Talk:Astrobiology

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Astrobiology was a good article nominee, but did not meet the good article criteria at the time. There are suggestions below for improving the article. Once these are addressed, the article can be renominated. Editors may also seek a reassessment of the decision if they believe there was a mistake. Reviewed version: April 3, 2008

Contents 1 Unprofessional Introduction 2 Intangible evidence? 3 Is this page copied... from... or to somwhere? 4 Drake equation needs to define its terms 5 Personal opinions 6 A little clarification 7 See "mountains, molehills..." 8 New User Note 9 Where does this fit in? 10 Lulz scientific illiteracy at work 11 Xenobiology 12 Strange article 13 Good Article nomination 14 GA Review

[edit] Unprofessional Introduction

Why asking questions in the beginning?!??! improve this article and WIKIFY IT PRONTO

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Many of this theories about alien life rely on the premise that the existence of water (and other physical circustances) in a planet leads or is a clue to the existence of life wich is in my view a false judgement and it points in many ways to spontaneous generation theories, wich were never proven and somewhat go back to pre-scientifical thinking. The whole question is how life happened in the Universe. It can be an extremely rare event (unique), or quite regular. I do not agree that non-living matter can generate living beings, otherwise I would start thinking that the right mixture of water, minerals and sunlight would create bacteria, worms or whatever. The circumstances in wich life appeared are still far beyond our understanding.--Fpenteado 16:47, 2 February 2007 (UTC)

Is it worth pointing out that the vast majority of scientists now use the term Astrobiology? C.F. the two scientific journals dedicated to the topic are "Astrobiology" and "The International Journal of Astrobiology", respectively. As "Xenobiology" has fallen out of favor in the science community, I'd suggest a name change... IdahoEv 07:51, 16 Oct 2004 (UTC)

I agree we should move to astrobiology, and google does too: Google:astrobiology (743,000 hits) vs. Google:xenobiology (9,430 hits many of which are Wikipedia or it's mirrors). Also there are journals and funding sources for astrobiology and it has become a more respectable enterprise. Xenobiology is not currently used. If there are no objections, I'll do the move soon. --Lexor|Talk 03:39, Dec 11, 2004 (UTC)

Lexor, you are correct. The page needs to be moved. It was originally named "astrobiology", but someone moved it in September. I have never understood the reasoning behind such a move, and it has bothered me for months. Since Astrobiology already exists as a redirect (after it was moved), I believe that the easiest way to preserve the history of Xenobiology is to temporarily delete the Astrobiology page, and then move Xenobiology to Astrobiology. --Viriditas | Talk 04:28, 11 Dec 2004 (UTC)

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the absence of life in the rest of the Universe is a falsifiable hypothesis

In what way is it falsifiable ? --Taw

Proven communication from extraterrestrials, or proven samples of extraterrestrial life, would disprove the hypothesis that we are alone in the Universe.

Isn't earth so unique? Everyone is striving so hard to find even a nonexistant grain of life on another planet, when the earth is teeming with life! Every single inch! -- The Anome

Try a thought experiment. G. W. Bush says US telescopes have picked up signals from aliens telling us to stop using drugs. Do you believe him? If not, do you have equal access to the telescopes to listen to them yourself? The hypothesis is probably NOT falsifiable in the strict sense, as the validation of where the 'living' material came from isn't going to determine if (a) the few scientists who can touch it weren't duped (b) it really came from space or (c) it's out of a military lab.

The motivations for such games are extreme, BTW, if it CAN be done it WILL be done, faking it I mean: 'Oops the alien thing got out of the lab and killed all the people who can't digest lactose, not our fault, just how it evolved, oops'. Of course only white folk digest lactose.

The Drake Equation doesn't provide any compelling reason to assume that extraterrestrial life exists, as it may be that some of the other fractions are so low we're the only planet that's ever had life on it. Hence, that argument is flawed, isn't it? --anon

Statement qualified - it should work for you now. --maveric149

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Xenobiology should rightfully include speculation about, and modelling of, and attempting even to try to CREATE, alternate life forms, and that is a bit different than the existing xenobiology/artificial-life distinction.

[edit] Intangible evidence?

"There is no current tangible evidence for intelligent extraterrestrial life"

What kind of evidence falls outside of the heading of "tangible evidence"? JWSchmidt 16:32, 12 Apr 2004 (UTC)

Psychic communication, teleportation, astral projection, crop circles, abductions... See pseudoscience. --zandperl 23:47, 12 Apr 2004 (UTC)

[edit] Is this page copied... from... or to somwhere?

Hi!

So... looking for Xenobiology on wikipedia, I have this file... good... but Google also comes up wit

We are the only planet to have life in the entire universe bigger than billions of light years? How probable is this naive statement?

[edit] Drake equation needs to define its terms

The Drake equation is presented without indicating what the various factors are. (Only the first four are mentioned). All the factors of that equation should be defined, or else the equation removed and referred to another page. —The preceding unsigned comment was added by 82.225.66.243 (talk) 05:58, 14 April 2007 (UTC).

[edit] Personal opinions

I am of the opinion, and I am unanimous on it, that to suggest that earth is the only planet in the entire universe be it known or unknown is self delusional. Why would God create just one planet capable of supporting life? 63.3.20.129 03:30, 17 April 2007 (UTC)

Which god? Their have been thousands of gods that man has made throughout history.72.231.182.73 03:16, 19 April 2007 (UTC)

I think he means spiritual, meaning there are limitless types you can believe in without a standard to grow upon. In any case a chance of extra terrestrial life is solid in that there is a constant change on all planets and that there are so many. Think of it it this way: there is a lottery, 100,000,000 people buy a ticket. Only one person wins. It is chance and someone eventually found the generated ticket, the planet in a hole was the someone, the someone was life on another planet. The next lottery starts, 100,000,000 people buy a ticket, someone eventually found the generated ticket, the someone was our earth, and life is on earth. —Preceding unsigned comment added by Brndon1988 (talk • contribs) 02:27, 23 September 2007 (UTC)

Is it just me, or is the idea of a unanimous personal opinion kind of hilarious? Just how many of your selves have to be in agreement here? --Totorotroll (talk) 14:01, 10 June 2008 (UTC)

[edit] A little clarification

Xenobiology and Astrobiology are not synonymous. Xenobiology means “biology of the foreigners”, biology distinct from humans. Astrobiology implies conditions on other planets suitable for supporting human life, or originating life as we are familiar with.

See: http://biocab.org/Astrobiology.html

Scientists, like Jack Cohen and Ian Stewart feel that the phrase 'conditions necessary for life' lacks imagination and is a shortsighted approach to the speculation of what extraterrestrial life might be like and where it might be found. So called 'habitable zones' (regions around stars that are conducive to Earth-type life -- not to hot nor too cold) are too narrow to have any meaning when applied to the search for life in the universe.

See: http://humanitieslab.stanford.edu/2/381

Highly recommended reading:

Non-fiction - What Does a Martian Look Like? by Jack Cohen, Ian Stewart

Speculative Fiction - Starquake! and The Flight of the Dragonfly by Robert L. Forward

Planetfall 13:14, 20 April 2007 (UTC)

I just added a bit, by taking out the ridiculous statement about life having to be carbon-based and oxygen-breathing. Nowhere do the biological criteria for life (even on Earth) require these characteristics. #2 would eliminate anaerobic bacteria - in all probability very like the first life forms here. The biological criteria for life are that a living organism:

1. Is highly complex and organized;
2. Takes energy from the environment and modifies it (metabolizes);
3. Is internally homeostatic (maintains internal biochemistry);
4. Responds to stimuli;
5. Reproduces (serially and/or sequentially);
6. Grows and develops (sometimes considered a subset of #5);
7. Has the ability to adapt physiologically (to its environment);
8. Adapts (or can adapt) evolutionarily (over generations); and
9. Contains internal information which allows it to carry out all of the above.

Notice that NOWHERE is carbon or oxygen mentioned (nor DNA, for that matter). If something has all of these characteristics, it is alive by present, mundane biological criteria. Even so, there are going to be questionable areas, as there are on earth. Is a virus alive? Some (myself included) would say no; others yes. Neither is clearly right or wrong, since it depends on interpretation. The big problem is that there is NO definition of life, and if you can't define something, how do you know is's there? Does that help a bit? Esseh 01:07, 27 April 2007 (UTC)

Where did you get that info from, Esseh? 1 3 7 8 and 9 all seem a bit questionable. I was always taught at school that a living organism obeys the 7 life processes "MRS NERG", which stands for movement, reproduction, sensitivity, nutrition, excretion, respiration and growth. — Jack · talk · 13:44, Friday, 27 April 2007

Hi Jack. Check any first year university text. For example, Campbell and Reece (2005). Biology, 7th ed. Pearson (not a great text, but OK). On p. 3, it lists 7 criteria (Fig. 1.2), and qualifies that as "Some properties of life." (emphasis mine). Those properties are (a)Order (my #1), (b)Evolutionary adaptation (my #8), (c)Response to the environment (my #4), (d)Regulation (my #3), (e)Energy processing (my #2), (f) Growth and development (my #6), and (g)Reproduction (my #5). So, that leaves out (of that admittedly incomplete list), my #7 and #9, which can be found in other texts. For a quick example of #7, stand in the cold for a few minutes. You begin to shiver - a physiological adaptation to cold, designed to warm the body. As for #9, that's a reference to DNA/RNA (on earth). Without them (or something like them), NONE of the others are possible. Arguably, it's the most important criterion.

Actually, my list is taken from multiple sources. As for your list - a plant or a sponge are alive. Does they move? Does they excrete (a sponge does)? How do they "know" how to do the things you listed?

Given that, name me one life form that does not have all of the characteristics listed. (Viruses don't count - as I said before, they're missing some, namely #1 (some quite simple), #2 and 3 (why antibiotics don't work), #6, and #7. However, even they have some!) Hope that helps. Esseh 23:22, 27 April 2007 (UTC) (Oh, and don't believe everything they teach you in school, or that you read in Wikipedia. Question everything, demand evidence, and think about it - it's the scientific way!) (Sorry - typos. Esseh 23:23, 27 April 2007 (UTC))

Fair enough, I mostly concede, as your argument is better referenced. While I do agree that viruses aren't alive, I also believe plants and sponges respire and therefore excrete waste (even if it is CO₂). Most creatures would violate your second point, as very few creatures are able to properly control their internal environment (eg all prokaryotes) — Jack · talk · 03:20, Sunday, 29 April 2007

(Apparently you edit-conflicted me - doesn't matter - answer's still the same. )Jack, I think you mean #3, and not true! Monera and the archaebacteria have very rigidly controlled boichemical environments. Most of the enxymatic reactions for life take place within very narrow boundaries of pH, salinity and other factors. All living organisms must maintain those conditions or die! (See again Campbell & Reece (d)). Note that this is not the same as homeothermy (constant internal temp), but is homeostasis. (Shivering was just an anthropocentric example.) Waste that's excreted is just a by-product of metabolism (my #2). Again, give me one example of a living thing that does not fit all of my criteria! (And no hard feelings, eh? This is just to clarify what criteria we should use to characterise life on other worlds - if and when we find it. Personally, I feel these criteria fit, as they fit all living things we know so far.) All the best. Esseh 03:34, 29 April 2007 (UTC)

[edit] See "mountains, molehills..."

Hi all. I've noticed that the "artist's impression" of Gliese 581 c has found its way here, too. Following my objection (and presumably some agreement) on that page, it is now gone. I suggest it meet the same fate here, and for the same reasons. See argument at talk:Gliese 581 c under the heading above. Esseh 04:16, 4 May 2007 (UTC)

[edit] New User Note

Hello, i am just a common veiwer of wikipedia, and i would just like to say that I really appreciate the artwork and photos on wikipedias pages, espcially on pages you wouldnt expect to see anything. (this isn't related to the above post). NewUser1 0:17, 8 May 2007 (UTC)

[edit] Where does this fit in?

Carbon globules in meteorite may have seeded Earth life--Svetovid (talk) 20:16, 18 January 2008 (UTC)

[edit] Lulz scientific illiteracy at work

For example, while science cannot prove string theory, there is a great deal of mathematical computation which implies the existence of strings of energy.

Hi, reality check. "Mathematical computation" cannot "imply" anything about the real universe. Math is not science. It is context-free and totally a priori. This is pseudoscientific bullshit, and so is astrobiology. Why? Because you cannot make generalizations about an unknown population based on a sample of one. Astrobiology can only tell us where Earth life could or couldn't exist. Not where life itself could or couldn't exist. --70.131.121.26 (talk) 14:20, 20 February 2008 (UTC)

[edit] Xenobiology

I chopped this bit from the intro because 1. The source is a bit dubious, or non-notable at the very least. And 2. It exhibits a misunderstanding of how language works. 'Etyomology is not destiny' as linguists like to say. 'Xenobiology' is no more 'technically' wrong because xeno means stranger in Greek, than talking about the Sun's 'Corona' is wrong because it is not actually a crown. but this is technically incorrect because its terminology means "biology of the foreigners".^[1] Ashmoo (talk) 13:50, 6 March 2008 (UTC)

It's unfortunate that so much of the effort that goes into wikipedia entries goes into pushing agendas. This isn't the place to lobby for one name over another. Xenobiology has been in use for awhile, and while it may be falling out of favor behind another reasonable term, Astrobiology, it isn't because the word was improperly coined. To say that it means "biology of the foreigner", as if we're speaking about biology of those outside our country, is just silly. What it means is "knowledge of foreign life", which is clearly an apt name for this field of study. It is at least as apt as Astrobiology, "biology of constellations". The point is, why even comment on whether Xenobiology is an acceptable term? It's not a popularity contest. Linking Xenobiology into Astrobiology clearly establishes that the latter is the favored term at this time. - JP

[edit] Strange article

• This is a very strange article as it contains leghty sections that are expanded in other articles, such as exosolar planets or alternative biochemistry. I beleive it may require trimming and main tags for the sections. It is a common opinion that better networked pages are infact better than a series of lenghty ones.
• Btw, about the Etymology (without an o).. Xenobiology is a term that appears in sci-fi, such as star trek, where Xenos stands for alien/foreigner: the ancient greeks had no word for ufos and alien originally meant foreigner anyway (ei. non-resident aliens are not from mars). googling it, Xenobiology appears as a ufology term for the study of extraterrestrial anatomy, whereas astrobiology is the speculative sceince/artform from this article.
• About non DNA genetic code Nucleic acid analogues is the page most similar to it --Squidonius (talk) 21:56, 6 March 2008 (UTC)

[edit] Good Article nomination

I have removed uninformative/inappropriate links. Now, I feel that this article is excellently formatted. I would like to nominate it for Good Article status. Teh Rote (talk) 23:08, 13 March 2008 (UTC)

[edit] GA Review

Here are my comments on the article, which I do not believe passes GA standards.

1. Well written - FAIL. The layout still needs significant work. The lead doesn't sufficiently introduce the topic, and doesn't grab the reader's attention with a coherent message. For example, is the etymology of astrobiology important enough to be the first fact mentioned? The table of contents also suggests layout problems. A section named "Research Outcomes" probably shouldn't be the first one after "Overview". The list of astrobiologists adds little to the article, and it's debatable whether or not "Rare earth hypothesis" is an "outcome". The "Political influence" section also seems unnecessary.

There are also more detailed issues that should be resolved. The variables of the Drake equation should be defined if it's deemed important enough to be written in the article. Are degrees offered at several universities (as in Overview) or only one (as in Criticism)?

There are also minor style problems throughout the article (missing commas, unbalanced parentheses, etc.) that should also be fixed. Many subjects are linked multiple times (I see at least 5 NASA links).

That being said, there is good material here. My suggestion would be to use the current Overview, Research outcomes, Methodology, and Life in the Solar System sections as the basis for the article and remove much of the rest. This could be the basis of an interesting GA.

2. Factually accurate and verifiable - PASS

3. Broad in its coverage - PASS

4. Neutral - PASS

5. Stable - PASS

6. Images - marginal FAIL. The DNA, chloroplast, asteroid, the artist's conceptions and Kepler images all seem like they were added for the sake of having images, but this can fairly easily be fixed. The other images are more appropriate and improve the article.