Converting light years to meters and miles

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Homework Help Overview

The discussion revolves around converting a light-year, defined as the distance light travels in one year, into both meters and miles. Participants are examining the calculations involved in this conversion using the speed of light.

Discussion Character

  • Exploratory, Mathematical reasoning, Assumption checking

Approaches and Questions Raised

  • Participants are attempting to calculate the distance of a light-year using the speed of light and are discussing the conversion factors needed for meters and miles. Questions arise regarding the origin of certain values and the methodology for calculating the distance over time.

Discussion Status

There is an ongoing exploration of the calculations needed to determine the distance of a light-year. Some participants have provided guidance on the steps to take, while others are questioning the assumptions made in the calculations. Multiple interpretations of the problem are being discussed.

Contextual Notes

Participants reference a specific value for the distance of a light-year in meters, which is stated as 9.46 Pm. There is also a discussion about the need to calculate the number of seconds in a year to complete the conversion.

TrimHopp
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Homework Statement



A light-year is the distance that light travels in one year. Find this distance in both miles and meters.

Homework Equations



Speed of light (c) = 3.00x10^8 m/s

The Attempt at a Solution



10^15 m/s
__________
3.00x10^8 m/s

That is to find meters...I think I can only find miles after I find meters by dividing that answer by 1609m

Thanks.
 
Last edited:
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I think google could help you with this.
 
TrimHopp said:

Homework Statement



A light-year is the distance that light travels in one year. Find this distance in both miles and meters.

Homework Equations



Speed of light (c) = 3.00x10^8 m/s

The Attempt at a Solution



10^15 m/s
__________
3.00x10^8 m/s

That is to find meters...I think I can only find miles after I find meters by multiplying that answer by 1609m

Thanks.

Where did 1015 m/s come from? and what are you doing/trying to do?

You were told how far light goes in a second, how about a minute? Then how about an hour? a day? 365.24 days? [a year]

Once you know how many meters, I wouldn't be multiplying by 1609. I don't think anything is more miles away from something that it is meters away from something! The end of my street is about 120 m away, but it is far less than even 1 mile.
 
Right peter, I meant divide. Thanks for that.

In the book where I get the problem from, it says 1 light year = 9.46 Pm (P being peta (15) and m being meters). I thought that was 10^15?
 
TrimHopp said:
Right peter, I meant divide. Thanks for that.

In the book where I get the problem from, it says 1 light year = 9.46 Pm (P being peta (15) and m being meters). I thought that was 10^15?

Yes, but then that makes the length of a light-year 9.46 · 1015 m. But if you know this, why divide by the speed of light? That would tell you the length of time it takes light to travel one light-year, yes?

You are being asked to compute the length of a light-year, given that light travels at (very nearly) c = 3.00 · 108 m/sec . You need to work out the number of seconds in a year. (You may use the distance you looked up as a check...) You then need to convert this value from meters into miles.
 

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