Does Traveling at Light Speed Affect Fuel Consumption and Time Dilation?

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Discussion Overview

The discussion revolves around the implications of traveling at speeds close to the speed of light, particularly focusing on the effects of time dilation on aging and fuel consumption during such journeys. Participants explore theoretical scenarios based on special relativity, examining how these factors interplay in a hypothetical space travel context.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants propose that if a ship travels close to the speed of light, the occupants would age significantly less than those on Earth, suggesting that the ship would only use a fraction of the fuel compared to the distance traveled relative to Earth.
  • Others argue that if the ship is not accelerating, it would not consume any fuel, raising questions about the conditions under which fuel consumption occurs.
  • A participant cites the special theory of relativity, stating that as speed approaches the speed of light, the energy required becomes infinite, implying that achieving such speeds is practically impossible.
  • One participant acknowledges the time dilation effect but emphasizes the unrealistic nature of achieving the necessary speeds without an immense amount of fuel, highlighting the need for a gradual acceleration and deceleration rather than instantaneous changes in speed.

Areas of Agreement / Disagreement

Participants express differing views on the feasibility of traveling at light speed and the associated fuel consumption. While there is some agreement on the effects of time dilation, the discussion remains unresolved regarding the practical implications and the energy requirements for such journeys.

Contextual Notes

The discussion includes assumptions about instantaneous acceleration and the neglect of practical limitations in space travel, which may affect the validity of the claims made.

daz59
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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
 
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daz59 said:
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
if it's not accelerating it won't use any fuel
 
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 !
 
daz59 said:
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
The short answer to your question is yes. It is true that the ship, along with everything and everyone in it, will experience a mere one hour passing.

You can also see a mind-boggling 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 100ly-in-1h 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 nigh-unimaginably large.
 
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