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Identical Orbit

12/31/2007 7:09 AM

Could it be possible that there is an identical planet orbiting the sun exactly opposite our orbit? ( We could not see because the sun would be blocking our direct observation.) James

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#1

Re: Identical orbit

12/31/2007 7:44 AM

No, because we have seen that part already with various space probes! The one that springs to mind is the probe that turned it's camera towards the solar system when it was leaving for its long voyage out into the great unknown! Sorry, can't remember its name, but it found no twin!

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#3
In reply to #1

Re: Identical orbit

12/31/2007 8:35 AM

Voyagers I and II.

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#2

Re: Identical orbit

12/31/2007 7:52 AM

Hello James,

No. The orbital configuration would be unstable. Over time, the two planets would converge in their orbits and would end up in a configuration much like Saturn's "shepherd moons" where each planet continually swaps position with the other.

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#6
In reply to #2

Re: Identical orbit

01/01/2008 3:20 AM

Hi -e and James. First, Happy New Year to all!

"The orbital configuration would be unstable. Over time,..."

Correct, but even in the short term, the elliptical orbit of Earth makes it highly unlikely that any object (even one tiny enough not to disturb other planets gravitationally) can 'hide' in such an 'opposition' orbit.

Jorrie

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#7
In reply to #6

Re: Identical orbit

01/01/2008 8:28 AM

In fact: such a merry-go-round, circular orbit (in a planetary solar system), as your question presupposes, would not happen in nature. Without such an orbit geometry (circular orbit), the chance of "eternal" concealment is quite implausible. So, ...refuted premise of question means all answers, correct or otherwise, are immaterial...same as saying...can't happen for it to happen! Right, Jorrie?

P's Stone

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#10
In reply to #6

Re: Identical orbit

01/01/2008 12:29 PM

Absolutely. The object would periodically "peek" out from behind the Sun; first on one side, then the other.

Happy New Year, Mr. Jorrie!

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#4

Re: Identical Orbit

12/31/2007 9:07 AM

The gravitational influence on the other planets would also be observable.

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#5

Re: Identical Orbit

12/31/2007 10:45 PM

Why not a balancing planet in another dimension of time or space that we cannot see?

Is it ever necessary for the solar system to have balancing planets?

Happy New Year to All,

Dan

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#8

Re: Identical Orbit

01/01/2008 12:22 PM

Look at the orbits of all the other planets and moons and asteroids either in our solar system or in exotic solar systems. How many of them contain two identical objects orbiting at 180 degrees out from one another? Not one. Things that are possible are witnessed now and then--they show up in nature. On the other hand, while a perfectly circular orbit is highly unlikely (and necessary for planets to orbit as you describe) and having two identical rocks at locations 180 degrees out from one another raises that unlikeliness to a huge power, when you have an infinite number of planets orbiting an infinite number of suns, if it is not absolutely impossible for something to happen, it becomes mandatory that it happen. And not just once, either. It would have to happen an infinite number of times.

There is a position in the orbit a certain number of degrees ahead of and behind a large body such as the moon where debris has a tendency to accumulate. Over the course of billions of years, only a few wheelbarrowloads of debris have actually accumulated in these positions, but if we were to enter a highly debris-strewn part of the milky way or if the earth is shattered by an asteroid, throwing up big chunks in the direction of the moon, these debris fields might eventually accumulate as much mass as the moon itself (nevermind that most of the debris would probably accumulate on the moon--let's imagine a highly unlikely scenario). The lunar objects ahead of the moon and behind the moon would then develop their own debris fields. You can see that if this were iterated several times, we would end up with an array of moons from which all of the other moons would be visible except the one on the other side of the earth. Gravitational forces would constantly correct the relationships between the lunar objects, eventually resulting in a very stable orbit for each.

The size of these objects is probably limited by some anomaly beyond my ken, but for a while in the 80s and 90s there was a movement to establish a space station in these lunar debris fields and it was headed by Winona Ryder's godfather who used to open his speeches with the question, "Who would like to live forever in space?"

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#9
In reply to #8

Re: Identical Orbit

01/01/2008 12:27 PM

rbixby writes: "There is a position in the orbit a certain number of degrees ahead of and behind a large body such as the moon where debris has a tendency to accumulate."

-----

Yes. These are the so-called Lagrangian Points. L4 and L5 are both stable enough to allow accumulation of debris. A number of satellites orbit these points, as well.

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#11
In reply to #9

Re: Identical Orbit

01/01/2008 1:13 PM

thanks. I knew there was a name for them, but I couldn't for the life of me remember it.

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#13
In reply to #9

Re: Identical Orbit

01/01/2008 5:18 PM

Good answer! I was not aware of this until now. Thanks

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#14
In reply to #9

Re: Identical Orbit

01/01/2008 5:22 PM

Look Ma... Look at me! I am a lernin' !

Seriously, very cool. I had no idea of such.

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#12

Re: Identical Orbit

01/01/2008 1:41 PM

Re: Identical Orbit:

Don't forget that several countries have sent Sun orbiter explorer vehicles around the Sun, plus we use the Sun's gravity to boost launch velocity of missions to other planets. I would be quite sure that if there were another planet in Earth's orbit, we'd have discovered it by now! Also, an "180-degree" Earth sister planet may have a serious gravitational effect on the solar system.

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#15

Re: Identical Orbit

01/01/2008 5:50 PM

Hi James,

It may be the reason you asked, but there was a movie made with that premise in mind. I think it was called The Planet on the Far Side of the sun.

S

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#16

Re: Identical Orbit

01/02/2008 11:06 AM

"Could it be possible..."

Maybe, but doubtful. Does it exist? No, we've looked, as others have noted. But it's been the subject of speculation and fiction for a good long time. Dubbed "Nemesis", I believe, and also the homeworld of a series of Edgar Rice Burroughs-style fantasy adventure thrillers, 'Gor' or 'Tor' or somesuch. Really purple prose - horrid drivel, IMNSHO.

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#17
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Re: Identical Orbit

01/02/2008 11:31 AM

Perhaps one could leap over the solar system in TWO bounds to reach that elusive hiding planet?

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#18
In reply to #17

Re: Identical Orbit

01/02/2008 1:08 PM

Sure, but can you imagine the amazing hotfoot you'd get from the center of those two bounds?!?

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#21
In reply to #18

Re: Identical Orbit

01/03/2008 1:32 PM

Oh no. You'd wanna do it at night.

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#22
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Re: Identical Orbit

01/03/2008 3:29 PM

D'oh! So obvious it escaped me...

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#19

Re: Identical Orbit

01/03/2008 10:33 AM

what about a teapot in the same position?

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#20
In reply to #19

Re: Identical Orbit

01/03/2008 12:32 PM

Starkle, starkle, little twink;

I wonder what you are, I think.

Up above the world so high,

Like a teapot in the sky.

Hmmm...could be!

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