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

spacetelescope.org

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

#81

Post by Lon7 »

monktastic1 wrote: post #78
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?

Phrased differently: the expected number of such planets is 1.

In most variations of such a calculation the expected number of planets would be 0. The fact that the actual answer is >= 1 might suggest that the calculation is not an accurate representation of reality.

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

#82

Post by saiya-jin »

zimpenfish wrote: post #69
saiya-jin wrote: post #17

Earlier quoted context omitted.

mankind has been extremely lucky with our environments, among others: - Jupiter & Saturn pick out most of the comets, so we encounter massive reset only very rarely - thanx to hitting other planet long time ago, we have a spinning molten metal core inside planet generating magnetic shield for all nasty radiation - moon gives us tides & stability - our sun is just the right size and age to be stable - we're located at…

> we're one of the first sentient arrivals Given we didn't arrive until 14.5bn years into the universe's existence, I'd find that extremely hard to fathom.

Our solar system is +-4bn years old, so there have been only cca 3 previous generations of similar stars (and it's kind of nice to have heavier elements from the first generations of stars in abundance - I would expect forming life just from He and H wouldn't work well).

Let's ignore the 'bn' part - this place is 14-old. Our system is 4-old. Life is 3-old. Multi-cellular is 2-old. Sentient is 0.00001 old. With usual star life has +- 10 to escape, or it will be destroyed. It doesn't sound so far-fetched to me.

But maybe it's all different - plenty of life all around the place, even super smart & evolved, but maybe speed of light simply can't be broken no matter what. That would dampen any rise of galactic civilization. Or some other unbreakable constraint.

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

#83

Post by monktastic1 »

Lon7 wrote: post #81
monktastic1 wrote: post #78

Earlier quoted context omitted.

Phrased differently: the expected number of such planets is 1.

In most variations of such a calculation the expected number of planets would be 0. The fact that the actual answer is >= 1 might suggest that the calculation is not an accurate representation of reality.

I'm not sure I'm understanding. It is a well-defined probability question to ask about the "expected number" of planets with life if there are 10^24 of them each with probability 10^-24, and the answer is 1.

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

#84

Post by JoeAltmaier »

Pigo wrote: post #80
Cthulhu_ wrote: post #22

Earlier quoted context omitted.

> And some people still aren’t sure if there is other life beyond Earth. :) Until we actually observe it, no, we can't be sure; the probability of it existing is high simply due to the sheer amount of dice rolls there are in the universe, but the likelihood of us observing it is low. We already know there is and was no intelligent life in our solar system besides what's on Earth; there's still hopes of finding traces…

That was my reaction as well. If you're being scientific about it, how can you be sure at all? We have observed exactly zero instances of life beyond Earth. We're all free to believe whatever we like. I have beliefs of my own, but I don't expect anyone to share them unless they happen to believe it too. I just hope people who are so sure of extraterrestrial life can comes to terms with the fact that they are making a…

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.

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

#85

Post by Pigo »

sudhirj wrote: post #74
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…

Any estimations about life outside Earth only become viable once we understand the factors that gave rise to it first, and their probabilities of occurrence. If the total probability is less than 10^24 (say) we might expect life elsewhere, but if it's 10^100 probably not. But either way, gut feel and intuition about this are pointless - by the anthropic principle, we're speculating about the possibilities of life onl…

There's always so much guesstimation and wishful thinking going on. It makes sense though because we see this magnificence and want explanations. It's frustrating because we learn so much about what we don't know, and worse, how much we'll probably never be able to know.

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

#86

Post by V-2 »

monktastic1 wrote: post #83
Lon7 wrote: post #81

Earlier quoted context omitted.

In most variations of such a calculation the expected number of planets would be 0. The fact that the actual answer is >= 1 might suggest that the calculation is not an accurate representation of reality.

I'm not sure I'm understanding. It is a well-defined probability question to ask about the "expected number" of planets with life if there are 10^24 of them each with probability 10^-24, and the answer is 1.

Yes it will be approaching 1, the same as for 10^24 coin tosses the number of heads would be approaching 50% (or 5*(10^23)).

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

#87

Post by luxcem »

kulu2002 wrote: post #25

Like Carl Sagan rightly said - "Cosmos is also within us. We're made of star stuff. We are a way for the cosmos to know itself.” We need to study ourselves more to comprehend this vastness.. [1] https://www.sciencealert.com/physicists-show-that-our-brains...

"Given enough time hydrogen starts to wonder where it came from and where it is going."

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

#88

Post by Pigo »

JoeAltmaier wrote: post #84
Pigo wrote: post #80

Earlier quoted context omitted.

That was my reaction as well. If you're being scientific about it, how can you be sure at all? We have observed exactly zero instances of life beyond Earth. We're all free to believe whatever we like. I have beliefs of my own, but I don't expect anyone to share them unless they happen to believe it too. I just hope people who are so sure of extraterrestrial life can comes to terms with the fact that they are making a…

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.

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

#89

Post by monktastic1 »

V-2 wrote: post #86
monktastic1 wrote: post #83

Earlier quoted context omitted.

I'm not sure I'm understanding. It is a well-defined probability question to ask about the "expected number" of planets with life if there are 10^24 of them each with probability 10^-24, and the answer is 1.

Yes it will be approaching 1, the same as for 10^24 coin tosses the number of heads would be approaching 50% (or 5*(10^23)).

Given the definition of "expected value," it is identically 1 (as opposed to merely "approaching it"). Sorry, I'm not trying to be pedantic.

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

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

#90

Post by V-2 »

olegkikin wrote: post #62
Razengan wrote: post #45

Earlier quoted context omitted.

We don't know all the factors under which life can exist. Even the lifeforms that we do know of, occupy a very broad spectrum in all metrics, existing at all sorts of extremes. We even have evidence of life we have never seen, will never encounter, and may never even have conceived as being possible to exist without that evidence: the enormous dinosaurs.

There's a huge difference between what evolved organisms can adapt to, and the conditions necessary to start life. Look, humans already adapted to being in space for prolonged periods of time. We adapted to every climate. But drop a naked human in a random spot on our planet, and he will die with high degree of probability. And that's after billions of years of evolution.

Out of which some 3 billion years had to pass before unicellular forms of life evolved into multicellulars.

Who knows if this jump alone should be taken for granted - plus, not many planets could provide 3 billion years of "good weather" (or staying habitable) to start with.

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