Question

Change 3 lightyears to _________ miles


307.5 = __________ Astronomical units


1 parsec is a distnce that corresponds to ______________ degrees

Answer 1

Type this into the Google search window:
1 parsec in miles
a Parsec corresponds to .0001 degrees

How far can light travel in one second? How many seconds in a year?

Or cheat, and type this in the google search window

3 lightyears in miles

The second makes no sense, what are the units on the left?

Answer 2

One parsec is the distance at which the Earth's orbit radius (1 a.u.) subtends one arc second (1/3600 degree). It equals 3.26 light years. Stars at that distance would shift back and forth one arc second per year, relative to more distant background stars, due to stellar parallax.

http://coolcosmos.ipac.caltech.edu/cosmic_classroom/cosmic_reference/distance.html