<p>If you take a slowly rotating asteroid with a large basin of trapped water, some solved minerals, and may be some gases, close to the asteroid's surface, to get an environment similar to a <a href="http://en.wikipedia.org/wiki/Hydrothermal_vent#Black_smokers_and_white_smokers" rel="nofollow">black smoker</a> by the heat of the sun, I wouldn't call it totally impossible.</p>

<p>The formation of such an asteroid is close to the limits of my imagination, might be as a remnant of a comet with a crust of dust baked together to a water-proof surface layer.</p>

<p>But that's pure speculation at the moment. May be we can learn more this year with <a href="http://en.wikipedia.org/wiki/Rosetta_%28spacecraft%29" rel="nofollow">Rosetta</a>.</p>

<p>Some biochemistry details: By the rotating asteroid part of the water undergoes a heating/cooling cycle. Provided there are enough prebiotic molecules, by this heating/cooling cycle kind of <a href="http://en.wikipedia.org/wiki/Polymerase_chain_reaction" rel="nofollow">polymerase chain reaction</a> (PCR) could multiply short occasional RNA or DNA fragments (<a href="http://en.wikipedia.org/wiki/Nucleotide" rel="nofollow">nucleotide</a> sequences). The difficult part is providing <a href="http://en.wikipedia.org/wiki/Taq_polymerase" rel="nofollow">polymerase</a>. It has originally been isolated from a <a href="http://en.wikipedia.org/wiki/Thermus_aquaticus" rel="nofollow">bacterium</a> living in hot springs, not quite dissimilar to black smokers. Information storage and replication (e.g. in RNA/DNA) is one important ingredient for life.</p>

<p><a href="http://en.wikipedia.org/wiki/DNA_polymerase_III" rel="nofollow">Polymerase</a> is an enzyme, mainly consisting of amino acids. <a href="http://science.gsfc.nasa.gov/691/analytical/PDF/Elsila2009.pdf" rel="nofollow">Glycine is the first amino acid found in cometary dust in 2009</a>. That's a first step, but there is a big gap. As an enzyme polymerase is a <a href="http://en.wikipedia.org/wiki/Protein" rel="nofollow">protein</a>, hence can be encoded by RNA or DNA.</p>

<p>To decode RNA to a proteine, kind of <a href="http://en.wikipedia.org/wiki/Ribosome" rel="nofollow">ribosome</a> is needed. A ribosome itself consists of <a href="http://en.wikipedia.org/wiki/Ribonucleoprotein" rel="nofollow">RNA and protein</a> (chain of amino acids). That's the basics of the replication mechanism.</p>

<p>Now we need a containment.
The simplest form of a cell-like structure is a <a href="http://en.wikipedia.org/wiki/Micelle" rel="nofollow">micelle</a>. Organic molecules with a polar group can form micelles.
<a href="http://www.gb.nrao.edu/astrobiology/gbtModel/astroBioARAA.38.1.427.pdf" rel="nofollow">This paper</a> contains a list of organic molecules found in interstellar medium.
Some of them could be used to synthesize appropriate molecules, but it's also quite a gap in this case.</p>

<p>A long way from what we know of extraterrestrial organic molecules to a bacterium.</p>

CC BY-SA 3.0
2014-03-20T16:16:43.100Z
2014-03-20T18:09:06.257Z
2014-03-20T18:09:06.257Z
Gerald
<p>If there were an asteroid orbiting its star within the habitable zone and this asteroid contained liquid water, would it be possible for simple life such as bacteria to form? </p>

CC BY-SA 3.0
2014-03-19T17:40:01.750Z
It is not known how life formed. It is not known if there is life out of Earth. Without data there are few constraints on "possibilities" (and impossiblities). I think the only serious answer is: Don't know.
LocalFluff
<life><habitable-zone>
Simple life on asteroids
TheBluegrassMathematician
# Simple life on asteroids

(Asked by: username_0 on 2014-03-19)

If there were an asteroid orbiting its star within the habitable zone and this asteroid contained liquid water, would it be possible for simple life such as bacteria to form?

**Tags:** life, habitable-zone
> **Comments:**
> **username_1**: It is not known how life formed. It is not known if there is life out of Earth. Without data there are few constraints on "possibilities" (and impossiblities). I think the only serious answer is: Don't know.  

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## 1 answers

### Answer by username_2 on 2014-03-20. Score: 3 | Accepted answer

If you take a slowly rotating asteroid with a large basin of trapped water, some solved minerals, and may be some gases, close to the asteroid's surface, to get an environment similar to a [black smoker](http://en.wikipedia.org/wiki/Hydrothermal_vent#Black_smokers_and_white_smokers) by the heat of the sun, I wouldn't call it totally impossible.

The formation of such an asteroid is close to the limits of my imagination, might be as a remnant of a comet with a crust of dust baked together to a water-proof surface layer.

But that's pure speculation at the moment. May be we can learn more this year with [Rosetta](http://en.wikipedia.org/wiki/Rosetta_%28spacecraft%29).

Some biochemistry details: By the rotating asteroid part of the water undergoes a heating/cooling cycle. Provided there are enough prebiotic molecules, by this heating/cooling cycle kind of [polymerase chain reaction](http://en.wikipedia.org/wiki/Polymerase_chain_reaction) (PCR) could multiply short occasional RNA or DNA fragments ([nucleotide](http://en.wikipedia.org/wiki/Nucleotide) sequences). The difficult part is providing [polymerase](http://en.wikipedia.org/wiki/Taq_polymerase). It has originally been isolated from a [bacterium](http://en.wikipedia.org/wiki/Thermus_aquaticus) living in hot springs, not quite dissimilar to black smokers. Information storage and replication (e.g. in RNA/DNA) is one important ingredient for life.

[Polymerase](http://en.wikipedia.org/wiki/DNA_polymerase_III) is an enzyme, mainly consisting of amino acids. [Glycine is the first amino acid found in cometary dust in 2009](http://science.gsfc.nasa.gov/691/analytical/PDF/Elsila2009.pdf). That's a first step, but there is a big gap. As an enzyme polymerase is a [protein](http://en.wikipedia.org/wiki/Protein), hence can be encoded by RNA or DNA.

To decode RNA to a proteine, kind of [ribosome](http://en.wikipedia.org/wiki/Ribosome) is needed. A ribosome itself consists of [RNA and protein](http://en.wikipedia.org/wiki/Ribonucleoprotein) (chain of amino acids). That's the basics of the replication mechanism.

Now we need a containment.
The simplest form of a cell-like structure is a [micelle](http://en.wikipedia.org/wiki/Micelle). Organic molecules with a polar group can form micelles.
[This paper](http://www.gb.nrao.edu/astrobiology/gbtModel/astroBioARAA.38.1.427.pdf) contains a list of organic molecules found in interstellar medium.
Some of them could be used to synthesize appropriate molecules, but it's also quite a gap in this case.

A long way from what we know of extraterrestrial organic molecules to a bacterium.


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