How do I calculate light years to years?

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Discussion Overview

The discussion revolves around calculating the time it takes to travel to a planet located 40 light years away, particularly in relation to how far into the past we are observing the planet. Participants explore concepts of light years, travel time, and the effects of relativistic speeds on aging during the journey.

Discussion Character

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

Main Points Raised

  • Some participants suggest that if a planet is 40 light years away, the light observed reveals the planet as it was 40 years ago.
  • Others inquire about how to calculate the age of travelers upon reaching the planet, emphasizing the need for a formula that accounts for travel speed and time dilation.
  • One participant notes that the travel duration depends on factors such as acceleration, top speed, coasting time, and deceleration, indicating that traveling near the speed of light could significantly reduce the experienced travel time.
  • A participant shares a link to a calculator and an equation for calculating relativistic effects, suggesting that the question posed is distinct from the initial inquiry about observing the planet.
  • Another participant acknowledges that the initial question was answered and expresses surprise at the simplicity of the answer.

Areas of Agreement / Disagreement

Participants generally agree on the concept that light years correspond to the time light takes to travel, but there is no consensus on the specifics of calculating travel time and aging during the journey, as multiple views and approaches are presented.

Contextual Notes

The discussion includes assumptions about travel speeds and relativistic effects, which are not fully resolved. There are also references to external resources for calculations that may not be universally accepted or verified.

Who May Find This Useful

This discussion may be useful for individuals interested in astrophysics, space travel, and the implications of relativity on time and aging during interstellar journeys.

Kronos5253
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I have a question, sparked by http://http://www.cnn.com/2009/TECH/12/16/super.earth.discovery/index.html" article, so I figured this would be the best place to put this.

That is said to be 40 light years away... So if we're seeing a planet 2.7 times the size of Earth with liquid water on it, and it's 40 light years away, how do you calculate how far into the past we are seeing this planet?
 
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Kronos5253 said:
I have a question, sparked by http://http://www.cnn.com/2009/TECH/12/16/super.earth.discovery/index.html" article, so I figured this would be the best place to put this.

That is said to be 40 light years away... So if we're seeing a planet 2.7 times the size of Earth with liquid water on it, and it's 40 light years away, how do you calculate how far into the past we are seeing this planet?

If it is 40 light years away, then the light we see reveals the planet as it was 40 years ago.
 
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sylas said:
If it is 40 light years away, then the light we see reveals the planet as it was 40 years ago.

In terms of light years, yes... I basically mean 'Earth years'.. Meaning if we were to travel to that planet, how old would we be when we got there?

I tried finding a formula to figure that out, but I haven't really found anything.. So any help would be appreciated :)
 
Entirely depends on how fast you travel there. Need to know acceleration, top speed, coasting time and deceleration.

The more of your journey you spend at near c, and the closer you get to c, the shorter the duration. There is no limit in principle to how short the duration can be by maximizing these two factors.

In my http://www.davesbrain.ca/science/gliese/index.html" I used the distance of 22.6 ly and an acceleration/deceleration of 1g. The result was a 22.6ly journey with the crew experiencing a mere 6.1 years.
 
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Kronos5253 said:
In terms of light years, yes... I basically mean 'Earth years'.. Meaning if we were to travel to that planet, how old would we be when we got there?

I tried finding a formula to figure that out, but I haven't really found anything.. So any help would be appreciated :)
Here's the equation and a calculator that you can plug sample values into if you don't want to do the calculation yoursefl: http://www.1728.com/reltivty.htm

Note that this question is completely different than the one you asked in your first post.
 
russ_watters said:
Here's the equation and a calculator that you can plug sample values into if you don't want to do the calculation yoursefl: http://www.1728.com/reltivty.htm

Note that this question is completely different than the one you asked in your first post.

Yeah I realized that... And I realized that the answer to the first post is the answer I was looking for haha... I figured it would be a bigger number, but it makes sense to me.

Thanks for the answers though everyone :)
 

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