151–160 of 279 posts
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> The thing is that even for a super low probability event, the size of the universe is so huge and such events must be happening all the time. But numbers can go arbitrarily low.
> But numbers can go arbitrarily low. Which begs the question, why 1, and not zero? I can buy zero, or a very large number. But 1 exactly? Nature doesn’t do that.
But in seriousness, I agree.
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The Drake Equation is filled with assumptions, like life must appear on a planet in the Goldilocks zone of a star. The whole equation has only one datapoint to extrapolate from. Tweak the equation's parameters and it will predict universes that only have one civilization per galaxy or worse! We have no way of knowing what those parameters are because we haven't seen other examples. A major reason we are interested in…
Even if you only had a handful of civilizations, the sheer time that has passed and size of the universe should mean that life should still be alot more apparent. With sublight velocities achievable today, I recall it would only take around a million years for a Von Newmann probe to cover the entire galaxy. Such a probe is quite conceivable, so why isn't there more evidence of such probes everywhere? Another point I…
What are the incentives to build and deploy such a thing though? We as a civilization fail to fund things that have a ROI of more than a few years, how are you going to fund something that pays off after a million year?
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That's just your interpretation. Take the equation at its face value and it does allow for life originating around some deep sea vents, like JamesLeonis speculated.
It does seem unlikely that such life forms would ever become spacefaring.
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The Goldilocks zone doesn't enter the Drake equation at all. As a reminder, this is the equation: https://en.wikipedia.org/wiki/Drake_equation#Equation It makes very few assumptions.
The equation itself makes no assumptions. But anyone trying to calculate something with it must. The last five factors in the equation will be filled in by assumptions based entirely on one data point, life on Earth. From your link: ne = the average number of planets that can potentially support life per star that has planets. fl = the fraction of planets that could support life that actually develop life at some poi…
Drexler and colleagues did that, and found "a substantial probability that we are alone in our galaxy, and perhaps even in our observable universe (53%–99.6% and 39%–85% respectively). ’Where are they?’ — probably extremely far away, and quite possibly beyond the cosmological horizon and forever unreachable."
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It does seem unlikely that such life forms would ever become spacefaring.
That's a separate term in the equation.
This could mean in the Drake equation ne -number of planets capable of life- is very small. A planet has to be hit with a comet big enough to deliver a large amount of water but not so big or fast to destroy it. And be in the Goldilocks zone of the star. Also the mass of the planet would play a part - gravity of more massive ones would be more likely to capture a comet. But again, too massive and I could see that ham…
Right. It's discouraging. We now know that many stars have planets, and some of them are even in the Goldilocks zone. But if it takes a planetary collision to get water... And only one planetary collision, because each one wipes out essentially all life. Look at the rest of the solar system. Mars - almost no water. Luna - almost no water. Venus, maybe water[1], but as steam. Too close to the sun and too hot. [1] http…
Earlier quoted context omitted.
> The thing is that even for a super low probability event, the size of the universe is so huge and such events must be happening all the time. But numbers can go arbitrarily low.
> But numbers can go arbitrarily low. Which begs the question, why 1, and not zero? I can buy zero, or a very large number. But 1 exactly? Nature doesn’t do that.
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This makes some sense actually. Does anyone have a counterargument to this?
It's backwards. Highly eccentric orbits are the default; near-circular orbits are the inevitable result of averaging out a large number of orbits after they collide. It's also ignoring the fact that we likely did have additional planets, but after interactions with other planets with nearby orbits, they would have been either ejected out of the solar system entirely, caused to collide, or herded into more circular (n…
The reason is that it was observed "too soon" because of its interaction with Neptune's orbit. Once we realized there were plenty of such objects in the range of Neptune's orbit but we also realized that these were not fully formed planets, we invented the term of dwarf planet, so Pluto was demoted to that status, which it shares with many other objects in the far out orbit.
So, it was just a classification thing. We could have also said all those others are also planets.
Earlier quoted context omitted.
The Goldilocks zone doesn't enter the Drake equation at all. As a reminder, this is the equation: https://en.wikipedia.org/wiki/Drake_equation#Equation It makes very few assumptions.
The equation itself makes no assumptions. But anyone trying to calculate something with it must. The last five factors in the equation will be filled in by assumptions based entirely on one data point, life on Earth. From your link: ne = the average number of planets that can potentially support life per star that has planets. fl = the fraction of planets that could support life that actually develop life at some poi…
The underlying model is just:
N*f
How many planets are there, and what proportion of them have detectable life?
The f does not have to be structured as fl->fi->fc, although we can see why you'd assume that kind of structure. It's simple to calculate the PI(series) when the model is just a funnel. Like the Million Dollar Money Drop gameshow.
But you could imagine a more complex model of probabilities that branches and merges. There could be events on the bayesian tree that amplify downstream events. For instance, suppose there is some pathway that if reached will leave certain minerals that future civilizations could use. This has happened already on earth at least once: lignin bearing plants could not be easily digested for a long time, and that led to coal formation during the carboniferous period.
You could imagine many such potential trees, but we only have one iteration.