Do you remember one of my past series (that never got its last episodes) Trolls Around The Solar System? It was basically my trolls exploring our solar system and trying to share some interesting facts with us. On one of their stops, they explored Jupiter, the gas giant and then they wandered around its moons. A few days ago scientists announced that they confirmed the existence of 12 new natural satellites around the planet.
Hi there! This is X31 and I'll be your speaker for today!
So, by 2015 we already knew that the Jovian moons were 67. Within the next year, 2 more were added and the number rose to 67 and a few days ago (July 17th, 2018) 10 more moons were confirmed adding a total of 12 moons which now sum to a total of 79 natural Jovian satellites! [1]
Will you let anyone else talk, please?
Hey, I am X42 and I'll be giving you a quick summary of that episode on the Moons of Jupiter.
Only four among this swarm of moons are the biggest ones: Io, Europa, Ganymede and Callisto. The moons orbit the planet in "zones" according to their proximity to the planet and their orbits. The inner moons follow the same orbit as Jupiter, whereas the outer ones, or irregular, spin the opposite way (retrograde orbit). It is suggested that those moons that are closer to Jupiter were created by a ring of gas and dust that was spinning around the planet and went through many phases of formation, destruction and re-formation until they finally rested to what we see today. Concerning the irregular satellites spinning farther from the planet, they must be asteroids "captured" by Jupiter's gravitational pull. [1, 2, 3]
Yeah, yeah, you said your lines, now it's my turn!
Hi! This is little X54!
Astronomers were looking for Planet Nine or the hypothetical Planet X (we are still also on a hunt to find this one). Their telescopes were pointed to the edges of our solar system trying to get any data that would prove the existence of an up-to-this-date unknown celestial object, a planet preferrably. Its existence would explain why distant objects of our solar system follow similar orbits (there had to be a body nearby to force them move like this). [4, 5, 6, 7, 8]
Mr Scott Sheppard (the leader of the team) said that they were lucky to have Jupiter pass by at this very specific area they were scrutinizing at the time.
You can say they hit two birds with one stone?
Don't interrupt me, X42, will you?
This was a rare coincidence they couldn't neglect. So, they gathered data, studied them and did their computations that led them to confirm:
9 retrograde moons and another 2 inner moons!
Out of which one is an oddball!!
Thanks for not interrupting, X42!
Sorry...
As I was saying,
... 9 of these new confirmed satellites are following orbits in the retrograde group; while the other 2 are closer to the planet, within the prograde group (orbiting in the same direction with Jupiter).聽They are also very small bodies (with diameters of 1-3 kilometers), which means that they are easily affected by gas and dust around the planet. If they were present at the early stages of the planet's moon formation, forces that acted back then would have probably caused them to move closer to the planet and follow different orbits. This is what makes astronomers believe that they were created later on. [4, 5, 6, 7, 8]
Can I add something now?
Yes, I'm done.
Thanks!
By studying those moon orbits, similar patterns occur. This implies that those smaller retrograde moons were once parts of three bigger satellites, with diameters of almost 100 kilometers. Those moons after crashing with other, prograde, moons left behind lots of smaller bodies orbiting around the planet. [7, 8]
The weirdo moon was also probably captured by Jupiter's gravity only... the other way than the rest of the retrogrades.
Really, X31?!
It's very likely, yes.
The 2 new prograde moons, might have originated from the same, bigger object that Jupiter pulled around it. They are just remnants after years of violent collisions with other moons of the retrograde group.聽[7, 8]
It is a cruel world out there...
And that's the beauty of it, X54! Creation needs destruction after all...
That's right, X42, at least in space!
Don't forget, for new bodies to form we need some others to die and leave "raw material" behind. Recycling is a tactic the universe has wisely been using for millions of years.
Now let me explain what this oddball means...
This rebel has an orbit farther from Jupiter than any other prograde moons. It means that it can easily stand in the way of the retrograde satellites, collisions will be hard to avoid and those moons will soon be once again dust to dust. Now, this mechanism is not impossible to have been a pattern out of which the moon groups we study today have formed and that this tiny satellite we see today is all that's left of a bigger moon after lots and lots of past collisions with other moons of the planet. [4, 5, 6, 7, 8]
Oh, have you heard?聽
The oddball already has a name, it's Valetudo (after the Roman goddess of health and hygiene, the great-granddaughter of Jupiter). [4, 5, 6, 7, 8]
But the others still don't have a name...
Can we be their godfathers? Astronomers are looking for suggestions 馃槣 [8]
I'll mail them our names!聽
After such a long space travel, we deserve to have moons named after us!
Oh we sure do, X54!
All in all guys, this was a really important discovery and luck was helpful!
Tracking moons is a hard task around Jupiter. The planet is huge and bright and its satellites are usually small and faint as they are not reflective enough, plus their light is obscured by the planet.
Studying moons is important, because they can reveal secrets about the creation of the Solar System. Moons were formed after the planets' formation was completed and this is implied by the fact that Jupiter still has a lot of smaller moons orbiting around it. By learning more about these satellites, we will understand better how the Solar System was made, the processes and the mechanisms. [4, 5, 6, 7, 8]
I agree, X31. It was a really cool find!
It certainly was, but we will need a few months before the official paper is published. [8]
That won't be a problem, guys,
... we'll have more time to explore other parts of the solar system in the meantime!
@ruth-girl