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Re: APOD: Kepler 78b: Earth Sized Planet... (2013 Nov 05)

Posted: Thu Nov 07, 2013 6:03 am
by Nitpicker
Chris Peterson wrote:
BMAONE23 wrote:Wouldn't it be better stated that "Judgement of evidence (through science) is a product of confirmation"? It seems to me that support or rejection of theory is better handled through confirmation of findings rather than consensus of arguement. Or am I misinterpreting your usage?
Of course, confirmation is critical. It's part of what creates consensus. But it's a different thing than what I'm talking about. The degree of consensus among experts about any theory correlates closely with the likely truth of that theory.
Looks a little backwards to me though ... what about:

Confirmation by significant degree of consensus among scientists in closely related fields, is a product of judgement of evidence.

But I don't think consensus is what separates science from other pursuits. It is rather the kind of rational, objective judgements made by individual scientists in closely related fields.

Re: APOD: Kepler 78b: Earth Sized Planet... (2013 Nov 05)

Posted: Thu Nov 07, 2013 6:18 am
by Chris Peterson
Nitpicker wrote:But I don't think consensus is what separates science from other pursuits. It is rather the kind of rational, objective judgements made by individual scientists in closely related fields.
I didn't suggest consensus separates science from other pursuits, only that it is critically important to how science operates, and most especially to how we assess scientific theories.

Re: APOD: Kepler 78b: Earth Sized Planet... (2013 Nov 05)

Posted: Thu Nov 07, 2013 6:26 am
by Nitpicker
Chris Peterson wrote:
Nitpicker wrote:But I don't think consensus is what separates science from other pursuits. It is rather the kind of rational, objective judgements made by individual scientists in closely related fields.
I didn't suggest consensus separates science from other pursuits, only that it is critically important to how science operates, and most especially to how we assess scientific theories.
Indeed you did not. Nor did I suggest you did. I was just trying to get back to the main point of my little "metaphysical side note", which I had perceived to drift somewhat. Apologies for the confusion.

Re: APOD: Kepler 78b: Earth Sized Planet... (2013 Nov 05)

Posted: Thu Nov 07, 2013 1:57 pm
by robgendler
owlice wrote:
robgendler wrote:
owlice wrote:Rob,

I didn't see Chris stating that he was speaking of complex life; where did he do so?

It seems to me you are very close to "true biologists = anyone working in biology (especially astrobiology) I disagree with." I certainly hope I'm wrong about that.
You have to admit astrobiology is a strange field.......the study of something in which we have absolutely no proof of its existence. I don't mean any disrespect....but to enter a field in which there is absolutely no proof of the existence of the subject matter would require an overzealous (and unrealistic) belief that it exists. Can you name another field of science which is similar? Also I'd love to see a few high ranking specialists in the field who have their "primary" training in the biological sciences. I doubt you can provide any. That says a lot since "biology" is part of the name they adopted. Again not a scientific field which I can regard in any serious manner.
But there IS proof of its existence -- life on Earth. I don't find astrobiology a strange field at all. I think it quite natural and reasonable to look for what is here out there.

I think I'm about to find a good deal of irony in your posts about this, however.... how much "primary" training (I take it by "primary" training, you mean academic coursework) do you have in astronomy?
As usual my comments are being taken by you as some personal insult rather than an open discussion between people having different opinions. The "irony" of me not having a degree in astronomy doesn't make any sense and I don't see the pertinence at all. I do astrophotography as a hobby, not a profession. As an analogy to explain my position....."gravity waves" are a theoretical phenomenon in physics, the existence of which has yet to be proved. If someone set up a graduate program offering a degree in gravity waves....wouldn't that seem weird? I certainly can understand physicists researching gravity waves but starting a program for "gavity waveologists" would seem pretty premature and downright silly and not something other scientists would take seriously.

Re: APOD: Kepler 78b: Earth Sized Planet... (2013 Nov 05)

Posted: Thu Nov 07, 2013 2:21 pm
by Chris Peterson
robgendler wrote:As an analogy to explain my position....."gravity waves" are a theoretical phenomenon in physics, the existence of which has yet to be proved. If someone set up a graduate program offering a degree in gravity waves....wouldn't that seem weird? I certainly can understand physicists researching gravity waves but starting a program for "gavity waveologists" would seem pretty premature and downright silly and not something other scientists would take seriously.
There already are people whose entire professional careers are focused on the study of gravity waves, and nobody finds it odd. The only reason that you don't find the field tied to a specific degree is that it is naturally part of astrophysics. An astrobiology degree makes perfect sense, however, as a well-educated astrobiologist will study what are classically separated fields- astronomy, geology, chemistry, biology. The few schools that offer astrobiology degrees do so because of that.

I don't know of anybody who thinks it is silly for astrophysicists to study gravity waves, and I don't know anybody who thinks there is something intrinsically silly about studying astrobiology. Of course, an individual researcher may approach any subject intelligently or otherwise, and that's how they should be evaluated.

Re: APOD: Kepler 78b: Earth Sized Planet... (2013 Nov 05)

Posted: Thu Nov 07, 2013 3:22 pm
by robgendler
Chris Peterson wrote:
robgendler wrote:As an analogy to explain my position....."gravity waves" are a theoretical phenomenon in physics, the existence of which has yet to be proved. If someone set up a graduate program offering a degree in gravity waves....wouldn't that seem weird? I certainly can understand physicists researching gravity waves but starting a program for "gavity waveologists" would seem pretty premature and downright silly and not something other scientists would take seriously.
There already are people whose entire professional careers are focused on the study of gravity waves, and nobody finds it odd. The only reason that you don't find the field tied to a specific degree is that it is naturally part of astrophysics. An astrobiology degree makes perfect sense, however, as a well-educated astrobiologist will study what are classically separated fields- astronomy, geology, chemistry, biology. The few schools that offer astrobiology degrees do so because of that.

I don't know of anybody who thinks it is silly for astrophysicists to study gravity waves, and I don't know anybody who thinks there is something intrinsically silly about studying astrobiology. Of course, an individual researcher may approach any subject intelligently or otherwise, and that's how they should be evaluated.
Chris..maybe you ought to read my comments more carefully. I never said the study of astrobiology is silly.I'm not against doing that type of research. However the establishment of an entire field with graduate degrees, etc based on something not even remotely proven to exist is a bit much. IMO it was probably spawned by SETI enthusiasts which explains the overzealousness of their crusade. Also agaon...I never said it was silly to study gravity waves (please read more carefully). I would think though it's a bit premature to establish a field with graduate degrees separate from physics to create Phd gravity waveologists.

Re: APOD: Kepler 78b: Earth Sized Planet... (2013 Nov 05)

Posted: Thu Nov 07, 2013 3:26 pm
by geckzilla
But you did equate astrobiology to a made up field of gravity waveology, which you called silly. Ergo, astrobiology is silly.

Re: APOD: Kepler 78b: Earth Sized Planet... (2013 Nov 05)

Posted: Thu Nov 07, 2013 4:04 pm
by Chris Peterson
robgendler wrote:I never said the study of astrobiology is silly. I'm not against doing that type of research. However the establishment of an entire field with graduate degrees, etc based on something not even remotely proven to exist is a bit much.
Well, I can't agree. It's possible we'll never know if life exists outside our system, yet looking for it will remain a valid area of research. And for the reasons I stated- that the field is multidisciplinary- it makes very good sense to establish it as a separate field, not merely a subdiscipline.

Indeed, simply studying how life developed on Earth goes far beyond biology, and is properly a field of study for people with extensive non-biological training, as well. I'd call that research astrobiology, as much as I do looking for life beyond Earth.

Re: APOD: Kepler 78b: Earth Sized Planet... (2013 Nov 05)

Posted: Thu Nov 07, 2013 4:22 pm
by robgendler
Chris Peterson wrote:
robgendler wrote:I never said the study of astrobiology is silly. I'm not against doing that type of research. However the establishment of an entire field with graduate degrees, etc based on something not even remotely proven to exist is a bit much.
Well, I can't agree. It's possible we'll never know if life exists outside our system, yet looking for it will remain a valid area of research. And for the reasons I stated- that the field is multidisciplinary- it makes very good sense to establish it as a separate field, not merely a subdiscipline.

Indeed, simply studying how life developed on Earth goes far beyond biology, and is properly a field of study for people with extensive non-biological training, as well. I'd call that research astrobiology, as much as I do looking for life beyond Earth.
My point is that practically "all" the people studying it are "outside" the field of biology....and that's for a very good reason. They have unrealistic expectations. Its a romantic endeavor for them based on fantasy. Evolutionary biologists have a very strong reality check built in by virtue of their training that tempers their enthusiasm. They understand the dismal odds of this kind of research. We'll have to agree to disagree.

Re: APOD: Kepler 78b: Earth Sized Planet... (2013 Nov 05)

Posted: Thu Nov 07, 2013 4:26 pm
by Chris Peterson
robgendler wrote:My point is that practically "all" the people studying it are "outside" the field of biology...
I think you are wrong about that. The papers I've read are almost all by biologists. I think you're conflating different types of research- looking for habitable planets is different from studying abiogenesis or certain aspects of evolution. Both are published under astrobiology, however, with the former being mostly astronomers, and the latter mostly biologists.

Re: APOD: Kepler 78b: Earth Sized Planet... (2013 Nov 05)

Posted: Thu Nov 07, 2013 4:55 pm
by Ann
My personal thoughts about the field of astrobiology is that it should study the only life that we know of in the universe - that is, the biosphere of the Earth - and do so from an astronomical perspective. That is, it should study Earth as a place in the universe and try to explain why this particular place is so habitable.

This, of course, implies trying to hunt down the actual emergence of life on the Earth. How did it happen? Why did it happen?
Chris wrote:

There is very good work being done in this area, and no reason to even think there is a well defined distinction between living and non-living.
...
But people have very interesting ideas- ideas that are consistent with our understanding of the early Earth environment and with our understanding of chemistry and biology. (There is a report out just today about the role of clay in the creation of life.) From a scientific standpoint, we're probably back in the realm of complex systems, meaning that no simple theory may exist to describe how life formed on Earth. Instead, we probably have a complex interaction of chemical and geophysical systems, along with an evolutionary process (evolution even before something reached the stage that we'd unambiguously call "alive"). And this over millions of years, perhaps. So it may not be testable in a lab at all, except in pieces, subsequently modeled by simulations. A complicated bit of science, to be sure.
I have been thinking about this - the idea that life formed gradually from non-life over many transitional forms and millions of years, and I find the suggestion absolutely compelling. It appeals to my amateur sense of scientific beauty, that much is certain.

But if that is how it happened, does that in itself prove that the same slow non-life-to-life process is likely to happen elsewhere? It happened once, yes. Does that mean it is bound to, or likely to, happen over and over again wherever there is a suitable planet in a habitable zone?

My objection to astrobiology is that I think that the emergence of life from non-life is not sufficiently well understood to use it as a starting point to draw conclusions from. I don't mean to criticize those who try to understand how life came about. Absolutely not! Clearly this of field of research is totally fascinating! I'm just saying that until we have a firmer understanding of how the life-creating processes work, it is just too hard to predict how often they will happen elsewhere. And that is why I think that astrobiology should really concentrate on life on Earth, because I don't think that astrobiologists necessarily know what they are talking about when they make assumptions about the nature and prevalence of life elsewhere.

Unlike Rob, I have no objection whatsoever to the study of gravity waves. No one has seen gravity waves yet, but we have a firm theory explaining why they should exist. I'd like to compare gravity waves with the Higgs particle, because for the longest time no one had seen the Higgs particle either, but particle physicists had a firm theory explaining why it should exist. All they needed to do to make Higgs come out of hiding was to build a gigantic particle accelerator, run the accelerator to its limit and work their own little backsides off in a totally heroic effort to spot the tracks of the stubborn little bugger as it exploded in a blast of particle glory. Finding the Higgs particle was hard, hard work, but the scientists knew why it should exist and how they should find it, and finally, finally they succeeded. The gravity waves people haven't succeeded yet, but who is to say that they won't do so in the future?

But I don't think astrobiologists have presented a firm theory explaining why there should necessarily be life on other planets. I don't think they have managed to make life on other planets a necessary part of any sort of standard theory explaining the universe. Let me put it like this: the Higgs particle had better exist, or so many assumptions about the universe we live in would have been proved wrong. Gravity waves had probably better exist too, because if they don't then there is something fundamental that we don't understand about the crucial role of gravity in the universe. But suppose we don't find any life away from Earth in the foreseeable future. What part of our understanding of the universe breaks down if we fail to find life away from Earth?

So in other words, I don't think we need to find life in space in order to make any sort of grand unified theory work. Life in other solar systems is optional to our understanding of the universe. It might be there or not, it might be rare or it might be there all over the galaxy. What exactly can we conclude about the laws of physics if life is rare, and what can we conclude about these laws if life is common?

This is my point. Astrobiologists are not working from a firm, rigorous theory explaining why the "exo-life" they look for is a necessary part of the universe. And not only do they lack a firm theory, but they lack any real observational evidence, too. The way I see it, they are floundering. Wasn't it Einstein who said something to the effect that anyone who has a fixed point to start from can dislocate the universe?

At least the gravity waves people have a beautifully firm theory to start from. Who knows if they can't dislocate the universe enough to find the waves that must be there?

Ann

Re: APOD: Kepler 78b: Earth Sized Planet... (2013 Nov 05)

Posted: Thu Nov 07, 2013 5:04 pm
by robgendler
Chris....find someone...anyone on this page with a degree in biology.

http://lasp.colorado.edu/life/directory.html

Re: APOD: Kepler 78b: Earth Sized Planet... (2013 Nov 05)

Posted: Thu Nov 07, 2013 5:27 pm
by Chris Peterson
Ann wrote:This is my point. Astrobiologists are not working from a firm, rigorous theory explaining why the "exo-life" they look for is a necessary part of the universe. And not only do they lack a firm theory, but they lack any real observational evidence, too. The way I see it, they are floundering.
No, they are working from a hypothesis. It is too early to form any solid theories. But the hypothesis is an incredibly good one: there is life on Earth, and there are countless Earth-like planets, thus we can reasonably expect life elsewhere.

How would you have any new science begin?

Re: APOD: Kepler 78b: Earth Sized Planet... (2013 Nov 05)

Posted: Thu Nov 07, 2013 5:44 pm
by owlice
robgendler wrote:Chris....find someone...anyone on this page with a degree in biology.

http://lasp.colorado.edu/life/directory.html
I know this was Chris's assignment, but I was curious so took a quick look... Among the "participating departments and partners" are CHEM (Dept. of Chemistry and Biochemistry), CIRES (Cooperative Institute for Research in Environmental Studies), EEB (Dept. of Ecology and Environmental Biology), MCDB (Dept. of Molecular, Cellular, and Developmental Biology), and PAOS (Program in Atmospheric and Oceanic Science).

Looks to me as though these people may know a thing or two about biology:
Ned Friedman
Norm Pace
Shelley Copley

Maybe these folks, too:
Ruth Ley (MCDB), molecular analysis of microbes in hypersaline ecosystems
Diane McKnight (ENGR), environments and ecology in Antarctica
Steven Schmidt (EEB), microbiology in psychrophilic environments
John Spear (MCDB), molecular analysis of microbes in hypersaline and hydrothermal ecosystems
James T. Hynes (CHEM), theoretical studies of peptide bond formation under pre-biotic conditions
Veronica Vaida (CHEM), chemical evolution and origin of life

I'll leave it as an exercise to others to suss out the exact degrees and peer-reviewed research of these folks.
robgendler wrote:
owlice wrote:
robgendler wrote: You have to admit astrobiology is a strange field.......the study of something in which we have absolutely no proof of its existence. I don't mean any disrespect....but to enter a field in which there is absolutely no proof of the existence of the subject matter would require an overzealous (and unrealistic) belief that it exists. Can you name another field of science which is similar? Also I'd love to see a few high ranking specialists in the field who have their "primary" training in the biological sciences. I doubt you can provide any. That says a lot since "biology" is part of the name they adopted. Again not a scientific field which I can regard in any serious manner.
But there IS proof of its existence -- life on Earth. I don't find astrobiology a strange field at all. I think it quite natural and reasonable to look for what is here out there.

I think I'm about to find a good deal of irony in your posts about this, however.... how much "primary" training (I take it by "primary" training, you mean academic coursework) do you have in astronomy?
As usual my comments are being taken by you as some personal insult rather than an open discussion between people having different opinions. The "irony" of me not having a degree in astronomy doesn't make any sense and I don't see the pertinence at all. I do astrophotography as a hobby, not a profession. As an analogy to explain my position....."gravity waves" are a theoretical phenomenon in physics, the existence of which has yet to be proved. If someone set up a graduate program offering a degree in gravity waves....wouldn't that seem weird? I certainly can understand physicists researching gravity waves but starting a program for "gavity waveologists" would seem pretty premature and downright silly and not something other scientists would take seriously.
Rob,

Wow! Wherever did you get the idea that I'm taking your comments as "some personal insult"?! I'm not insulted at all! (Why would I be? I'm not an astrobiologist.) I'm amused by your comments, not insulted by them. You think I should agree with you ("must admit astrobiology is a strange field"). I don't.

Re: APOD: Kepler 78b: Earth Sized Planet... (2013 Nov 05)

Posted: Thu Nov 07, 2013 5:45 pm
by Ann
Chris Peterson wrote:
Ann wrote:This is my point. Astrobiologists are not working from a firm, rigorous theory explaining why the "exo-life" they look for is a necessary part of the universe. And not only do they lack a firm theory, but they lack any real observational evidence, too. The way I see it, they are floundering.
No, they are working from a hypothesis. It is too early to form any solid theories. But the hypothesis is an incredibly good one: there is life on Earth, and there are countless Earth-like planets, thus we can reasonably expect life elsewhere.

How would you have any new science begin?
Indeed, Chris, a new science has to start by someone formulating a hypothesis.

What I'm saying is that we are at a stage where the hypothesis of life away from Earth has not been truly tested at all. Therefore we find ourselves in the situation of Democritus; he could formulate a hypothesis about atoms, but he had no way of testing if atoms truly exist. Today we are making observations to find actual life away from Earth, but all of them have come up absolutely empty. What do we really know about what it takes to make a planet not only habitable, but truly inhabited? Eventually we should know more, hopefully a lot more, and then we can really start quantifying and describing life away from Earth. But for now I think that any attempts to describe how much life there is in our galaxy, let alone in the universe, is slightly silly. It is far less silly to make estimates about the prevalence of simple life than to try to guesstimate how many technological civilizations that exist out there, but for now, when we know so very little, even trying to count the planets that are likely to host bacterial life seems rather iffy to me.

Ann

Re: APOD: Kepler 78b: Earth Sized Planet... (2013 Nov 05)

Posted: Thu Nov 07, 2013 5:46 pm
by Chris Peterson
robgendler wrote:Chris....find someone...anyone on this page with a degree in biology.

http://lasp.colorado.edu/life/directory.html
Three of them are biologists. There are also atmospheric physicists, geologists, planetary scientists, even a philosopher. None seem to call themselves "astrobiologists". They are members of an astrobiology research team, meaning they collaborate. You can be sure they are members of other research teams, as well.

Sorry, I think your example here demonstrates astrobiology done right: a very diverse team loosely collaborating on projects where there is a common interest. All of the researchers have long lists of papers which have nothing to do with astrobiology, as well.

Re: APOD: Kepler 78b: Earth Sized Planet... (2013 Nov 05)

Posted: Thu Nov 07, 2013 6:07 pm
by owlice
Ann wrote:try to guesstimate how many technological civilizations that exist out there
Ann,

Where in this discussion did that occur? I missed it.

Re: APOD: Kepler 78b: Earth Sized Planet... (2013 Nov 05)

Posted: Thu Nov 07, 2013 6:16 pm
by Ann
owlice wrote:
Ann wrote:try to guesstimate how many technological civilizations that exist out there
Ann,

Where in this discussion did that occur? I missed it.
Admittedly this post is not about counting technological civilizations, but at least about counting solar systems hosting intelligent life forms.

Ann

Re: APOD: Kepler 78b: Earth Sized Planet... (2013 Nov 05)

Posted: Thu Nov 07, 2013 6:18 pm
by Chris Peterson
Ann wrote:It is far less silly to make estimates about the prevalence of simple life than to try to guesstimate how many technological civilizations that exist out there, but for now, when we know so very little, even trying to count the planets that are likely to host bacterial life seems rather iffy to me.
While the whole idea of looking for intelligent life is what generates headlines and magazine articles, that represents only the tiniest piece of what we might call "astrobiology". The field is primarily about understanding biogenesis, the relationship between atmosphere and biological systems, and identifying planets that have characteristics similar to Earth's. All are perfectly valid areas of research, and for most researchers who have publications that might include "astrobiology" as a keyword, astrobiology itself represents only a small part of their total research interests.

We know of one type of planet that does host bacterial life. So it seems eminently reasonable to develop "Earth-like" filters that can be applied to the exoplanet database.

Re: APOD: Kepler 78b: Earth Sized Planet... (2013 Nov 05)

Posted: Thu Nov 07, 2013 6:47 pm
by geckzilla
Ann wrote:Today we are making observations to find actual life away from Earth, but all of them have come up absolutely empty.
Considering that simple life as we know it does not emit easily detectible forms of energy, this sounds about right. It's going to be very hard to find evidence of life from even the most heavily life-laden exoplanet out there. We can barely even directly detect exoplanets at this point. Maybe that's the point you are trying to make--that it is impossible and hopeless to even try looking--and all I can do is disagree from a very visceral part of myself. Finding life which developed independently from Earth, whether it's in our solar system or in another, has got to be one of the most important and profound endeavors in the entire history of humanity.

Re: APOD: Kepler 78b: Earth Sized Planet... (2013 Nov 05)

Posted: Thu Nov 07, 2013 7:39 pm
by robgendler
geckzilla wrote:
Ann wrote:Today we are making observations to find actual life away from Earth, but all of them have come up absolutely empty.
Considering that simple life as we know it does not emit easily detectible forms of energy, this sounds about right. It's going to be very hard to find evidence of life from even the most heavily life-laden exoplanet out there. We can barely even directly detect exoplanets at this point. Maybe that's the point you are trying to make--that it is impossible and hopeless to even try looking--and all I can do is disagree from a very visceral part of myself. Finding life which developed independently from Earth, whether it's in our solar system or in another, has got to be one of the most important and profound endeavors in the entire history of humanity.
Yes....I agree with you. It would be an important and meaningful discovery....and yes lets continue to refine the techniques for exoplanet detection. My point is that lets wait for some real evidence of extraterrestrial life before we establish this as a distinct field. There now exist institutions, societies and graduate degrees being given in astrobiology. Isn't this putting the cart before the horse? Someone had to actually do successful neurosurgery before there became the field of neurosurgery. When I started out in astronomy I would observe the andromeda galaxy wondering if there was another being on M31 observing the Milky Way. I fully understand the feeling. Later I read extensively about the history of life on our planet and it gave me a very strong reality check regarding the chances of that history repeating itself on some other world. It gave me pause. That said life may exist elsewhere but the numbers of potential worlds being passed around are way too optimistic IMO.

Re: APOD: Kepler 78b: Earth Sized Planet... (2013 Nov 05)

Posted: Thu Nov 07, 2013 10:34 pm
by Nitpicker
These days, you could pick a university degree out of a hat and get a sillier one than astrobiology. At least astrobiology is a combination of two strongly academic fields. What are your opinions of university degrees in business management? I expect it won't be long before a degree will be offered in common sense (although if I were giving it, you'd fail at the point of enrolment).

Re: APOD: Kepler 78b: Earth Sized Planet... (2013 Nov 05)

Posted: Thu Nov 07, 2013 11:16 pm
by mjimih
I asked earlier, but not very well. Um does the periodic table give up any clues about whether there are potentially other ways to create life besides "carbon based"? And if so, someday after more research, we shall be looking for a wider variety of exo-planet types that may be habitable hopefully. Not just temperate rocky water-laden ones like Earth.
Right now science (a scientist) is a-stir about Titan's oceans harboring life. We also found mystery bubbles in the rocks on Mars. I also heard that a planet with free oxygen in an atmosphere, is a sign of life possibly.
My point is we shouldn't keep our ET search too limited. We must be creative (Einstein comes to mind). We are assuredly not the ONLY kind of life. We are Earth life. And I predict it will be exceedingly difficult to spot life's signs in an exo-atmosphere, simply because of just the sheer number of types out there that we haven't even a clue about. And the distances.
So...
Does the periodic table (which is the same table used by all aliens, everywhere), give up any clues about whether there are potentially other ways to create life besides "carbon based"? The answer will help us to know more about what to look for in potential habitable planet candidates.

Mark

Re: APOD: Kepler 78b: Earth Sized Planet... (2013 Nov 05)

Posted: Thu Nov 07, 2013 11:24 pm
by Nitpicker
mjimih wrote:So...
Does the periodic table (which is the same table used by all aliens, everywhere), give up any clues about whether there are potentially other ways to create life besides "carbon based"? The answer will help us to know more about what to look for in potential habitable planet candidates.
See:
http://en.wikipedia.org/wiki/Hypothetic ... ochemistry

Silicon (just below Carbon in the periodic table) based life forms would seem to be the most likely alternative. (I have a vague memory of such a life form being discovered in some deep sea vent on Earth, but maybe that was fiction.)

Re: APOD: Kepler 78b: Earth Sized Planet... (2013 Nov 05)

Posted: Thu Nov 07, 2013 11:32 pm
by mjimih
thanks!

those deep sea tubes get all their nutrients from minerals in the hot vents. Which is unique if I remember right.