Discovery Suggests the Solar System Has Two Planes of Orbital Alignment | Hacker News Reader

Discovery Suggests the Solar System Has Two Planes of Orbital Alignment

sciencealert.com

47 pointsgumby10 comments

After a cursory read of the article, I'm not sure the title is doing the article any favors here. From my read, it sounds like

a. This is about comet orbitals of the solar system

b. There appear to be _at least two_ planes of comet orbitals that are not co-planar with the planetary plane (both at roughly 60 degrees from the planetary plane)

c. One of these orbitals was initially empty (the article calls this the "empty orbital")

d. Over time, solar- (and galactic-?) tides filled the empty orbital

I think there is a lot here, but, again, cursory read.

With regards to b., I think the article is saying that one comet plane is in alignment with the planetary plane, but the planetary plane itself is off by 60° from the galactic plane.

Doesn't conservation of momentum mean that a 'new' orbital is created by the interactions of two or more other orbitals?

Even with tides, how do you explain >=2 planes if you didn't start with 2 to begin with? To get new tracks you're either amplifying small differences or averaging larger ones, aren't you?

I'm curious if this new discovery could eliminate the case for a Planet X(https://solarsystem.nasa.gov/planets/hypothetical-planet-x/i...).

I have no clue, I'm just curious since both try to explain the strange orbits of Kuiper Belt objects.

Or maybe there are other planets on this plane and either a) we didn't know to look there or b) it's really hard to look there, so we didn't.

I hope someone who knows more about stuff like this can weigh in!

I saw something about this recently.

One, there was selection bias, in that certain parts of the sky were easier to get observation time for discovering these parabolic orbits. As we've found more, the sample size has erased some of the anomalous properties.

Two, the patterns that remain may be explained by the last star that crossed our path, perturbing the oort cloud, rather than a Planet X.

It is an interesting idea that the galactic tide pulls things into this odd ecliptic. Now factor in the solar system is oscillating above and below the galactic ecliptic and tell me when the next rain of asteroids is about to start :-)

The oscillation above and below is probably what actually causes the angle to be roughly 60 degrees.

> It could have been generated, the researchers say, by the galactic tide - that is, the gravitational field of the galaxy itself. Over time, this could have pulled some of the long-period comets askew.

I'm confused. Does this mean objects in the empty ecliptic were originally on the ecliptic?

I was about to write ‘yes’, but on closer reflection it’s a genuine ambiguity. The Oort Cloud (as I understand it) is roughly shaped like a bubble that then gives way to the ecliptically-aligned Kuiper Belt. If the article had mentioned tidal effects of the galaxy upon the latter, I would answer in the affirmative, but as it is... I’m not so sure.

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