Expert: Jayendra Upadhye - 11/19/2006

Question
Excellent response.  I feel slightly more educated.  Still, I like to eliminate speculation, where possible.

This is a multi-part question, I suppose.

Part I:  Can we accurately predict the positions of all planets far into the future?

Part II:  If the answer to Part I is "Yes", can we say (without speculation) that no planetary alignment will ever occur?

What little I know about physics (center of mass/gravity) tells me that some kind of physical anomaly would occur if the planets were to line up on one side of the sun in a straight line.  I'm not worried about it happening...just curious.  Might give us something to look for in other solar systems -- some kind of radiation anomaly, perhaps.

Regards,
Abundantmind
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The text above is a follow-up to ...

-----Question-----
If several (or all) planets in a solar system became aligned (or nearly aligned) along an axis, would this cause a gravitational singularity that might affect the orbit of any one (or more) of the planets in the system?
-----Answer-----
Dear Jed,
When such questions occur to one, one must just first look at history!
The solar system has been around for 4.5 billon years!
Countless times all planets did get alligned with each other, but we are still there!

This allighnment if at all it happens is always a "fleeting" phenomenon by cosmic standards!

As such, no effect should be there.
However, remember small perturbations are occuring all the time. No one is immune from gravity!
But these may be too insignificant to be percievable over 10s or 100s of years.
[note gravitational resonances between orbits of pluto and neptune.]

As i had thought, refer..
http://www.etsu.edu/physics/etsuobs/starprty/22099dgl/planalign.htm

the probaility of all planets coming into a perfect straight line is once in 8.6 * 10^46 years!!

by then the milky way (sun having long faded away) will have itself evolved into an elliptical galaxy and be deeply embedded in the monstrous virgo cluster of galaxies!! or even further into the "great attractor" the unseen puller of the virgo cluster!
[the collision of the andromeda and milky way galaxies will form a new elliptical galaxy a few billion years from now].

Jayen

Answer
Jed ...Jed..
Hold your horses!
Science is NOT religion.
No scientist says anything with 100% certainity!
Rather answers furnished by science are based on observational data (historical perspective, and inferenced data that was made use of to predict an outcome, and which was found to be "reasonably accurate".
[That is when a postulate becomes accepted "theory".]
That huge figure i gave you earlier is also likewise a hypothesis only. who the hell is going to live 10^84 years? to see if this is true?

But then one need not indeed live that long to see what is the drift of that answer.

It only means it is "impossible" or improbable" that the event you have in mind will ever occur.
That's all!

No, even if such an occurance happens, nothing great about that, no radiation or singularity will happen.
As there is no known phenomenon to support what you say.
By the way, the sun is much much more massive than all the planets combined.

Try picturing 9 fleas pulling a ball of steel a few kg in weight..that will tell you what you are looking at!

Jed!
i somehow have a hunch you have a "pet theory" up your sleeve!
[I would know! I have a dozen pets in my own "kennel"].
Tell you what...it is much more wonderful to "wonder" and yet have ones feet firmly grounded in science.
The joy of the hunt is in the pursuit!
I think you will understand.

Hope that suffices.
Jayen