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Astronomers discovered something strange about asteroid Phaethon | Space

Phaethon is just the 11th known asteroid to demonstrate a changing rotational period

The Japan Aerospace Exploration Agency intends to launch its DESTINY+ mission to the near-Earth asteroid Phaethon in 2024, with the aim of flying by the space rock in 2028, so this “potentially hazardous” asteroid has been studied intensely in the lead-up to the mission.

Researchers recently made one particularly notable discovery about Phaethon: Its spin is speeding up. The asteroid’s rotational period is decreasing by 4 milliseconds per year. Even a small change like this could impact the DESTINY+ observations. Knowing the specific spin rate allows the team to more accurately predict the asteroid’s orientation during the spacecraft’s flyby — in turn, that allows the team to be more specific with their observations.

It’s rare for an asteroid’s spin to change; Phaethon is just the 11th known asteroid to show a change in its rotational period, and it’s the largest of those space rocks, with an average diameter of 3.4 miles (5.4 kilometers).  …