Light years

[modeller]

Does anyone know a way of finding and explaining how far away a star is in light years. I know it's linked to the red shift and the known speed of light. I've tried Google but without success. Plenty of sites tell you what light years are but not how they are found in the first place.

[ChuckFickens]

thought it was triangulation..


the earths orbit is pretty large, measure angle to star, wait a little while until the earth is in a different position in it's orbit, measure angle to star again, repeat a few more times and the distance can be worked out.

[ChuckFickens]

well you got me thinking :) I was half right

triangulation is how they find the distance to close stars.

http://science.howstuffworks.com/question224.h tm

[ACtheTROLL]

I'm pretty certain the answer is 42

[modeller]

The problem is with stars that are more than 500 light years away. A large bright star say 2000 light years away would look the same as a smaller one at only half that distance and of course what of those which don't radiate within the visual spectrum. There is the further problem of the expansion of the universe and the galaxies moving away from each other. Are they moving at a uniform rate?

[Pigletion]

I thought the parallax method was used (or a development thereof) to find the distance. If you know the distance, then you can calculate the amount of light years.

[boobesque]

The distance is measured in light years

[Pigletion]

^ .. or in parsecs