Moon — is not the only natural satellite of the Earth, it is actually their set. However, these satellites orbiting our planet temporarily. That was the conclusion at the Massachusetts Institute of Technology and the University of Hawaii.
As an example, they cite a small asteroid seen in Earth orbit in 2006. He described the turns around the planet until 2007. As a result, studies of gravitational fields of the Moon and the Earth, scientists have come to the conclusion that such a "tightening" of space objects in orbit happens quite often. According to them, at any given time, the Earth must be at least one such satellite with a diameter of at least 1 meter.
The study of these "space visitors" it is important to prepare for the conquest of space. Trial planting easier to implement on an asteroid orbiting the Earth, ITAR-TASS reported.
From the internet.