Earth has a second Trojan asteroid, astronomers just confirmed!

Earth has a second Trojan asteroid, astronomers just confirmed!
NOIRLab/NSF/AURA/J. da Silva/Spaceengine

Astronomers have found a second asteroid in earth’s Trojan belt. The newly-discovered companion of planet earth is called 2020 XL5 asteroid.

The 2020 XL5 asteroid is a kilometer-wide carbonaceous space rock. It has been found at earth’s L4 Lagrange point – a place where the gravitational forces of Earth and the Sun balance out, creating a stable point in which objects can become trapped.

A paper published in Nature Communications also confirms that 2020 XL5 will be stuck at L4 for another 4000 years.

Scienitsts call it the second Earth Trojan ever discovered; the first one was found in 2010. Other planets too have these trojans.

Jupiter too has thousands of trojans, so many that the asteroid swarms at Jupiter’s L4 and L5 points and these rival the number of objects in the main asteroid belt itself.

There is a mission to study Jupiter’s Trojans, named Lucy. It was launched in October and will arrive at Jupiter’s L4 point in 2027.


Other planets too have trojan asteroid. Neptune has 29 known trojan asteroids, Mars too has over a dozen of them in its Lagrange points.

However, earth Trojan asteroids are too hard to see because we have to stare nearly directly towards the Sun to find them. This is what makes it so daunting to search for them.

Earth’s 2nd Trojan Asteroid discovered

This c-type asteroids like 2020 XL5 tend to have low albedo’s. It reflects very little light. This is what also makes spotting Earth Trojans a difficult challenge.

How how was 2020 XL5 discovered then? Well, a short period just before sunrise and just after sunset is the time when the Sun is blocked by the horizon. This is when the Lagranges points are still visible in the sky. Also, this is not an ideal observing situation but indeed enough to take a quick look.

As per the data, this is a ‘transient trojan,’ meaning it did not begin in Earth’s L4 point. It was rather captured, and it won’t remain there forever either. Astronomers say that it will remain in the L4 neighborhood for at least the next 4,000 years.

Moreover, the attempt to find Earth Trojans does not rely on Earth-based telescopes. Scientists will keep searching for more Earth Trojan asteroids. These can help teach us a lot about the era of planetary formation.

As they have the leftover material from the times of earth’s formation.

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