14 Nov 2019

Saturn just knock down Jupiter in number of moons!


Saturn just knock down Jupiter in number of moons, after the discovery of 20 new moons by scientists, Saturn now have 82 moons where Jupiter have 79 moons. All these new moons are orbiting Saturn just like it's old moons but with variety of time period to complete their rotation around Saturn.

Two of them takes 2 years to complete a rotation around the Saturn where other 18 takes more than 3 years. One of the new moons have farthest known orbit around Saturn.

All these new moons are nearly similar in size whose diameter is around 5 kilometres. Seventeen of the new moons orbit Saturn backward — or in retrograde — compared to the planet's other natural satellites.

How do we even know Saturn has moons?

Although most planets of the Solar system are visible to the naked eye and have been known to humans since antiquity, it wasn't until Galileo Galilei turned a telescope on Jupiter in 1610 that we discovered Earth was not alone in having an orbiting companion.

Galileo saw Jupiter's four largest moons and could make out what we now know are Saturn's rings. Decades later, with better telescopes, Christian Huygens and Giovanni Domenico Cassini observed Saturn's moons.

It became clear that the giant planets are surrounded by multitudes of satellites, resembling smaller versions of the Solar system.

By the middle of the 19th century, telescopes had improved enough that the first eight moons of Saturn – including Titan, the largest one – had been viewed directly.

The introduction of photographic plates, which enabled the detection of fainter objects with long-exposure observations, helped astronomers increase their count of Saturn's moons to 14.

The retrograde moons have orbits resembling some of Saturn's other already-known moons. And after observing them, scientists are predicting that they are pieces of a big moon who orbits Saturn in past.

The moons were discovered by a team led by Scott S. Sheppard at the Carnegie Institution for Science and using the Subaru Telescope on Hawaii’s Mauna Kea.

It was a long journey (literally) to the next big improvement in our view of Saturn's moons. Many of the smaller moons were not discovered until the Voyager fly-by missions in the 1980s and the more recent 13-year stopover of the Cassini spacecraft in Saturn's orbit.
Until these closer visits, we knew little about the moons aside from the fact that they existed.
One of Cassini's goals was to explore Titan, which is the only moon in the Solar system with a thick, smoggy atmosphere. Another was to take a look at Saturn's other mid-sized moons, including frozen Enceladus, which may hold an ocean of liquid water beneath its icy crust.

Cassini also discovered much smaller moons, so-called "shepherd moons" that interact with Saturn's rings by carving gaps and wavy patterns as they pass through a rubble of rocks and snowballs.

These close-up observations from space advanced our understanding of individual moons that stay near to Saturn. Recently, many more moons have been found in orbits much further from the planet.

These more distant moons could only be detected with large optical telescopes such as the Subaru telescope at Mauna Kea in Hawaii. The telescope is equipped with sensitive cameras that can detect some of the faint objects separated by millions of kilometres from Saturn.

To confirm that these objects are indeed associated with Saturn, astronomers have to observe them over days or even months to reconstruct the shape and size of the moon's orbit.

Such observations revealed a population of moons that are often described as "irregular" moons. They are split into three distinct groups: Inuit, Gallic, and Norse. They all have large, elliptical orbits at an angle to those of moons closer to the planet.

Each group is thought to have formed from a collision or fragmentation of a larger moon. The Norse group consists of some of the most distant moons of Saturn, which orbit in the opposite.

Once again this discovery of Saturn new moons proves that, here is many hidden things in our solar system. This things were hidden until now because of only one reason "we were lacking of technology to discover them".