Not a big one like Luna of course, but has the Earth ever had a smaller captured-asteroid type satellite similar to Mars’ moons?
Not that we know of. Certainly at some point in it’s 4.5 billion-year history, it may have.
Earth sort of has a second moon now: Cruithne.
There’s also J002E3 which apparently is a piece from an old Saturn V that’s been alternately orbiting the sun and the earth since the 1969.
http://www.cnn.com/2002/TECH/space/09/23/apollo.moon/index.html
Apparently about a year ago, astronomers found an object that appeared to be a second moon in earth’s orbit. But it was determined to be a leftover Saturn rocket from the Apollo days. Not sure if it’s still in Earth’s orbit or not though.
Depends on your definition of a second “moon.” After the giant impact when a Mars-sized body slammed into the earth (according to latest theories) lots of material was thrown into space. Most of that mass coalesced into what would become the Moon. But certainly lots of little pieces orbited the Earth until they were either captured by the Earth as meteors or became part of the Moon or were thrown off into nothingness.
A book has just come out detailing these latest developments, The Big Splat, or How Our Moon Came to Be, by Dana Mackenzie.
They say that the Saturn V piece is going to pass really close to the moon sometime soon, and there’s a chance it might hit the moon.