This is still vastly more believable than the Moon encountering a new planet every episode.
Even if it was traveling at near light speed, it should take thousands of years before they encounter another planet. And if they were traveling that fast, they would barely see these planets for a fraction of a second before continuing on their journey :-)
at light speed, the next solar system is 4-5 years away. but yes. although we can assume that what they ran into were all rogue planets because i don't remember seeing any stars. who knows what's out there that we haven't detected yet.
still remains the problem of everything needing to be pitch black all the time. i think even without finding any other planets they had a magic light source on the moon.
i am assuming the most optimistic outcome that is physically possible, no matter how unrealistic. because if we go by statistics we'd have to scrap most movies that are about an unrealistic (but possible) event.
Even if it was traveling at near light speed, it should take thousands of years before they encounter another planet. And if they were traveling that fast, they would barely see these planets for a fraction of a second before continuing on their journey :-)
But well, great scifi show back then.