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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)

#151

Post by blauditore »

woodandsteel wrote: post #142
wu-ikkyu wrote: post #133

Earlier quoted context omitted.

Do you think the periodic table contains all the elements in the universe?

Yes, since from what I understand, any heavier elements would be so unstable they wouldn't last a billionth of a second.

That's the general assumption, even though there might be another stable "island" of fairly stable isotopes for higher-order elements than observed so far. But as I said, they'd need to be created first through nuclear fusion of lower elements, so their existence is obviously less likely, let alone life forms evolving on top of them.

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

#152

Post by flukus »

V-2 wrote: post #90
olegkikin wrote: post #62

Earlier quoted context omitted.

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.

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

We might be a slow developer and poor representative sample in that respect, but without more data it's hard to tell.

> plus, not many planets could provide 3 billion years of "good weather" (or staying habitable) to start with.

I suspect the opposite will be true, red dwarfs are the most common type of star and are stable for trillions of years. Even if the average time it took multi cellular life was 30 or 300 billions years then it might not matter for life evolving there. They do come with some other caveats though: https://en.wikipedia.org/wiki/Red_dwarf#Habitability

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

#153

Post by zimpenfish »

saiya-jin wrote: post #82
zimpenfish wrote: post #69

Earlier quoted context omitted.

> 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…

> there have been only cca 3 previous generations of similar stars

That assumes they're consecutive, not overlapping. Assume it takes 4-old, space them out by 0.1-old, and you could have 100+ generations between the first and us.

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

#154

Post by laumars »

bluGill wrote: post #99
TeMPOraL wrote: post #57

Earlier quoted context omitted.

> Isn't that even more interesting? Why hope to find life, when we know life is already possible? We know it's possible, but we've also seen it happen only once . The observational data we have suggests the universe is mostly dead - that is, not complex . Or, in other words, boring . Discovery of any complex process on a comparable level to even simplest of what we call life would be a civilization-changing breakthro…

Most existing religions are silent on the subject of life elsewhere. Since they do not say "it doesn't exist" finding life doesn't mean anything (it might even grow as they have a new group of life to convert). Religion tends to be very careful to stay in the area of not providing a testable hypothesis which means that new alien knowledge won't prove it wrong.

It depends on the preacher. Some are more traditional eg arguing that Earth is unique for hosting life because God created the Earth and that the universe is just there to demonstrate the epic scale of God's power.

Source: I'm not religious but I've been dragged to plenty of sermons by the extended family.

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

#155

Post by kamaal »

ryandrake wrote: post #138
kamaal wrote: post #48

Earlier quoted context omitted.

A better strategy is to start mining asteroids. Sell mined stuff on earth to make enough money to build ships and lift necessary bootstrapping material out of the gravity well. Also plenty of water out there and sunshine, burning hydrogen as fuel should be possible. Now you will have enough machinery in space to mine building stuff and enough fuel. Gradually build permanent colonies in space. It won't get all humans…

Even if there were bars of pure gold just sitting there on asteroids (or even floating in orbit) for us to take, it would cost more to get them than just mining them on Earth. People underestimate the stupendous economic cost of doing anything in space.

Oh well not gold.

But if you told them they could get unlimited clean fuel. There could be plenty of funding to extract water/ice from asteroids and send it back to earth.

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

#156

Post by vog »

CuriousSkeptic wrote: post #108
maze-le wrote: post #52

Earlier quoted context omitted.

> Right now there is more evidence for the universe to be finite rather than infinite. There is the observable universe and there are good reasons to believe that there is "some universe" beyond the observable universe. The observable universe is finite, the reason for that is the geometry of spacetime and the consequences of it (cosmological horizon/particle horizon). But I would not make absolute statements about w…

But if there can be no data about it. Does it even make sense to talk about it as existing? IIUC everything in the observable universe is sufficiently far away from anything else that any causal relationship with anything is either from before inflation or within the universe we can observe. And given how the existence of matter seems to be rather connected to time, it self a by product of interaction, it seems to fo…

> But if there can be no data about it. Does it even make sense to talk about it as existing?

To be honest, that question never made any sense to me, because this whole discussion is merely about refining a semantic detail of the common word "existing". It says nothing about the particle itself, but just about our language.

For me, a far more interesting question is: Is it relevant? (for science?)

And the answer is: As long as it doesn't interact in any way with us, it is certainly not relevant whatsoever.

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

#157

Post by simonh »

marcosdumay wrote: post #118
simonh wrote: post #65

Earlier quoted context omitted.

>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.

My apologies, I meant Daedalus. I can’t find any references to the Orion project you describe, though there have been several real spacecraft and related systems by that name.

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

#158

Post by lhkdfsakhljd »

TaylorAlexander wrote: post #110
jdtang13 wrote: post #107

Earlier quoted context omitted.

I'm tired of hearing these types of extremely confident lay-assertions about life beyond earth. It's true that the number of planets is incomprehensibly large, but it could also be true that the probability of a particular planet developing life is incomprehensibly small. In physics and chemistry, there are some odds that remain so extremely small even when you roll the dice many many times. Stop using "incomprehensi…

Let’s talk numbers. There’s 250 billion stars in our Milky Way galaxy. Our local supercluster has 100,000 galaxies in it. Previous estimates were that there are 100-200 Billion galaxies in the observable universe and this article suggests the figure is 10x as much as that. The Kepler telescope has been discovering planets around nearby stars for a while now, and the impression we get are that at least half of the sta…

so about 2^75? That means I only need to identify 75 independent things on earth that have a 50-50 chance of ocuring on another planet. I need to identify less things as long as I find something with long odds.

- Dense enough to hold an atmosphere - far away enough from the star - close enough - right star ... ect

Carbon life is probably the only life possible, maybe silicon. Carbon just has way to many things going for it (especially the bootstrapping process - try randomly creating something that behaves like a transistor vs. an amino acid).

But what I think is the crux of the matter is that it's all irrelevant: what the numbers suggest is that life elsewhere is probably irrelevant to the human experience < we're necessarily too far apart for our light cones to intersect.

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

#159

Post by marcosdumay »

simonh wrote: post #157
marcosdumay wrote: post #118

Earlier quoted context omitted.

> ... 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.

My apologies, I meant Daedalus. I can’t find any references to the Orion project you describe, though there have been several real spacecraft and related systems by that name.

You can start at Wikipedia:

https://en.wikipedia.org/wiki/Project_Orion_(nuclear_propuls...

Basically nothing of it was actually built (nuclear propulsion wasn't an well accepted idea - for good reasons that won't matter as soon as we start building in space). There was just some very small scale prototypes.

In comparison, project Daedalus moved much faster.

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

#160

Post by simonh »

marcosdumay wrote: post #159
simonh wrote: post #157

Earlier quoted context omitted.

My apologies, I meant Daedalus. I can’t find any references to the Orion project you describe, though there have been several real spacecraft and related systems by that name.

You can start at Wikipedia: https://en.wikipedia.org/wiki/Project_Orion_(nuclear_propuls... Basically nothing of it was actually built (nuclear propulsion wasn't an well accepted idea - for good reasons that won't matter as soon as we start building in space). There was just some very small scale prototypes. In comparison, project Daedalus moved much faster.

Those were launch systems or in-system vehicles though, and much cruder and less efficient than Daedalus which was optimised for interstellar travel.
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