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There is no close-up image of Jupiter's Trojans. The 3D model shows an artist’s impression.

Belt

Jupiter's Trojans

Jupiter has two swarms of rocky companions: one flies ahead of it, one behind it. They are called Trojans and are like fossils from the time when the planets formed. The Lucy probe is flying there right now.

▶ View Jupiter's Trojans in the 3D model

Fact file

Type: Belt

Interesting facts about Jupiter's Trojans

Two huge swarms of asteroids share Jupiter's orbit: one runs 60° ahead of it, the other 60° behind.
There are probably more than a million chunks larger than 1 km – almost as many as in the entire Asteroid Belt.
They are named after heroes of the Trojan War: the Greeks in front (e.g. Achilles), the Trojans behind (e.g. Patroclus).

Formation

At these two places (Lagrange points L4 and L5) the pull of the Sun and that of Jupiter balance in such a way that chunks stay trapped there – and have done for billions of years.

Composition

The Trojans are dark and reddish, probably leftovers from the time the planets formed, perhaps captured from the outer Solar System.

Exploration

NASA's Lucy probe has been on its way since 2021 and is due to visit several Trojans from 2027 – the first mission to go there.

In comparison

Earth has a small “Trojan” too: the asteroid 2010 TK7, just 300 m across.

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