The discovered moon is the smallest: its diameter is less than 5 km
Tamara Traubman
Astronomers announced yesterday that they may have discovered an unknown holiday moon around Jupiter, the first Jupiter's moon to be discovered in about 20 years.
The researchers said that if their observations are confirmed, it will be the smallest of the 16 (already known) moons orbiting Jupiter - less than five kilometers in diameter (compared to the 3,475 kilometers of Earth's moon). At this stage the small moon has no name, only the designation S/1999J1 and its diameter is calculated to be 4.5 km. "It's exciting to realize that you're the first person to see something that no one has seen before," Jeff Larsen, a team member from the University of Arizona's Spacewatch project, which scans the solar system with the Kitt Peak telescope in search of comets and asteroids, told reporters.
Larsen and his colleagues discovered the moon in observations conducted in October and November last year, when Jupiter was at its closest point to Earth in its 12-year orbit around the Sun. The researchers said that before they give the moon a name, they want to make more observations to confirm the discovery. Larsen noted that "this moon belongs to a group of moons moving in the outer part of Jupiter, in a strange orbit, opposite to that of Jupiter's inner moons".
Astronomers believe that the origin of this outer group of moons is in asteroids that were captured by the gravity of Jupiter, the largest of the planets in the solar system. Astronomers from the University of Arizona and Cambridge, Massachusetts participated in the discovery. At first they thought it was an asteroid, since the research is an extensive project called Spacewatch (the sky scanner) designed to locate asteroids that may collide with the Earth. But now the mask has been "removed" from the face of the mysterious celestial body and it turned out that it is a moon belonging to the system of Jupiter's moons. This fact came up only now after it was clarified that the moon revolved around Jupiter and not around the sun.
