Who is THIS guy at Europa? Options

[karolp]

It can be seen in the opening sequence of Bush's "Renewed Spirit of Discovery" material available here:

http://www.nasa.gov/mission_pages/explorat...sion_video.html

It reminds me of the "android" which was supposed to spacewalk outside the ISS station. Is it the same guy or something else? Are there any documents about implementing this robot on Europa?

[ljk4-1]

Why, it is Tobor the Conqueror of the Seven Galaxies! And now he is apparently
claiming Europa as his next victory!

Firs of all, Jupiter is not that big in the Europan skies, no matter how many times
space artists like to depict the gas giant as looming large over every one of its
moons. If you have a copy of The New Solar System put out by Sky & Telescope
magazine, there is an artist's depiction of how big Jupiter really looks from each
of the four Galilean moons. Even Io's view isn't that big, but it sure is bigger
than how we see Luna from Earth.

And secondly, I doubt we'll be seeing an explorer like that in our lifetimes.
But prove me wrong here, please. Plus, where is his drilling equipment/cryobot
to explore the Europan ocean? Or did he already deploy it? And why am I
referring to a robot as a he?

[Guest_BruceMoomaw_*]

"And why am I referring to a robot as 'he'?"

Flat chest, LJK. Flat chest. Do you really think "Helen O'Loy" in the Lester del Rey story would have had so much sex appeal if she hadn't had metal boobs?

Although I will say that, as NASA pictorial PR goes, this particular scene does seem to me to win the Booby Prize. Which is saying something.

[karolp]

Gentlemen, if you could kindly shift your focus to the FACE of the android, you could notice startling resemblance to the face of this individual:

http://www.cnn.com/2004/TECH/space/08/23/r...nasa/index.html

Which bring about the original question: was Robonaut ever intended for Europa missions - even as very preliminary conceptual work?

[AndyG]

Firs of all, Jupiter is not that big in the Europan skies, no matter how many times
space artists like to depict the gas giant as looming large over every one of its
moons.

Maybe they've gone for the virtual telephoto lens, and virtually moved back a bit, in order to make it look virtually more impressive?

That said, psychologically it would easily dominate the (Jupiter-facing!) sky over Europa. Jupiter is more than twelve degrees across: bigger than a fist at arm's length. My brightness calculator suggests magnitude -17.6 when it's full - a hundred times brighter than our full moon.

...I wonder at what depth photosythesis becomes impossible for any Europan ice-bound life? That is, could you live deep enough to avoid the radiation nasties, and still enjoy the sun?

Andy

[Guest_Myran_*]

karolp wrote: was Robonaut ever intended for Europa missions - even as very preliminary conceptual work?

I think the work you see on that adress are to be viewed as the works of Chesley Bonestell which was published in National Geographic when I was young, er younger at least.
And so its a depiction of 'what might be' and nothing that are currently considered.

[lyford]

Which bring about the original question: was Robonaut ever intended for Europa missions - even as very preliminary conceptual work?

Yeah and you never see him and Boba Fett at the same party....

[Guest_BruceMoomaw_*]

Regarding Europan photosynthesis: there's been a surprising amount of speculation on it. While I haven't followed it in detail, the consensus, I think, is that it would be very difficult for it to evolve in the first place, because microbes that got close enough to the surface to benefit from sunlight -- although they might sometimes survive for a little while -- wouldn't survive in big enough numbers for the mutation to become dominant. Of course, it depends on the optical qualities of the ice, about which we know almost nothing.

[AndyG]

Regarding Europan photosynthesis: there's been a surprising amount of speculation on it. While I haven't followed it in detail, the consensus, I think, is that it would be very difficult for it to evolve in the first place, because microbes that got close enough to the surface to benefit from sunlight -- although they might sometimes survive for a little while -- wouldn't survive in big enough numbers for the mutation to become dominant. Of course, it depends on the optical qualities of the ice, about which we know almost nothing.

Indeed.

That said, a quick googling returns info from AMANDA, the Antarctic Muon and Neutrino Detector Array, with some real world (albeit this world) data on the visible properties of Antarctic Ice. This page reports visible light could be detected to a depth of 300m from the surface, ten times as far as expected, in ice that is bubble-rich; and deeper, bubble-free ice at a depth of 1500m allowed visible light to travel hundreds of metres.

Given that there are Earth bacteria where single molecules of chlorophyll can exist on one photon per eight hours, and that only a few metres of ice would provide enough protection from the hard radiation bathing Europa, there may well be a Europan sweet spot (sweet shell?) where photosynthesis could occur.

As to its evolution: why not? Photosynthesis is an ancient trick for Earth's microbes. The first stage, photoreception (at IR frequencies rather than visible/UV ones) would be an obvious evolutionary advantage around any black smokers deep in the Europan ocean.

Optimistic Andy

[Guest_Richard Trigaux_*]

... The first stage, photoreception (at IR frequencies rather than visible/UV ones) would be an obvious evolutionary advantage around any black smokers deep in the Europan ocean.

Optimistic Andy

I read recently in a science review that such photosynthesis was seriously considered for organisms around black smokers. There is no sunlight here, but the water in the black smokers is very hot, nearby red hot, it even emits a small amount of visible glow, and probably a lot of infrared. In infra red black smokers would appear like luminous flames lighting all the surroundings.

[Cugel]

And to top it all of: from the on-line version of science (april 7) we hear that black-smokers are out and primeval soup is in.

The article is by Feng Tian and claims that the hydrogen losses of the early Earth atmosphere were much less than previously thought. Because vulcanos are a constant source of hydrogen it probably was pretty abundant: 30% (volume) of the atmosphere. (4 billion years ago). This makes the famous Miller/Urey experiment a lot more realistic and takes away the need for alternative origins of life. Such as black smokers. I wonder if this reduces the likelyhood of life on (in?) Europa.

[centsworth_II]

...hydrogen losses of the early Earth atmosphere were much less than previously thought....takes away the need for alternative origins of life. Such as black smokers.

Black smokers didn't need to be invented as a possible source of life; they exist. It seems to me that the questions of whether life could or did arise around black smokers or on the surface are independent of each other.

[Cugel]

Black smokers didn't need to be invented as a possible source of life; they exist. It seems to me that the questions of whether life could or did arise around black smokers or on the surface are independent of each other.

Maybe I don't understand what you're saying, but isn't it so that life around black smokers is related to all other life forms on Earth and actually share a common ancestor? If that is so, there can be only one environment which produced that common ancestor. Of course, I am not claiming that if we prove that life on Earth originated in shallow seas there cannot be life on Europa. But for Earth, there must be a single place of origin.

Still, I can't help believing that if life really started here in that warm and sunlit sea, it would make life on icy moons rather unlikely. We could actually turn that point around. That is, if we can prove that there is NO life on Europa, we can rule out black smokers as the origin of life on Earth.

[Guest_BruceMoomaw_*]

Maybe I don't understand what you're saying, but isn't it so that life around black smokers is related to all other life forms on Earth and actually share a common ancestor? If that is so, there can be only one environment which produced that common ancestor.

Actually, not so. There is a rival theory which makes a good deal of sense, pointing out that Hadean and Archaean Earth was probably fairly low-temperature most of the time -- but was struck at intervals of several tens of millions of years by monstrous giant impactors that very likely heated the entire ocean of Earth to near, or over, the boiling point. It is thus entirely possible that life on Earth initially evolved in tepid water, but that the only microbes that could survive these huge impacts were those few which had already evolved to tolerate extremely high-temperature water -- and thus, while they were not the initial "common ancestor" of all life on Earth, they were its one "common surviving ancestor". Kevin Zahnle has worked this theory out in considerable detail; he calls it the "high-temperature bottleneck" model of early terrestrial life, and it explains equally well the fact that the most primitive genes in present-day Earth microbes seem to be those found in high-temperature Archaea. (And, as he points out, it also includes the strong possibility that some of those giant impacts wiped out life on Earth totally, so that it then had to evolve from prebiotic compounds from scratch once more.)

[centsworth_II]

Maybe I don't understand what you're saying...

There is not necessarily only one path to life. Perhaps life can arise on a world where deep black smokers provide the only safe environment. Perhaps it can arise on a world where sun-bathed surface waters provide safe haven.

The origin of life may have begun several times on Earth -- under different conditions -- only to reach a dead end or be wiped out. The oldest common ancestor of all current life on Earth was probably not the earliest form of life on earth.

Earth certainly had many sources of prebiotic compounds and energy. Was every aspect of Earth's pre-life environment necessary to life's origin? (And what was that environment anyway?) Or is nature able to produce life from a somewhat different environment? Finding life -- or not -- in other parts of the solar system will help answer that question.