Observable Universe contains 10x more galaxies than previously thought (2016) • Hacker News Board

Re: Observable Universe contains 10x more galaxies than previously thought (2016)

#111

Post by padobson » Thu, Jan 04, 2018, 5:53 PM UTC

Retric wrote: post #77

Scarblac wrote: post #71

Earlier quoted context omitted.

> Even the lifeforms that we do know of, occupy a very broad spectrum in all metrics, existing at all sorts of extremes. But all lifeforms we know evolved from one common ancestor, it's one tree of life. As far as we know life evolved here only once. So we know that once life happens it can become completely ubiquitous, but it doesn't say anything about that crucial first step.

> But all lifeforms That's not nessisarily true. Single celled organisms have a rather fluid exchange of genetic information even our 'single cells' are really several different organisms. It's possible life evolved many times on earth and current single celled organisms and thus all life has a mismatch of ancestors. Further, life may regularly evolve even today, but simply get eaten due to the stiff competition. PS:…

> It's possible life evolved many times on earth

It's also possible it evolved elsewhere and rode here on a meteor - or was brought here by some other lifeform several orders of magnitude more advanced than us, using earth as their own cosmic terrarium.

Re: Observable Universe contains 10x more galaxies than previously thought (2016)

#112

Post by falsprofet » Thu, Jan 04, 2018, 5:53 PM UTC

Pigo wrote: post #88

JoeAltmaier wrote: post #84

Earlier quoted context omitted.

To nitpick: there is life on the International Space Station (beyond Earth). I don't mean 'in it'; I mean on it . Bacteria colonize some external surfaces. So life can apparently adapt to extra-Earth locations. The leap of faith is then, that it hasn't left Earth, or that life on Earth didn't come from somewhere else to begin with? Because either scenario becomes plausible. It'd be strange to believe it didn't happen…

So long as people acknowledge that what they think is a belief or hypothesis, I love to hear it. I guess everyone is forced to believe something un-provable about life. Looking at all of those galaxies forces you to come to terms with how little any of us really know for sure.

> I guess everyone is forced to believe something un-provable about life

> Looking at all of those galaxies forces you to come to terms with how little any of us really know for sure.

Only if you are forced to look at all that - in detail - and since that's not essential to a mundane life, there is no obligation to believe anything much.

I mean, I'm trying to make a point about believe in distinction to knowledge. There is yet a weaker modus operandi, which I'd call awareness for now, but that's a loaded term, too. If you hold two thoughts about contradicting possibilities in mind at the same time, that's not believe. Believe happens when externalities force a decision, also called leap of faith. Then you choose to believe in one possibility. Knowledge on the other hand means the possibility of round about 1.

Re: Observable Universe contains 10x more galaxies than previously thought (2016)

#113

Post by Buttons840 » Thu, Jan 04, 2018, 5:56 PM UTC

citation_please wrote: post #53

FreeHugs wrote: post #50

Earlier quoted context omitted.

Meaning if there are 24 factors crucial for life to evolve, and each has a 10% chance of occurring - it's actually quite likely only one planet would win on this lottery. Is it? What is the probability?

I believe the post above was working out math that would make it so the probability would be 1 / #(of planets in the universe), which, following the law of large numbers, would mean that given an infinite number of universes, those universes would tend to have exactly one planet (Earth in our universe's case) that would have life.

In other words, the odds of there being life elsewhere in the universe is:

a very large number of planets * a very small chance of life forming = ???

We don't really know how small the chances of life are. It may be that the chances of life forming are so small it dwarfs the number of planets in magnitude. It may be an incredible miracle that we live.

It seems that whenever an article says "there are more planets than we expected", someone concludes "this makes it more likely that there is life somewhere out there", but it's also fair to conclude that "this means the odds of life forming are lower than we previously thought" since we haven't actually found any other life. As Fermi asked, where is everybody?

Re: Observable Universe contains 10x more galaxies than previously thought (2016)

#114

Post by AnIdiotOnTheNet » Thu, Jan 04, 2018, 5:58 PM UTC

blauditore wrote: post #94

esarbe wrote: post #66

Earlier quoted context omitted.

I agree with you in that we will probably never have contact with another sentient species of extra terrestrial origin. The distances are to vast, the lifetimes of civilisations and even species too short and so on. However I do think that you vastly underestimate the probability of life. Take a look at https://en.wikipedia.org/wiki/Earliest_known_life_forms . See how quickly life appeared once the earth had cooled d…

But it's fairly likely to be carbon-based, as carbon is the simplest existing element with the maximum amount of valence electrons. And generally, simpler (= lower ordinal number) means more stable, as well as more likely to arise (as less energy is required, e.g. in stars).

It may not be based on elemental matter, or matter at all.

Re: Observable Universe contains 10x more galaxies than previously thought (2016)

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Post by marcosdumay » Thu, Jan 04, 2018, 5:59 PM UTC

esarbe wrote: post #66

V-2 wrote: post #44

Earlier quoted context omitted.

> How, when given the evidence of practically infinite planets out there [...] can we even consider the possibility that this is the only planet with life? Human minds aren't good with very large numbers. What seems "practically infinite" to us - isn't, really. The number of all planets in the universe is said to be in the ballpark of 10^24. Meaning (obviously) if you keep on dividing it by 10, in just 24 steps you g…

I agree with you in that we will probably never have contact with another sentient species of extra terrestrial origin. The distances are to vast, the lifetimes of civilisations and even species too short and so on. However I do think that you vastly underestimate the probability of life. Take a look at https://en.wikipedia.org/wiki/Earliest_known_life_forms . See how quickly life appeared once the earth had cooled d…

> See how quickly life appeared once the earth had cooled down?

What if life can only appear as a planet is finishing to cool down?

Re: Observable Universe contains 10x more galaxies than previously thought (2016)

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Post by Razengan » Thu, Jan 04, 2018, 6:02 PM UTC

TeMPOraL wrote: post #55

Razengan wrote: post #9

Earlier quoted context omitted.

> For the "rogue" planets, it's easy -- we can be pretty sure they don't have any life. Why? Even if you assume all life requires heat and/or light, a rogue planet could produce heat/light from geothermal or other chemical activity. A rogue planet drifting through certain nebulas might have more surrounding material for the processes of life to work with. The life on a rogue planet may even be "artificial", say a col…

> A rogue planet drifting through certain nebulas might have more surrounding material for the processes of life to work with. Keep in mind that nebulae are in reality less dense than industrial-grade vacuum. From the point of view of a rouge planet passing through one, it's pretty much still empty space.

What about the regions of nebulas that are about to coalesce into stars? Wouldn’t they have some kind of protostellar “stuff” at point that makes the region more active than the rest of the average nebula?

https://en.wikipedia.org/wiki/Molecular_cloud

Re: Observable Universe contains 10x more galaxies than previously thought (2016)

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Post by e40 » Thu, Jan 04, 2018, 6:04 PM UTC

esarbe wrote: post #66

V-2 wrote: post #44

Earlier quoted context omitted.

> How, when given the evidence of practically infinite planets out there [...] can we even consider the possibility that this is the only planet with life? Human minds aren't good with very large numbers. What seems "practically infinite" to us - isn't, really. The number of all planets in the universe is said to be in the ballpark of 10^24. Meaning (obviously) if you keep on dividing it by 10, in just 24 steps you g…

I agree with you in that we will probably never have contact with another sentient species of extra terrestrial origin. The distances are to vast, the lifetimes of civilisations and even species too short and so on. However I do think that you vastly underestimate the probability of life. Take a look at https://en.wikipedia.org/wiki/Earliest_known_life_forms . See how quickly life appeared once the earth had cooled d…

See how quickly life appeared once the earth had cooled down?

https://en.wikipedia.org/wiki/Panspermia

I find this a compelling possibility.

Re: Observable Universe contains 10x more galaxies than previously thought (2016)

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Post by marcosdumay » Thu, Jan 04, 2018, 6:07 PM UTC

simonh wrote: post #65

hanbura wrote: post #26

Earlier quoted context omitted.

>I also doubt humanity will find a way to travel fast enough to get to another solar system within a human lifespan. The next solar system is only four lightyears away. Given the will to break nuclear test ban treaties we think we could develop nuclear pulse propulsion drives that achieve about 10% the speed of light. Even after accounting for acceleration and deceleration that gets us there in a human lifespan. Gran…

>Even after accounting for acceleration and deceleration that gets us there in a human lifespan... It gets _something_ there in a human lifespan. The only really well though out models for that are Daedalus and Icarus, and they would involve flybys only of probes the size of a hockey puck, or a washing machine at most. The cost of which would be civilisation impoverishing. I think it's a very reasonable chance that h…

> ... or a washing machine at most.

The Orion project was designed for sending a city-sized space ship to Alpha Centaury in ~100 years.

The hard part seems to be how to build a city-sized ship, not how to move it.

Re: Observable Universe contains 10x more galaxies than previously thought (2016)

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Post by mabbo » Thu, Jan 04, 2018, 6:17 PM UTC

Razengan wrote: post #3

And some people still aren’t sure if there is other life beyond Earth. :) That's entire galaxies. Not just stars, and that's just the observable universe. We are still being surprised by the lifeforms we observe here on Earth, and the environments and conditions they can thrive in (including the outer hulls of our spacecraft), and we still have yet to discover and catalog all the life on our planet. Life may even com…

> can we even consider the possibility that this is the only planet with life?

Yes, we can. I don't personally think life is all that rare in the universe- we agree there. But I think it's perfectly fair that it's possible we're alone.

It's really a question of how many unlikely events lead to us existing and how improbable those events are. People always start with "Let's imagine only 0.1% of planets have conditions for life! How rare that must be!". But is 0.1% a fair estimate? What if the true number is 1E-20? Or 1E-40? 0.1% is easy for humans to understand and think about so we always start there. Then apply the same reasoning to the jump from single-cell life to multi-cell life, to the odds of become larger animals, the odds of becoming intelligent.

We don't know what the odds are, so we always use odds that sound low but are actually quite large.

Just like humans are biased towards not seeing how big the universe is, you (like everyone else) are biased towards using probabilities in the realm of human understanding. That is just as wrong.

The question isn't how big the universe is, it's the comparison of how-big to how-unlikely.

Re: Observable Universe contains 10x more galaxies than previously thought (2016)

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Post by cs1717p » Thu, Jan 04, 2018, 6:18 PM UTC

piquadrat wrote: post #30

Razengan wrote: post #3

And some people still aren’t sure if there is other life beyond Earth. :) That's entire galaxies. Not just stars, and that's just the observable universe. We are still being surprised by the lifeforms we observe here on Earth, and the environments and conditions they can thrive in (including the outer hulls of our spacecraft), and we still have yet to discover and catalog all the life on our planet. Life may even com…

@ASmallFiction had a beautiful, succinct take on this recently: "Are we alone in the universe?" she asked. "Yes," said the Oracle. "So there's no other life out there?" "There is. They're alone too." https://twitter.com/ASmallFiction/status/946608733982822401

While, of course, it is technically possible, it seems very reasonable to infer that we may be in a small window in which we haven't connected to other intelligent life. In just 100 years we have gone from being barely able to fly at all, to being close to becoming a multiplanetary lifeform.

The evidence becomes more and more every day that life is not a one in a trillion miracle but a natural product of certain environments. To assume we will never have contact with other lifeforms seems like a huge jump.