Comment by xlm1717 | Hacker News Reader

Comment by xlm1717 | Hacker News Reader

The article dismisses natural explanations as "wanting", but then goes on to dedicate half the article to aliens?

It claims that another star having a close encounter with KIC 8462852 (the star discussed in the article) and stirring up its comet cloud "would be an extraordinary coincidence". There is, in fact, evidence that such an encounter happened in our own solar system, "only a few millennia before humans developed the tech to loft a telescope into space." Calculating the speed and trajectory of a particular star, astronomers found that it would have crossed within the radius of the Oort Cloud approximately 70,000 years ago, producing exactly the scenario that "would be an extraordinary coincidence."[1]

Additionally, astronomers have checked stars in the galaxy for the possibility of a close encounter with our solar system, and find dozens of such candidates to come close to our solar system, sometimes within the radius of the Oort cloud, within the next million years (some as close as 240,000-470,000 years from now).[2]

The idea that a passing star would stir up the comet cloud of KIC 8462852 should not be dismissed as a coincidence, especially not to give leeway to discuss the potential for intelligence to build megastructures, when we see that such a coincidence is not even that rare for our own solar system.

[1] http://iopscience.iop.org/article/10.1088/2041-8205/800/1/L1...

[2] http://www.mpia.de/~calj/stellar_encounters/stellar_encounte...

It sounds like you've concluded that because comet-cloud stirring happened in our solar system, it is "not even that rare" elsewhere. What's special about ours? Intelligent life also happened in our solar system, but you seem to consider it unlikely elsewhere.

It seems hasty to extrapolate either way without more data.

You don't need additional data when you can figure out the statistical likelihood of it happening by taking existing trajectories and number of stars in the galaxy. He is saying given what we know, it happens so frequently that it's not a surprise that it even happened to us.

> Intelligent life also happened in our solar system, but you seem to consider it unlikely elsewhere.

Occam's razor, plain and simple.

If the strange variations in that star's brightness turned out to be caused by an alien civilization, that would be way, way cool. But before we jump to conclusions, we should explore more mundane explanations; given the unusual observations, it should still be very interesting, whatever the cause.

Nobody, not the article or any of the comments, seem to have jumped to any conclusions.

The article suggested possibilities, including comets. And reasons why it might not be that. And it included aliens, and some things that would be expected if it was that. All depending on more data which the article explained, they are waiting to collect.

Intelligent life building something big "approx half the size of the star".. mh, either they gave up on nano technology or they have found out that macro technology is better:)

The question is can disrupted comets or oorts block over 20% of the light from the star. A comet nucleus is a lot smaller than a star.

But comet nuclei also outgas quite a bit as they approach the star.

Wouldn't that cause a larger infrared emission (consistent with a young star)?

The article addresses this possibility with the fact that they would expect more infrared radiation which they don't see.

As with everything, they're looking for more data.

Yeah, in a galaxy of billions of stars, why would they think it's unusual to find one with its Oort Cloud 'recently' disturbed?

Because of math? This survey is for nearby stars. The star in question is, in fact, only 1500 light years away. The chances we'd observe a rare phenomenon in a small subset of stars (the article says the survey was for ~150K stars) is, according to the authors of the paper, exceedingly rare.

Given the author of the paper is doing a proposal to point a radio telescope at the star says to me that chances are decent enough to justify further investigation.

That's some rather motivated sounding reasoning. If it's so common, why is it only this one star where we see the pattern? The point is, it's rare and the effect would be short lived.

Also, I don't think just any passing star would produce the effect they're talking about. They mentioned the star being significantly dimmed by matter that must be very close. A star passing through the Oort cloud wouldn't have done that, it would throw a few (maybe thousands?) comets closer in, but not into a tight orbit around the sun.

I don't think you're really giving enough credit to how rare this scenario is.

The star that supposedly disrupted the cloud would have to be in the neighborhood but it isn't according to current data. But it might be in which case it would be very dim. That's why more data is needed.

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