The planets alignment question

[DaveChase]

How frequently would all the planets of a system be in a straight line?

(I know the answer will be different for each solar system.)

I am looking for general occurence like once in every 10,000 years or such.

I.e. from the star to the farest out planet draw a straight line between all the planets

Scenario 2
From the farest out planet draw a straight line through all the planets and the star but they are not neccesarily all on the same side of the star.

Scenario 3 (the rarest of them all)
1 planet (the habitial one) is on one side of the star and all the other planets are on the other and you can draw a straight line through all the planets and stars.

Scenario 4 (??)
a)All the planets are on the same side of the star.
b)all the planets are on the same side of the star and within 90 degrees of each other
c)all the planets are on the same side of the star and within 45 degress of each other

Thanks for any help with this

Dave

 

[far-trader]

Originally posted by DaveChase:
How frequently would all the planets of a system be in a straight line?

Never. Orbits all have some inclination eccentricity and so will never be in a "straight line". Never. Now if you mean in the same plane perpendicular to that of the mean orbital plane of the system, then it's only rarely and dependant on the number of bodies.

Originally posted by DaveChase:
(I know the answer will be different for each solar system.)

Quite, and the odds get longer the more planets you have in the system.

Originally posted by DaveChase:
I am looking for general occurence like once in every 10,000 years or such.

Scenario 1 - From the star to the farest out planet draw a straight line between all the planets.

For our solar system, for all the planets to be in the same alignment as seen from the sun is on the order of once every 180 trillion years. That's pretty close to NEVER!

Scenario 2 - From the farthest out planet draw a straight line through all the planets and the star but they are not neccesarily all on the same side of the star.

The number I found for this, again for our solar system, is about once every 340 million years but that calculation was for all the superior planets on one side of the sun and all the inferior ones on the other side which probably better fits your scenario 3.

Scenario 3 - 1 planet (the habitial one) is on one side of the star and all the other planets are on the other and you can draw a straight line through all the planets and stars.

Too much math

See answer to Scenario 1 above. i.e. NEVER!

Scenario 4a - All the planets are on the same side of the star.

That's your scenario 1 isn't it?

Scenario 4b - All the planets are on the same side of the star and within 90 degrees of each other.

Ah, within 90 degrees is rare but not that bad, on the order of once every 200 years.

Scenario 4c - All the planets are on the same side of the star and within 45 degress of each other.

Again probably not all that rare, like 4b above but not so often. No numbers but I'd guess once every few millenia.

Originally posted by DaveChase:
Thanks for any help with this

Dave

You're welcome, but you do know that there is no physical significance to planetary alignments, right? I mean zero, none, nada, zilch.

 

[DaveChase]

Originally posted by far-trader:

Scenario 4a - All the planets are on the same side of the star.

That's your scenario 1 isn't it?
</font><blockquote>quote:</font><hr />

Nope. all the planets on the same side (within 180 degrees of each other?

Originally posted by DaveChase:
Thanks for any help with this

Dave

You're welcome, but you do know that there is no physical significance to planetary alignments, right? I mean zero, none, nada, zilch. [/QB]</font>

thanks for the information. When you said figured/math did you have any reference source/site? thanks

Dave

 

[far-trader]

Originally posted by DaveChase:

Originally posted by far-trader:

Scenario 4a - All the planets are on the same side of the star.

That's your scenario 1 isn't it?

Nope. all the planets on the same side (within 180 degrees of each other?

D'oh! Of course

That should happen pretty often I'd think.

Originally posted by DaveChase:
thanks for the information. When you said figured/math did you have any reference source/site? thanks

Dave

Originally I think Phil's Bad Astronomy (fun site click this link )

But my notes weren't handy so I googled and came up with this site that borrows from Phil's and is specific to this question of Planetary Alignments.

HTH. You're welcome, have fun

 

[far-trader]

Hmm, just thought I should clarify those NEVERs above

By that I mean it's unlikely to ever happen in reality but being a game, and given the number of solar systems in charted space, and a PC's nack for being in the right place at the wrong time (or the other way around), well by all means the referee can simply make it so. The games the thing! I'd just make it a once in a campaign thing

 

[Spinward Scout]

Hey Dave and Everyone,

Interesting topic. There was a Japanese comic I read once that had a larger planet align in front of a smaller one creating a gravitic lens from the parent star - effectively making the larger planet a giant magnifying glass. And anyone who grew up with a magnifying glass knows what it can do to paper, ants, etc... BOOM! goes the smaller planet. By the way, the big internet rumor was that all the planets were supposedly going to align on 5/5/05, and the world was supposed to end. But like almost all other internet rumors, this turned out to be false. Or did the world end and I missed it?

Dameon

 

[Malenfant]

There was a Japanese comic I read once that had a larger planet align in front of a smaller one creating a gravitic lens from the parent star - effectively making the larger planet a giant magnifying glass

Ah, the wonder that is 2001 Nights

. Awesome, awesome series that was.

I don't think that would work in practise though, IIRC the focal point for stars is like, about a lightyear away from them or something. And I don't think it'd focus that strongly anyway. But it was a cool story.

Aligning planets don't do anything though. They have no noticeable effect at all on eachother when aligned (at least, none more than they usually have which is a tiny gravitational tug).

 

[Fritz_Brown]

Well, they will make it hard to see all the planets, if they really are in a line with you.

 

[Spinward Scout]

Yeah, that was it Mal - 2001 Nights. I only got to read two of the graphic novels. Whoever did the stories for those did a great job.

Something I was thinking about was Scenario 3. Now let's say Earth is that one planet on the other side of the sun. So, now you have the gravitation pull from not only the Sun, but also from 8 other planets pulling on Earth from exactly the same direction. Would tidal forces be affected? I mean, the reason we have waves in the ocean is because of gravity from the moon, right? Or is the gravity from those 8 planets so insignificant in comparison to the Sun that they would be drowned out? Are any of those planets having an affect on us right now?

Dameon

 

[Fritz_Brown]

The tidal effects of the moon tend to drown out everything else, yes. Now, if you could get thos planets to stay exactly opposite us, all in a line, you might change our orbit, as the forces would no longer be balancing each other....

 

[Andrew Boulton]

The Sun affects us because it's very big, the Moon because it's very close. If you want to be picky, yes, all the other planets affect us too - as does every other object in the universe - but by an infinitesimal ammount. Your monitor probably has a greater gravitational pull on you than Mars.

 

[Fritz_Brown]

That all depends on what's on his monitor, Andrew!

 

[TheDS]

maybe that's why sitting too close to your TV will rot your brain... or something like that.

 

[Keklas Rekobah]

How frequently would all the planets of a system be in a straight line?

Never.

The reasons being:

1) Different orbital inclinations (as noted previously).

2) Non-harmonically related orbital periods.

Harmonically-related orbits have rational orbital periods. This means that there is some ratio between them that is easily defined by two integer values, at least one of which must be prime. If the values of the orbital periods are rational then one or both planets will eventually be thrown out of the system or forced into non-harmonically related (or "irrational") orbits.

Typical rational values are: 1:2, 1:3, 1:4, ..., 2:3, 2:5, 2:7, ..., 3:5, 3:7, ..., 5:7, ...

A typical example of an irrational number is the value of Pi, which is the ratio of the circumference of a circle to its diameter. There is no known pair of numbers that can be expressed as a ratio to describe the value of Pi beyond the sixth decimal point (355 / 113 = 3.1415929..., where Pi = 3.1415926...; for an error of slightly less than 0.0000085 percent). If the ratio of the periods of two planetary orbits can be expressed as Pi, then the orbital periods are non-harmonic, and it is likely that the orbits are stable, and the likelyhood of these two worlds lining up is very small, even if the two worlds had the exact same orbital inclination.

A more detailed description and proof of this principle requires some knowledge of orbital mechanics, and a total rejection of Bode's Law, which is merely a coincidental agreement between a lucky guess and reality. Any orbits defined by Bode's Law will be inherently unstable over millions of years.

 

[DaveChase]

Originally posted by Heretic Keklas Rekobah:
How frequently would all the planets of a system be in a straight line?

Never.

The reasons being:

...

2) Non-harmonically related orbital periods.

Harmonically-related orbits have rational orbital periods. This means that there is some ratio between them that is easily defined by two integer values, at least one of which must be prime. If the values of the orbital periods are rational then one or both planets will eventually be thrown out of the system or forced into non-harmonically related (or "irrational") orbits.

...

A more detailed description and proof of this principle requires some knowledge of orbital mechanics, and a total rejection of Bode's Law, which is merely a coincidental agreement between a lucky guess and reality. Any orbits defined by Bode's Law will be inherently unstable over millions of years.

Of course this is way 1 AU is exactly how long in light seconds

And easily defined simply means that most everyone understands it

I guess I will be the arguementive one here, Prove to me that it can or has never happened. ( Sorry, just a layman history buff and I seem to recall way to many, it can't be done, defined or exist because it is just fiction.) Mind you it might take a super computer years (eons) to discover the 9 billion names of God (if you don't recongize the reference it is a science fiction story

Dave

 

[Keklas Rekobah]

You want me to prove that the planets in the Solar system have never been in a straight line.

Such proof is based on the assumption that the current orbital configuration of our Solar system has remained unchanged since its formation. Application of Occam's Razor lends support to this assumption because it is the simplest assumption to make.

The orbital inclination in degrees for each planet in the Solar system is:

MERC 7.0
VENU 3.4
ERTH 0.0
MARS 1.9
JPTR 1.3
STRN 2.5
URNS 0.8
NEPT 1.8
PLTO 17.2

Note that the orbits are not tilted "up" or "down" on the same side. Thus, Pluto may be 17.2 degrees below the ecliptic, while Mercury is 7.0 degrees above it, for a total of 24.2 degrees for diferential inclination! This also means that even when all of the planets are at one of the two points in their orbits where they are all on the ecliptic, none of them will be in the same direction from Sol.

Any further proof I could provide would require a course in orbital mechanics.

 

[TheDS]

Originally posted by DaveChase:
Of course this is way 1 AU is exactly how long in light seconds

And easily defined simply means that most everyone understands it

I guess I will be the arguementive one here, Prove to me that it can or has never happened. ( Sorry, just a layman history buff and I seem to recall way to many, it can't be done, defined or exist because it is just fiction.) Mind you it might take a super computer years (eons) to discover the 9 billion names of God (if you don't recongize the reference it is a science fiction story

Dave

Was any of this important enough for me to ask you to translate it into English so I can read it?

 

[DaveChase]

Originally posted by TheDS:
</font><blockquote>quote:</font><hr />Originally posted by DaveChase:
Of course this is way 1 AU is exactly how long in light seconds

And easily defined simply means that most everyone understands it

I guess I will be the arguementive one here, Prove to me that it can or has never happened. ( Sorry, just a layman history buff and I seem to recall way to many, it can't be done, defined or exist because it is just fiction.) Mind you it might take a super computer years (eons) to discover the 9 billion names of God (if you don't recongize the reference it is a science fiction story

Dave

Was any of this important enough for me to ask you to translate it into English so I can read it? </font>[/QUOTE]OK, so I typed to fast this morning

way should be why (first note)

Arguementive has to many vowels (third note)


And satire is not one of your strong suits? LOL

We will just have a difference of opinion I guess.

Dave

 

[DaveChase]

Originally posted by Heretic Keklas Rekobah:
You want me to prove that the planets in the Solar system have never been in a straight line.

Such proof is based on the assumption that the current orbital configuration of our Solar system has remained unchanged since its formation. Application of Occam's Razor lends support to this assumption because it is the simplest assumption to make.

...


Any further proof I could provide would require a course in orbital mechanics.

So your proof is based on assumption (ROFL) I needed that after 9 hours of work and 4 hours of city council meetings

And further proof would require me to become a SME on orbital mechanics. LOL

That sounds like ' Believe me, we have been to the moon. No, really we have put men on the moon. Here look at these nice space rocks from the moon.' LOL HAHAHAHAH)

So, does your assumptions count some of the planets being hit by say comets, or other planetiod like bodys on werid orbits? (i.e. the orbits cross the orbits of other planetiods)

Does your assumptions explain the astriod belt and why astriods are also found out side of said belt?

BTW the asking for proof was a retorical, satire comment. Great for causing discussions but not meant as actual fact questions.

Have a great one

Dave

 

[Malenfant]

It's one thing for a small rock to hit a slightly bigger rock and break it up into fragments that are scattered into lots of different orbits at lots of different orientations around the sun, that may themselves end up hitting other rocks and maybe even planets.

Planets don't do that though. You want to smash planets apart and knock their fragments into different orbits, you need a very much larger rock, the sort that doesn't exist in the solar system anymore.

And the asteroid belt is just leftover junk from the solar system's creation, that wasn't allowed to coalesce into a single body because of Jupiter's gravitational influence. Not a single shattered planet.

And er, we have been to the moon. And we do have rocks from the moon too.