Just pondering this topic while waiting for the tower to load one day: When traveling between planets in Destiny, it usually takes between 10 and 30 seconds to arrive at your destination. However, planets are so incredibly far apart that that would not be possible, even at the speed of light. Light takes about 8 minutes to reach Earth from the Sun and about 78 minutes to reach Saturn from the Sun. So, the distance between Earth and Saturn is about 70 light minutes (assuming the Earth and Saturn are lined up nicely). So, next time when you are taking a trek back to the tower after patrolling the Dreadnaught, remember that you're completing a journey that takes at least an hour in just a few seconds :)