All the planets except Venus and Mercury have moons. Any particular reason?
Good question Linda, you are making me think.
This was a fact I had always accepted without giving it much thought. First thing that comes to mind is that most of the other moons, except Earth's, are captured asteroids. Since the Earth, Venus and Mercury are too far away from the asteroid belt, they missed out on being able to grab a few during solar system formation. Earth's moon is a special case and has other theories behind its existence. The Earth's moon is believed to have been a result of collision with another object 4? billion years ago when the Earth was being formed. It is widely regarded to be a fluke, a highly unlikely occurrence.
When you take into account the proximity of Venus and Mercury to the sun, another factor comes into play. The sun's gravity would surely have affected the odds of these planets' ability to capture and retain a smaller body like an asteroid or any other mass coalescing during solar system formation.