Measuring the Universe

speed of light (c) = 3 x 10⁸ m/sec (Actually: 299 792 458 m/sec) or approximately 186,000 miles/sec

1 meter (m) = the distance traveled by light in a vacuum in 1/300 000 000 of 1 second (Actually 1/299 792 458 of 1 second)

1 kilometer (km) = 1 x 10³ m

1 light year (LY)= 9.46 x 10¹⁵ m             

 1 light year (LY)=9.46 x 10¹² km  (9.46 trillion km)      

 1 light year (LY)=5.88 x 10¹² miles (approximately 6 trillion miles)

1 light year (LY)=the distance traveled by light in 1 year

1 astronomical unit (AU)=the distance from the Earth to the Sun

1 AU=1.5 x 10¹¹ m

1AU=9.3 x 10⁷ miles

1AU=1.58 x 10^-5 LY

1 parsec=3.26 LY