Poll: Where is everyone?

[datalol-jack]

Yes but Physics and Chemistry are the same everywhere, including in that far away galaxy. Life is a self-sustaining, replicating entity, right? Evolution is a consequence of replication so there can't be another model as it's an inherent characteristic.

Galaxies have quite a few differences but their foundation is mavity so the model is the same for each and every one of them.

Replication and mutation are important but a carbon-based molecular infrastructure isn't strictly a universal requirement. Whatever the biochemistry, it must fit the requirements of variety, stability and size to carry biological information. Carbon appears the perfect element to form such a molecular infrastructure, yet even before we get to exotic matter, there are other candidates. And even our core assumptions are based on what is observable on Earth in absence of any advances in synthetic biology, among other things which can throw them into doubt.

In short, don't assume universality by composition lightly.

 

[Trusty]

Replication and mutation are important but a carbon-based molecular infrastructure isn't strictly a universal requirement. Whatever the biochemistry, it must fit the requirements of variety, stability and size to carry biological information. Carbon appears the perfect element to form such a molecular infrastructure, yet even before we get to exotic matter, there are other candidates. And even our core assumptions are based on what is observable on Earth in absence of any advances in synthetic biology, among other things which can throw them into doubt.

In short, don't assume universality by composition lightly.

There aren't many alternatives though i don't think? Silicon perhaps?

We can deduct pretty well that carbon is going to be pretty much the pre cursor to advanced life. It's atoms move so freely to create other molecules which gives us that diversity. I'm trying to remember my A-Level chemistry there.. I could be completely wrong tho haha

 

[datalol-jack]

There aren't many alternatives though i don't think? Silicon perhaps?

We can deduct pretty well that carbon is going to be pretty much the pre cursor to advanced life. It's atoms move so freely to create other molecules which gives us that diversity. I'm trying to remember my A-Level chemistry there.. I could be completely wrong tho haha

Should be sufficient to understand most of this entry then: https://en.wikipedia.org/wiki/Hypothetical_types_of_biochemistry. Yes, on a basic level Silicon is the most plausible element albeit less versatile, but there's more. Sagan used to be a big speculator on solvent alternatives to water, as the entry nicely mentions under his pic. The Glasgow experiment on self-assembly is also in there. Pretty fun I thought.

 

[v0n]

Kevlar, among quite a few other things, will last until the Sun destroys the planet.

The absence of the oil/coal we removed and burned will also be observable until the planet's destruction.

Radioactive sediments etc. etc. Tones of traces really.

Kevlar, good call, but don't aramids degrade with friction and pressure and ultraviolet? Interesting thought for someone in chemistry - if we found 100+ million year old version of synthetic fibres, traces of something ripped to shreds and compressed over and over then spread for hundreds of miles in layers of rock - wouldn't we just give it a name and presume they occur naturally?

Absence of oil/coal - presumably they would be new layers of the stuff created after so much time?

Radioactive sediments wouldn't last that long, but presumably whatever species rule the Earth gazillion moons from now would just treat those as perfectly mineable natural resources if they were inclined that way?

 

[Trusty]

Should be sufficient to understand most of this entry then: https://en.wikipedia.org/wiki/Hypothetical_types_of_biochemistry. Yes, on a basic level Silicon is the most plausible element albeit less versatile, but there's more. Sagan used to be a big speculator on solvent alternatives to water, as the entry nicely mentions under his pic. The Glasgow experiment on self-assembly is also in there. Pretty fun I thought.

I'll read up, yea fascinating stuff. Check out the Vital Question by Nick Lane, amazing book on biochemisty.

 

[datalol-jack]

I'll read up, yea fascinating stuff. Check out the Vital Question by Nick Lane, amazing book on biochemisty.

Thanks. Will get it from the Kindle Store tomorrow.

 

[Amp34]

I could be wrong but I think that's unlikely. 500 years ago we were at the center of the Universe which is now a laughable conception but let's not forget that the idea was based on products of imagination(mostly religions) and very few observations, let alone using the scientific method.

Current ideas are much more solid, the amount of evidence behind them is immense. Discovering what Dark Matter and Dark Energy are won't magically invalidate relativity or quantum interference. There are more than just a few loose ends but their discoveries will simply be more precise theories of what we already have today, depressing as it may be.

The current theories are basically just ideas that fit the evidence. While most may well be correct there almost certainly will be major leaps forward in scientific understanding in the future. It may be by practically invalidating one of our existing theories, or it could be an entirely new field of science is discovered and something as fundamental as newtons laws may have to be written for it. Science is ever changing and to believe we have all the basics down is probably going to come back and bite us in the arse.

 

[Trusty]

Thanks. Will get it from the Kindle Store tomorrow.

You won't be able to put it down quality book. Talented writer that Nick Lane

 

[Cern]

Yes but Physics and Chemistry are the same everywhere, including in that far away galaxy. Life is a self-sustaining, replicating entity, right? Evolution is a consequence of replication so there can't be another model as it's an inherent characteristic.

Galaxies have quite a few differences but their foundation is mavity so the model is the same for each and every one of them.

I'm not suggesting the laws of physics and chemistry vary across the universe, these seem to be constants as far as our current theories can tell.

But as you say, galaxies do differ. Is it not possible there's a galaxy out there where the conditions are different enough to not require natural selection because there's no need to compete? Perhaps due to abundance of resources. Perhaps due to a lack of competing species?

We've already observed on Earth that evolution is not a constant and can proceed at different speeds. In some cases glacially slow, with some species currently alive having been essentially unchanged for millions of years. In some cases quite rapidly with observable change in a matter of a few generations. And there's microbes on Earth currently which perhaps haven't fundamentally changed at all for billions of years.

 

[Trusty]

I'm not suggesting the laws of physics and chemistry vary across the universe, these seem to be constants as far as our current theories can tell.

But as you say, galaxies do differ. Is it not possible there's a galaxy out there where the conditions are different enough to not require natural selection because there's no need to compete? Perhaps due to abundance of resources. Perhaps due to a lack of competing species?

We've already observed on Earth that evolution is not a constant and can proceed at different speeds. In some cases glacially slow, with some species currently alive having been essentially unchanged for millions of years. In some cases quite rapidly with observable change in a matter of a few generations. And there's microbes on Earth currently which perhaps haven't fundamentally changed at all for billions of years.

You need the evolution, there's no hierarchy otherwise. Self replicating simple organisms would not pass on dna which is slightly different if you were all the same. The variation in dna is what leads to more complex organisms. It's inherent in progression of life.

It's sort of like a chicken and egg scenerio, what came first? well obviously the egg, that's where the variation happens which leads to the modern chicken.

 

[datalol-jack]

I'm going to throw another spanner in the works: undecidability and completeness as it relates to empirical science. A tough nut to crack if you're looking for either certainty, universality, determinism or perfection.

 

[Trusty]

This is not a philosophy class

Edit...wait, i've got a philosophy question actually. Why can't we eat babies?
Edit...i'm not a complete wierdo, it's from something Sam Harris said in a podcast about philosophy classes

 

[Amp34]

Kevlar, among quite a few other things, will last until the Sun destroys the planet.

The absence of the oil/coal we removed and burned will also be observable until the planet's destruction.

Radioactive sediments etc. etc. Tones of traces really.

Oil will replenish itself in a couple of hundred million years. IIRC (can't find any hard data on this from a quick google search) most oil extracted by is is Jurassic and younger, with a significant proportion of that being from Cenozoic sources.

Coal, well the Carboniferous was so named, but how would they know there was coal there in the first place? You'd have to have a remarkably stable Craton for mine workings to survive 200 million years. There is still going to be plenty of coal fields from the Anthropocene and late Cenozoic. That's also assuming the potential previous civilisation actually used fossil fuels as much as us.

That said the burning of the fossil fuels will certainly create a global marker, but again, will it be recognised for what it actually is. We don't entirely understand why the PETM occurred. There are theories, but no hard particularly cement one theory as the defacto cause. Perhaps the future organism could look at what we are now starting to call the Holocene/Anthropocene boundary and decide it may have been caused by a major burning of organic matter caused by a cataclysmic event and a dirty/radioactive comet.

Without context it can be ****** hard to work things out, and as much as I would like to think most of what we theorise is broadly accurate, I bet the earth science community have made some massive errors. If only we had a time machine so we can go back and see if the Deccan Traps was really a major cause of the demise of the dinosaurs. The entire period of human history is pretty much encased in a few mm of abyssal plain sediment.

 

[Cern]

This is not a philosophy class

Edit...wait, i've got a philosophy question actually. Why can't we eat babies?

Some species do. And no, I'm not advocating it

 

[datalol-jack]

This is not a philosophy class

Pure and applied mathematics, Trusty. Philosophy, oof, now that would be pushing even my amateur Renaissance-man self; I do dabble, but once you know anything about decision problems, you lose interest in the undecidable ones. Unless you want to talk ethics, infanticide is more zoology than philosophy: we can but there are consequences.

 

[Amp34]

Kevlar, good call, but don't aramids degrade with friction and pressure and ultraviolet? Interesting thought for someone in chemistry - if we found 100+ million year old version of synthetic fibres, traces of something ripped to shreds and compressed over and over then spread for hundreds of miles in layers of rock - wouldn't we just give it a name and presume they occur naturally?

Absence of oil/coal - presumably they would be new layers of the stuff created after so much time?

Radioactive sediments wouldn't last that long, but presumably whatever species rule the Earth gazillion moons from now would just treat those as perfectly mineable natural resources if they were inclined that way?

It's not radioactivity per se, in the sense of OMG it's going to give me cancer. Rather its usually a change in the ratio between one isotope of an element an another. One of the main isotopes used for palaeoclimate study is the ratio of C12/C13 (amongst others).

As such our age may be defined by the change in the ratio of Uranium isotopes (U235/238 for example), which would be different to the natural ratio that would have occurred prior to our nuclear testing. With a half life of around half a billion years it's not going anywhere fast.

 

[Zethor]

Kevlar, good call, but don't aramids degrade with friction and pressure and ultraviolet? Interesting thought for someone in chemistry - if we found 100+ million year old version of synthetic fibres, traces of something ripped to shreds and compressed over and over then spread for hundreds of miles in layers of rock - wouldn't we just give it a name and presume they occur naturally?

Absence of oil/coal - presumably they would be new layers of the stuff created after so much time?

Radioactive sediments wouldn't last that long, but presumably whatever species rule the Earth gazillion moons from now would just treat those as perfectly mineable natural resources if they were inclined that way?

Some of the Kevlar will degrade but not all of it, we made a lot of it and we spread it all over the planet so some of it will most likely remain for billions of years.

In the past 100 years we removed a lot of the coal that resulted from the plants which lived 300 million years ago. If we disappear today, a geologist living 1 billion years from now will notice that the amount of coal found in the geological record decreased dramatically 1.3 billion years ago and then it started to recover. They will then correctly conclude someone took it.

The radioactive sediments will last as long as the planet in the geological record. Geologists will see traces of nuclear reactions within a very short period of time (about 1300 in the 20th century).

 

[Trusty]

I'm not advocating it

Why not?

Pure and applied mathematics, Trusty. Philosophy, oof, now that would be pushing even my amateur Renaissance-man self; I do dabble, but once you know anything about decision problems, you lose interest in the undecidable ones. Unless you want to talk ethics, infanticide is more zoology than philosophy: we can but there are consequences.

I had a guess it was some sort of philosophy quote. I did maths at AS-Level, didn't do A-Level though, couldn't be chewed, was too interested in sport.

That question about babies came from a Sam Harris podcast i listened to, he dabbled with philosophy at uni i think and apparently those were quite acceptable questions, i suppose you get straight to the moral crux with questions like that, no bs, straight to the morals.

 

[datalol-jack]

Why not?



I had a guess it was some sort of philosophy quote. I did maths at AS-Level, didn't do A-Level though, couldn't be chewed, was too interested in sport.

That question about babies came from a Sam Harris podcast i listened to, he dabbled with philosophy at uni i think and apparently those were quite acceptable questions, i suppose you get straight to the moral crux with questions like that, no bs, straight to the morals.

Pretty much.

Philosophy: anything goes; there are two great meta-traditions: Western Analytical and Continental (Eastern sort of melds into it, but some would classify it on its own)... the only difference is that in Western analytical philosophy it takes a while to get to the crazy.

Here's another one:

You air balloon is descending fast. Alongside yourself you find a pregnant woman, an old man, a child, a world-leading scientist, Paris Hilton and your pet dog, Dingo. All your ballast is gone and you're not allowed to kill yourself. Whom do you throw out first? Second? And so on.

 

[Cern]

But that's just the thing guys - nothing we make or throw away will last more than few million years. Not metal, not concrete, not rubbish. Even the thickest plastic water bottle will turn to dust in 800-1000 years. Glass bottle in 4000-5000 years at best. Radiation from Chernobyl - slightly over 1000 years. We all know what happens to unmaintained metals and brick houses exposed to the elements - we've all seen what happens to old cars, big artillery guns, boats and ruins merely tens or hundreds years old. The oldest human structures of "lost civilisations" - the most weather and time resistant stuff made by our own species - which usually amounts to a few oddly shaped stones on the same hill, too close together to be incidental, range from 5.5k years in case of Stonehenge all the way to Göbekli Tepe estimated at about 12k years ago. The oldest cave painting we discovered - approx 40,000 years old. The oldest stone tool ever found - arguably estimated to be 2.8 million years old. That's the best we can do. Sings of our DNA according to google could in optimal scenario last up to maybe 6.8 million years although it would most likely be mostly unreadable after 1.5 million years. In comparison mother nature's greatest hits - Grand Canyon - up to 70 million years old. White Cliffs of Dover, approx 85 million of years old. Now imagine 150 million years. 200 million years. Scale. Perspective

Yes, pretty much everything we've manufactured will return to dust and molecules eventually. But some of it will leave an imprint in the geological record. Just like fossils.

I'm sure you realise that fossils are not the actual bones of the dinosaurs etc, but rather imprints left behind in the rocks. Well with such a vast amount of human detritus left on this planet, it's extremely likely that at least some part of it will enter the geological record, become part of the rock. And as such leave a trace for future intelligent life to find.

So, if there had been previous intelligent life on this planet we should expect to find traces of it in the geology. And we haven't. And given how hard we've been searching for fossils, including in the oldest known rocks, it's highly likely we never will because it's just not there.