
#1
Dec2009, 11:42 PM

P: 111

I have a question, sparked by this 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? 



#2
Dec2109, 12:03 AM

Sci Advisor
P: 1,750





#3
Dec2109, 10:42 AM

P: 111

I tried finding a formula to figure that out, but I haven't really found anything.. So any help would be appreciated :) 



#4
Dec2109, 10:44 AM

P: 15,325

How do I calculate light years to years?
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 treatise on Gliese 581 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. 



#5
Dec2109, 06:27 PM

Mentor
P: 22,000

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



#6
Dec2109, 07:03 PM

P: 111

Thanks for the answers though everyone :) 


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