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A Trillion Worlds
- hamilyon2 8y agoCould this mean the great filter is likely behind us?
- cobbzilla 8y agoIt's likely there is no great filter; there exist reasonable claims that the Fermi Paradox has been "dissolved" [1] [2]. [1] https://news.ycombinator.com/item?id=17302924 https://news.ycombinator.com/item?id=17302924 [2] https://news.ycombinator.com/item?id=17560462 https://news.ycombinator.com/item?id=17560462
- fbreton 8y agoIf I understand this study correctly, their conclusion is that it is likely that intelligent species are very rare in the universe. This still implies a "Great Filter", but it would have to be behind us.
- deleted 8y ago[deleted]
- logfromblammo 8y agoWe're only about 5.5 billion years away from intelligent species being either very common in this galaxy, or completely nonexistent. Which is to say that we need to start building interstellar transport vessels soon.
- ceejayoz 8y ago"We substituted some guessed numbers for our own" isn't so much a "reasonable claim" as a thought experiment. Even accepting their numbers, it's hardly "dissolved". > When we update this prior in light of the Fermi observation, we find a substantial probability that we are alone in our galaxy, and perhaps even in our observable universe (53%–99.6% and 39%–85% respectively).
- Tossrock 8y agoThe key insight isn't the substituion of new numbers, it's the use of probability distributions with error bars throughout the calculation, as opposed to picking a single number. The canonical paradox is that even if you pick very small numbers for all the unknown terms, the resulting expected number of communicating civilizations is still high. This work shows that it isn't a paradox when viewed through the lense of a probability distribution, because even if the expected number is high, that's because of a long tail of super high, low probability numbers, while most of the probability is actually on 'alone in galaxy'.
- madeuptempacct 8y ago"reasonable claims that the Fermi Paradox has been "dissolved"" There is nothing reasonable or new in either one of those links. Seems like people quoting trash is how myths perpetuate. P.S. Wrapping a quoted quote in the same kind of quotation marks is kind of liberating after years of " 'ayyy' " or "\"ayyy\"".
- shmageggy 8y agoI would have liked to hear about how they are now accounting for the inherent bias of our detection process to find large, close-to-star planets, because those are the ones that produce the best signals. I remember that that used to be a big issue in drawing any statistical conclusions about expolanet data. Has there just finally been enough data collected that we can model our own bias?
- cwmma 8y agoThe article says that half of the nearby stars have these large close-in planets, which would suggest that even if there are biases in the detection mechanism it's still at least as common a type of system as ours.
- empath75 8y agoYeah exactly this. We’re not finding any solar systems like our own because we _can’t_. It’s possible that the majority of stars that we don’t see planets around look exactly like ours and we wouldn’t know.
- jerf 8y agoI have read in other articles that, yes, this very obvious issue has been taken into account and yes, there is still a surplus of solar systems not like ours even so. Hard to link one, though, since there's a lot of noise from articles that don't mention this.
- adminonymous 8y agoAlong the lines of this "detection bias," I've long wondered if there's another bias: the orbital angle of the exoplanets with respect to the plane of ours. If the detection is based on transit across the star of the system, what if we're looking at the axis of the planetary system, and not its equator? All systems similarly oriented toward our instruments would come up as a false negative, no? (I'm not an astronomer, please correct my jargon).
- wlesieutre 8y agoYou're correct that most of our detection is by transits in front of stars and will only see planets with orbital planes aligned toward us. However, it's super cool to note that we've actually directly imaged expoplanets orbiting around their stars in other planes: https://en.wikipedia.org/wiki/List_of_directly_imaged_exoplanets https://en.wikipedia.org/wiki/List_of_directly_imaged_exopla... Another possibility is detecting planets by the wobble that they introduce in the star's position. I'm not well read on the subject, but I wonder if Gaia's position measurements via parallax are accurate enough for this. EDIT: A bunch more information from Wikipedia on detection methods https://en.wikipedia.org/wiki/Methods_of_detecting_exoplanets https://en.wikipedia.org/wiki/Methods_of_detecting_exoplanet... The space-based observatory Gaia, launched in 2013, is expected to find thousands of planets via astrometry, but prior to the launch of Gaia, no planet detected by astrometry had been confirmed.
- bpd1069 8y agoI wonder if there is any models exploring the possibility that our system is uncommon due to 2 systems merging? IOW, Sol ejected a companion star and assimilated the planets from the other.
- Ultimatt 8y agoOr Jupiter is just the failed to to get big and ignite companion and there are models for that.
- nerdponx 8y agoOff-topic, but I really appreciate that they offer "Cookie Settings", giving me the option to disable ad-tracking cookies. Yes, the button is almost invisible gray-on-gray, but it's there. Is this the GDPR showing its usefuless already?
- andreygrehov 8y agoYep. I've seen it a lot lately. Most of them are powered by a third-party service. This one is coming from https://www.onetrust.com/products/cookies/ https://www.onetrust.com/products/cookies/.
- brianberns 8y ago> Half of nearby stars have at least one (and often several) worlds with masses substantially greater than Earth and orbital periods ranging from mere days to weeks Perhaps it just seems like such large inner exoplanets are so common because they're easier to find with our current techniques?
- samatman 8y agoIt says "half of nearby stars" That's common. It's half! They're also easier to find, sure. Maybe the other half are exactly like Sol but we can't tell yet. But nothing can make 1 out of 2 stars near enough to make out into something uncommon, except our local cluster of stars itself being weird in some way. Which is possible.
- ianai 8y agoTo me, that sounds like the Star forming process often results in masses below critical orbiting formed stars. I’m wondering whether they’re all gaseous. It also seems a little too uniform to believe without much more study. We could easily find out these sorts of systems have asteroid belts and planets at a farther distance than we can easily detect. Or maybe the failed stars failed because they suck up the metals in the system (anything past helium in this sentence).
- jerf 8y agoSo, this is actually a big deal, in the "centuries-long arc of science" sense. For hundreds of years, science has operated under the Copernican Principle [1], which in a nutshell is that there is nothing particular special/unique about us. Our position on the planet is not special. Our planet is not special. Our solar system is not special. Our galaxy is not special, etc. It has been a scientifically-fruitful tool for a very long time. It has even embedded itself into the "default worldview" of the scientifically minded as a law of the universe. But it was never more than a heuristic, and the data is increasingly coming in that the Copernican Principle breaks down at the solar system scale. In fact our Solar System is at least somewhat rare. It is certainly possible that the more we study the rarer it will become. (It can't really go the other direction at this point.) It's going to take decades for this to properly percolate through the philosophy of science and its implications to be properly chewed on for a lot of the Big Questions. (Note I'm not making any claims about the outcome of that process here; any such things you read into this are your own worldview poking out. I'm just saying, this is a really big event in the history of science. The sort of result that 23rd century textbooks are going to be calling out in the primary text as an important event.) [1]: https://en.wikipedia.org/wiki/Copernican_principle https://en.wikipedia.org/wiki/Copernican_principle
- baq 8y agois 0.1% of a trillion special or not? :)
- jerf 8y agoFor you, that is a personal decision about the nature of "special". But I feel confident in saying, having watched the debate about the Great Questions for a couple of decades and seen at least the last ~150 years of it, and seen how firmly the default science position has entrenched itself on the hill that the Earth is completely not special [1], it's enough to falsify that position. And that's a big deal on its own. Is it possible the Earth is just a 1-in-10000 special case? Sure. But even that is enough to open the door to the question why that is, instead of the question just getting shouted down. [1]: For a modern day manifestation of this idea, consider how casually it is accepted in the "default scientific worldview" that it is very likely that we will find life in the Solar System, and virtually certain we will find it in the rest of the Universe. I'd submit that a rational look at the data gives you no reason to expect life in the rest of the Solar System at this point, with a lot of reasons to expect it won't happen, and I'll be generous and say that we simply have no data about other solar systems. (A less generous jerf would point out that to the extent we have data, it certainly seems negative for large-scale civilizations, which means all the data we have is negative, but I will concede that's somewhat weak for various reasons.) This confidence does not stem from evidence, or even any particularly well-backed scientific theories. It comes from the history of the debate over the Great Questions, and the general trend/desire to ensure that nothing is special about Earth, because the default science worldview would very much like to stuff the commonness of life and the non-specialness of humanity in the religious people's faces. You'll note I keep carefully referring to the "default science worldview", rather than simply saying "science", because I do not believe the two are the same. The default science worldview takes a number of steps that science qua science can not actually justify. Coming from me, this is merely an observation, not a criticism, since I believe any worldview has no choice but to step beyond science qua science, because "real science" underspecifies the universe by quite a bit.
- mrfusion 8y agoI would think most of their findings are related to the types of exoplanet detection methods we have. Talk to my when you’ve detected all planets in a random representative sample of stars.
- cpeterso 8y agoIf you are interested in exoplanets, I recommend Adam Frank's book "Light of the Stars: Alien Worlds and the Fate of the Earth". He discusses the history of the Fermi Paradox, the Drake Equation, and how what we know about exoplanets can inform us about Earth's history and future. https://smile.amazon.com/dp/0393609014 https://smile.amazon.com/dp/0393609014