Human Universe

[davkt]

Think Prof Cox fell into the trap of considering all other societies would act like we do. Also his argument about Von Neumann machines only really holds true if there were lots of them as there are an awful lot of stars in just this little galaxy and possibly even more planets than stars!

[JamesF]

I've just finished watching the latest programme.  I'd say it was the best so far.

Yet despite that I struggle to find a thread of consistency between the programmes as regards the likelihood of the evolution of complex life.  In the second programme he proposed the idea that our evolution (therefore including the evolution of eukaryotic cells) was near inevitable, yet in this one he holds eurkaryotic cells up as an example of something that is probably very rare.  I'm not sure I see how it can be both.  I think there were a number of other hypotheses presented that could have done with a little more substantiation too.

The discussion of the von Neumann machines was interesting.  It strikes me though that a very broad interpretation could be placed upon what might constitute such a machine.  Ptarmigan may well be right.  We could be those machines.  Or, in fact, we might actually be massive colonies of those machines.  At some level a human being is like a huge pile of bacteria that have "learned" to co-operate and co-exist.  So if some advanced species wanted to populate the galaxy and had no idea what conditions it might find, why not just spread bucketloads of the smallest effective reproductive unit you had that shared your ancestry, and allow evolution to take care of the rest?

James

[Ruud]

Yes, where are those von Neumann machines, unless they are staring us in the face - in the mirror?

I stopped watching after episode two. I enjoy writers like Barrow and Hofstadter. I'm pretty sure I learned of von Neumann machines through them. Would it be worth my while catching up with the Human Universe?

[ollypenrice]

There are so many anthropomorphic assumptions in discussions of extraterrestrial life. Aliens might be 'malevolent.' Malevolence is a word invented by humans to descirbe humans. The idea that it might be applicable to other forms of life is to make a vast swathe of anthropomorphic assumptions. Another popular one, based on nothing but assumption and our own experience, is that there is inevitably a link between the evolution of high intelligence and the creation of high technology. But what if there were life in an environment that was not in any way hostile? Would technology evolve there?

And so on and on. Alien life does not have to be like human life.

Olly

[wxsatuser]

Life as we know it.

Interesting to note that Kepler did'nt find any planets around G class stars.

If Kepler had kept going it is believed they would have found a few.

May be Cox is right until we have better data.

[chiltonstar]

After watching the last episode again, I was reminded of the Puddlian fable by Feinberg and Shapiro about a colony of rotifers in a puddle and their observations on life and whether it could exist elsewhere......

Chris

[JamesF]

Alien life does not have to be like human life.

I think there's a deeper point hidden inside that statement.

It's quite possibly not a defensible argument to propose that alien life should be similar to human life, or Earth-based life.  But the question then arises as to how we would recognise it as life at all and I don't think we can necessarily say that we would.  When we talk about searching for life elsewhere in the galaxy I'd suggest there has to be an implicit acceptance that we really are only searching for life that may be quite similar to that we see on our own planet and that we might completely miss other forms that could be right under our nose.

James

[Kropster]

There is no reason to assume that it is possible to construct a viable Von Neumann machine within the lifetime of any civilisation. So, as we are not flooded with them, it does not mean there aren't civilisations out there... just ones that can't construct Von Neumann machines.

[Knight of Clear Skies]

As a practical measure we should probably start by looking for things we recognise, while keeping an open mind for other possibilities. After all, one of the few things we know for sure is that our particular type of ecosystem works. In a universe-sized chemistry lab it's hard to say what could happen but we do know, for example, that it's easier to string together complex carbon-based molecules than to do the same with silicon. It's not unreasonable to expect extra-terrestrial life to be carbon based, although we can't rule out the existence of some game-changing principle  we aren't aware of.

If we ever did discover life elsewhere I suspect it might be a little like wandering into Aldi or Lidl, disconcertingly familiar yet strangely different.

After all, it will be life shaped by the same kinds of selection pressures as here on Earth. While the phase-space of possible organisms must be truly vast we can expect some convergence on simple solutions. (We see this on Earth among lineages separated by millions of years of evolution.) Just don't be surprised to find liquorice in the breakfast cereal.

[chiltonstar]

I think the point made above that we ourselves may be von Neumann machines seems to be a valid one.

What better way to disseminate life thoughout the Galaxy/Universe than pack a probe with basic bacteria that could evolve into any life form, mixed with ice etc, and send it off to orbit a star with a period such that it passed through any planetary system every few million years or so scattering bugs to any potentially receptive environment (The old idea of comets thus bringing life to Earth may not be daft after all).

Self-replicating primitive DNA chains are likely to be far, far better basic life-building machines than some heap of cogs and resistors....

Chris

[andrew65]

Forget life in the universe I'd rather have a bowl of coco pops

[Knight of Clear Skies]

On Beta Ceti Alpha, the coco pops eat you.

[cotterless45]

Eeeeeeek !

[chiltonstar]

Eeeeeeek !image.jpg

Is this another selfie, Nick?

Chris

[Ptarmigan]

>> "The old idea of comets thus bringing life to Earth may not be daft after all"

Panspermia - Anaxagoras, Sir Fred Hoyle, Wickramasinghe et al.

Hoyle he of the "Steady State" - made sense to me !

Von Neumann _machines_  :- genetic_engineering_ and  nano _technology_
makes one wonder , ,

Another thought :-

all that stuf in our DNA that isnt genes, thought to be leftover garbage, well I think maybe we need to find an inteligent species to tell us what it says ie. break the code for us,

maybe our Neumann builders left us some "How to" in there for when we do become intelligent ?
 

[Macavity]

If we were able to develop long distance interstellar travel (I'm not terribly optimistic) for future colonisation, the fact that advanced (eukaryotic) life might not have developed, could be a distinct advantage. No *intelligent* aliens to ZAP us! And perhaps planets (closer to home) with nice friendly bacteria - Archaea to create oxygen-rich atmospheres? But I sense we'd have to take / make our own food. A diet of Pond Slime might get boring rather quickly... 

http://en.wikipedia.org/wiki/Archaea

In similar vein, the following amused me:

http://www.biology.arizona.edu/cell_bio/tutorials/pev/page2.html

See: "Sympathy for the life of bacteria"! 

If you were bacteria:

• You have 0.001 times as much DNA as a eukaryotic cell.
• You live in a medium which has a viscosity about equal to asphalt.
• You have a wonderful "motor" for swimming. Unfortunately, your motor can only run in two directions and at one speed. In forward, you are propelled in one direction at 30 mph. In reverse your motor makes you turn flips or tumble. You can only do one or the other. You cannot stop.
• While you can "learn", you divide every twenty minutes and have to restart your education.
• You can have sex, with males possessing a sexual apparatus for transferring genetic information to receptive females. However, since you are both going 30 mph it is difficult to find each other. Furthermore, if you are male, nature gave you a severe problem. Every time you mate with a female, she turns into a male. In bacteria, "maleness" is an infective venereal disease.
• Also, at fairly high frequencies, spontaneous mutations cause you to turn into a female.
• Eukaryotes have enslaved some of your "brethren" to use as energy generating mitochondria and chloroplasts. They are also using you as a tool in a massive effort to understand genetics. The method of recombinant DNA is designed to exploit you for their own good. There is no SPCA to protect you.
• The last laugh may be yours. You have spent three and a half billion years practicing chemical warfare. Humans thought that antibiotics would end infectious diseases, but the overuse of drugs has resulted in the selection of drug resistant bacteria. They didn't realize that this was only the first battle, and now the war is ready to begin.
• Humans think this is their era. A more truthful statement would be that we all live in the age of bacteria.