is deep enough to serve as a landing pad
for another smaller planet. As long as
the actual contact between us and the other
planet was controlled (ropes? rockets?)
there shouldn't be much of an issue.
Pluses: Easy to go to "another world,"
plenty of opportunities (hopefully)
on guest planet, an ecosystem that would
be fun to exploit or cherish, depending
on who got there first. It would be interesting
climbing onto the guest planet.
From a boat in the Pacific Ocean, one
could climb upwards to the underside
of the guest planet. Also, I'm assuming
the planet is actually smaller (in this case
much smaller) than our planet. You saw
"Melancholia" by Lars Von Trier? A lot
of that movie takes that into account.
Another planet bumping into ours
basically means the end our planet.
That is something to strongly consider.
When I was around 9-years old, I had
a dream that a smaller version of the moon
landed on the cul-de-sac at the end
of our block in a subdivision of Atlanta.
In the dream, it was actually exciting,
everyone in the neighborhood was buzzing
around. I remember thinking, "Holy cow,
the moon is at the end of our block."