Total Planetary Alignment

[NightHawk043]

Gave it a search, but couldn't find any info on it,

Does anyone know at what date every planet in the kerbol system will first come into total alignment? (at least on a 2D plane).

I was thinking about all the various cosmic events that must be screenshotted. (or hit with that telescope mod).

[Boex]

Well to be honest, just 3 planets coming into alignment is going take a bloody long time, let alone all 7...

If you allowed 5 degrees either way from the midway planet (Duna) it would be 36 times more unlikely than cracking a 7 digit code in one try.

[NightHawk043]

yeah true. It wouldn't have to be that accurate. I mean, The last "Greater Planetary Alignement" back on May 5, 2000, put the inner 6 planets within 25 degrees, with the outer planets closer to 90 degrees.

I was just thinking with the reduced complexity of the KSP universe, + the ability to fast forward time, it might be possible to calculate / view a more accurate one. After all, while the math would be complicated, it certainly wouldn't be as complicated as that for reality.

Edited August 28, 2013 by NightHawk043

[aNewHope]

As far as I know, the period of the Kerbol system is about 1.57 x 10^21 years. (link)

That is longer than the lifetime of the universe. Only at one point in this period all planets may be aligned. If you want to wait for this to happen you gonna have a bad time.

[NightHawk043]

Actually If you ignore moons, and add an acceptable error of say 20%, there would be a lot more than one instance, i'd be willing to guess the first instance would be within the first couple of hundred years.

[Frederf]

Heck, when are all in the same hemisphere of the solar angle?

[katesp]

Aren't Jool and Eeloo on a 3:2 orbital resonance? So they wouldn't line up in order...Eeloo and Jool would have to be on opposing sides of the Sun to line up

[M4ck]

Aren't Jool and Eeloo on a 3:2 orbital resonance? So they wouldn't line up in order...Eeloo and Jool would have to be on opposing sides of the Sun to line up

They would only never meet if they were on a perfect 1:1 resonance, so no, they line up with each other as well, just like other planets. The farther from 1 the resonance is, the more often a pair lines up together.

[Scarecrow88]

Shouldn't be too difficult to work out, just need to know the orbital period of all the planets and find the lowest common denominator.

[Cykyrios]

The lowest common denominator would only give you the period of the system (which is about 4.96E+28 seconds according to mcirish3, including all the moons).

However, if you know when the planets align, you can of course know when the next alignment will occur, if you know the overall period.

To find the planetary alignment, you need to know when each planet lines up with every other planet, and a way to do this is through iteration: at some point in time, compute the position of the planets, then add some amount of time and get the new positions, etc.

I believe someone managed to find the time when all planets but Eeloo line up... On my end, I'm trying to get this working as well, and got Moho, Eve, Kerbin and Duna to line up:

This happens at around 785680 days in a save (if you edit your save to several days before that time, you could probably get a better picture than mine).

My algorithm takes about 8 seconds to find that, but it seems to require several minutes to find a time when Dres is also aligned... I still have to work on it.

[Scarecrow88]

Yeah realised common denominator wouldn't give solution whilst i was driving to work, as it doesn't take in to account the actual position if the planets.

[Janggoth]

This has to be one of the nerdiest sections on the forums. Congratulations.

Now, continue being smart...

[Traches]

I love that I play the same game as smart people.

[daffy]

Definitely me too!