Say life is discovered on mars..

[JcR]

As mentioned earlier, "DNA" is certainly not the starting point of life. It would be the product of evolution itself; from much earlier and simpler self-replicating molecules.

Unless some sort of seeding took place, I would think it unlikely that any other life in the solar system would be DNA based.

Maybe simple replicating molecules is as far as life will evolve in certain environments.
Until a new curve is thrown into the mix. Maybe we where just a lucky mix.
I think a lot if life itself was just the by-product of the occurrences alone.
And the odds of the same mixture of events happening anywhere else in the Universe.
I can't help to think that something is in the code, inside the driving force behind it. A design to it all.
Why would simple based life structures even bother.
A big bang, excited molecules and energy abundant.
why does life need to fit itself into the picture anyways.
Again I can't help to think that life will emerge wherever it gets it's chance
to get a foothold. Even if it is as simple as life will permit it to be.
What are the odds of a one-time occurrence anyways.
When I see so many stars.

 

[JcR]

Why does existence have to have a point?

Well A "point" is of our own design. So why not make them.

 

[Crowlogic]

How about the entry into Earth's atmosphere? Would the friction cause the rocks to heat up so much that they are sterilized?

Not if its a big frozen comet with some organisms stashed deeply in its core. As the comet vaporizes due to friction it slows down. But it can eventually break up high above and the smaller pieces reaching the ground/ocean at a reasonable speed with some organisms intact. When the Space Shuttle broke up it entered the atmosphere at orbital speed but after it broke apart pieces came to earth that weren't destroyed by atmospheric friction and intense heat thereof. Lots of ways for organic material to reach the earth in a still viable condition.

 

[William Parcher]

Not if its a big frozen comet with some organisms stashed deeply in its core. As the comet vaporizes due to friction it slows down. But it can eventually break up high above and the smaller pieces reaching the ground/ocean at a reasonable speed with some organisms intact... Lots of ways for organic material to reach the earth in a still viable condition.

(I split your post.) So, the above is reasonable?

When the Space Shuttle broke up it entered the atmosphere at orbital speed but after it broke apart pieces came to earth that weren't destroyed by atmospheric friction and intense heat thereof.

I'm fairly ignorant of reentry theory and methodology, but I wonder if this is a proper analogy. Were not the SS pilots in the process of executing a calculated reentry when the ship burned up? Would a comet (with no pilot) make the same sort of entry?

 

[JcR]

I guess it is possible a comet (if it even had some sort of biological entity)
carrying Bio matter survived entry and the massive energy created when
it collides with the surface of the Earth. Then possibly it may just get absorbed
and rendered useless, having little or no effect on it's surroundings or with
our life development. Or it adapts to it's new home here and Mingles in.
Maybe space riders in or on objects reaching our surface are attacked like a foreign virus.
If they survive the earlier onslaughts of the journey.

 

[LONGTABBER PE]

fairly ignorant of reentry theory and methodology, but I wonder if this is a proper analogy. Were not the SS pilots in the process of executing a calculated reentry when the ship burned up? Would a comet (with no pilot) make the same sort of entry?

Not exactly, its more like HVAC 101

The objects speed and distance ( measured in time) versus its size/mass in the atmosphere determines the heat and time said object is subjected to heat.

So depending on material,density and core temp an object could survive.

Its like HVAC. Put a torch against a block of ice. The core temp never changes regardless of how hot the fire. Once the fire is removed, the remaining ice is still @32f.

 

[William Parcher]

So, the ice/water that these comets could carry to Earth is ice/water from the celestial body that they originated from; or ice/water they picked up in space? How does that work?

 

[LONGTABBER PE]

So, the ice/water that these comets could carry to Earth is ice/water from the celestial body that they originated from; or ice/water they picked up in space? How does that work?

I'm not a Chemical Engineer or know much about outer space but water is H2o and "ice" is H2o @32 or below.

Given the temp of "space" is between absolute zero to whatever range one is to a given star- I can see many ways water/ice could be made from various impacts, novas, planets being hit by asteroids and knocking mass into space.

Then depending on a number of variables, removing enough latent heat to survive a short heating such as a re entry

 

[JcR]

Comets can also contain frozen Methane ammonia CO C02
Theory is they come from the most outer regions of our solar system.
the Oort cloud and kuiper belt theory. Cosmic junk and certainly plenty of
hydrogen and other elements in space. an interesting article.

 

[fuelair]

http://news.yahoo.com/s/livescience/20090112/sc_livescience/lifeasweknowitnearlycreatedinlab


RNA self replicating and evolving - though not Martian.

 

[JcR]

http://news.yahoo.com/s/livescience/20090112/sc_livescience/lifeasweknowitnearlycreatedinlab


RNA self replicating and evolving - though not Martian.

Watching non-life duke it out with life-like mannerisms.
That would be very interesting to actually witness this process.

 

[Beerina]

I wonder about the definition of life. These has been around these parts fo ra while:
"The basic timeline is a 4.6 billion year old Earth, with (very approximate) dates:
* 3.8 billion years of simple cells (prokaryotes)",from Wikipedantic,
As a derail, would a Von Neuman machine qualify as life?

Well, there's a quote that "Biologists no longer argue about whether a virus or a seed is 'alive'." Why? Because they understand the mechanisms of how they operate. "Life" has lost it's panache in science. There are just atoms doing things differently.

So would a self-replicating machine "count"? Well, it is what it is. A thing that reproduces itself. Presumably some kind of evolution would work on it, even if there was no DNA-type stuff, per se. There must be reproduction errors once in awhile. Usually these would end up with a "stillborn". Once in awhile, it would end up with a sterile but functional "child". And other times, the error (or some other error) would be the grandchild's outcome, with that being reproduced.

Mighty slow, perhaps even slower that the original life which relied on chemical errors and stray neutrons and whatnot to drive evolution. But eventually...