Crystalline ‘life’ mentioned in that nasa link is a very interesting concept - a guy called Cairns-Smith developed theories in that area that are well-respected as an original contribution to origin of life thinking and research.
The capacity of inorganic crystals to store and propagate information is well-established, and CS framed this as a primitive genetic system. This wouldn’t be most people’s idea of ‘life’, but you can see what he’s talking about.
He then went on to speculate that a ‘genetic takeover’ occurred, whereby a biological system emerged that was infinitely more efficient and powerful as a genotype. Provocatively, he posited that there would have been some information transfer from the crystalline life to the biological, the inorganic crystal acting as a sort of template - I’d need to check his book again for the details of this idea.
So very out-there thinking, but has stimulated real research and like I say is seen as a v creative and original contribution.
I don’t think that silicon computers would emerge naturally, but they don’t need to. If organic carbon-based life can make them on our world, they could be made anywhere, and it is conceivable that artificial life of this kind is far more common in the universe than naturally evolved life. Once we can engineer self-replicating, autonomous machines, just watch them go.
Realistically, I doubt that they will be using silicon much at that stage - but they will surely exhibit most or all of the characteristics of life, depending on how they are designed.
Maybe it is communicating and we just are not capable of detecting it or recognizing it. Perhaps those crazy’s walking around talking to themselves and picking up satellite signals are actually communicating with God. :rolleyes:
Depends what you mean by recognise - if those experiments were carried out and established a genetic takeover scenario from inorganic to biological then it would be an amazing result, establish a new field, but it wouldn’t be recognised as life in any definitive way as the term is so broad and subjective. A rock is not a life-form to most people’s way of thinking, but if we uncovered hidden dimensions to a putative crystalline genome then that might change.
It would lead to a discussion and data exchange / analysis around the idea of life on earth, certainly, if that’s what you mean. It would frame the debate in terms most people are comfortable with and would lead to new thinking. In contrast to some other life-form that is just beyond our ken and cannot be recognised or spoken about in any meaningful way, which is a dead end as I think you are pointing out.
The points above about carbon are I think pretty critical. For evolution to get somewhere it needs variety to select from, and if you go right back to the primordial soup, carbon and its friends gave it a huge variety of things to select behaviours from. Molecules that have a huge range of characteristics, and eventually amongst them, building blocks and ways of encoding for assembly of them. Once that was kick started it was just a matter of sitting back and waiting. It took a very long time to get that far.
Which is perhaps the critical point - it took a very very long time for any life as we understand it to arrive. Once single celled organisms were here, most of the real work was done.
However there are questions about our lack of imagination. Our planet isn’t all that old, there are planets billions of years older. That may be time for wildly different systems to evolve. These wildly different systems may involve extreme chemistry. For instance, chemistry at very high pressures and temperatures. It may be that there are viable interesting complex systems if you have silicon (or something else) at a few thousand bar, and 1000C. Cook that for a few billion years, and maybe we do get a silicon creature. Albeit one that can only survive at the bottom of an ocean of molten iron on a planet ten times the size of the Earth. They may also live lives at a totally different pace to us. A year to us may be a day to them. Conversations with them might be very dull. Some odd planet may still be evolving such life in a few billion years time, maybe well past when our planet has been fried by the bloated red giant our sun will form. And human descendants? Immortal computational souls in silicon that long forgot their fleshy beginnings?
Really cold might be interesting too. In a soup of superconducting super-fluids there might be physics and complexity we have essentially no hint of an understanding of.
Hard not to recommend Stanislaw Lem’s The Cyberiad when thinking about mechanical lifeforms and the nature of the universe.
This is actually not true. Once Earth cooled enough for liquid water to form, prokaryotic life arose very quickly. This could be due to the fact that life invariably forms when conditions are right, or it could be due to already existing organisms arriving from outside the Earth, or it could be that Earth is that one random planet that won the lottery 300 times in a row, or maybe something else. But Earth is about 4 billion years old, and life has been around on Earth for almost all of that time. Note that Eukaryotic life is only 2 billion years old, multicellular life is only 650 million years old, the dinosaurs went extinct 65 million years ago, and anatomically modern humans evolved 200,000 years ago.
Fair point. I was really thinking that it took about half the time to get us to eukaryotic life, and the rest to get us here. So as a very broad brush, the hard work was getting us there. I guess really the next critical bit was multicellular - after that it got fast.
From various cites on the web, it looks like multicellular life has also been around for a couple billion years, not just 650 million, and has evolved from unicellular life many times. But maybe you meant differentiated multicellular life, as opposed to just multiple copies of cells that all look the same. I couldn’t quickly find when that first occurred.