Conspiracy Theories

[Enigma]

10 hours ago, MixuFruit said:

Fermi Paradox and the Great Wall - if the sheer size of the galaxy means other intelligent life evolving is a statistical certainty, why haven't we seen any of them? If that means there is some cataclysmic obstacle that stops any civilisation travelling and making contact, we're either the first to pass it (good) or haven't yet reached it (bad).

Pray there’s intelligent life somewhere out in space, because there’s bugger all down here on Earth.

[shuggz]

14 hours ago, Hillonearth said:

The odds must be wildly against Earth supporting the only life in the universe considering the sheer amount of planets out there. Intelligent life might be a bit thin on the ground though...we seem to be doing a cracking job of initiating our own extinction, so it could be that the lifespan of a technological civilisation may normally be so short that the chances of two of them existing at the same time and contacting each other are tiny.

I saw a documentary once that was speculating on the possibilities for first contact which said the absolute worst first message we could get from aliens would be "Stop broadcasting now - they'll hear you."

Which I suppose could only be topped by a second message of "Too late. We already have."

Ah,the dark forest theory..i.e. in a forest full of predators and prey, both do their utmost to remain "invisible", as soon as they do anything to reveal themselves then they are at a disadvantage See the book The Three Body Problem by Cixin Lui,and its follow ups The Dark Forest and Deaths End. A bit of a read, and it is fiction , but makes you think .

[NotThePars]

Ah,the dark forest theory..i.e. in a forest full of predators and prey, both do their utmost to remain "invisible", as soon as they do anything to reveal themselves then they are at a disadvantage See the book The Three Body Problem by Cixin Lui,and its follow ups The Dark Forest and Deaths End. A bit of a read, and it is fiction , but makes you think .

That ending/ reveal in TBP is great. I really ought to read the other two books. I’m too dumb to get what’s going on half the time though.

[Bairnardo]

We could see more if the tech was improved but we’d still only ever be able to see a tiny fraction because we’re limited by the speed of light and expansion. Assuming light speed is an absolute limit of course.

Know what blows my mind...... When you think about it in relative terms. Our galaxy and our planet must be, if you go far enough out into the Universe, the size of a grain of sand in comparison to something else. Or smaller. Infinitely small even.

I hope when you die you get to zoom out and see the whole picture. That would be class.

[shuggz]

1 hour ago, NotThePars said:

 

That ending/ reveal in TBP is great. I really ought to read the other two books. I’m too dumb to get what’s going on half the time though.

 

It's well woth it...gets even weirder .

[NotThePars]

[emoji872]

[GordonS]

On 07/01/2021 at 21:14, Hillonearth said:

The odds must be wildly against Earth supporting the only life in the universe considering the sheer amount of planets out there.

I've never understood the logic in this. Despite Earth being around for a wee while now and it being a great place for life, as far as we know life has only begun once. That's why we're related to grass and mushroom and worms and cats and Cardi B. As far as we know, there is no branch of living things that came into being any more recently than billions of years ago.

We have a sample size of one, so we cannot possibly know how likely or how improbable that life can spontaneously begin. Sure, there's a big universe out there, but with an entire planet and billions of years life has only begun once. There could be billions of planets just like ours and life may not have occurred on any of them.

[Fullerene]

58 minutes ago, GordonS said:

I've never understood the logic in this. Despite Earth being around for a wee while now and it being a great place for life, as far as we know life has only begun once. That's why we're related to grass and mushroom and worms and cats and Cardi B. As far as we know, there is no branch of living things that came into being any more recently than billions of years ago.

We have a sample size of one, so we cannot possibly know how likely or how improbable that life can spontaneously begin. Sure, there's a big universe out there, but with an entire planet and billions of years life has only begun once. There could be billions of planets just like ours and life may not have occurred on any of them.

As Carl Sagan said "there are more stars in the universe than grains of sand on planet Earth".  Even if there are billions of Earth-like planets without life - that still leaves plenty that possibly do."

[GordonS]

4 minutes ago, Fullerene said:

As Carl Sagan said "there are more stars in the universe than grains of sand on planet Earth".  Even if there are billions of Earth-like planets without life - that still leaves plenty that possibly do."

But it doesn't, because you can't extrapolate *anything* from a sample size of one. The beginning of life may have been the most unlikely thing that has ever happened in the entire universe. 

[welshbairn]

On 08/01/2021 at 09:10, Hillonearth said:

FTL is beyond us for the foreseeable - the best we have to offer at the moment is the theoretical Alcubierre drive, construction of which would depend on the discovery of certain types of exotic matter, and the drawbacks of which include the complete inability of the crew to control the craft at FTL speeds and the likelihood that its "bow-wave" would destroy the destination planet as the craft decelerated towards it.

The maths seems to have changed a bit but at one time they said to get it to work you'd have to convert the entire mass of a galaxy into energy to get it to work, which would not only be unsound environmentally speaking, but possibly genocidal on an incalculable scale. 

[Johnstoun]

3 hours ago, GordonS said:

I've never understood the logic in this. Despite Earth being around for a wee while now and it being a great place for life, as far as we know life has only begun once. That's why we're related to grass and mushroom and worms and cats and Cardi B. As far as we know, there is no branch of living things that came into being any more recently than billions of years ago.

We have a sample size of one, so we cannot possibly know how likely or how improbable that life can spontaneously begin. Sure, there's a big universe out there, but with an entire planet and billions of years life has only begun once. There could be billions of planets just like ours and life may not have occurred on any of them.

Life on earth might have begun and been snuffed out hundreds, thousands of times before the planet stabilised enough for it to stick. I’m inclined to believe that as long as the conditions for life are there, life will happen. Whether it lasts is another matter.

[Bairnardo]

Fun fact, we're only just inside the conservative habitable zone of our own star
 

The Scotland of 560b for me please.

[Hillonearth]

Just now, Bairnardo said:

2 minutes ago, MixuFruit said:

Fun fact, we're only just inside the conservative habitable zone of our own star
 

The Scotland of 560b for me please.

Four times winner of the 560b World Cup apparently.

[coprolite]

4 hours ago, GordonS said:

I've never understood the logic in this. Despite Earth being around for a wee while now and it being a great place for life, as far as we know life has only begun once. That's why we're related to grass and mushroom and worms and cats and Cardi B. As far as we know, there is no branch of living things that came into being any more recently than billions of years ago.

We have a sample size of one, so we cannot possibly know how likely or how improbable that life can spontaneously begin. Sure, there's a big universe out there, but with an entire planet and billions of years life has only begun once. There could be billions of planets just like ours and life may not have occurred on any of them.

Fully agree your point about not being able to extrapolate from a single sample.

Not sure you can be certain that life only started once. The whole absence of evidence not being evidence of absence thing. 

It's possible that there have been false starts that we haven't seen or have seen and didn't recognise in the fossil record.

It's possible that apparent similarities that could indicate a single ancestor (eg cells with neucleic acids coding for protein) are examples of convergent evolution. 

There might also have been a load of unsuccessful starts since bacteria arose that have just not been able to get a foothold because of the incumbent's success. 

It also depends hugely on how you define life. If you want to go with a self replication based one, without including things like respiration as a criteria then there are probably more phenomena out there that meet that definition. 

[Fullerene]

I would suggest that given enough time and the right conditions, that life can start anywhere.  If that were true, then it probably didn't start on Earth in just one place and spread to the rest of the planet.  Instead it started in various places around the globe.  It might even have been wiped out many times but returned when the conditions were right again.  Given that there more than a hundred thousand millions stars in this galaxy and maybe some with suitable planets, I would suspect the right conditions would exist on some other planets too.

Not sure how I could prove any of this.  I will have to give it some thought.

 

[GordonS]

5 hours ago, MixuFruit said:

You can theorise though. We don't know exactly how life started but experiments in the 50s showed you could make amino acids and cell-like structures by blasting mixtures of organic molecules with electricity. So if we start with it being caused by something along those lines, and knowing that organic molecules and electricity are everywhere, it's reasonable enough to assume it's not a particularly rare phenomenon. 

I want to read this book which says life is a thermodynamic inevitability, interesting concept.

https://www.amazon.com/Every-Life-Fire-Thermodynamics-Explains/dp/1541699017

 

We can't say it's not rare when we've only ever found it once in nature. 

3 hours ago, Johnstoun said:

Life on earth might have begun and been snuffed out hundreds, thousands of times before the planet stabilised enough for it to stick. I’m inclined to believe that as long as the conditions for life are there, life will happen. Whether it lasts is another matter.

True. But this has been a very life-y planet for a long time and we only know of it happening once.

2 hours ago, coprolite said:

 

Not sure you can be certain that life only started once.

Sure, that's why I said "as far as we know".

This whole thing is a thought experiment. The universe is a big place and there will be lots of Earth-like places. But I go with evidence, and the evidence we have so far is that life began on Earth only once. We don't have the faintest idea how likely it is that there are other planets with life.

[coprolite]

14 minutes ago, GordonS said:

We can't say it's not rare when we've only ever found it once in nature. 

True. But this has been a very life-y planet for a long time and we only know of it happening once.

Sure, that's why I said "as far as we know".

This whole thing is a thought experiment. The universe is a big place and there will be lots of Earth-like places. But I go with evidence, and the evidence we have so far is that life began on Earth only once. We don't have the faintest idea how likely it is that there are other planets with life.

We haven't firmly established yet that life began on earth. It seems most probable though. 

There is evidence of life elsewhere (in Venus' clouds). It is just very far from conclusive at this stage. 

[Cyclizine]

There's nothing that says life has to be based on DNA/RNA like here. That's just what we see in earth due to the conditions here. It's feasible that other forms of life could be based on entirely different chemistry in entirely different conditions.

[Fullerene]

2 hours ago, MixuFruit said:

The one that always blows my mind a bit is that proteins have chirality, they're twisty and they can be twisty left or twisty right. All life on earth uses only the left-chirality versions. Why?

IIRC you asked this once before on the Quick Questions thread but didn't get any answers.

Better luck this time. 

[Fullerene]

Just now, MixuFruit said:

I did a search for chirality and apparently said this in the pub etiquette thread. Me neither.

I was also going to ask:

Is this left chirality some sort of conspiracy?

If so, can you explain further.