5 replies to this topic

[TenMon]

Pozdrav svima! Pitanje glasi:
Šta pokreće život? Drugim rečima, kako je život nastao? Ovo je važno pitanje jer nam posredno govori da li u svemiru postoji život osim na Zemlji.

Evo nekih teza/pitanja koje bi mogle da se upotrebe u diskusiji:

-Ĺ ta je Ĺľivot? Ĺ ta je potrebno za odrĹľavanje Ĺľivota?
-Mislite li da je nastao:
1) tako što su nas stvorili vanzemaljci, bogovi ili Bog
2) kao neminovnost na planetama poput Zemlje ako postoji dovoljno vremena (biološki determinizam)
3) slučajno, samo na Zemlji, i neće se ponoviti nigde u svemiru
4) ...?

-Milerov eksperiment je omogućio stvoranje amino-kiselina ali...
-...verovatnoća da nastanu proteini koji su biološki relevantni nasumičnim reakcijama između molekula je 1:10^130!*
-Da li bi teraformiranje Marsa bio moralan ÄŤin? A neke druge planete ili meseca?
-Kako zamišljate živi svet na Zemlji kroz 1000, milion, milijardu godina?
itd.


*Paul Davis, "Are We Alone?"

Edited by TenMon, 24 November 2005 - 23:22.

[Dunadan]

-Da li bi teraformiranje Marsa bio moralan ÄŤin?

<{POST_SNAPBACK}>

who's gonna complain? the speck?

[zagor]

-Ĺ ta je Ĺľivot? Ĺ ta je potrebno za odrĹľavanje Ĺľivota?
-Mislite li da je nastao:
1) tako što su nas stvorili vanzemaljci, bogovi ili Bog
2) kao neminovnost na planetama poput Zemlje ako postoji dovoljno vremena (biološki determinizam)
3) slučajno, samo na Zemlji, i neće se ponoviti nigde u svemiru
4) ...?

<{POST_SNAPBACK}>

Tacan odgovor je pod 3

[Gonzo]

Tacan odgovor je pod 3

<{POST_SNAPBACK}>

Delimicno tacan. teorijski je moguce da se pojavi jos negde.

[TenMon]

Evo malo detalja koji mogu da pomognu...

"..The belief that earthlike conditions are all that is necessary for life to emerge, given enough time, is known as biological determinism. This viewpoint proceeds from the assumption that life is somehow written into the laws of nature, and is therefore inevitable given the right conditions. Christian de Duve is a well-known biological determinist, who describes life as a "cosmic imperative"..."

"...Since even the simplest known life form is incredibly complex, and could not conceivably spring into existance fully-formed by chance alone, biological determinism supposes that there is a prebiotic stage where chemistry favours the formation of those moleculs that are biologically relevant. In other words, the laws of physics and chemistry are slanted in favour of life..."

"...The basic laws of physics are simple, mathematical and general. Life is complex, non-mathematical and specific. Clearly the laws of physics and chemistry alone will not explain life. That is not to say that life violates the laws of physics and chemistry, only that one requires more than these laws to explain biogenesis. Therefore, if life is widespread in the universe, it suggests that there are organising principales at work in addition to basic physical laws that can fast-track matter along the road to life. The philosophical consequences of this are profound..."

"...It is possible to compute the probability against life forming as a result of the accidental shuffling of molecules. For example, the chances of making a short protein by chance, given a supply of appropriate amino acids as building blocks, is about 10^130 to one. If this was the way that proteins initially came to exist, it is clear that they will have synthesised themselves only once, and that we will be alone in the universe. People often say that the universe is so vast it is unreasonable to believe we are alone, in spite of the unlikelihood of life. This argument is nonsense. The number of earthlike planets within the observable universe is probably no larger than 10^20. This number is trivially small compared to the odds against making even a single protein by random molecular combination, let alone all the other complex molecules needed for life. Most scientists conclude from this arithmetic that chance alone isn't the correct explaination for biogenesis. The enormous odds against life forming by random molecular shuffling may be taken as a measure of one's justification to disbelieve the chance hypothesis..."

"...the fact that amino acids are easy to make is no guarantee that life is easy to make..." (ovde se aludira na eksperiment Miller-Urey iz pedesetih kada su u laboratoriji stvorili amino-kiseline) "...Synthesising amino acids from simple organic materials is thermodynamically favoured, that is, it is a 'downhill' process in which energy is released - rather like the formation of crystals from a solute. It is then no surprise that amino acids are found to be so widespread and easy to make. By contrast, linking amino acids together in a long chains to form peptides, the stuff of proteins, is thermodinamically 'uphill'. This means it will not happen spontaneously any more than water will run uphill spontaneously. To make peptide bonds means driving against the natural thermodynamic gradient, which requires an input of energy..."

"What makes life special is not complexity per se, but the fact that its complexity is organised or specified in a very particular way..."

"..Life works not by submitting to the directionality of chemistry, but by circumventing what is chemically and thermodynamically 'natural', and, through the exercise of software control, harnessing energy when needed to build what it requires..."

iz
"Are We Alone?" by Paul Davies, Centre for Basic Research
Burnside, South Australia

A što se teraformiranja Marsa tiče... šta ako tamo postoji život, mi ga ne pronađemo, počnemo da teraformiramo planetu i uništimo starosedeoce? To je možda jedina prepreka da se to učini..

[Gonzo]

By contrast, linking amino acids together in a long chains to form peptides, the stuff of proteins, is thermodinamically 'uphill'. This means it will not happen spontaneously any more than water will run uphill spontaneously. To make peptide bonds means driving against the natural thermodynamic gradient, which requires an input of energy..."

I isparavanje vode je "uphil", zahteva upliv enbergije, pa se ipak desava spontano u prirodi. Bez ikakve intervencije Boga, Apsoluta, Njega, Onog koji stvara i razara, ..