The main asteroid belt of the solar system lies between the orbits of:

The main asteroid belt is a broad, ring-shaped region between the orbits of Mars and Jupiter, roughly 2.2 to 3.2 Astronomical Units (AU) from the Sun, where most of the solar system's asteroids orbit.

What asteroids are:

• Asteroids are rocky or metallic bodies, smaller than planets, that orbit the Sun.
• They range in size from a few metres to several hundred kilometres across.
• Most are irregular in shape.

Contents of the belt:

• The belt contains millions of asteroids, including more than a million larger than 1 km across.
• Despite this large number, the total mass of the belt is only about 3 percent of the Moon's mass.
• The four largest objects, Ceres, Vesta, Pallas and Hygiea, contain about half of the belt's total mass.

Asteroids are spread over a vast space, so the average distance between them is about a million km. Spacecraft pass through the belt without difficulty.

Why no planet formed there:

• The strong gravity of nearby Jupiter disturbed the material in this region, stirring up the bodies so that they collided too fast to stick together.
• So, the material never came together to form a planet.
• Types of asteroids: C-type (carbon-rich, most common), S-type (stony) and M-type (metallic).

Asteroids outside the main belt:

Trojan asteroids share Jupiter's orbit, gathered in two groups ahead of and behind the planet.

Near-Earth asteroids have orbits that bring them close to the Earth. They are closely watched because of the small risk of impact.

NASA's DART mission in 2022 deliberately crashed a spacecraft into the small asteroid Dimorphos and changed its orbit, testing a method of planetary defence.

Missions:

• NASA's Dawn mission visited Vesta and Ceres.
• NASA's Psyche mission, launched in 2023, is travelling to the metal-rich asteroid Psyche.

Why not the other options?

• ✗There is no asteroid belt between Earth and Mars, Jupiter and Saturn, or Venus and Earth.