Scientists puzzled by a blue asteroid: it spins faster and faster on its axis

3200 Phaethon is listed as a near-Earth object (NEO).


It is one of the few asteroids that has a predominant blue color among the rocks of the universe.

Asteroid 3200 Phaethon is having a very strange behavior that has baffled scientists who study it: it is spinning faster and faster on its axis.

The large blue rock, one of the few with this hue, 5.4 kilometers in diameter, is reducing its rotation period by 4 milliseconds, a figure that may not sound big, but it is considerable for a star of its size.

What is Phaethon?

Phaethon is a rock classified as a near-Earth object (NEO), although it does not pose a danger to our planet.

Its closest point to the Sun is only 20.9 million km, a third of the orbit of Mercury. In 1983, when it was discovered, the best theory about its color was also modulated: it is so close to the Sun that its surface temperature reaches 800 degrees Celsius, enough to vaporize the ferrous molecules that give other asteroids their reddish hue and leaving only rock and minerals that reflect light in bluish tones.

According to experts, several thousand years ago, the asteroid 3200 Phaethon left a trail of dust, which is actually responsible for the Geminids. This makes Geminides a unique phenomenon, as most meteor showers come from dust from a comet, not an asteroid .

It is being studied very closely, and because of this, the unusual behavior of the asteroid has been noted by a team of scientists led by the Arecibo Observatory and the University of Central Florida .

Based on observations from 1989 to 2021, researcher Sean Marshall of the Arecibo Observatory in Puerto Rico created a model to study the asteroid before the Japan Aerospace Research Agency (JAXA) DESTINY+ mission began, which is planned to send in 2024.

How has Phaethon changed?

According to scientists, the asteroid makes one rotation around its axis in 3.6 hours. However, its rotation period is shortened by about 4 milliseconds per year.

The scientist suggested that the discrepancy between theory and practice can be explained by a change in the speed of the asteroid’s rotation. Perhaps this occurred as a result of a collision or “interaction” of the asteroid with some comet in December 2020.

To date, scientists believe that the speed of rotation of asteroids does not normally change unless it is affected by external events.

It is known that in the XXI century t shirts, the asteroid will approach Earth several times: it will happen in 2050, 2060 and 2093. It also approached our planet on December 10, 2007 (it flew by at a distance of 18.1 million km) and on December 16, 2017 (it flew by at 10.31204 million km, which is equivalent to 27 distances to the Moon).