Trojan Asteroids Found In Neptunian Orbit

Agent Provocateur writes to mention a release at Science Daily about three rogue asteroids discovered by the Carnegie Institute. The objects are in about the same orbit as Neptune, lending evidence that the planet has a cloud of these 'Trojan' celestial bodies. From the article: "Trojan asteroids cluster around one of two points that lead or trail the planet by about 60 degrees in its orbit, known as Lagrangian points. In these areas, the gravitational pull of the planet and the Sun combine to lock the asteroids into stable orbits synchronized with the planet. German Astronomer Max Wolf identified the first Jupiter Trojan in 1906, and since then, more than 1800 such asteroids have been identified marching along that planet's orbit. "

Comments

Obviously

[Rob T Firefly]

Neptune uses Trojans to guard against Spatially Transmitted Debris.

Re:Obviously

[Anonymous Coward]

Wouldn't Uranus need more protection than Neptune?

Re:Obviously

[Anonymous Coward]

Neptune uses Trojans to guard against Spatially Transmitted Debris.

Is Neptune afraid he'll catch something from Uranus?

Re:Obviously

[Junior J. Junior III]

Considering Neptune's proximity to Uranus, that's a good thing I'd say.

Re:Obviously

[aztektum]

Man I can't wait until 2261 when they change Uranus's name in order to put an end to stupid joke's like that.

Re:Obviously

[epgandalf]

I didn't know they changed the name of Uranus in the fourth season of Babylon 5.

Re:Obviously

[Black.Shuck]

Word. Lets see them make fun of Urectum.

In other news

[Volante3192]

...ya know, I could make a joke about prophylactics and the 7th planet...but I'm sure the suggestion alone is enough for the crowd to finish the punchline...

Re:In other news

[specific]

Why aren't Trojans gathering around Uranus? Doesn't it need to be protected, too?

Re:In other news

[Anonymous Coward]

That's right...in fact someone already made the joke just before you, I'm assuming you read it and decided to try and whore for karma? You could have at least waited a few minutes.

Dick.

Damn you, malware writers

[Opportunist]

At least leave the other Planets alone, isn't this planet big enough for you?

nyuk-nyuk

[MrSquirrel]

Trojan asteroids? I hope the computers on the International Space Station have up-to-date virus definitions!

I sense a bad movie coming on

[spineboy]

with all sorts of advertising tie ins.

Ah yes.. perfect....

[Churla]

Now to locate one of these running parallel to Earth and use it for my base of operations when I take over...

Oh yezzzzzzz

Re:Ah yes.. perfect....

[Artifakt]

Here you go:

http://www.astro.uwo.ca/~wiegert/3753/3753.html

I'm keeping Cruithne itself for my own Uber-secret plan for world domination, but the article lists several others - Happy Bwaaahhh-hah-hah-hah'ing!

1800ish and 3?

[bano]

If there are 1800 known, why is 3 additional ones being found all the important?

Re:1800ish and 3?

[ChristTrekker]

I believe it was saying that 1800 Jovian Trojans have been found. These are the first Neptunian Trojans to be discovered. Being that much farther from the sun, they are far more difficult to detect. Also, since Neptune's mass is less than Jupiter's and it is further from the main asteroid belt, it might not have as many to begin with.

Re:1800ish and 3?

[Anonymous Coward]

The first Neptune trojan was discovered in 2001. These three were discovered since then over the course of the last 2-3 years. Not particularly new, but the paper finally got published.

Re:1800ish and 3?

[4D6963]

Also, since Neptune's mass is less than Jupiter's and it is further from the main asteroid belt, it might not have as many to begin with.

Yeah, but it still has the Kuiper asteroid belt. That's maybe not as important as the one belt between Jupiter and Mars, but it's still something.

Wrong planet

[Dan East]

I thought astronomers searched the obvious places first. They really should have looked for these things around Uranus.

Dan East

Re:Wrong planet

[turthalion]

Yes, you're right.

After all, they're ASS-teroids.

Making the other obvious joke about the original poster fully expecting trojans in the region of Uranus is left as an exercise.

Re:Wrong planet

[menace3society]

Nah, astronomers prefer bare-backing.

how can they be in rest?

[Anonymous Coward]

strange a mass in space is kept under gravitational balance by pulling forces of jupiter and the sun.. Ehm what's the contra force that kept them from falling into this plannet ???

Re:how can they be in rest?

[SEWilco]

If there is a repulsive effect, it probably is a resonance effect of orbital mechanics. For example, an object near L4 when attracted back toward the planet would be pulled into an orbit with a smaller radius and thus tends to orbit faster than the planet and moves away from it.

Re:how can they be in rest?

[merlin_jim]

It's been proven that you can't have stability using only attractive forces in a static system.

The classical proof is, take any number of magnetic, electrical, and gravitational forces that are fixed relative to each other. There is no arrangement of these forces that produces a point of both equilibrium and stability.

Good thing planets move. Trojan points are just two of the five lagrange points. When any two gravitational bodies orbit each other, there will exist points of equilibrium where all gravitational forces cancel each other out - this is called a lagrange point. That's great but you also have to consider the concept of stability and sensitive dependence on initial conditions. For instance, L1, the simplest to calculate of the lagranges, is a point on a line connecting the centers of mass of the two bodies such that the pull from each body is the same. Slip a little in either direction, and thanks to the inverse power law, you see a greater pull from the body you slipped closer to, pulling you further out of equilibrium. The L1 point is not stable - objects there don't tend to stay there.

Think of it like a hill with a flat top. You can put a marble perfectly balanced at the top of the hill, but eventually something will push it a little to the side and it'll roll down.

The other points are L2 and L3, both on the same line as L1, but beyond either the smaller or the larger of the bodies, depending on if you're talking about L2 or L3. L4 and L5 are the trojans, 60 degrees ahead or behind of the smaller body in its orbit. L1 through L3 are unstable, though certain very non-circular orbits about those points are stable over periods of time. L4 and L5 are stable; a minor perturbation will pull the object slightly out of the point, and then coriolis effects pull it into orbit about the lagrange point. If you've ever read The Smoke Ring or related works you're familiar with this concept: go east to go up, go up to go west, go west to go down, go down to go east. The more scientific way of putting would be that faster orbits rise, slower orbits fall. If you move vertically in your orbit you don't change the speed of the orbit, and the average distance from your orbital center will always be the same for a specific speed for the same mass that you're orbitting. Move vertically simply makes your orbit more or less elliptical.

Now why do these coriolis forces affect only the L4 and L5 points in this manner? Because L4 and L5 are valid orbital points even if you take out the second body and convert those to basic orbits - orbital distance of an object is not dependant on that object's mass (until it gets massive enough to noticeably perturb the object around which it orbits - such as in the earth/moon system), only on it's speed. At the L1, L2, and L3 points the object is in equilibrium but it's natural orbit without the second mass would be highly elliptical, thus minor perturbations there tend to make elliptical orbits around one of the masses in the system (and that's why highly perturbed orbits about these points are quasi-stable), while at the L4 and L5 points a minor perturbation results in minor orbit changes, but the point of equilibrium stays the same.

Re:how can they be in rest?

[Kelson]

To add to the detailed explanation by merlin_jim, here's Wikipedia's entry on Lagrange points, which includes a couple of diagrams showing where L1-L5 are located in an orbital system.

Re:how can they be in rest?

[ChristTrekker]

They're only "at rest" relative to the moving reference frame. Like how you perceive the earth itself to be "at rest" but of course you know it is moving - well, you're moving with it.

Not Asteroids - More Likely To Resemble Comet

[szyzyg]

At this distance they're more likely to be captured Edgeworth-Kuiper Belt Objects and therefore more likely to resemble comet nuclei. Neptune already has a large number of EKBO's in a 3:2 resonance, including the "planet" Pluto - we sometimes call objects in the 3:2 resonance with Neptune 'Plutinos'. So, the fact that some objects get caught in this stable 1:1 resonance hardly surprises me, but it's nice to have someone actually identify such objects.

Re:Not Asteroids - More Likely To Resemble Comet

[Belgarion89]

So, basically what you're saying is, "that's no asteroid, it's a comet?"

Re:Not Asteroids - More Likely To Resemble Comet

[Anonymous Coward]

He's saying, "These aren't the 'roids you're looking for."

Trojans?

[CrimsonAvenger]

From the Article:

One of the new Trojans has an orbit that is more steeply tilted to the plane of the solar system than the other three.

The burning question is - how can they call it a "trojan asteroid" if it doesn't occupy the same orbit as Neptune? A significant orbital inclination vis a vis Neptune makes it a passing stranger at best, not something captured in Neptune's Lagrange points.

Re:Trojans?

[wileyAU]

The burning question is - how can they call it a "trojan asteroid" if it doesn't occupy the same orbit as Neptune? A significant orbital inclination vis a vis Neptune makes it a passing stranger at best, not something captured in Neptune's Lagrange points.

Not quite. The L4 and L5 Lagrange points are kind of like gravitational collection points. There is a fairly large area surrounding these points where objects can play around based on whatever other forces are affecting them, but still remain trapped by the Lagrange point. So, if you look at a "top-down" view of the solar system, the asteroid would be moving in lock-step with Neptune's orbit at the Lagrange point. But if you look at a "side-on" view, the orbit would follow kind of a wave patern, with one period equal to one orbit.

OT: fiscal conservatives

[ChristTrekker]

What about the Constitution or Libertarian parties?

Obligatory

[fwwr5007]

With all those Space Trojans floating around....

"The spirit is willing, but the flesh is spongy, and bruised."

Gotta love Google AdWords!

[RobertB-DC]

Google supplied these ads for the article:

Jupiter's Finest Florist
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www.11Flowers.com/Jupiter

Local Jupiter Florist
Same Day Jupiter Delivery Guarantee Family Owned For Over 90 Years!
www.FlowerShopping.com/Jupiter

I'm especially interested in Same Day Jupiter Delivery. That would be a great scientific *and* floral achievement. In particular, the "Local Jupiter Florist" that's been "Family Owned for over 90 Years" -- is the Jupiter location new, or have they been there since around 1915 (thereby missing that terrible flu outbreak)? I can't imagine there would have been much business for flowers on (or near) Jupiter in the early 1900's, but then, making a living would come in a distant second behind "staying alive" in that location.

Re:Gotta love Google AdWords!

[spiderworm]

I got this one:

Moving to Jupiter Fl?
Research, homes, community & school for Jupiter and surrounding areas
www.simmondsrealty.com

Considering the size of Jupiter, the noxious atmosphere, and the lack of animal or plant life (at least, as we know it), I daresay real estate on Jupiter is rather cheap. The schools on Jupiter (and in surrounding areas) are stellar... or so I hear.

Re:Gotta love Google AdWords!

[RobertB-DC]

The schools on Jupiter (and in surrounding areas) are stellar... or so I hear.

Much better than on Mars. Mars ain't no kind of place to raise your kids. In fact, it's cold as hell. And there's no one there to raise them if you did. At least, that's what a passing rocket man told me. Of course, he also mentioned all this science he didn't understand, too.

Re:Gotta love Google AdWords!

[Anonymous Coward]

Jupiter Hotel
View Hotel Photos, Features & Deals at ORBITZ. Book Rooms Now & Save!
www.ORBITZ.com

Sure, the rooms are cheap, but the airfare is outrageous. And I wouldn't drink the water.

This thread should be linked on the front page..

[p!ssa]

as the listing of the worst, lamest, most redundant bad jokes ever made on /. Seriously, I usually just scan the threads for Funny and this is the worst I have EVER seen, all we need now is 1.) In Soviet Russia OMG PONIES!! wear the trojans 2.???? 3. profit ^WUranus

did I miss any, HOLY MOTHER OF GOD MAKE IT STOP!!

Re:This thread should be linked on the front page.

[Kelson]

all we need now is 1.) In Soviet Russia OMG PONIES!! wear the trojans 2.???? 3. profit ^WUranus...did I miss any

You must be new here -- you forgot the Beowulf cluster of Natalie Portman's hot grits on a first post.

Re:This thread should be linked on the front page.

[Tipa]

you also forgot:

lol... this is not a dupe!

Trojan Asteroids??

[Criceratops]

So... they are ... horse-shaped???? (horrible thought) DON'T BRING ONE HOME, NASA!!! IT IS FULL OF GREEK WARRIORS YOU IDIOTS!! I mean really, our national MHPC (milli-helen per capita) is low enough already that cocker-spaniel-like-"got-de-downs"-eyed-trailer-fo lk are being turned into superstars for vaguely carrying an R&B tune. ow. Don't let them take our national reserves of hotchickery! ---- crappy triceratops

Re:Trojan Asteroids??

[Criceratops]

How gauche of me...

I done posted without any formatting.

Sorry, won't happen again.

---
crappy and unformatted triceratops