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EnderW25
2002-Jan-03, 05:18 AM
Or was it just a wild guess and he happened to hit the jackpot? We didn't discover Europa had oxygen on it until Voyager passed by, correct? Or was it later? Either way, that's still a good 15 years past when Clarke wrote the book. Why did he pick Europa as the planet where new life would evolve?

EckJerome
2002-Jan-03, 09:37 PM
Have we discovered oxygen on Europa? I didn't think it had any atmosphere...or if it does, it is tenuous at best.

Are you referring to the book "2010?" Theories regarding the possibility of life on Europa (in oceans under the surface) have been around since shortly after the Voyager flybys, and before Clarke wrote that book. I don't think he mentions life on Europa at all in "2001."

In other words, he picked Europa because, at the time he wrote the book, it had (and still does have) a better chance for harboring life than anywhere else in the solar system (besides Earth, of course).

Still, Clarke is a remarkable visionary and seems to have a keen sense of what other worlds may really be like. A prime example of that is in his book "Earthlight" which opens with a monorail ride across the surface of the moon. Written in the late 1950s, the popular image of the moon's suface then was that of a rough and craggy surface. But Clarke's vision was that of softened hills and a landscape covered in thick dust. He pretty much nailed it.

In the third odyssey "2061" he has a scene of astronauts on the surface of Comet Halley. While it will be a while verifiying that environment, he painted a rather plausible picture.

He is also credited with the invention of the communication satellite, having envisioned (in his writing) a device orbiting the Earth that could reflect signals.

Eric

Russ
2002-Jan-03, 09:45 PM
On 2002-01-03 16:37, EckJerome wrote:
Have we discovered oxygen on Europa? I didn't think it had any atmosphere...or if it does, it is tenuous at best.


I'm not sure that anyone considers it a "discovery" perse. Just an axiom. Atmospheres and seriousness asside, if you have water you have oxygen. It's the O in H2O as you may recall, and can be seperated out by various natural processes. /phpBB/images/smiles/icon_wink.gif

EckJerome
2002-Jan-04, 08:14 PM
On 2002-01-03 16:45, Russ wrote:

Atmospheres and seriousness asside, if you have water you have oxygen. It's the O in H2O as you may recall, and can be seperated out by various natural processes. /phpBB/images/smiles/icon_wink.gif


Yes, it can be...but water molecules are not oxygen molecules (basic chemistry here), and I've not heard that we found "oxygen" on Europa. Doesn't mean we haven't, I just haven't kept up with the discoveries.

Still, oxygen implies we are talking about atmospheres here...and it is ridiculous to consider that Europa could have an oxygen-atmosphere capable of supporting life.

I think it is very confusing astronomy to infer that oxygen would make life possible on Europa when, in fact, it would be the presence of water and organic compounds. Gaseous oxygen was poisonous to early life on Earth...and is still considered useless (a waste product) by most plant life. But I didn't get the impression that Endor was thinking of alleged Europan oxygen as being a waste product from existing life.

Eric

Donnie B.
2002-Jan-05, 12:31 AM
Actually, the presence of gaseous oxygen in the atmosphere of an Earthlike planet is often cited as a strong sign of active life.

The reason is that oxygen is highly reactive, and won't last long if it's not constantly being replaced. On our home planet, the only significant source of gaseous oxygen is photosynthesis.

All else being equal, if we ever detected a planet with a strong free-oxygen signal in its atmosphere, we'd have strong evidence for life.

Lusion
2002-Jan-05, 05:58 PM
On 2002-01-04 15:14, EckJerome wrote:
...
Gaseous oxygen was poisonous to early life on Earth...and is still considered useless (a waste product) by most plant life.
...

Just a correction here: Plants do metabolize oxygen, using pretty much the same process we do, and even produce carbon dioxide as a biproduct of this. This is their respiration cycle, which is the same cycle we use. The only difference is that plants through photosynthesis convert carbon dioxide into oxygen (and sugars), and they convert more CO2 to O2 than they metabolize O2 to CO2. So, as a whole, it's true that plants consume CO2 as a resource and release O2 as a biproduct, but it's not true that O2 is unused by them.

A better example does exist on earth, however--some anaerobic life (eg, bacteria) find O2 poisonous (such life, obviously, is not found sitting on the surface).

So I agree with your general point... just not your example.

EckJerome
2002-Jan-07, 05:00 PM
On 2002-01-04 19:31, Donnie B. wrote:
All else being equal, if we ever detected a planet with a strong free-oxygen signal in its atmosphere, we'd have strong evidence for life.


And so I ask of the board for the THIRD TIME...have we found any trace of atmosphere on Europa that contains oxygen?

To date, and to my knowledge, all hypotheses of life on Europa are based upon observations suggesting large bodies of water beneath its icy surface. I have NEVER heard of any direct clues suggesting life itself on Europa...only the conditions that could support it. These are not the same things.

Frankly, I'm trying to clarify if the original poster had heard something I hadn't, or if he was pulling half-truths and/or incorrect information (IOW, bad astronomy) from some nether region.

Eric

ToSeek
2002-Jan-07, 05:15 PM
On 2002-01-07 12:00, EckJerome wrote:

And so I ask of the board for the THIRD TIME...have we found any trace of atmosphere on Europa that contains oxygen?



Yes:

Hubble finds oxygen atmosphere on Europa (http://www.jpl.nasa.gov/galileo/europa/hst.html)

EckJerome
2002-Jan-07, 06:24 PM
On 2002-01-07 12:15, ToSeek wrote:


On 2002-01-07 12:00, EckJerome wrote:

And so I ask of the board for the THIRD TIME...have we found any trace of atmosphere on Europa that contains oxygen?



Yes:

Hubble finds oxygen atmosphere on Europa (http://www.jpl.nasa.gov/galileo/europa/hst.html)


Thank you!!!

And quoting from the article, "Unlike Earth, where organisms generate and maintain a 21% oxygen atmosphere, Europa's oxygen atmosphere is produced by purely non-biological processes."

It is definitively stated that this oxygen atmosphere is is not and should not be associated with possible life on Europa...and that the extrmeme rarity of the atmosphere and cold temperatures would make it unsuitable for life as we know it.

To come full circle...at the time he wrote "2010," Clarke had plenty of evidence from the Voyager probes to pinpoint Europa as a candidate for life. (The subsequent discovery of oxygen on Europa neither supports nor detracts from that debate.)

Eric

EnderW25
2002-Jan-07, 07:35 PM
My apologies on confusing Hubble with Voyager. But then, two decades in astronomical time is but a mere second. If only history professors agreed with me...

Anyway, so Hubble discovered it in 1995 and Clarke wrote 2010 in 1985. That means that when Clarke wrote the book, he didn't know that Europa would contain an oxygen atmosphere. Again, this means that he's either on the forefront, scientifically, or just a really really lucky guesser.

EckJerome
2002-Jan-08, 08:57 PM
On 2002-01-07 14:35, EnderW25 wrote:
That means that when Clarke wrote the book, he didn't know that Europa would contain an oxygen atmosphere.


How is that relevant? We've already gone over the fact that the Europan oxygen discovered by Hubble has no bearing whatsoever with regard to possible life on Europa; it cannot support life nor does its presence have anything at all to do with biological processes. I don't see how that counts as any sort of prophesy on Clarke's part.

Eric

EnderW25
2002-Jan-09, 01:15 AM
Perhaps you're misunderstanding me. I'm not under the illusion that there's life on Europa. I'm saying that, with the Oxygen atmosphere there's the possibility for life, now or in the future. I'm saying that, out of all the planets and moons and objects within this solar system that Clarke could have picked in his story as a place with an oxygen atmosphere, he picks the one that actually does have an oxygen atmosphere. He does this ten years before we knew it to be true.
I'm not granting Clarke with any sort of psychic ability here. I'm just saying that, at the most, he's a brilliant scientist who understood things before his time. At the least, it's a pretty cool coincidence. Whichever.

GrapesOfWrath
2002-Jan-09, 01:30 PM
Clarke wrote a lot of science fiction, and made a lot of predictions, based upon resonable theories of the time. I'd be surprised only if none of his guesses turned out to be right.

I'm not sure that the story A Full of Moondust could actually occur on the moon as we know it. Anybody know any more about this?

ToSeek
2002-Jan-09, 02:01 PM
On 2002-01-09 08:30, GrapesOfWrath wrote:
I'm not sure that the story A Full of Moondust could actually occur on the moon as we know it. Anybody know any more about this?


I don't think it's completely ruled out, but it's highly unlikely that there's a valley of dust on the Moon, as the story requires. It's a favorite book of mine, though - would love to see them make it into a movie!

David Hall
2002-Jan-09, 03:58 PM
I don't think Clarke had any real prescience about Europa. He was of course always up on the current status of knowledge at the moment, and he knew the cutting-edge thinking on Europa. I think what he really latched onto was the theory that there is a liquid ocean there. Since that was what had people thinking there was a possiblity for life, what with concurrent discoveries of deep-sea vent life on Earth, he decided to build it into his novel. I also think another reason it came about was from him wanting to include a disasterous Chinese refueling mission.

It was just chance that the discovery of oxygen connects to his story, but looking back, it was natural for him to choose Europa for other reasons.

On another note, I love "A Fall of Moondust" also. But I'm thinking now that it couldn't happen because moon dust is rough and clingy and subject to vacuum cementing. Not really sure there though, but one of the Niven short stories I've read recently said about the same thing. In the story, the Moon didn't have that kind of fluid-like sand, but Mars did, because Mars had a thin atmosphere and the Moon didn't.

EckJerome
2002-Jan-10, 06:08 PM
On 2002-01-08 20:15, EnderW25 wrote:
Perhaps you're misunderstanding me. I'm not under the illusion that there's life on Europa. I'm saying that, with the Oxygen atmosphere there's the possibility for life, now or in the future.


And I'm saying that every bit of science is telling us that this oxygen is completely unrelated to the possibility of life on Europa, now or in the future.

Life is possible because there may be oceans...it has nothing to do with oxygen. That's pretty much how Clarke wrote it too. That plant thing that got the Chinese mission erupted out of a fissure in the ice, it didn't live on the surface...the reason it was near the surface was sunlight. Everything I recall reading was in line with our understanding of Europa at that time. (I know because I had written a school paper about possible life on Europa just months before "2010" came out.)



I'm saying that, out of all the planets and moons and objects within this solar system that Clarke could have picked in his story as a place with an oxygen atmosphere,


Did Clarke actually attribute an oxygen atmosphere to Europa in "2010?" (Forgive me, it's been 15 years since I read it.) I recall the disaster of the Chinese mission, but I can't remember such specifics being mentioned as an oxygen atmosphere.



I'm just saying that, at the most, he's a brilliant scientist who understood things before his time. At the least, it's a pretty cool coincidence. Whichever.


In the case of Europa, I don't think it is either. I'm not sure how one defines understanding things "before their time." Clarke did a lot of research for his novels and it showed. That he was able extrapolate the latest in science fact and theories into fiction, I think, is a point of creativity rather than thinking before his time. (The Hubble article does state that Europan oxygen, discovered in 1994, had been predicted by scientists...Clarke may have been aware of that prediction when he wrote the book.)

I will say that Clarke's writing is brilliant and that he had a gift for making his settings feel real, and his concepts plausible. But, in the end, I'm not sure that his prophetic track record goes beyond that of many science fiction writers.

Eric

The Rat
2002-Jan-11, 02:50 PM
I don't think he mentions life on Europa at all in "2001."

Eric

He couldn't; in the novel '2001' they went to Saturn, not Jupiter. Many forget that '2010' and subsequent novels were sequels to the film, not the original book.

And why did Kubrick only go as far as Jupiter? Special effects costs. They had a hard enough time getting a convincing looking gas giant. Putting rings around it would have been too much work.

informant
2002-Jan-11, 08:29 PM
Quote:
------------------------------------------------------------------------

I don't think he mentions life on Europa at all in "2001."

Eric
------------------------------------------------------------------------

"2001" does mention Europa briefly, when the Discovery passes by Jupiter on its way to Saturn.
Almost a decade before the Voyager missions, Clarke describes it as an ice covered moon.
An interesting coincidence, if you think that back then he couldn't have guessed that ten years later Europa would be a very interesting moon to talk about.


<font size=-1>[ This Message was edited by: informant on 2002-01-12 07:39 ]</font>

informant
2002-Jan-12, 12:46 PM
Please disregard my last post. I missed a very important part of Eric's post.
No, Mr. Clarke does not mention *life* on Europa in "2001". And no, he didn't come up with that idea; he was inspided by an article which came out after the Voyagers' findings. It's all in the preface to "2010".
On the other hand, The Rat, the Discovery does fly by Jupiter on its way to Saturn in the novel "2001".

GrapesOfWrath
2002-Jan-13, 05:03 PM
Welcome to the BABB, informant. Try out the edit post feature. You don't have to live with your mistakes anymore. :)

informant
2002-Jan-14, 07:56 AM
Thank you, but I thought that I had been so wrong that it was better not to erase my mistake.
Speaking of which, I went to check, and the article which first proposed that there might be life on Europa is mentioned in the "Acknowledgements" section at the end of the novel "2010", not in the Preface. My bad, again. Oh, well...

Russ
2002-Jan-15, 04:36 PM
I think it's important to mention that Clarke's biochemistry for Europa was not O2 based. As you may recall, the few "accidental" incursions onto Europa the humans had to be careful with their rocket exhaust because it's primary component was oxygen and that was poisionous to the locals.

lpetrich
2002-Jan-20, 09:52 AM
The molecular-oxygen atmosphere of Europa is most likely due to photodissociation of water by solar ultraviolet light and energetic particles from Jupiter's magnetosphere; the water in Europa's icy surface becomes hydrogen and oxygen.

The hydrogen escapes relatively quickly, because of its light weight, while the oxygen stays behind longer and gets seen more easily.

The ice layer is most likely at least a few kilometers thick, and there is unlikely to be very much light below it -- and light is necessary to drive the splitting of water into hydrogen and oxygen, since that is an endothermic, energy-consuming reaction.