It is no longer the only one. The next time you look at the moon at night, think about that. There is another, much smaller and temporary, but it is another. The Center for Minor Planets, based in Washington, announced it recently. It exists for about three years. It is the other moon that orbits the Earth.
Another moon, yes, but not so much
Of course, it is an exciting discovery. But we must weigh it in its correct measure. This new natural satellite is not as impressive as our well-known Luna. And it is not for two reasons. The first is that according to the measurements made by astrophysicists, it is a "mini-moon." No more than about six meters in diameter. And the second, because he may not be with us for much longer.
The star body was sighted by astronomers Theodore Pruyne and Kacper Wierzchos. He appeared in the telescope at Mount Lemmon Observatory, near the city of Tucson, Arizona. It happened on February 15.
Subsequent observations allowed to calculate the orbit of this miniluna. On February 25, the Center for Minor Planets made the announcement that the celestial object called 2020 CD₃ was orbiting the Earth.
The 2020 CD₃ is essentially a small sample of the asteroids whose orbits intersect with those on Earth. Sometimes, these asteroids are close to colliding with the Earth. Although in the case that the 2020 CD₃ crashed against the planet there would be no problem. Its small size would disintegrate in the atmosphere before hitting the ground.
Instead of threatening Earth with a crash, the 2020 CD₃ chose another way to move through these regions. In its course to our planet it was taken in an orbit much farther than that of our permanent Moon. As the scientists explained, these "mini-moons" come and go constantly. 2020 CD₃ is probably in its final laps before it is released from the Earth's force of gravity.
The Earth always has the possibility of being accompanied by "minilunas" of a size larger than one meter. They would give at least one trip to the planet before continuing its course. None of those bodies remain long. Why? Because of the gravitational interference of our Moon and even the Sun. They make the orbit of these objects not stable.
But it is also difficult to predict the orbit of "mini-moons." By their size, they are influenced by the force produced by solar radiation. For now we know very little about dimensions, shapes and reflection of space bodies to be able to calculate orbits accurately.
Other objects that have been called Earth's "moons" actually orbit around the Sun. But they do so in the same trajectory of the Earth. These are known as "quasi satellites" of the Earth. One of them, the 1991 VG, seems to have completed at least one genuine Earth orbit in 1992. And I could repeat it in the future.
So, although The other moon that orbits the Earth is an interesting discovery, don't expect a catastrophic collision. No other additional moonlight for that night walk. Although, at least for a while, our main moon does have the company of a very small cousin. Like a fleeting love, it will never come back.