Typically orbit the sun at approximately 3 au?

Answer 1

Not much. Earth is at 1 AU, by definition, and Mars is at about 1.5 AU. Between Mars and Jupiter (about 5 AU) there are no large planets; it is thought that Jupiter's gravity interfered with planets forming near it. Instead, there are billions of asteroids, which are of similar chemical makeup to the inner planets (i.e. mostly rocks and metals), but much smaller, ranging from smaller than a sand grain to the size of U.S. states. We have observed several thousand of the larger ones; these are irregularly-shaped rocky things the size of cities. The largest, Ceres, is almost 600 miles across and orbits between 2.54 and 2.98 AU. So, I suppose I could say that Ceres is at 3 AU, once every 4.5 (Earth) years.

See http://en.wikipedia.org/wiki/Ceres_(dwarf_planet) for more about Ceres.

Answer 2

That probably refers to asteroids. There is a large belt of asteroids between the orbits of Mars and Jupiter.

That probably refers to asteroids. There is a large belt of asteroids between the orbits of Mars and Jupiter.

That probably refers to asteroids. There is a large belt of asteroids between the orbits of Mars and Jupiter.

That probably refers to asteroids. There is a large belt of asteroids between the orbits of Mars and Jupiter.

Answer 3

Objects that orbit the sun at approximately 3 astronomical units (au) are located three times the average distance between the Earth and the Sun. This distance is considered part of the outer solar system, where objects like asteroids, comets, and dwarf planets are commonly found. Examples of bodies that orbit at around 3 au include the asteroid belt and the dwarf planet Ceres.

Answer 4

That probably refers to asteroids. There is a large belt of asteroids between the orbits of Mars and Jupiter.