Ingredients of Life Found Around Sun-Like Star

smooth wombat writes "NASAs Spitzer Space Telescope has detected the basic organic building blocks of life in a ring orbiting in the 'habitable zone', that area where Earth orbits the Sun and where water exists on the borderline between gas and liquid, in a nearby stellar nursery. When acetylene and hydrogen cyanide combine with water they form adenine, one of the four bases of DNA. The detection supports the widely held theory that many of the molecular building blocks of life were present in the solar system even before planets formed, thus assisting the initial formation of complex organic molecules and the start of life itself." Though it was a little shakier than this observation, we've discussed the possibility of life elsewhere in the galaxy before.

Comments

Drake equation

[tpjunkie]

I'd say this would definitely incresase the probability of the drake equation resulting in a non-zero answer. Complex organic molecule formation is one of the biggies that you need for development of life.

DNA in space?

[lawpoop]

I just thought of something while looking at the graphic -- what if RNA and DNA originally assemble in the pre-planetary cloud and hang around, falling into condensing planets and so forth?

I think the current popular theory, IIRC, is that RNA molecules somehow stack up in a tidal pool, where they are gently rocked back and forth. Some correct me please.

So how hard would it be to get DNA to link up in microgravity? Sure, there's more radiation around to blast things apart, but that might be a good thing -- you could get molecules you might not get otherwise without the blowing apart. Also, in microgravity, molecules can float around in 3 dimensions.

Re:DNA in space?

[lawpoop]

I'm gonna have to disagree with your comment. Oxygen is not 'optional' ,as you say, rather it's detrimental to the formation of life. Some have speculated that DNA-based life could not arise in an aerobic environment. It's just too desctructive.

After further consideration...

[mister_llah]

"""
The detection supports the widely held theory that many of the molecular building blocks of life were present in the solar system even before planets formed, thus assisting the initial formation of complex organic molecules and the start of life itself.
"""

Wait, so finding organic molecules around a planet supports this how? Can we tell the age of those particles, or that stellar nursery? If we are to believe a lightning strike can create life from amino acids and things of this nature... why would this support that conclusion in particular?

Maybe I'm missing the point. Perhaps someone can explain things to me?

Life is software, not hardware

[dtjohnson]

Life is not the presence of particular molecules. Life is the plan by which the molecules are constructed into a living organism. Molecules without the plan by which they operate are no different than computer hardware without any software installed on it. Finding hydrogen cyanide and acetylene present around another star is more a comment on the improving ability to detect molecules at a distance than it is on the presence of the 'building blocks of life.' It would have been much more remarkable if they had NOT found those substances since they are composed of carbon, hydrogen, and nitrogen which we would expect to be ubiquitous in the universe, based on our present knowledge. Claiming to have found the 'building blocks of life' around another star is just hype to help pump up the budget for next years work.

Re:Wait - so Moby had it right?

[pnewhook]

We are all made of stars?

Actually, even the bible tells us this is so. "Ashes to ashes... dust to dust...".

Could interpret this literally and say that we (the Sun, Earth and life on it) are made from interstellar dust initially, and that's where we end up when the solar system ends its life and turns back to ashes and dust when the sun explodes.

It is agreed in all probability

[Dark Coder]

I'll point out the criteria to a successful adenine (a component of DNA) creation as I recall from various scientific sources (Intelligent Design not withstanding):

1. Gravity of at least 0.4 G is a requirement (micro-gravity need not apply here as a recent ISS scientific experiement shown with regard to catalyst of acytelene/water/hydrogen under electric sparks/shocks)

2. Swirling motions (tidal pool is nature's best liquid/air agitators)

3. Minimal radiation (asinine will not remain cohesive for long under gamma bombardments)
        This means a heavy shielding must be in place, which means dense air and/or planet

4. Lightning... the very most improbable of all aspect of the building block starter. It's gotta strike at the right place and the right time, preferably near the tidal pool.

I'd gotta hand it to mother nature and God, we are one lucky fools on this unqiue planet, Earth.

Re:statistical black hole

[rbanffy]

Your post implies the simplest viable life form is DNA based with highly specialized structures like ribosomes when, in fact, they are not required to form from the primordial soup.

Life can start simple. A single molecule that reacts with other molecules around it and makes imperfect copies of itself is enough. Given time, all suitable molecules will be used and live, even if primitive, will be everywhere.

Since the copies are not perfect, mutation does happen and you will have a lot of different "copiers" in your soup, some better that the others, some building more complex structures that can, in turn, copy themselves.

I agree with you. Expecting cell based lifeforms in the first week of a biosphere is ludicrous, but you are wrong. Cells, nuclei and DNA are only one way of life to express itself. It happens to be the way we know because once a certain kind of life dominates, there is little space left for other forms. It happened here.

There are sure other forms of organization that happened all over the place. Remember: billions of places over billions of years make a lot of attemps on life.

Re:In other news

[sam_handelman]

Here's the best story available at the moment:

  First came RNA, which combines the catalytic properties of proteins and the hereditary properties of DNA in a single molecule. So RNA can provide a template for new RNA (by base complimentarity) and also catalyse the polymerization of RNA onto itself. The odds of randomly assembling such an RNA are of course excruciatingly low - but we have a hundred million years and many, many RNA polymers floating around during that period. Furthermore, if we were on a planet where this had never occurred - would we be here to talk about it?

  RNA molecules form spontaneously in conditions like those on the early earth, given the right organic ingredients (i.e. in the presence of the molecules we see in that gas cloud, if they were on a planetary surface).

  Phospholipids (or other molecules, with similar charge properties) also form spontaneously, and arrange spontaneously into lipid bilayers.

  Since these lipid bilayers would have a strong tendency to concentrate whatever was in them when they floated away, the insides of these lipid bilayers would be ideal locations for these self-replicating RNA to congregate. I will refer to these proto-cells as "collectives of RNA molecules".

  Over time, these RNA molecules evolve new catalytic activities. It has been well established - in experimental studies - that randomly varied RNA can, indeed, evolve new catalytic activities. It takes a while, but we've got an aeon to burn.

  Three new RNA activities are key:
a) Creating a "template" version of themselves/eachother consisting of DNA, rather than RNA. This will eventually become the inherited genome - but originally, this would confer a selective advantage because DNA molecules are more stable than RNA. Even today, no organism can synthesize DNA without first synthesizing a little RNA as a "primer" to get synthesis started.
b) Making proteins as an aid to catalysis. The first proteins were probably non-informative polymers (like starch). Most likely, they served as bound cofactors (like heme iron in hemoglobin) and the like for RNA enzymes. Since proteins are almost universally superior catalysts to RNA, the first collective of RNA that had the ability to synthesize protein would have a great advantage. Even today, the fundamental reaction of protein synthesis is catalyzed by the RNA component of the Ribozome, although modern Ribozomes have a great many proteins that "help" the process.
c) Synthesising additional phospholipids to make more membrane. As time goes on and the amount of free phospholipid floating in the water declines, this becomes a great selective advantage to any proto-cell, since it can reproduce more proto-cells limited only by available energy and reduced carbon.

  With these three - perfectly understandable - adaptations, you have evolved from a soap bubble full of RNA into a cell.

  ---

  Obviously, this story need not be true, and there are many details missing (or incorrect.) At the moment, however, it is the best explanation we have, and it is certainly possible.