there is no 'golden standard' for the speed you presume yourself to have.
That speed is also a golden standard. For every observer, that observer will presume himself to have speed zero, also a constant.
Said observer could presume himself from a different reference frame, but then light speed and everything else changes from the constant values it would otherwise have.
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No :)
Look it up for yourself.
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Sorry Halc, I'm tired. And you're pretty smart too :)
I'll give you a example.
You have a sun. You have three ships at 'relative speeds'. You need three to prove that although relative speeds are equivalent there still is a difference in displacements. Or maybe you just need two using the sun, but I'll stay with three. All three shoot a laser towards that sun, it reflects it by a mirror being at rest with it outside its 'gravitational potential'
What will the three ships measure?
'c' or not?
They do have different speeds.
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What relativity builds on, when it comes to defining a 'commonly shared universe' isn't 'c', although there is where it starts. It's 'proper time' and 'proper length'.
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And the proofs of that is LorentzFitzGerald transformations, and SpaceTime Intervalls. They work, and they will give you the viewpoint of that other frame of reference, translated into its 'proper time' and 'proper length'.
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I am tired, saw that I wrote 'contractions' instead of 'transformations',
Anyway :)
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Actually, stating that 'c' is observer dependent isn't anything new. Every constant comes from locally made experiments. There exist no 'objectively made experiment' uncoupled from the experimenter that I can think of. What I think could be a possible interpretation is to take 'proper time and length' seriously, as a sort of 'golden standard' for relativity. But that craves one to turn everything around.
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If one do one will have to redefine what uniform motion 'is', and with that one will need to take a new look at accelerations.That's unavoidable from a definition in where proper time and length are equivalent for all uniform motions becoming a 'golden standard'. But I tend to do so at times. Uniform motion seems extremely weird to me.
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Yes Halc, from what I call a 'global point of view' they are frame dependent. But you can turn it around and use a local definition. If you do then proper length and time becomes a equivalence for all uniform motions locally defined. That fits 'black box experiments' and how uniform motion behave generally. If 'time' was a 'illusion' you have a third alternative, but that one I don't agree with.
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The problem with using that 'global definition' is that it presumes a outside, from where you can observe those 'frame dependencies' and I doubt that one and so do relativity as far as I've seen. The 'local definition paints' your universe for you on the other tentacle, and that painting is always your reality.
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Halc, it is a simple explanation. What it say is that those ships have different speeds relative each other as they each one do a two mirror experiment being in uniform motion. All three reach a same result, namely 'c'. Doesn't matter that one can prove that they all have different uniform motions.
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Is it possible to achieve relativistic speed? Nearly a speed of light in order to travel the deep space?
Here's some hard data: Suppose a space traveler accelerates at 1g for 1 year. 1g is a perfectly reasonable acceleration ... powerful cars can do it for 5 or 10 seconds. At the end of 1 year of 1g acceleration, the space traveler will be going about 0.774c (relative to an inertial observer co-located and initially stationary with the traveler at the starting point) ... i.e., a little more than 77% of the speed of light. That's fast enough to produce the well-known relativistic effects.
But 1 year is a long time to maintain 1g of acceleration of a spacecraft big and heavy enough to carry (and support) a few human beings. It is in principle possible, but we don't have the capability of doing that yet. It would require an enormous amount of energy. Perhaps it might be possible to carry along that much stored nuclear energy. Or perhaps enough anti-matter could be taken along. Or perhaps ways might be found to continuously transmit enough radiant energy from the earth to supply the space craft. Practical or not, though, it isn't impossible in principle.
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That's true Mike, but for each percent of 'lightspeed' gained from that first relativistic speed you described you will need more power than before, and for the last few millionths of percents you should reach a demand of needing more 'energy' than existing in the universe.
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Is it possible to achieve relativistic speed? Nearly a speed of light in order to travel the deep space?
Sure. Relativistic speeds are accomplished daily at particle accelerator labs. Also, cosmic rays contain relativistic particles. So you have relativistic particles hitting your body all day long. As far as deep space goes, we'll need shielding to block such harmful rays.