Scientists discover an asteroid trapped near Earth for the next 4,000 years

Looks like our two known trojan asteroids are relatively new.

"Primordial trojan asteroids are ones that have been sharing the planet’s orbit since the planet’s formation, but both of Earth’s trojans so far are passing visitors. Scientists speculate that they may have been captured in this orbit at some point, calculating that asteroid 2020 XL5 may have been captured just 600 years ago."

"Trojan asteroids are objects that share an orbital path with a planet in the Solar System, and they are found in gravitationally stable regions known as Lagrangian points. These are pockets in space where the Sun’s gravitational pull is balanced out by Earth’s gravity, holding objects in place. Earth has five Lagrangian points, and the James Webb Space Telescope is currently orbiting the Sun in the Earth-Sun L2 Lagrangian."

Includes a link to the research in Nature.