Question

it is estimated that light travels 100 000 years to travel the full distance across our galaxy, the milky way. If light travels 3.0x10^8 m every second, how long is the Milky Way? (1year=3.2x10^7s)

Answer 1

distance (m) = speed (m/s) * time (s)
10^5 years * 3*10^8 m/s * 3.2*10^7 s/yr = 9.6*10^20 s

or, as is usually written, 100,000 light-years (duh)

Answer 2

234