how many miles is one light-year and how do you maesure one billion light years ?

Question

My question was, how many miles is one light year and how do you measure one billion light years,please answer in technical terms.

Answer 1

5.879×10^12 miles in one light year. Mutliply this by 1 billion.

Answer 2

Others have answered the first part of your question, but if I read you right, you want to know how we measure a billion light years. The only way to do it is by red shift. There are three ways to measure great distances. Heliocentric parallax is good for measuring up to a few hundred light years.
Then greater distances are estimated by using variable stars with period/luminosity correlation like RR Lyrae and Cepheid variables. Their periods of magnitude indicate their size. Their spectra indicate their temperatures. From this data we can determine rough distances to them using the inverse square law of light, and consequently to clusters and galaxies we see them in.
But even these, as bright as some of them are, cannot be resolved in any more than just a few of the closest galaxies. Since the Universe is apparently expanding uniformly in all directions, the farther away a galaxy or quasar is, the more red shifted its spectrum is. At first there is a lot of guesswork, but thanks to the enormous number of distant objects, we start to get statistically reliable distances.
A billion light years is well into the range that would be measured by red shift.

Answer 3

1 light year = 5.878499814^12 miles. Thats the distance light can travel in one year's time. Light travels at 670,616,629.4 mph in a vacuum.

1-billion light years = 5.878499814^21 miles.

Answer 4

light travels at 186,000miles/second. to get that into miles per year, we have to multiply 186,000 x 60 sec/min x 60min/hour x 24 hours/day x 365 days/year to get:

5.865696 x 10^12 = 1 light year,

then we multiply that by 1 billion to get:

5.865696 x 10^21 = 1,000,000,000 (1 billion) light years

note: notice how the first number (5.865696) does not change, but the exponent (signified by the "^") does.

Answer 5

One light year (in miles) = 186,000 miles/sec *
pi*10^7 sec per year = 6,000,000,000,000 miles appx. BTW, pi*10^7 is a nifty approximation.

To find one billion light years, just tack on another 9 zeros, or if your hand hurts, 6x10^21 miles. For God sakes, don't use a meter stick.

Answer 6

The second measurement is a megaparsec.

Answer 7

1 light year = 9,460,730,472,580.8 km.