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Dude
SFN Die Hard
USA
6891 Posts |
 Posted - 01/25/2006 : 16:40:01
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This is a subject that deeply interests me.
http://www.msnbc.msn.com/id/11013519/
There are some new technologies and new telescopes comming online in the next 10 years or so that will increase our ability to detect earth-sized planets significantly.
Wonder what the response will be when the first verified report of organic molecules on a planet around another sun is published...
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Ignorance is preferable to error; and he is less remote from the truth who believes nothing, than he who believes what is wrong.
-- Thomas Jefferson
"god :: the last refuge of a man with no answers and no argument." - G. Carlin
Hope, n.
The handmaiden of desperation; the opiate of despair; the illegible signpost on the road to perdition. ~~ da filth |
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Dr. Mabuse
Septic Fiend
Sweden
9688 Posts |
Posted - 01/25/2006 : 17:16:29 [Permalink]
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quote:
Originally posted by Dude
This is a subject that deeply interests me.
http://www.msnbc.msn.com/id/11013519/
There are some new technologies and new telescopes comming online in the next 10 years or so that will increase our ability to detect earth-sized planets significantly.
Wonder what the response will be when the first verified report of organic molecules on a planet around another sun is published...
It doesn't even have to be organic.
A much more unique signature would be O2 and O3. Both are clear indicators of an atmosphere which is not in chemical equilibrium. Something has to produce molecular oxygen and ozone, they don't occur naturally without some kind of photosynthesis.
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Dr. Mabuse - "When the going gets tough, the tough get Duct-tape..."
Dr. Mabuse whisper.mp3
"Equivocation is not just a job, for a creationist it's a way of life..." Dr. Mabuse
Support American Troops in Iraq:
Send them unarmed civilians for target practice..
Collateralmurder. |
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Hawks
SFN Regular
Canada
1383 Posts |
Posted - 01/25/2006 : 20:36:30 [Permalink]
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quote:
A much more unique signature would be O2 and O3. Both are clear indicators of an atmosphere which is not in chemical equilibrium. Something has to produce molecular oxygen and ozone, they don't occur naturally without some kind of photosynthesis.
Not necessarily true. O2 and O3 are good indicators, but nothing conclusive. From PlanetQuest:
quote:
However, we know of non-biological processes that can also result in an oxygen-rich atmosphere. The runaway greenhouse effect on Venus is one example. A frozen, Mars-like planet big enough to hold its oxygen would be another.
I would also naively have thought that a planet where most things in contact with the atmosphere are already oxidised would produce the same result (don't ask me to explain how this would happen - I wouldn't have a clue. I'm a biologist, goddammit).
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METHINKS IT IS LIKE A WEASEL
It's a small, off-duty czechoslovakian traffic warden! |
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HalfMooner
Dingaling
Philippines
15831 Posts |
Posted - 01/25/2006 : 21:07:39 [Permalink]
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quote:
I wouldn't have a clue. I'm a biologist, goddammit
My sincere sympathy. ; ) It's fun to take comments out of context! |
“Biology is just physics that has begun to smell bad.” —HalfMooner
Here's a link to Moonscape News, and one to its Archive. |
| Edited by - HalfMooner on 01/25/2006 21:11:25 |
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HalfMooner
Dingaling
Philippines
15831 Posts |
Posted - 01/25/2006 : 21:18:36 [Permalink]
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quote:
Religious bondage shackles and debilitates the mind and unfits it for every noble enterprise.
James Madison, Fourth President of the Untited States.
But its even more fun than the secular kind.
(See what I meant in my last post?) |
“Biology is just physics that has begun to smell bad.” —HalfMooner
Here's a link to Moonscape News, and one to its Archive. |
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HalfMooner
Dingaling
Philippines
15831 Posts |
Posted - 01/25/2006 : 21:27:56 [Permalink]
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Seriously speaking, I find the accelerating extrasolar hunt fascinating. At first, it seemed the galaxy was mainly planeted with bizarre super-Jupiters in blazingly hot orbits near their stars, or sometimes in wildly eccentric orbits. But now it's accepted that this impression was "selection bias" caused by the fact that existing techniques could only detect the giants and oddballs.
Finding this newest planet is exciting. It looks as though detection of "Earths" is going to begin happening even earlier than expected, due to cleverly designed techniques. |
“Biology is just physics that has begun to smell bad.” —HalfMooner
Here's a link to Moonscape News, and one to its Archive. |
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Dr. Mabuse
Septic Fiend
Sweden
9688 Posts |
Posted - 01/25/2006 : 23:06:16 [Permalink]
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Well, Oxygen presence alone won't cut it, one would have to compare relative levels to other atmospheric gasses. While both Venus and Mars do have oxygen in the atmosphere, in both cases it's measured to less than 1% of the total atmospheric pressure.
http://www.ed.psu.edu/ci/Papers/STS/gac-3/in07.htm
Absorbtion spectra would give measurments of free oxygen relative to N2, CO2, SO2 (and other nasties).
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Dr. Mabuse - "When the going gets tough, the tough get Duct-tape..."
Dr. Mabuse whisper.mp3
"Equivocation is not just a job, for a creationist it's a way of life..." Dr. Mabuse
Support American Troops in Iraq:
Send them unarmed civilians for target practice..
Collateralmurder. |
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HalfMooner
Dingaling
Philippines
15831 Posts |
Posted - 01/25/2006 : 23:14:52 [Permalink]
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Dr. Mab wrote: quote:
Absorbtion spectra would give measurments of free oxygen relative to N2, CO2, SO2 (and other nasties).
I seem to recall in my lifetime when this technique couldn't even be reliably applied to Mars. Now, we're getting set to try it on extrasolar planets. Progress! |
“Biology is just physics that has begun to smell bad.” —HalfMooner
Here's a link to Moonscape News, and one to its Archive. |
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Dude
SFN Die Hard
USA
6891 Posts |
Posted - 01/26/2006 : 00:31:42 [Permalink]
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quote:
I seem to recall in my lifetime when this technique couldn't even be reliably applied to Mars. Now, we're getting set to try it on extrasolar planets. Progress!
Hopefully it will reveal some complex organic molecules out there somewhere.
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Ignorance is preferable to error; and he is less remote from the truth who believes nothing, than he who believes what is wrong.
-- Thomas Jefferson
"god :: the last refuge of a man with no answers and no argument." - G. Carlin
Hope, n.
The handmaiden of desperation; the opiate of despair; the illegible signpost on the road to perdition. ~~ da filth |
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HalfMooner
Dingaling
Philippines
15831 Posts |
Posted - 01/26/2006 : 11:22:18 [Permalink]
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| Please don't jump on me too hard for this admittedly ignorant question, but is it theoretically possible that DNA itself could be detected by spectrascopy? |
“Biology is just physics that has begun to smell bad.” —HalfMooner
Here's a link to Moonscape News, and one to its Archive. |
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Hawks
SFN Regular
Canada
1383 Posts |
Posted - 01/26/2006 : 14:34:00 [Permalink]
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quote:
Originally posted by HalfMooner
Please don't jump on me too hard for this admittedly ignorant question, but is it theoretically possible that DNA itself could be detected by spectrascopy?
Yep. But it would have to be "fairly concentrated" and there shouldn't be too many other contaminants. Ie, you really need to extract and purify it first. If it worked, however, it would of course only be useful if our aliens had DNA as their genetic material in the first place. |
METHINKS IT IS LIKE A WEASEL
It's a small, off-duty czechoslovakian traffic warden! |
| Edited by - Hawks on 01/26/2006 14:34:32 |
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JohnOAS
SFN Regular
Australia
800 Posts |
Posted - 01/26/2006 : 14:57:08 [Permalink]
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Very interesting. I too, await the fundies responses to discovery of life elsewhere in the universe. Unfortunately, the odds aren't superb that it'll happen in my lifetime, but you can be a skeptic, scientist and optimist simultaneously, right? While the discovery itself would outshine the shock of those who think the whole universe is just for us, it could be a real boon to the effort to eradicate some of the fringe dweller cults. Mind you there'll be a gazillion alien-based ones to take their place.
For those that are interested in such things, the eZine from New Scientist is pretty good, and posted a bulletin email about this discovery last week. Although obviously some of the material is abbreviated versions of stuff you have to be a paid subscriber to get, it's generally well worth a read. They also have a free weekly audio download.
NewScientistEzine
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John's just this guy, you know. |
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Hawks
SFN Regular
Canada
1383 Posts |
Posted - 01/26/2006 : 15:43:34 [Permalink]
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quote:
Very interesting. I too, await the fundies responses to discovery of life elsewhere in the universe.
Depends on the fundie. Tom Cruise would LOVE it. |
METHINKS IT IS LIKE A WEASEL
It's a small, off-duty czechoslovakian traffic warden! |
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HalfMooner
Dingaling
Philippines
15831 Posts |
Posted - 01/26/2006 : 16:07:06 [Permalink]
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Hawks declared:
quote:
Yep. But it would have to be "fairly concentrated" and there shouldn't be too many other contaminants. Ie, you really need to extract and purify it first. If it worked, however, it would of course only be useful if our aliens had DNA as their genetic material in the first place.
Thanks, Hawks. From what you write, it appears you made the enormous error of answering the question I actually asked, rather than the question of which I was thinking.
Sorry, but I should have tried to make it clear that I was thinking about astronomically remote spectroscopy. So to rephrase, is it theoretically possible that, through astronomical means, it might someday be possible to detect DNA (or some hypothetical alien analog that performs a similar genetic function)? |
“Biology is just physics that has begun to smell bad.” —HalfMooner
Here's a link to Moonscape News, and one to its Archive. |
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JohnOAS
SFN Regular
Australia
800 Posts |
Posted - 01/26/2006 : 18:49:15 [Permalink]
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quote:
Originally posted by HalfMooner
Sorry, but I should have tried to make it clear that I was thinking about astronomically remote spectroscopy. So to rephrase, is it theoretically possible that, through astronomical means, it might someday be possible to detect DNA (or some hypothetical alien analog that performs a similar genetic function)?
Spectroscopy is pretty good at telling you exactly (in the molecular/atomic realm at any rate) is in a particular sample. The main problems with "astronomically remote spectroscopy" (I like that term) as I see it are:
1. Spatial resolution.
You have to be able to "look" at a small enough region to be sure that the spectroscopic features you've identified as being of the right types and in the right proportions to be DNA, are in fact contstrained sufficiently that the identification still makes sense. The optics we have at our disposal certainly aren't even close to being up to the task, and the diffraction limit would suggest that any terrestrial systems are unlikely to be able to circumvent this problem any time soon.
2. Wavelength Penetration.
A lot of our spectroscopy is performed in the ultra-violet to Infrared wavelength ranges. For most life forms we're aware of, the DNA iteself is buried far enough inside it's host, that any spectral information we get would be that of the "container", not the contents. Generally speaking, the surrounding material has broadly similar spectral properties, so it's ability to mask what's underneath are significant. There are focal tricks that can sometimes be performed to limit this effect in some instances, though most of these techniques would be impossible at astronomical distances.
Our best bet currently is to look for large features (like forests / atmospheric effects) that are indicative of some sort of life. Unfortunately this precludes looking for the little critters/cells.
Of course, there are people far smarter and more qualified than I working on these problems, but I think this is a reasonbably accurate summary of the state of affairs. |
John's just this guy, you know. |
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HalfMooner
Dingaling
Philippines
15831 Posts |
Posted - 01/26/2006 : 19:07:33 [Permalink]
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Thanks, JohnOAS, for taking the time and effort to reply. I actually understood most of that, and can begin to appreciate the technical limits in attempting to identify genetic material across vast lightyears.
One point: Isn't it remarkable that we can even discuss such difficulties? I mean, there have been some wonderful advances for us to even seriously consider such a future possibility. |
“Biology is just physics that has begun to smell bad.” —HalfMooner
Here's a link to Moonscape News, and one to its Archive. |
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