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Light speed and time. 
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#1
Dec706, 03:16 AM

P: 8

Something I was wondering, since time slows down as we approach the speed of light. Say a person in a ship travailing close to the speed of light only ages by one hour when the rest of the earth ages by 100 years, does that mean the ship only uses one hours worth of fuel? But travels 100 years relative to earth?
Darren 


#2
Dec706, 04:23 AM

P: 75




#3
Dec706, 04:52 PM

P: 5

According to special theory of relativity, when speed limits to speed of light, energy (kinetic energy) limits to infinity. because mass limits to infinity.
m2 = m1 / SQRT(1  (v/c)^2) *when we approach the speed of light, necessary amount of energy is too much !! 


#4
Dec706, 05:35 PM

P: 15,319

Light speed and time.
You can also see a mindboggling implication of this: that star that was 100+ light years away when you were on Earth, is now much, MUCH closer (this is the length contraction component to relativity), which is why it can be reached with a mere hour of fuel expended. But As others are pointing out, it's not that easy. Reaching speeds that manifest that amount of time dilation would burn through an unimaginable amount of fuel  even if it could be done  which it can't. The journey specified requires starting out at Earth and achieviing infinite acceleration to .99999+ c (such that there is no ramp up component to your speed) and then reversing at the other end so that you spend your entire 100lyin1h journey at .99999+c. Your passengers and equipment will be vapourized. As you make your experiment more realistic, you will see that the journey must become a long rampup to ~c and then a long ramp down to 0. The time dilation is still significant, but the fuel expended becomes nighunimaginably large. 


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