(1.863 * 10^5 miles / sec) * (60 sec / minute) * (60 minutes / hour) * (24 hours / day) * (365 days / year)

Cancel out units.

5.795 * 10^12 miles / year

Create a table by multiplying years by the expression above

Years Miles

1___________5.795 * 10^12

10__________5.795 * 10^13

100_________5.795 * 10^14

1000________5.795 * 10^15

10000_______5.795 * 10^16

100000______5.795 * 10^17

With a diameter of about 5.875 x 10^17 miles and based on the table it would take light 100000 years to travel across our galaxy