Terraforming Mars

[dcmike]

"care to explain why you think virus' fall from the sky pre-evolved to infect complex Earth life?"

Again I state, I am not a biophysicist but only referring to claims made by scientists who believe in the feasibility of Panspermia and or Exogenesis. I can’t tell you what particular vehicle they use to get here. For all I know they get to a certain distance and then call a cab. However, it is believed by some that some primitive media could survive the trip. Life makes a habit of overturning theories. Just as I am not personally in possession of unequivocal evidence that it did happen, you are not in possession of irrevocable proof that it cannot.

On May, 2001, two researchers from the University of Naples claimed to have found live extraterrestrial bacteria inside a meteorite. Geologist Bruno D'Argenio and molecular biologist Giuseppe Geraci claim the bacteria were wedged inside the crystal structure of minerals, but were resurrected when a sample of the rock was placed in a culture medium. They believe that the bacteria were not terrestrial because they survived when the sample was sterilized at very high temperature and washed with alcohol. They also claim that the bacteria's DNA is unlike any on Earth.[24] They presented a report on May 11, 2001, concluding that this is the first evidence of extraterrestrial life, documented in its genetic and morphological properties. Some of the bacteria they discovered were found inside meteorites that have been estimated to be over 4.5 billion years old, and were determined to be related to modern day Bacillus subtilis and Bacillus pumilus bacteria on Earth but appears to be a different strain. Panspermia - Wikipedia, the free encyclopedia[25]

The theory postulated concerning the 1918 flu pandemic was that it drifted down from the upper strata and was then harbored by birds in some way. They ask the question – how could a new strain of microbe infect the whole world at once without a transmission vehicle? Scattered and remote tribes of Eskimos who were not only cut off from the rest of the world, but also each other, caught the same strain of virus at the same time the rest of the world did.

Evolution? Fruit flies, via some genetic tinkering, evolved right before the eyes of a single researcher. Fruit flies are far more complex than viruses. Are not viruses just genetic strands wrapped in protein capsids? Life here is based on the five most common elements in the entire universe.

In quoting me “rules” that pertain to life here on this planet you are failing to persuade me that you are in possession of all knowledge of all possibilities of all life everywhere in the entire universe.

We are not really even debating the same issue. You are trying to convince me that nothing we are not in full command of can happen. In my other ear Günter Nimtz (a German physicist at the University of Cologne) says that even Albert Einstein’s cherished belief that nothing can go faster than the speed of light (not even light) is no longer bullet proof. He encoded a laser beam with music data, sent it nearly five times the speed of light and subsequently played the music at the other end. His method – quantum tunneling.

My debate is not about biology, it is about philosophy. You want to convince me that nothing can supersede the orderly limitations of tenured theories. My only response to you is that the path of history is littered with the remains of dogmas stating ‘what can’t happen’.

“Few people are capable of expressing with equanimity opinions which differ from the prejudices of their social environment. Most people are even incapable of forming such opinions.”…… Albert Einstein

[Thunderbird]

Objections to panspermia and exogenesis

Objections to panspermia and exogenesis

Life as we know it requires heavy elements carbon, nitrogen and oxygen (C, N and O, respectively) to exist at sufficient densities and temperatures for the chemical reactions between them to occur. These conditions are not widespread in the Universe, so this limits the distribution of life as an ongoing process. First, the elements C, N and O are only created after at least one cycle of star birth/death: this is a limit to the earliest time life could have arisen. Second, densities of elements sufficient for the formation of more complex molecules necessary to life (such as amino acids) only occur in molecular dust clouds (109–1012 particles/m³), and (following their collapse) in solar systems. Third, temperatures must be lower than those in stars (elements are stripped of electrons: a plasma state) but higher than in interstellar space (reaction rates are too low). This restricts ongoing life to planetary environments where heavy elements are present at high densities, so long as temperatures are sufficient for plausible reaction rates. Note this does not restrict dormant forms of life to these environments, so this argument only contradicts the widest interpretation of panspermia — that life is ongoing and is spread across many different environments throughout the Universe — and presupposes that any life needs those elements, which the proponents of alternative biochemistries do not consider certain.

Space is a damaging environment for life, as it would be exposed to radiation, cosmic rays and stellar winds. Studies of bacteria frozen in Antarctic glaciers have shown that DNA has a half-life of 1.1 million years under such conditions, suggesting that while life may have potentially moved around within the Solar System it is unlikely that it could have arrived from an interstellar source.[32] Environments may exist within meteors or comets that are somewhat shielded from these hazards.

Bacteria would not survive the immense heat and forces of an impact on Earth — no conclusions (whether positive or negative) have yet been reached on this point. However most of the heat generated when a meteor enters the Earth's atmosphere is carried away by ablation and the interiors of freshly landed meteorites are rarely heated much and are often cold. For example, a sample of hundreds of nematode worms on the space shuttle Columbia survived its crash landing from 63 km inside a 4 kg locker, and samples of already dead moss were not damaged. Though this is not a very good example, being protected by the man-made locker and possibly pieces of the shuttle, it lends some support to the idea that life could survive a trip through the atmosphere.[33] The existence of Martian meteorites and Lunar meteorites on Earth suggests that transfer of material from other planets to Earth happens regularly.

Occam's Razor implies that when developing a hypothesis, we should avoid making evidentially unsupported presumptions about things if at all possible. See heuristic arguments. From this perspective, geogenesis appears to be the default assumption when compared with panspermia or exogenesis. The former assumes a single step: that life originated on Earth, where it is now commonly observed, excluding the presumption that life formed elsewhere, in places where it has never been observed before. Geogenesis eliminates the unsupported presumption of life existing beyond the Earth, but requires a lot to happen in a relatively short time frame in order for life to arise. Exogenesis allows for a longer period of time than could be offered on Earth. Given that an understanding of life's emergence remains speculative, however, the perception of which presumption (life beyond Earth or life emerging rapidly) is preferable can be less than clear.

Supporters of exogenesis also argue that on a larger scale, for life to emerge in one place in the Universe and subsequently spread to other planets would be simpler than similar life emerging separately on different planets. Thus, finding any evidence of extraterrestrial life similar to ours would lend credibility to exogenesis. However, this again assumes that the emergence of life in the entire Universe is rare enough as to limit it to one or few events or origination sites. Exogenesis still requires life to have originated from somewhere, most probably some form of geogenesis. Given the immense expanse of the entire Universe, there is a higher probability that there exists (or has existed) another Earth-like planet that has yielded life (geogenesis) than not. This explanation is more preferred under Occam's Razor than exogenesis since it theorizes that the creation of life is a matter of probability and can occur when the correct conditions are met rather than in exogenesis that assumes it is a singular event or that Earth did not meet those conditions on its own. In other words, exogenesis theorizes only one or few origins of life in the Universe, whereas geogenesis theorizes that it is a matter of probability depending on the conditions of the celestial body. Consider that even the most rare events on Earth can happen multiple times and independent of one another. However, since to date no extraterrestrial life has been confirmed, both theories still suffer from lack of information and too many unidentified variables.

Source: wikipedia article “Panspermia”

[dcmike]

From the quote in my last post

(from meteorite)"..........Geologist Bruno D'Argenio and molecular biologist Giuseppe Geraci claim the bacteria were wedged inside the crystal structure of minerals, but were resurrected when a sample of the rock was placed in a culture medium. They believe that the bacteria were not terrestrial because they survived when the sample was sterilized at very high temperature and washed with alcohol.

Pretty robust, no? There goes thermal sterilization.

"..........and were determined to be related to modern day Bacillus subtilis and Bacillus pumilus bacteria on Earth but appears to be a different strain"

And these were apparently billions of years old. Puts into question the issue of eons of co-evolution.

And here is my point from your post....

"Both theories still suffer from lack of information and too many unidentified variables."

As stated above - neither theory is absolute.

Again, we debate on different levels. You fight valiantly for stolid absolutes and I defend the science of uncertanty. If this issue were any other philosophical issue I would take the same track and state that no matter how much we collectively know, it is very little in regards to what there is to know. And he who claims to have the last word on reality is fooling himself. The last word, like tomorrow, never comes. It is more important to know what you don't know than be so assured of what you do know!

[Thunderbird]

Originally Posted by dcmike

[b]

As stated above - neither theory is absolute.

Again, we debate on different levels. You fight valiantly for stolid absolutes and I defend the science of uncertanty. If this issue were any other philosophical issue I would take the same track and state that no matter how much we collectively know, it is very little in regards to what there is to know. And he who claims to have the last word on reality is fooling himself. The last word, like tomorrow, never comes. It is more important to know what you don't know than be so assured of what you do know!

Life emerging from the terrestrial environment is an actual theory because we have real models to study. Panspermia and exogenesis are not theoretical models because their is nothing of any real substance to study. Just because there exists unresolved information gaps in our understanding on origins of the first life is not a qualifier for opposing scenarios as equal, or validate other scenarios as actual scientific models. You still need enough critical provable information to warrant calling it a theory.

The same applies to UFO's as extraterrestrials, if they are, are they are not, is not a real scientific debate, because their is nothing that can be called real information to study.

[dcmike]

"The same applies to UFO's as extraterrestrials, if they are, are they are not, is not a real scientific debate, because their is nothing that can be called real information to study."

Though an interesting concept, I pay no attention to UFO stories. Neither do I state that because there is no hard evidence to support, that constitutes hard evidence that they do not exist.

"an actual theory" - is linguistically an oxymoron -
1 - "For the scientist, "theory" is not in any way an antonym of "fact"."
2 - "In common usage, the word theory is often used to signify a conjecture, an opinion, a speculation, or a hypothesis."

Hence, both panspermia and exogenesis are indeed theories.

[modest]

Originally Posted by dcmike

"an actual theory" - is linguistically an oxymoron -.

An actual scientific theory is not in any way an oxymoron.

Originally Posted by Thunderbird

Life emerging from the terrestrial environment is an actual theory because we have real models to study. Panspermia and exogenesis are not theoretical models because their is nothing of any real substance to study.

Is there any evidence of either?

-modest

[Thunderbird]

Originally Posted by dcmike

"The same applies to UFO's as extraterrestrials, if they are, are they are not, is not a real scientific debate, because their is nothing that can be called real information to study."

Though an interesting concept, I pay no attention to UFO stories. Neither do I state that because there is no hard evidence to support, that constitutes hard evidence that they do not exist.

"an actual theory" - is linguistically an oxymoron -
1 - "For the scientist, "theory" is not in any way an antonym of "fact"."
2 - "In common usage, the word theory is often used to signify a conjecture, an opinion, a speculation, or a hypothesis."

Hence, both panspermia and exogenesis are indeed theories.

This is a science forum so the distinction between the common usage of the word theory and the scientific usage is of upmost importance.

A scientific usage is a workable model that can be used as a tool for organizing more information. Let me put in in the most practical terms . I can study biology as having terrestrial origins and go beyond current chemical based models and make an attempt to construct a Quantum Mechanical model. This may be going out on a limb, however I would still have information to use as building materials. You need something to work with.

[Thunderbird]

Originally Posted by modest

An actual scientific theory is not in any way an oxymoron.



Is there any evidence of either?

-modest

We have plenty of evidence of life as a terrestrial phenomenon , as part and parcel of the planet. The how life formed is the debate. Origins of life is about working with what we have available, and what we have is a vast amount of life to study on the earth and a vast record contained within the earth.

[Moontanman]

[quote]

Originally Posted by dcmike

"care to explain why you think virus' fall from the sky pre-evolved to infect complex Earth life?"


The theory postulated concerning the 1918 flu pandemic was that it drifted down from the upper strata and was then harbored by birds in some way. They ask the question – how could a new strain of microbe infect the whole world at once without a transmission vehicle? Scattered and remote tribes of Eskimos who were not only cut off from the rest of the world, but also each other, caught the same strain of virus at the same time the rest of the world did.

First of all I have no problem with the theory of panspermia, it would seem to be unlikely but not impossible, but contrary to popular belief, virus's are not primitive organisms, they might appear to be simple but they have evolved over billions of years along with their hosts, virus's are not separate and apart from the ecosystem they live in, they are an intimate part of Earth life, and not an outside agency. As for how the virus could have spread in 1918 if indeed birds spread it then you have answered your own question, humans do become infected with bird virus' due to the fact the humans have lived in close association with various bird for thousands of years. When animals live in close proximity they often exchange various infectious agents. If bird carried the virus then Eskimos could well contracted the virus from birds. no extraterrestrial source of a pre evolved virus to infect humans is needed or even possible.

Evolution? Fruit flies, via some genetic tinkering, evolved right before the eyes of a single researcher. Fruit flies are far more complex than viruses. Are not viruses just genetic strands wrapped in protein capsids? Life here is based on the five most common elements in the entire universe.

I think the key here is via some genetic tinkering. As I said a virus may look simple but it has evolved along side it's hosts for a very long time. for a virus to form independent of multicellular life and then for it to be able to infect a an organism it has nothing in common with is a fantasy, not science or even a hypothesis much less a theory.

[CraigD]

Originally Posted by Moontanman

… care to explain why you think virus' fall from the sky preevolved to infect complex Earth life?

This question, I think, is a key one on the subject of the possibility of extraterrestrial disease-causing organisms.

Discussions at hypography and various sources cited encyclopedia articles such as wikipedia article “Panspermia” show reasonable support for the hypothesis that many known terrestrial organisms could survive extended periods of travel through space to Earth’s surface.

However, medical science shows that organisms that can cause disease in organisms with which they have had no previous contact are rare to non-existent. Pathogens generally must evolve to be suitable to infect particular species or closely related families of species. So while an extraterrestrial organism might physically survive a trip through space to Earth, it seems unlikely that it would cause disease.

I can think of two possibly explanations that circumvent this objection:

• Parallel evolution. Perhaps all life, regardless of where they evolves, is similar enough to interact pathogenically.
  
  This seems a weak argument, as on Earth pathogens of one species commonly coming into harmless contact with others species is the norm. That organisms evolved elsewhere should be dramatically more versatile appears to have no explanation or supporting empirical evidence.
• Organisms arriving on Earth from space originated on Earth. There’s strong evidence that ejections of material from Earth into space was common in Earth’s early history (ie: during the Hadean eon Earth’s first 0.8 billion years of history following its accretion about 4.6 billion years ago), so much material falling from space to Earth may have originated on Earth. It’s possible material from Earth fell to Mars, then was later ejected to return to Earth.
  
  The main problem with this explanation is that biological theory has the earliest life on Earth appearing not before about 3.5 BYA, long after theories of planet formation have material no longer being ejected from Earth. For it to be viable, its necessary to assume that at least some great impact and ejection events occurred billions of years after they ceased being commonplace.

Note that, as they don’t propose that the origin of life on earth is from space, these scenarios aren’t truly “pansperia”, but rather that Earth’s ecosphere is much larger and more tenuous than conventionally imagined.

As for whether any such theory is actually correct, I don’t think there’s enough evidence or modeling to conclude yes or no with much confidence. Like so many planetary astronomy and ancient biology questions, this one seems to have many reasonable but uncertain answers.

As it relates to the colonization of Mars, these idea suggest that terrestrial life may have actually colonized Mars billions of years ago, without any intelligence being involved. As continued exploration of Mars samples increasing amounts of data in increasing detail, it should be possible to confirm or rule out many such theoretical scenarios.