Astronomers discover 12 new moons orbiting Jupiter - one on collision course with the others

[turbinetree]

A head-on collision between two Jovian moons would create a crash so large it would be visible from earth

One of a dozen new moons discovered around Jupiter is circling the planet on a suicide orbit that will inevitably lead to its violent destruction, astronomers say.

Researchers in the US stumbled upon the new moons while hunting for a mysterious ninth planet that is postulated to lurk far beyond the orbit of Neptune, the most distant planet in the solar system.

The team first glimpsed the moons in March last year from the Cerro Tololo Inter-American Observatory in Chile, but needed more than a year to confirm that the bodies were locked in orbit around the gas giant. “It was a long process,” said Scott Sheppard, who led the effort at the Carnegie Institution for Science in Washington DC.

Jupiter, the largest planet in the solar system, was hardly short of moons before the latest findings. The fresh haul of natural satellites brings the total number of Jovian moons to 79, more than are known to circle any other planet in our cosmic neighbourhood.

https://www.theguardian.com/science/2018/jul/17/astronomers-discover-12-new-moons-orbiting-jupiter

[maveric]

1. Kick

[Docreed2003]

2. K&R...crazy cool

[brush]

3. Hmmmm? If they missed that many around Jupiter how many...

have they missed around Saturn and the other large planets?

[Jim__]

4. A short youtube video

[turbinetree]

5. Wado------------Thank you

I love science.....................

[Blue_true]

6. One key question.

Jupiter has been around for around 4.4 billion years and if one believes the theory that planets and many circular moons formed from that disk. Why didn't that collision take place many times over 4.4 billion years? The moons of Jupiter would have regularly encountered each other often over that time period. It takes Jupiter around 11 years to complete one orbit of the Sun, even if you assumes that each of it's moons move around the planet slower, that would still mean hundreds of thousands times the moons would have encountered each other. Is it possible that the moons WILL NOT collide and something else will happen?

[muriel_volestrangler]

7. The smaller moons are the result of previous collisions, or captures of asteroids

that weren't previously orbiting Jupiter. From the article:

Nine of the new moons belong to an outer group that orbit Jupiter in retrograde, meaning they travel in the opposite direction to the planet’s spin. They are thought to be the remnants of larger parent bodies that were broken apart in collisions with asteroids, comets and other moons. Each takes about two years to circle the planet.

Two more of the moons are in a group that circle much closer to the planet in prograde orbits which travel in the same direction as Jupiter’s spin. Most likely to be pieces of a once larger moon that was broken up in orbit, they take nearly a year to complete a lap around Jupiter. Which direction the moons swing around the planet depends on how they were first captured by Jupiter’s gravitational field.

Astronomers describe the twelfth new Jovian moon as an “oddball”. Less than a kilometre wide, the tiny body circles Jupiter on a prograde orbit but at a distance that means it crosses the path of other moons hurtling towards it.

[Blue_true]

8. Don't want to be the guy that put the turd in the punchbowl, but.

If all of the moons have a periodicity of 1 to 2 years, then the number of orbital encounters for two particular moons would range from 4 to 9. Shouldn't someone seen a collision during investigations of Jupiter over the last century or so. During a century, the Earth would have been in the same solar sky with Jupiter something like 1100 times, that's a lot of time to see nothing from events that theoretically should have happened 50 to 100 times during that period. It is possible that something happened when astronomers could not view Jupiter.

Sorry about being a dick. It is just that I find questions about space facinating. There is just so vastly much that we don't know.

[muriel_volestrangler]

10. As LeftInTX says below, they're not all on the same plane

They all orbit round the centre of Jupiter, but if the plane of one is just one degree tilted compare to another, at that distance from the planet (about 20 million km), that would mean a separation of about 350,000 km (almost the Earth-Moon distance) between them, even if they were "at the same point" of their orbits. Plus the orbits are quite elliptical (eccentricity well above 0 in the possible range from 0 - perfectly circular - to 1 - an infinitely long ellipse) in the table at that link. That can mean that though one orbit "crosses" another, it's more like a long thin orbit that fits in between a circular one, but is only longer than it when it's outside the plane of the circular one.

The end result will be that the orbits don't truly coincide at any point. But if two, or more, happen to get close at some time, their gravity might pull them around so that they will collide later. It all gets very complicated, and only computer simulations can work it out over a long period. But there's no "should have happened" about it.

There are diagrams here - insanely complicated, and at all angles: https://sites.google.com/carnegiescience.edu/sheppard/moons/jupitermoons

[FSogol]

11. Wait a minute! Jupiter has planes?

[Blue_true]

12. Yeah. War planes, booze party planes, planes for republicans, hmmm.

That last one gives me an idea.

[LeftInTX]

9. The article says it takes about a billion years for a collision

The moons are not on the same plane.

They are also very small. One of them is less than a Km.
Odds of collision are very low.

[Blue_true]

13. Ok, that makes sense. Now can see why nothing has been seen.

BTW, do you know what you will be doing 500 million years from now? I plan a cookout to watch Jupiter's moons collide.