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Wiki says "TRAPPIST-1 is an ultracool dwarf star that is approximately 8% the mass of and 11% the radius of the Sun. It has a temperature of 2550 K and is at le
by r721 10y ago
Wiki says "TRAPPIST-1 is an ultracool dwarf star that is approximately 8% the mass of and 11% the radius of the Sun. It has a temperature of 2550 K and is at least 500 million years old."
https://en.wikipedia.org/wiki/TRAPPIST-1 https://en.wikipedia.org/wiki/TRAPPIST-1
Too young star for alien life hopes?
- stupidcar 10y agoWell, it's "at least" 500m, but is probably much more[1]: "Determining the ages of such small stars is difficult because they evolve so slowly over their lifetimes of trillions of years but it is estimated to be in excess of a half a billion years and is probably much more." And abiogenesis occurred on Earth within about 500m years of the Earth's formation, so life can clearly arise pretty quickly. It's complex, multi-cellular life that seems to be hard part. Although this is based on our observations of a single example. [1] http://www.drewexmachina.com/2016/05/03/habitable-planet-reality-check-trappist-1/ http://www.drewexmachina.com/2016/05/03/habitable-planet-rea...
- hughes 10y ago> trillions of years This is off by several orders of magnitude. Like estimating the age of your neighbor to be somewhere around 400,000 years old.
- dwaltrip 10y agoUh? I think it's widely accepted that our best models of small stars are fairly well understood, and predict that they will continue to fuse hydrogen in their cores for more than a trillion years.
- kakarot 10y agoReferring to an average of 1-2 trillion years as "trillions of years" is either misleading, uninformed, lazy, or a combination of the 3. When dealing with hard science it's important to choose your descriptors wisely. Most readers will not follow up.
- lutorm 10y agoUh, "1-2 trillion" IS "trillions". I'm not sure how you can make that out to be misleading. Stating "trillions" in lieu of "tens of trillions" or "hundreds of billions" might be misleading, but this is not.
- kakarot 10y agoIt seems the rest of HN disagrees with me, but when I hear "trillions" I think in plurality of trillions, a handful maybe, but afaik these things don't really live past 2 trillion years
- Retra 10y agoThat's because that number is a reference to a plurality of years, not a plurality of trillions.
- kakarot 10y agoIf you say so, I guess I'm just wrong about this. Thank you for trying to clarify for me, instead of just downvoting me into oblivion like everyone else.
- Retra 10y agoI don't think you're "just wrong," there's definitely some ambiguity. You can use "trillions" to denote the scale or magnitude of a value and also to denote a denomination.
- kakarot 10y agoI definitely think it's a an interesting case of context, because if you say a quantity "could even be in the hundreds" it is unambiguously stating it could be within the singular hundreds. But change that into "is in the hundreds" and suddenly you aren't so sure. Even the term "hundreds" alone seems to carry less ambiguity than its superiors, thousands, billions, etc. The higher the quantity, the more imprecision when using the plural form. I guess I was just trying to encourage a little more precision when talking astronomically, though retroactively I see that I could have been less of a dick about it.
- hughes 10y agoAh, my bad. I thought the model was in reference to the current age of the star, not the expected duration of fusion.
- sampo 10y agoThat is not talking about the age, but about the possible life span, into the future.
- tokipin 10y agoI'd be surprised if there isn't other microbe-like life in our own solar system. And the path from microbial to "complex" life is just a matter of whether the environment provides enough energy to support it (nearby sun + photosynthesis in our case). This is because cellular communities will always have certain niche advantages (homeostatis etc). Complex life developed on Earth because it is advantageous in a physics/evolutionary sense, not because the universe accidentally slipped on a banana. Complex life is only an "accident" in that the search algorithm took a while to find the maxima. Otherwise it's just a matter of running the search long enough, and for that all you need is a star.
- mullen 10y agoI think this is why there is no life on any of the planets. The star is just too young. However, the star could have a life span of 5 trillion years, it is safe to say that life could form on the planets and have plenty of time to develop.
- 1001101 10y agoMaybe several times over independently. Hopefully we won't have to speculate long. As Jill Tarter says, "we count one, two, infinity." Still waiting for two, and I hope it happens in my lifetime.
- dwaltrip 10y agoIn the Q&A session they said it's difficult to constrain the age of the long-lived ultraviolet dwarf stars once they finish the active early phase, as their lifecycle progresses so slowly. They live for more than a trillion years, compared to stars like our sun which are larger and burn through their fuel in less than 10 billion years. It's somewhat counterintuitive, but the bigger a star is, the faster it uses up its fuel, despite having much more of it. As size increases, the rate of fusion in the star's core increases such that the extra fuel isn't enough to prevent the lifespan from shortening. In fact, a common type of supernova occurs in stars that are at least 8 times the size of the sun, burn through their fuel in less than 100 million years, and then go out in style. Crash course astronomy has some great videos on this stuff: https://youtu.be/PWx9DurgPn8 https://youtu.be/PWx9DurgPn8
- deleted 10y ago[deleted]
- JumpCrisscross 10y ago> it's difficult to constrain the life of the long-lived ultraviolet dwarf stars What's the upper bound on their estimate for TRAPIST-1's age?
- biot 10y agoThe upper bound is the age of the universe.
- perlgeek 10y agoThis may sound a bit snarky, but it's actually quite a good boundary. Current estimations for the age of the Universe are around 12 to 14 billion years, which isn't much compared to a trillion year life span of such a star.
- ianai 10y agoPlot twist: It's actually 2 trillion years old. Everything we know of the universe is wrong! (I'd bet I'm not the only one who'd find that a more interesting option.)
- 6502nerdface 10y ago> Too young star for alien life hopes? Not necessarily -- life on Earth may have arisen a remarkably short time after accretion, perhaps even in the first few hundred million years. See this old HN discussion: https://news.ycombinator.com/item?id=10415212 https://news.ycombinator.com/item?id=10415212
- sampo 10y agoEarth is 4.5G years old, and the earliest undisputed microbial life fossils are 3.5G years old, so that gives 1000 million years. But we can also say that Earth was cool enough for liquid water 4.4G years ago, and there are some findings suggesting microbial life already 4.1G years ago. So only 300 million years, at maximum.
- dgudkov 10y agoMoore's Law applied to DNA complexity hints that life could be way older than Earth itself: https://www.technologyreview.com/s/513781/moores-law-and-the-origin-of-life/ https://www.technologyreview.com/s/513781/moores-law-and-the...
- acqq 10y agoI suspect something's not right, on their graph, mammals are on the top, but this flower has 50 times bigger genome than a human: https://en.wikipedia.org/wiki/Paris_japonica https://en.wikipedia.org/wiki/Paris_japonica
- infinite8s 10y agoPlants often have much larger genomes than animals due to whole chromosome replications. Since they are much simpler phenotypically this isn't nearly fatal.
- lutorm 10y agoThat's "at least"; the age is a lower limit. These stars basically live forever, even in astronomical terms, and evolve extremely slowly, so all you know is that it's not "young".