Our solar system has just expanded … Again!
Thanks to the work done by a group of Carnegie scientists led by Scott Sheppard, we now know that Jupiter (for now) has 79 moons, the highest number of natural satellites for a planet in our solar system.
The twelve moons discovered are divided into three main groups.
There are nine outer moons that revolve around Jupiter with retrograde motion, then in a direction opposite to the rotation direction of the gaseous giant, in about two years. In turn this more external group of moons is divided into three orbital subgroups, and this would suggest that they are the remains of three larger celestial bodies that for some reason have shattered.
Two moons instead revolve around Jupiter more internally, with a period of about a year, moving in the same direction of rotation of the planet. Given the great resemblance between the two orbits, it is supposed that these two moons are actually fragments of a larger celestial body, also this perhaps shattered by a collision with other moons.
Finally, there is a rather “reckless” moon, which orbits Jupiter in about a year and a half, dangerously intersecting the orbits of the outer moons. Just 1 km wide, the new moon was named Veltudo, nephew of Jupiter, goddess of health and hygiene.
The discovery happened practically by chance. The team led by Scott Sheppard, in fact, was looking for celestial bodies classifiable as planets beyond the orbit of Pluto. By chance, during the observations, Jupiter was very close to the area of the sky that the scientists were studying, and this led to the discovery of these moons last year. The discovery was only recently announced because to be sure that those moons were orbiting around Jupiter, it was necessary to observe them repeatedly over a period of months.
Here are Sheppard’s words about this discovery:
Jupiter found itself close to our field of view, in which we were searching for very distant objects belonging to our solar system. The discovery was an example of serendipity: we found the new moons around Jupiter while we were looking for planets at the edge of the solar system.
To this discovery has also contributed Gareth Williams, of the International Astronomical Union’s Minor Planet Center, which has calculated the orbits of these new twelve moons:
Several observations are needed to confirm that an object is actually orbiting around Jupiter, so the whole process lasted a year.