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Our Solar System Isn't Normal

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Re: Our Solar System Isn't Normal

#81

Post by chc »

calinet6 wrote: post #78
chc wrote: post #63

Earlier quoted context omitted.

Well, the obvious answer would be: Track whether a user has clicked on the link and disable the vote buttons until they have.

For pete's sake, can't someone wax poetic on a slightly related subject of interest without it having to be taken as a polarizing direct criticism of the article? My bad, move along.

You're surprised that people assume your comments are on-topic? I'm surprised by your surprise. In general, when everybody is talking about a topic and you add something to that discussion, they will try to interpret it in a light that makes it relevant. That's just how our brains process communication.

If you intentionally mean to go off-topic (which you usually shouldn't, but we'll assume you have something really amazing to say), it's best to explain that you're not actually talking about the topic at hand but you thought it was interesting because X. That way people will be able to read your comment in the light in which it was intended rather than straining to find relevance.

(Incidentally, I have no idea why you responded this way to my comment, which is explicitly about ways to ensure people read articles before voting on comments about the articles, and is not about you at all. Maybe you assumed it was on the topic of your comment?)

Re: Our Solar System Isn't Normal

#82

Post by qdog »

chc wrote: post #62
qdog wrote: post #33

I think everyone here concentrating on sampling bias is missing the point. The evidence in solar systems so far does NOT fit the theory involving a frost line, and giants like Jupiter are unexpectedly observed tightly orbiting suns. Whether our solar system is normal is conjecture, but our model for how solar systems are(were?) formed is obviously flawed. Pretty interesting find, imho.

I don't see how the fact that gas planets are capable of migrating inward shows that our model for planetary formation is deeply flawed. I didn't think the current model said that it was impossible for planets to migrate inward. The point about sampling bias is that our current techniques are bad at spotting systems like ours. If this is true (I think it is, but I'm not qualified to say), we wouldn't expect the evide…

Perhaps I mangled that a bit, instead of frost line I should have just said the seemingly most popular theory of how the solar system formed. From the article the bit that caught my eye:

Mike Brown, an astronomer at Caltech, wrote me that while everybody is busy hunting for an Earth-like planet, they missed this story. "Before we ever discovered any [planets outside the solar system] we thought we understood the formation of planetary systems pretty deeply." We had our frost line. We knew how solar systems formed. "It was a really beautiful theory," he says. "And, clearly, thoroughly wrong."

Re: Our Solar System Isn't Normal

#83

Post by ajross »

calinet6 wrote: post #78
chc wrote: post #63

Earlier quoted context omitted.

Well, the obvious answer would be: Track whether a user has clicked on the link and disable the vote buttons until they have.

For pete's sake, can't someone wax poetic on a slightly related subject of interest without it having to be taken as a polarizing direct criticism of the article? My bad, move along.

I was surprised at the depth of this thread too. But honestly, yeah. If you're going to wax poetic, it behooves you to let the audience know you're launching into a digression. Instead you started with a quote and a "Not exactly", which sounded like you were making an argument about the substance of the link.

I don't even disagree with your point. But I posted because I did find the linked article interesting (if a little fluffy) and thought your digressive correction was missing some of that substance.

Re: Our Solar System Isn't Normal

#84

Post by rjd »

qdog wrote: post #33

I think everyone here concentrating on sampling bias is missing the point. The evidence in solar systems so far does NOT fit the theory involving a frost line, and giants like Jupiter are unexpectedly observed tightly orbiting suns. Whether our solar system is normal is conjecture, but our model for how solar systems are(were?) formed is obviously flawed. Pretty interesting find, imho.

I did some reading into this last year while I was stuck in bed sick and what I came across was it was to do more with light pressure than a frost line. The frostline has more to do with where water is likely to form than how a come to exist.

Light has trouble pushing heavy materials outwards, so theres a denser percentage of them in close to a star, the lighter the material the more it gets pushed out, high percentage of hydrocarbons in outer planets. Like a giant centrifuge. So our system should be fairly standard unless the rules of physics are different elsewhere.

That doesn't exclude random formations as you are dealing with super heated eddies, explosions etc... during formation. Or even stars pulling there planets in. Both our planet set up, and hot Jupiters are to be expected because its a giant chaotic exploding mess.

Re: Our Solar System Isn't Normal

#85

Post by danielweber »

IsaacL wrote: post #77
gwern wrote: post #75

Earlier quoted context omitted.

I don't think it's a good candidate; certainly it pushes some amount of the Filter into our past, but even if only 1 in 700 solar systems is Sol-like, there are so many we'd still expect to see tons of aliens. For a single-step Filter or for solar systems to even be a majority of the filter, you need a step so unlikely that it can push the presence of interstellar life down from, like, trillions of star systems to ~1…

Thanks for the reply, and yes, that makes sense. What would you predict as the most likely other steps in the filter? Looking at our own planet, I would guess that it's a combination of a) it being simply infeasible to send large animals to distant stars (we haven't yet colonised the moon or even made a serious attempt to colonise low earth orbit, and we might not do so before we run out of cheap energy) and b) techn…

LEO is a weird place to colonize. There aren't any resources there. The moon is also pretty tough, being no atmosphere and Carbon in ppb quantities. Mars is a good candidate, though.

I imagine that if there were another planet in the solar system capable of supporting native life with just 18th-century technology, we would already have sent people there, even if it were a multi-year trip. Which would provide big economic drivers for interplanetary transport.

Re: Our Solar System Isn't Normal

#86

Post by bitwize »

That is AWESOME. The fact that there is so much diversity of planets and solar systems out there flabbergasts me. I don't even care about what kind or whether there's life out there -- just thinking about how there are so many different worlds with prevailing conditions that I never even dreamed of gives me the chills.

Space... space... so much space... gotta see it all...

Re: Our Solar System Isn't Normal

#87

Post by Filligree »

IsaacL wrote: post #77
gwern wrote: post #75

Earlier quoted context omitted.

I don't think it's a good candidate; certainly it pushes some amount of the Filter into our past, but even if only 1 in 700 solar systems is Sol-like, there are so many we'd still expect to see tons of aliens. For a single-step Filter or for solar systems to even be a majority of the filter, you need a step so unlikely that it can push the presence of interstellar life down from, like, trillions of star systems to ~1…

Thanks for the reply, and yes, that makes sense. What would you predict as the most likely other steps in the filter? Looking at our own planet, I would guess that it's a combination of a) it being simply infeasible to send large animals to distant stars (we haven't yet colonised the moon or even made a serious attempt to colonise low earth orbit, and we might not do so before we run out of cheap energy) and b) techn…

Another apparently obvious filter is the development of advanced nanotechnology and AI. However...

Although I'd immediately agree that those are filters hindering the spread of any humanlike civilisation, it doesn't at all stop the spread of other, technological forms - the "vile offspring", to borrow a term.

Honestly, I have no idea what might work as a future filter, at this point. I don't think the expense could be it; that's going to drop, quite abruptly once uploading (or straight-up AI) works well enough.

Re: Our Solar System Isn't Normal

#88

Post by bitwize »

unreal37 wrote: post #16

I had no idea that: "Or maybe it got ejected — astronomers are finding emigrant planets, lonely orbs that wander the universe with no star, just drifting. Maybe one of those used to live here." There are planets not orbiting stars? I searched Google for "emigrant planets" and the npr article is the number 1 result for that. I think he invented the term. What are these called if I wanted to find more information about…

Holy smokes, Sha Ka Ree.

Re: Our Solar System Isn't Normal

#89

Post by dandelany »

schiffern wrote: post #79
lutorm wrote: post #57

Earlier quoted context omitted.

True, but occultations are also very biased towards planets with small semimajor axis, because the solid angle that produces an occultation goes roughly as 1/a.

You use "but" as though you're disputing some statement I made, when I intentionally avoided making any statement outside my knowledge. I said Kepler does use occlusion, and does not use wobbling. I'm not trying to single you out here. I'm just curious what one has to say on HN so as not to be corrected. Is there some "don't assume I've implicitly made a bunch of unsupported remarks" initialism that I can tack on to…

No need to get defensive, lutorm was just pointing out that the assumption made by the OP is still supported. His comment was simply a productive, interesting addition to yours, unlike this complaint.
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