How did our Solar System form? Where did the planets come from?
NASA's Lucy mission has just set out on a four billion-mile journey to find out.
The spacecraft will travel to seven of the Trojan asteroids; these swarms of icy bodies loop the Sun ahead and behind Jupiter's orbit.
These asteroids are locked in a gravitational wells called Lagrange Points, where the gravity of Jupiter and Sun balances out. This keeps the bodies static where they would otherwise have been flung out of the Solar System entirely.
The gravitational anomaly means these asteroids are some of the oldest bodies in the Solar System, and can tell us a great deal about how the planets formed.
Sources and further reading:
Lucy Mission Overview at NASA
Lucy Launch Coverage at NASA Live
Featured image: Lucy and a Trojan Asteroid | Credit: NASA/Made with Space Engine