In the early hours of February 15, two astronomers at the Mount Lemmon Observatory 9,000 feet above Tucson, Arizona, noticed a small asteroid-like object near the Earth. Kacper Wierzchos and Theodore Pruyne from the Catalina Sky Survey saw this object moving against the steady backdrop of the stars. Wierzchos said that the object near the Earth was not much different from an asteroid, except that it was not orbiting the Sun. It was orbiting the Earth. This minimoon has been named 2020 CD3. The discovery was announced by the Minor Planet Center. So far, the astronomers do not have enough data to establish what the minimoon is made of, the NYT report states. However, the astronomers are convinced that the object orbiting the Earth is not made of rocket debris or due to human activity.
Why is it called a minimoon?
  1. 2020 CD3 is being called a minimoon because it is orbiting the Earth just like the Moon does.
  2. However, it is not actually a moon but an asteroid-like object, about the size of a car, with a diameter of 1.9-3.5 metres. 
  3. The minimoon is temporary and will eventually break free from the Earth’s orbit.
When did the minimoon start orbiting the Earth?
  1. The gravity in the Earth-Moon system captured the little asteroid-like body, which then started orbiting the Earth due to the pull around 18 months to a year ago.
What makes minimoon so rare?
  1. Several primaeval objects are travelling around the solar system, mostly circling the Sun in the belt of asteroids between Mars and Jupiter. 
  2. Sometimes the gravitational force of Jupiter send these objects towards the inner solar system where they orbit near the Earth
  3. However, only rarely do any objects orbit the Earth. If the discovery holds true, the 2020 CD3 would only be the second minimoon to have been ever found.
When is 2020 CD3 likely to leave the Earth’s orbit?
  1. The 2020 CD3 is likely to leave the Earth’s orbit in the next two weeks, the NYT report quoted NASA’s Centre for Near-Earth Object Studies Director Paul Chodas as saying. 
  2. He added that the astronomers discovered the object close to its departure.