The distance that light travels in one year is called a light year. A light year is 9,56 * 1012km.
a. Show with a calculation that the speed of light is around 3,0 * 108 meters per second.
b. The star Pollux is 3,3 * 1014 km away from us. How many light years is the distance between Pollux and Earth?
c. The light of the star Sirius takes 8 years and 282 days to reach us. How many kilometers is the distance between Sirius and Earth.
+128475 a.
Number of meters in a light year = 9.56 * 10^12 * 1000 = 9.56 * 10^15 m
Number of secons in a year = 3600 * 24 * 365 = 31536000 sec = 3.1536 * 10^7 sec
So ..... 9.56 * 10^15
___________ ≈ 3.03 * 10^8 m / s ≈ 3 * 10^8 m / s
3.1536 * 10^7
b. 3.3 * 10^14
__________ ≈ 34.5 light years
9.56 * 10^12
c. Distance = [ 8 + 282/365 ] * [9.56 * 10 ^12 ] ≈ 83866082191780.8 km
