Everyone knows and loves the moon. What you may not know is that it's not Earth's only natural satellite. In 1997, another body was discovered, 3753 Cruithne, also called a quasi-orbital satellite of Earth. This means that Cruithne doesn't orbit Earth in a nice ellipse the same way our moon does. Instead, Cruithne scuttles around the inner solar system in what's called a horseshoe orbit.