Study finds our galaxy may be full of dead alien civilisations

illustrate a point.

No point that you seemed to be able to understand.

one is idiocy.

You were claiming that Darwinian evolution fails to explain the complexity of life as it exists now, because somebody's attempt to model process sugge st that it isn't fast enough. John Larkin was claiming that similar attempt s to model the appearance of DNA based life had suggested that the process was too slow to produce life as we know it in the 13 billion years availabl e.

In both cases people seem to be a bit too confident about the quality of th eir mathematical models.

It strikes me as a point well worth making. Richard Dawkins makes much the same point at greater length in his book.

The people who claim that evolution is too slow are mostly religious nutter s - "creation science" is the way they chose to describe their particular l unacy - and like most propaganda it is delivered with a big enough dose of flattery to make it attractive to John Larkin.

And where exactly are your "facts"?

--
Bill Sloman, Sydney

One argument that is reasonably strong is that basic life as in coloured self replicating slimes evolved *very* quickly from the moment that the planet had cooled enough so that there was liquid water on the surface.

Prelife chemistry from even before RNA world looks like it may have been peptide based and still has remnants and relics around in scrapie and BSE. Infective agents that are in no way alive but are stable and capable of self replication if they find the right environment.

It probably isn't that improbable that life as in self organising replicating something or others get started. Green photosynthetic things were the second choice forced to choose red and blue light because there was already an encumbent absorbing the green light (rhodopsin based). Turns out that green plant photosynthesis eventually won - otherwise we would have red trees and grass. There are still red photosynthetic things about but they ultimately ended up as parts of eyes.

It is quite likely around a given star that photosynthetic life will evolve to use whatever peak wavelength the star emits.

Where it gets tricky is for the evolution of complex life which requires several rare and unusual steps that have only ever occurred a very few times. Notably a cell getting inside another without being eaten and developing a symbiotic relationship so turbo powering the larger cell. That is pretty much how eukaryotes got the edge over bacteria and archaea. It took nearly half the age of the Earth to get to this stage. And another billion years before there was any multicellular life.

These days the astronomers answer to the question is that planets are very common (thousands have been discovered). Earth like ones are less common but still plenty of them. Life is probably common but intelligent life is rare. We should be mainly looking for microbes. Venus having (or not having) phosphine in the atmosphere could be an indicator.

The next generation of planet hunting telescopes will be able to look at the atmospheric spectrum of planets and if they get it right distinguish those which are out of equilibrium (a sure fire way of detecting life if the molecules are short lived organics like methane in an oxygen rich environment or traces of oxygen in a methane and hydrogen gas giant).

We may well be able to detect life at great distances spectroscopically with the new generation of instruments. Martin Rees has an interesting take on the question a rough summary in this article (free access):

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Regards, 
Martin Brown

....but not reasonable.

Taking the view that "I am special" is statistically false. Just try telling your boss to shove it because you believe that you are irreplaceable....

I am not the centre of the universe, the Earth isn't the centre of the universe, the sun isn't the centre of the universe, the Milkyway is not the centre of the universe.....

Physical processes are never unique. Never.

Thus, for example, its just not reasonable that whatever process created this Big Bang, only created the one.

-- Kevin Aylward

- SuperSpice

They do. It just requires a larger system.

The problem is actually worse that the evolution of DNA, its the atomic Lego that we are constructed from. Its electrons, protons, absolutely everything. The probability of obtaining all the required matched components is stunningly low.

When the probability of winning is stunningly low, one has to buy more tickets to win. Its truly that simple.

Physical processes are never unique. Never.

Thus, the probability that this big bang, with its particular laws of physics, is unique, is just not reasonable.

String theory, apparently, gets one 10^500 universes.

Randomly generated universes, is the *only* rational solution to existence that terminates.

A conscious machine (god) or a non conscious machine (master equation) inherently requires an explanation as to why THAT master equation, which requires a further explanation for the solution to that solution. It never ends.

Once there is a truly random process generating universes, our existence is a guaranteed certainty.

Without randomly generated universes, there is zero chance that we could exist. Its the elephant in the room.

-- Kevin Aylward

- SuperSpice

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** Fair enough - but it may easily be that no other is ever going to be observed by humans.

So, scientifically speaking they do not exist.

..... Phil

Biochemists with a big Creationist axe to grind... Goddidit as the explanation for everything that we don't yet understand.

It is more likely to be roughly one for any planets that can support all three phases of water. The Earth didn't remain sterile for long after it had cooled to that point. Life as in coloured slime is probably common.

It might even be possible for other good polar solvents to support life although water is very unusual in that its solid phase floats which protects the bulk volume from freezing solid. It is also composed of two of the most common elements in the universe.

If we found some novel life in Venus's atmosphere or Mars soils or on one of the Jovian or Saturnian moons we would have something to compare against. Right now the best we have are isolated forms of archaea at hot springs and deep sea vents. There is a tiny chance that something somewhere even on Earth does not share a last common ancestor with us.

Some of the weird and wonderful slow living lithosphere rock eating microbes might be sufficiently different. I know the Mars researchers have a site for such experiments in the deepest UK mine.

Life almost certainly started with a few autocatalysing molecules that were able to self replicate in some very limited way in the primordial soup. Then going up in complexity through RNA world which can actually do more things and finally to DNA. Viruses and viroids were the next step up and they are still with us today so they are survivors.

They mostly target plants. They are the best candidates so far for abiogenesis relics since they can be autocatalytic and act as enzymes.

Geological time allows for a lot of permutations to be tried out.

That's odd - because we are. I know! Lets invoke a "Miracle" to explain everything that we don't understand and declare it all solved.

Bad idea to try and understand things scientifically because it might upset the God of the gaps if you remove some more of his domain.

--
Regards, 
Martin Brown

It is quite likely to be one. The Earth wasn't sterile for long after it had cooled sufficiently for liquid water to form.

Biassed math written by creationists who deliberately ask the wrong question about DNA and then crucify a randomly chosen straw man.

I expect RNA can do it. RNA world preceded DNA and it is quite possible that other much more primitive self replicating molecules preceded that. DNA has the advantage of being more stable and so better at commincating its pattern on to subsequent generations. RNA allows a lot more trial and error to occur spanning a much wider parameter space more quickly.

Even in DNA based life forms it is mRNA that does all the doing. DNA is just a somewhat more stable way of storing its genetic code.

Infectious agents like the prions causing scrapie and BSE may well be modern day variants of the sort of self replicating non-life molecules that eventually led to abiogenesis in the primordial soup. Given the right environment molecules will arise by pure chance to exploit that energy resource. In the case of prions one misfolded protein was enough since it was capable of catalysing the misfolding of others.

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Regards, 
Martin Brown

Serious biologists have done the math and chemistry about soup, and found it improbable. So they are considering other paths to DNA life. That sounds pretty scientific to me.

Then some clever scientists should brew up some self-replicating RNA that has a path to making working DNA. Of course, that would be intelligent design.

The big issue with DNA isn't the structure, it's the programming.

Exactly. Code.

Not in the books I've read. The authors merely suggest that the soup theory doesn't work, so other mechanisms must be considered.

Anti-Creationist paranoia, the fear of even hinting about anything that might approach intelligent design, blocks off a lot of thinking.

More mockery that precludes thinking. That's common and cheap.

The obvious next question is 'how did the intelligent designer come to be?'

Jeroen Belleman

I doubt there is one. Someone who wraps the ever growing prostate gland around the pee pipeline does not look intelligent. Most dwellers of this newsgroup will sing the praise of this sooner or later.

Reminds me more at kids who mutilate their hamster, so they can have more fun at playing doctor.

Gerhard

The preconditions for life include more than just a way to code the required information, but also the ability to form a barrier (cell wall) to contain them and the mechanisms they code for.

It has long been thought that this probably occurred at the boundary of a shallow sea (there seems to be a need for cyclic evaporation), but some recent work show that the cellules of the required kinds ALREADY self-assemble from molecules that randomly occur around geothermal vents (hot springs and geysers). There are cycles of evaporation and temperature with chemistry that produces molecules that are polar at one end, non-polar at the other, and these self-assemble into small bubbles.

Within those, *any* coding mechanism which assists *any* process that facilitates the formation of these cellules, and also assists the formation of copies of the coding mechanism, constitutes primitive life.

It doesn't need to be DNA. It doesn't need to be RNA. It doesn't need ribosomes. It doesn't need to work more than 0.0000001% of the time. It just needs to make it a *tiny* bit more likely to form a copy than a fresh cellule that's not a copy. A tiny advantage is all that's needed for nature to start "climbing the slope".

That seems entirely plausible to me.

Clifford Heath

But not to a scientist. The Earth has clays, in addition to soups, and the surface areas in those clays are enormous. Soup might be more like the first sparks-and-bottles experiments that made amino acids, but it wasn't all that this planet had for early environments.

One possibility is that some other self-organizing system could evolve life and intelligence along a more incremental path. After doing that for a million or a billion years, it might decide to invent DNA and us.

Something amazing certainly happened.

Of course, any such ideas back up against "what created this universe and its rules?"

And the intelligent designer theory just happens to pop into their minds.

Actually it blocks off a lot of misleading thinking that's aimed a keeping theocrats in control, but John Larkin is blind to that.

Which leaves the question of how the original self-organising system might have evolved. Occams Razor makes this a poor argument.

Since our ball started rolling with RNA rather than DNA, John Larkin's biochemists weren't a well-read bunch.

Not a useful question. It makes every kind of sense to work out how this universe works and what it's rules are, but speculations about other universes are untestable and not all that productive.

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Bill Sloman, sydney