I didn't wrangle the lower limit that way -- it just fell out. If it hadn't, perhaps I couldn't be typI'm glad the lowest number was one.![]()
I didn't wrangle the lower limit that way -- it just fell out. If it hadn't, perhaps I couldn't be typI'm glad the lowest number was one.![]()
The asymmetry in time dilation, as exhibited by the twin paradox, is actually not a result of the acceleration and deceleration. It's the result of the travelling observer taking measurements in more than one reference frame. If you use the correct Lorentz transform, t'=gamma*(t-(v*×/c^2)), you can show that the travelling observer really does experience less time passing.Time doesn't pass for you on the ship moving at c so your journey takes 0 seconds for you. The elapsed time measured at your starting point based on observing your journey is distance/velocity = 10 light years/c = 10 years.
If you travelled 1 million light years at c, 0 seconds would pass for you, 1 million years back home.
For a speed v less than c, the time dilation factor is 1/sqrt(1-(v/c)^2), which goes to infinity as v tends to c, as in your example.
For v less than c, one might think that as the motion is relative, each observer would observe clocks ticking more slowly for the other observer. This is true, however, it is possible to show that less time does pass on the ship, provided it starts and finishes in the same inertial frame of reference as the stay at home observer. The asymmetry arises because the ship has to accelerate and decelerate.
At 0.98c, the time dilation factor is 5, which, for the 10 light-year trip example, assuming extremely rapid acceleration and deceleration, would mean about 10.2 years would have passed on Earth and 2.04 years on the ship. The predicted effect of time dilation has been confirmed many times by the enhanced decay times of rapidly moving elementary subatomic particles such as muons.
I wouldn't be surprised if there were a new state of degenerate matter that could perfectly replicate the first five minutes of an I Love Lucy episode--and make us think ET was playing our TV programs back to us.
If i am not mistaken he began looking at the problem from the Flyby Anomaly. Flyby Anomaly still seems the best way, to me, to test many of these assymetric-thrust ideas. The former needs to be looked at anyway, whether it involves the latter, so why not handle two matters at once.I kind of like his QI theory but I dislike the abbreviation of "to", "for", and "are" to "2", "4", and "r" in his tweets. I believe McCulloch has also proposed an FTL drive based on QI theory but I don't know enough about it to spot any flaws in its conception.
ETA: Mike McCulloch's blog mentions an asymmetrically accelerating horizon approach to generating thrust. It sounds like a plausible and testable mechanism.
https://physicsfromtheedge.blogspot.com/?m=1
I kind of like his QI theory but I dislike the abbreviation of "to", "for", and "are" to "2", "4", and "r" in his tweets. I believe McCulloch has also proposed an FTL drive based on QI theory but I don't know enough about it to spot any flaws in its conception.
ETA: Mike McCulloch's blog mentions an asymmetrically accelerating horizon approach to generating thrust. It sounds like a plausible and testable mechanism.
https://physicsfromtheedge.blogspot.com/?m=1
So at the NASA Innovative Advanced Concepts symposium this month, the team working on Dr Woodward's Mach Effect Gravity Assist (MEGA) put through a proposal to send a nuclear powered craft at .4c to Proxima Centauri. This is an actual proposal. Obviously the propulsion is a novel idea, but the craft itself is derived from Jupiter Icy Moons Orbiter (JIMO) which was a concept seriously looked at for a nuclear powered unmanned spacecraft in the early 2000's.
Since this is about the most serious near-time proposal for a starship, I thought it might be of interest. The documents are located here.
http://ssi.org/today-at-nasa-niac-2017/
a video of Doctor Fearn's presentation on the starship:
http://www.solstation.com/stars3/100-gs.htm
Here’s a list of all stars within 100 lys.
Most of them have been reached by our oldest radio signals already.
I'm beginning to be of the opinion that we're all alone in this stellar neighborhood, at least in terms of starfaring civilizations. Intelligent life may be rare enough and rarely gets that extra nudge to begin some equivalent of the agrarian revolution and the (relatively) quick journey to technology that develops after that. Human beings existed for well over 100,000 years on earth moving around and settling everywhere they could, but once someone came up with the idea of staying put and planting seeds, it was a pretty short time to where we are now. If, for instance, some catastrophe had only left north and south america settled, it would have taken longer due to a lack of beasts of burden and certain geographic challenges, but it was going to happen. But if the entire world had been some place not helpful for transitioning to that economy and lifestyle, it would never have happened. If most living worlds are water worlds, all the moreso due to a lack of combustion and metallurgy.
To be even more bleak: some civilization in the galaxy, even in the universe, had to be first to get out beyond the gravity well on its own power. Someone had to be "the founders". I know its astronomically hard to fathom, but what if its us?
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