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From SR we know that the measurement of space and time are relative to the specific reference frame of the observer.

What about measuring energy content?

When an object is accelerated to a near light speed, constant velocity it takes allot of energy to get there, and that energy is essentially 'stored' within the object, right?

If I'm within the reference frame of that object, but have no knowledge of the history of being accelerated (say I was in cryo-sleep), is there any way as an observer I can measure or determine that the energy within the object I'm traveling with has increased?

If not, then how do we know here on earth, or as a whole solar system or galaxy, that we are not traveling near light speed?

docscience
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    possible duplicate of Is energy content of a system different dependending on the observer? – Ellie Dec 31 '14 at 21:51
  • Energy is observer dependent and we are traveling at nearly the speed of light for the overwhelming number of observers in the universe. That's what the Hubble expansion does... the further out something is, the faster it is moving away, and since most of the stuff is "really far out" because most of the volume in a spherical shell is near the surface, that means that almost everything in the universe is moving away from everybody at almost the speed of light. And that is actually getting worse because of dark energy. – CuriousOne Dec 31 '14 at 21:52
  • @CuriousOne , so 'getting worse' meaning things are headed towards some apocalyptic event? And isn't 'far out' and 'really far out' relative to the edge of the observable universe as it is from them to us? So then who's time frame is dilated? – docscience Dec 31 '14 at 21:58
  • Current mainstream physics basically predicts a cold, empty, ever "shrinking" visible universe. In about 4 billion years Andromeda will be merging with the Milky Way, the two will form a large spherical galaxy and most other "stuff" will redshift out of the visible universe. Anybody who isn't gravitationally bound to the remaining object will never be able to come back "here". The "edge" of the universe is really just the past of our local visible universe. Everybody else has a different visible past, but the distance in time to that past is roughly the same. – CuriousOne Dec 31 '14 at 22:06
  • @CuriousOne : Whaaat? That's terrible! I understand that the humankind would have disappeared long time before, and whatever we learnt, all the knowledge, art, etc. is in vain. So, is our universe oscillating, it returns to something small, and after that a new Big-Bang? – Sofia Dec 31 '14 at 23:46
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    @Yep, your life is meaningless! Meaningless, I say! ;-) – CuriousOne Jan 01 '15 at 00:15

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