Where did life come from?

[jsc248]

Hi All,
I have recently been reading a lot of different theories into how life actually developed here on Earth, and I had no idea there were so many different views.
Lightning striking a primordial amino acid soup. Impact of magnetite asteroids carring aggressive DNA. I myself am inclined to agree with the cometary impact theory. Comets, also called dirty snowballs, carry water as well as other organic compounds. It is my own personal theory that a comet impacted Earth carrying organic compounds and hit at a point that contained our primordial DNA/amino acid soup and the heat produced as an after effect provided the catylist for life to form.
Does anyone agree, and if not I'd like to hear your own theories.
Thanks gang.
jsc248.

[gavwvin]

It seems to me that life arriving on Earth from a comet only relocates the question of how life came to exist, rather than answer it.

[jsc248]

You could be right Gavwvim, but it does (if the correct theory) lend strength to the argument that life could exist everywhere that comets exist. If comets exist in every star system were planets have formed (it is commonly accepted that comets are waste leftover after planet formation) then life could exist in abundance. So maybe the question is academic and every planetary system has it's ownlife forming force in the comets of its system.
What do you think?
jsc248.

[Betelgeuse]

Hi jsc248 and gavwvin,

It's correct panspermia is the theory that life came to Earth from somewhere else nad this being the most obvious and detailed hypothesis. As you've discussed it may be from inside a comet, in a meteorite from another planet in our Solar Sytem (some believe from Mars), or it may very well be from a form of bacterial spores carried by light pressure from another solar system, this being by deliberate or accidental intention by a type of alien intelligence, or by some other unknon mechanism - this is an interesting thought, that could be open for discussion!

The origin of life on Earth is basically very much an open question, aand as I read on the web - there aren't too many astronomers/astrophysicists who truly believe that the panspermia theory could be ruled out with the current evidence we have. We don't actually have much evidence!

Regards
Rigel

[Bobunf]

"I have recently been reading a lot of different theories..."

I don't think any of this, including panspermia, rises to the level of hypothesis, let alone theory. What tests have been performed, or are even possible? At what depth would any such idea actually explain, in any useful detail, any phenomenon?

Speculation is the right description, I believe.

Let's try to keep our language more precise, and not use the word "theory" incorrectly, so we don’t have to deal with silliness like, “Evolution is just a theory.”

Bob

[GOURDHEAD]

Let's try to keep our language more precise, and not use the word "theory" incorrectly, so we don’t have to deal with silliness like, “Evolution is just a theory.”

Here is a dictionary definition of theory:

1 : the analysis of a set of facts in their relation to one another
2 : abstract thought : SPECULATION
3 : the general or abstract principles of a body of fact, a science, or an art <music theory>
4 a : a belief, policy, or procedure proposed or followed as the basis of action <her method is based on the theory that all children want to learn> b : an ideal or hypothetical set of facts, principles, or circumstances; often used in the phrase in theory <in theory, we have always advocated freedom for all>
5 : a plausible or scientifically acceptable general principle or body of principles offered to explain phenomena <wave theory of light>
6 a : a hypothesis assumed for the sake of argument or investigation b : an unproved assumption : CONJECTURE c : a body of theorems presenting a concise systematic view of a subject <theory of equations>
synonym see HYPOTHESIS

The generic definition covers a lot of ground. How would you focus or limit a "special forum definition" to achieve a higher degree of disambiguation?

[jsc248]

Hi Gang
Gourdhead has quit rightly pointed out that any of these explanations for life are covered by the word theory. As you can see in the dictionary explanation No.2 Theory-abstract thought, speculation. Guess you cant argue with that can you?
jsc248.

[Betelgeuse]

Not a sausage&#33; We&#39;ll use speculation in the future&#33;

[Gambit Star]

We are just one possibility of the infinite free form energy source, I believe all that we can comprehend is due to our nature, the nature of the universe.

[ChromeStar]

I maintain that you can&#39;t know for sure which theory is correct for life on earth, because we were&#39;nt here to witness it happening.

But i personaly think the life eveloving on earth by it&#39;s self theory is more probable then the commet theory.

[Betelgeuse]

But i personaly think the life eveloving on earth by it&#39;s self theory is more probable then the comet theory.

Alright&#33; I respect your descision, but I for one choose to believe the panspermia speculation. During the early period of the Earth&#39;s history the sort of collisions with comets we&#39;re talking of were literally ordinary. Astrobiologists have discovered certain comets that have actually been found to contain amino acids - the building blocks of life, so, to cut a long story short, they could very well have brought life to Earth&#33;

If we want to discuss arguments against this, how about this:

I came accross something on the web that claimed that alien bacteria had been found high up in the earth&#39;s atmosphere - a balloon flight from Cardiff, Wales that was hovering at an altitude of 41 kilometres had recovered clumps of microbes that most probably had their origin in outer space. From what astrobiologists have said, the microbes look like terrestrial cells but, the likelyhood that they could have been lifted up from the ground in the quantity that was found (I&#39;ll try and find the exact amount) wasn&#39;t very liable. There&#39;s also the risk that there had been some sort of contamination between the microbes which would then diminish the speculation&#39;s prospects.

It&#39;s quite interesting - we&#39;re discovering more everyday, so I&#39;m quite annoyed with myself because I actualy choose to accept to the panspermia theory without attempting to think outside the box and wait for the ever-arriving proof we have....

[ChromeStar]

sup Rigel

i&#39;m aware of that bacteria findings.

You may be intrested to know that little spiders have also be found floating at those altitudes. :P

Also: it is quiet difficult to decide whether or not theory A or B is correct.
both present good evidense - we can&#39;t really know for sure which one is correct. <_<

for now i suppose it&#39;s best to choose the one you think is best and stick with it until further evidense for either pops up.

i might add merely thinking like

so I&#39;m quite annoyed with myself because I actualy choose to accept to the panspermia theory without attempting to think outside the box and wait for the ever-arriving proof we have....

and

Also: it is quiet difficult to decide whether or not theory A or B is correct.
both present good evidense - we can&#39;t really know for sure which one is correct.

for now i suppose it&#39;s best to choose the one you think is best and stick with it until further evidense for either pops up.

is thinking out of the box in it&#39;s self

[Nereid]

Theory: it has a fairly precise meaning in science (as Bobunf mentioned; the dictionary definition #5 is not bad, for just a few words) ... so are we going to use the word with its &#39;scientific meaning&#39;?

If we&#39;re interested in where life on Earth came from, what sort of data would help us to start making a testable theory? What sort of advances - in chemistry, geology, planetary science, ... in the next 50 years or do - do you think might move us a significant distance along the road to having a decent theory to test?

[GOURDHEAD]

What sort of advances - in chemistry, geology, planetary science, ... in the next 50 years or do - do you think might move us a significant distance along the road to having a decent theory to test?

About all we can expect to do is eliminate theories or aspects of them. Whatever we find that could have worked will not be proof that it was the causal form. Panspermia is not mutually exclusive with Earth-located spontaneous generation. We may contain effects from both sources....or neither and it&#39;s probably too late to sort all that out unless The Zookeeper chooses to tell us. We will probably concentrate on lifeless worlds (at least those thought to be) to do our terraforming and will necessarily have to insert a limited biota which will imediately begin its own march to its own drummer making it difficult for the natives to identify their origin unless sufficient records are kept or someone goes back and tells them.

Knowing the complete set of what might have happened is almost as good as knowing what did happen.

Scientific theories lend themselves to falsification; we can never be sure of proof.

[Buffy]

my theory on what life is .. is that souls are build up out of negative and positive energy. this can cause electricity which functions our brains. You could basiccly compare our body with a car.. you start of with almost nothing and with the negative and positive energy u decide what you want to buy for your car. a car also needs fuel and u absorb negative and positive energy from your surroundings. Thats how your environment can change you.

I believe every soul is equal but the *body&#39;s* are different. for example a tree is a bike and a human body is an rocket. a bike is limited to a certain things like a tree is limited to growing and taking up sunlight they use their energy to grow and they gain energy from their surroundings. but they have no brain like humans.

I believe when you die nothing is left but a cloud of energy, all your memory and knowledge will be left in ur dead body. This energy might be used for another body but it might be used to start a thunder storm etc.

[Ola D.]

Hey Buffy,
About absorbing negative and positive surrounding energy, did you inspire that from the science of macrobiotics and the ancient chinese teachings?

[Buffy]

uhh no I thought of it myself, I searched for the answers inside of me

[Namit]

Dear jsc248,
According to what I have studied about your ques. I have this,

Life originated in the form of unicellular living objects.Life, as we know today took millions of years to form A cell however is not a simple structure. It is made up of proteins, carbohydrates fats and many other things. Pbviously these things were formed long ago even before the cell originated.
A scientists Miller has shown that a strong electric spark, produced at 60,000volts, while passing through a mixture of ammonia, methane, hydrogen and water vapour is able to form amino acids. These acids come together to form protein molecules. some 3500 million yrs ago the Earth&#39;s atmosphere was rich i these gases. The earth was warmer the atmospheric pressure was much greater and the light was quite intense. The electric spark may have been the lightning. The cell came to be formed after the protein molecules came to be formed.

Let me know if this is useful,

Bye,
Namit[namit_p@vsnl.com]

[astromark]

Good stuff Namit. yes usfull.
but the molecules were lonlly and bored so they began to reproduce, and thus here we are, still at it.

[astromark]

:blink: Why cant these theories be tested. :unsure: Amino acids and the other components of the primival swamp. couldent we just zap it all with bolt or two of electrical energy and see if any thing moves? Yes I suspect this has all been done ... and No. Just warm mud. I will go on thinking that life evolved where we find it. In the hot places deep under our ociens where volcanic vents have changed the chemical balance. Or high in our atmosphear where electrical impolses might just triger a microb into life.

[Namit]

Dear astromark,
Read your reply in the Life in Space coloumn. You had said the following.

"In the hot places deep under our ociens where volcanic vents have changed the chemical balance. Or high in our atmosphear where electrical impolses might just triger a microb into life."

As you have said many scientists have tried creating life based on their inspiration of Miller&#39;s experiment. Most commonly accepted theory is that life originated in water as water could provide a lot of useful substances to the simple cell as we see today. example is the amoeba which is an unicellular protozoa and it lives in water.

This is what I have to say to your post.


Bye for now,
Namit

[3rdvogon]

Originally posted by ChromeStar@Dec 23 2004, 08:41 PM
sup Rigel

i&#39;m aware of that bacteria findings.

Surely the key thing when finding any strange cells bacteria or otherwise:

Is to examine the structure of their mitochondrial DNA. Unlike the DNA from a cell nucleus which is subject to all all the normal changes (dividing and recombining) that occur during the reproductive cycle, the mitochondrial DNA is almost unchanging in that it mutates at slow and relatively steady rate. This has proved very useful in tracing human ancestry making it possible to track the dispersal patterns of the human races and their origins. It also allows the tracking of species divergance over the evolutionary family tree.

Therefore it surely should be possible to examine any strange cell that is found and determine if it fits into the terrestrial evolution time-line or if its something that is outside that pattern and therefore clearly of alien origin.

[scorpio711]

Back to Rigel&#39;s comments on "alien bacteria found at 41km altitude over Cardiff...". I&#39;m a bit surprised that earth-origin bacteria have been ruled out as very improbable &#33; To me it is exactly the opposite. The Earth is full of germs and bacteria, everywhere, even in extremely hostile environments. And to me, bacteria would be easily transported by winds and air currents to high altitude, despite harsh conditions. Well a bacteria has been found on the moon, on one camera (if I remember well) left by a previous expedition, a couple of years later... and back in normal conditions, the bacteria revived.
So for me, and using Occam&#39;s razor principle, I think it is more probable that these bacteria are earth-bound bacteria.
By the way, could you find the reference/url of this in the net?

[scorpio711]

3rdVogon, yes you are very right, mitochondrial DNA helps very much to find origin of a cell... as long as the cell includes mitochondriae, which is not the case of all the cells. In particular bacteria are prokaryotes which have no mitochondria. Eukaryotes (such as animal cells) have mitochondria.
However, bacteria are well known by biologists, there is a classification existing, so one could easily say if these bacteria found at high altitude belong to existing families or not.

[3rdvogon]

Originally posted by scorpio711@Feb 16 2005, 07:51 PM
as long as the cell includes mitochondriae, which is not the case of all the cells. In particular bacteria are prokaryotes which have no mitochondria. Eukaryotes (such as animal cells) have mitochondria.

I stand corrected.

I always believed that any cells which consume Oxygen and excreate CO2 have mitochondriae.

I guess that as bacteria do not reproduce sexually, that therefore their nuclear DNA mutates with steady progressions. Thus tracing the steps of lineages is easier than with the nuclear DNA from animals which use sex.

It just shows that a little knowledge is a dangerous thing but then I am not a Biologist just a simple former army officer.

[Pierre]

I believe with comet no? I like comet.