Planets Aligning

I watched one of the worst movies I have ever seen last night, Tomb Raider.
There were three things in it that were worth seeing. Lara Croft's
telescope, and two other assets I won't mention in this family oriented
newsgroup.

My niece asked me about the planets aligning concept and if it were
possible. I seem to remember in the past we have partial alignments, but my
answer to her was that a perfect straight line of all 9 (8 for you
anti-plutites) planets was not possible...I don't think.

Can anyone help?

--
BenignVanilla
Pond Site: www.darofamily.com/jeff/links/mypond

In message , BenignVanilla
writes
I watched one of the worst movies I have ever seen last night, Tomb Raider.
There were three things in it that were worth seeing. Lara Croft's
telescope, and two other assets I won't mention in this family oriented
newsgroup.

My niece asked me about the planets aligning concept and if it were
possible. I seem to remember in the past we have partial alignments, but my
answer to her was that a perfect straight line of all 9 (8 for you
anti-plutites) planets was not possible...I don't think.

It can't happen in the strict sense of all the planets being lined up in
a telescope field or a straight line in space because the orbits lie in
different planes. There's probably a minimum area of space all nine
planets can occupy as seen from the Sun, and given the availability of
tools such as VSOP87 (thanks, Greg) it's the sort of thing you can
probably find using a PC. Just don't ask _me_ to do it!
But there's no physical reason the planets couldn't form a very tight
group; it's not like the Galilean moons of Jupiter which _can't_ line
up.
Didn't the planets lining up feature in one of the McGuyver movies ?
(sp? - Richard Dean Anderson) No marks for originality, then.
--
"Roads in space for rockets to travel....four-dimensional roads, curving with
relativity"
Mail to jsilverlight AT merseia.fsnet.co.uk is welcome.
Or visit Jonathan's Space Site http://www.merseia.fsnet.co.uk

|-|erc wrote:

There's also the probability element. For a planet to be aligned within 1 degree,
it has one chance in 360 of being in the right spot, about one day a year, or
several days running every several years for each larger planet.


You're assuming random, independent motions for the planets --
perhaps a useful simplification for a 'plausibility check', but in
fact the synodic cycles are far from random, and of course they're
all tied to the earth's year (let alone resonance effects such as the
one Greg mentioned). Moreover there's a second dimension to consider;
as Jonathan pointed out each planet's orbital plane is inclined to
all the others', so in order to align within a given angular distance
each of a set of planets must have two 'favourable' parameters, not
just longitude.

--
Odysseus

"Odysseus" wrote
|-|erc wrote:

There's also the probability element. For a planet to be aligned within 1 degree,
it has one chance in 360 of being in the right spot, about one day a year, or
several days running every several years for each larger planet.


You're assuming random, independent motions for the planets --
perhaps a useful simplification for a 'plausibility check', but in
fact the synodic cycles are far from random, and of course they're
all tied to the earth's year (let alone resonance effects such as the
one Greg mentioned). Moreover there's a second dimension to consider;
as Jonathan pointed out each planet's orbital plane is inclined to
all the others', so in order to align within a given angular distance
each of a set of planets must have two 'favourable' parameters, not
just longitude.

hi Odysseus, yes I was giving a best case probability just on one parameter,
but enough to show its not probable atleast with the random assumption.
What do you mean not random, if the planets are aligned then it will take
the order of 2 million billion years to align a second time, following their orbits.
Do you mean not random positions or not random with respect to other orbit rates.
Being able to measure an orbit with respect to our own year doesn't imply
a dependence between the two.

The resonance effect can disqualify the calculation but the planets still cross each
other, just at the same set of ordinates. It would require more than one resonance
effect to disqualify all the planets from lining up in longitude given infinite time.

Herc