Why We are Alone in the Galaxy | Marc Defant | TEDxUSF
But wait, there's more!
Where is Everybody? Why Haven't We Found Extra-Terrestrials?
A little more on this. The Earth and the Moon are a system. The Moon does not neatly orbit around the center of mass of the Earth. Instead, the center of mass of the Earth, and the center of mass of the Moon, both orbit around the center of mass of the pair (the barycenter). This wobbling makes it much harder for an object being pulled towards the center of mass of the Earth-Moon system to follow a straight line. All of that extra mass out there is pulling an object away from the center of mass of the Earth-Moon system.
SkyMarvels™ EARTH-MOON BARYCENTER (celestia celestia4all)
As an example of how this works, look at the crazy, almost half-century trip of Apollo 12's third stage. It was fired out into a heliocentric orbit around the Sun, but kept getting pullled back into the Earth-Moon system's gravity well into a geocentric orbit around us, then ejected out into a heliocentric orbit again, and then back into geocentric orbit. It is like a piece of driftwood bobbing along a tideline in the ocean, sometimes getting pulled away by one current, sometimes by the other.
But wait, there is even more!
Jupiter shepherds large transient objects (asteroids) into a belt outside the orbit of Mars. The very large mass of Jupiter, well outside of the inner Solar System, is a unique and very good thing for us fragile creatures on the Earth. Notice the Asteroid Belt is not a neat circle in between the orbits of Mars and Jupiter, it is very different. That will be explained in the post that follows.
Jupiter 'shepherds' the asteroid belt, preventing the asteroids from falling into the sun or accreting into a new planet.
Now, the above video is beyond cool, because it illustrates four of the five Lagrange points (L1, L3, L4, and L5).