Sic et Non self deconstructs

[Guest]

DrW,

That would be my vote for most likely place in the Solar System to find life. I’d like to see it happen.

Res Ipsa,

Given what I believe to be our relative ages, your chances look better than mine ;-).

________________

ETA:

What do you think about the above described LSD microdosing?

Would you think about trying it?

If it really could help you achieve a higher level or consciousness, would you have tried it as a TBM?

[_Kittens_and_Jesus]

Haven't any of you ever read the 2001 Series by Arthur C Clarke? Europa is the answer, not Enceladus.

[_DrW]

Haven't any of you ever read the 2001 Series by Arthur C Clarke? Europa is the answer, not Enceladus.

Once the space probes got out there, they found out that Europa's orbit lies within Jupiter's magnetosphere, which traps charged particles from the solar wind, as do Earth's van Allen belts. The radiation from Jupiter's magnetosphere is intense and broad spectrum and some components have high enough energy to damage electronic hardware on space probes as well as any organic chemicals or biological systems at or near the surface of Europa. Enceladus is within Saturn's magnetosphere but the resulting radiation field is not as intense as for Europa.

Enceladus is tidal locked to Saturn and Europa is tidal locked to Jupiter, just as our moon is to Earth. So both ice moons will have higher radiation hemisphere (facing their planet) and a lower radiation hemisphere (facing away from their planet).

Both Enceladus and Europa are subjected to higher cosmic ray fluxes than here on Earth. Calculations from measurements of ionizing cosmic radiation fluxes in the neighborhood of both moons indicate that they would be similar to that measured on the surface of Mars.

The core of Enceladus is thought to be comprised of solid rubble and therefore porous and capable of generating more heat in relation to its mass because of the friction among solid particles caused by tidal forces. Europa's core is thought to be solid, much like that of Earth's moon, comprised mainly of iron, nickel and silicates.

Water ice is reasonably good at attenuating ionizing radiation, so most radiation damage to organic chemicals would be confined to a few meters from the surface on both ice moons. This means that any deep water biological organisms that developed near the cores of these moons might continue relatively undisturbed.

The main difference in their estimated chances of harboring life lie in the fact that we know for sure Enceladus has a salt water ocean containing organic compounds because Cassini sampled its water volcano plumes.

Evidence for a salt water ocean on Europa comes from spectral observations of salt in the surface ice. Whether or not there are organic molecules in the subsurface water is not yet known.

Advantage (for now): Enceladus

[_Gadianton]

When it comes to what David Chalmers has called the “hard problem” of consciousness, Dehaene responds that "mental experience is a pre-scientific concept that will disappear as we better understand the connections in the brain. It is from data on the brain and behavior gathered and reported by researchers like Dehaene and other laboratory scientists that the theorists and philosophers develop their concepts.

That's the most common response (or a member of the 'future theory' category of response. ;) I have that book somewhere deep in a box so just going from memory, but Chalmers does anticipate that argument and offers his rebuttal. I can't remember if I agreed with his response.

My response is a little uncertain. I believe this very well could be the case, but I'm ambivalent over how meaningful it is. As an example: the idea I've mentioned several times about people's intuitions shifting towards accepting strong A.I. (not sure i have the right terminology) robots that can be fully human with feelings and everything, is more often than not intuitive for people nowadays given the rapid advance of computing and so much exposure to the idea in science fiction. But that's not necessarily a great reason for believing it. That people may give up overthinking it one day and move on doesn't mean the issue has been properly resolved.

[_Arc]

When it comes to what David Chalmers has called the “hard problem” of consciousness, Dehaene responds that "mental experience is a pre-scientific concept that will disappear as we better understand the connections in the brain. It is from data on the brain and behavior gathered and reported by researchers like Dehaene and other laboratory scientists that the theorists and philosophers develop their concepts.

That's the most common response (or a member of the 'future theory' category of response. ;) I have that book somewhere deep in a box so just going from memory, but Chalmers does anticipate that argument and offers his rebuttal. I can't remember if I agreed with his response.

My response is a little uncertain. I believe this very well could be the case, but I'm ambivalent over how meaningful it is. As an example: the idea I've mentioned several times about people's intuitions shifting towards accepting strong A.I. (not sure i have the right terminology) robots that can be fully human with feelings and everything, is more often than not intuitive for people nowadays given the rapid advance of computing and so much exposure to the idea in science fiction. But that's not necessarily a great reason for believing it. That people may give up overthinking it one day and move on doesn't mean the issue has been properly resolved.

Lately there seems to be increasing doubts in the community about the eventual ability to achieve so called strong A.I., defined as creating a machine that can exhibit human quality intelligence and perhaps even consciousness. Having a computer pass the Turing Test would be a gateway milestone in that direction.

To put things in perspective, one could ask the question as to what we hope to gain, or how will we benefit, from 'understanding' consciousness.

- Is it to improve the chances of actually advancing to strong A.I.?

- Is it for better medical treatment or psychological care of those with impaired consciousness or who are stuck in limited or restricted brain states?

- Is to to understand how to achieve some higher consciousness in ourselves?

- Some studies link higher states of consciousness including curiosity, insight, pattern recognition, memory, attention, abstract thinking ability, etc., to increased intelligence. Would a better understanding of consciousness help determine or define the genetic basis for intelligence (now believed to be determined by hundreds of genes)?

I tend to view things more like Dehaene than like Chalmers. I don't see our incomplete understanding of consciousness to be any more of a 'hard problem' or hindrance in the cognitive sciences than the incomplete understanding of dark matter is to physicists. They assume the existence of WIMPs (weakly interacting massive particles), figure someday WIMPs will be detected; and don't worry much if it's not today.

The fact that we don't understand dark matter does not stop physics from providing scientific discoveries that form the basis for all kinds if useful devices. The smart phone that allows instant communication with essentially anyone anywhere in the world with voice and video, navigation by accessing satellite GPS, access to radio and TV content and viewing of stored or streaming movies, is but one example.

As described above, we know a lot about brain function and consciousness and are learning more every year. Many think it unlikely that we will ever reach a perfect or complete understanding of consciousness. I don't think failure to do so represents any more of a problem than does the incomplete understanding of dark matter.

[_Kittens_and_Jesus]

Haven't any of you ever read the 2001 Series by Arthur C Clarke? Europa is the answer, not Enceladus.

Once the space probes got out there, they found out that Europa's orbit lies within Jupiter's magnetosphere, which traps charged particles from the solar wind, as do Earth's van Allen belts. The radiation from Jupiter's magnetosphere is intense and broad spectrum and some components have high enough energy to damage electronic hardware on space probes as well as any organic chemicals or biological systems at or near the surface of Europa. Enceladus is within Saturn's magnetosphere but the resulting radiation field is not as intense as for Europa.

Enceladus is tidal locked to Saturn and Europa is tidal locked to Jupiter, just as our moon is to Earth. So both ice moons will have higher radiation hemisphere (facing their planet) and a lower radiation hemisphere (facing away from their planet).

Both Enceladus and Europa are subjected to higher cosmic ray fluxes than here on Earth. Calculations from measurements of ionizing cosmic radiation fluxes in the neighborhood of both moons indicate that they would be similar to that measured on the surface of Mars.

The core of Enceladus is thought to be comprised of solid rubble and therefore porous and capable of generating more heat in relation to its mass because of the friction among solid particles caused by tidal forces. Europa's core is thought to be solid, much like that of Earth's moon, comprised mainly of iron, nickel and silicates.

Water ice is reasonably good at attenuating ionizing radiation, so most radiation damage to organic chemicals would be confined to a few meters from the surface on both ice moons. This means that any deep water biological organisms that developed near the cores of these moons might continue relatively undisturbed.

The main difference in their estimated chances of harboring life lie in the fact that we know for sure Enceladus has a salt water ocean containing organic compounds because Cassini sampled its water volcano plumes.

Evidence for a salt water ocean on Europa comes from spectral observations of salt in the surface ice. Whether or not there are organic molecules in the subsurface water is not yet known.

Advantage (for now): Enceladus

My post was a joke meant to appeal to people well versed in the Holy Trinity of Scfi Fi (Asimov, Clarke and Bradbury) as well as people that love Kubrick.

As a person with a scientific background I appreciate your answer. I wasn't aware of that particular moon or the possibility of life upon it.

That being said, would it be so surprising to find life in odd places like methane lakes or gas clouds on other planets? We never thought we'd find life near volcanic vents in polar regions, but we did.

[_DrW]

That being said, would it be so surprising to find life in odd places like methane lakes or gas clouds on other planets? We never thought we'd find life near volcanic vents in polar regions, but we did.

While I agree it is more likely than not that life exists elsewhere in the universe, and perhaps even in our solar system, I think it unlikely it will be found in the methane lakes of Titan or the atmospheric clouds of the gas planets,

Since the presence of carbon, hydrogen, oxygen, nitrogen and sulfur, (CHONS), as well as liquid water and sufficient free energy for chemical reactions, seem to be minimal requirements for abiogenesis, methane lakes would be a highly unlikely environment in which to find life. Abiogenesis in the clouds of gas planet atmospheres would be unlikely as well.

Due to their lack of CHONS in sufficient local concentrations and their cold temperatures, (-180 degrees C), the methane lakes of Titan do not have the chemical diversity, liquid water, or the free energy needed to support abiogenesis of carbon based life.

Many of the same problems apply to the gas clouds that comprise the atmospheres of gas planets. They are cold, so not much free energy is available to drive chemical reactions. They lack sufficient chemical diversity, are subjected to intense radiation fields, and do not offer any stable catalytic substrates to promote the kinds of reactions required for abiogenesis as we understand it.

On the other hand, the kinds of deep ocean vents you mentioned could well be present at the solid state cores of both ice moons. These might offer a very similar environment to those found on Earth, which appear conducive to abiogenesis. On Earth, they exist in a temperature range, and with sufficient chemical diversity and readily available sources of chemical energy, to support abiogenesis and anaerobic metabolism once life is established.

Science fiction fans have no doubt encountered silicon based life forms such as Star Trek's Horta. In the last century there was speculation that silicon based life forms might exist. Silicon has many chemical properties in common with carbon. Both are Group IV elements on the periodic table so have valence of 4 and can form dioxides, for example.

And therein lies the first of many problems for any sort of silicon based life form or metabolism. Carbon dioxide is a gas and is soluble in water. It can readily diffuse into plants cells from the atmosphere for making sugars by photosynthesis, for example. Silicon dioxide is a solid (sand) and insoluble in water. It would not be as available for reactions in the gas and liquid phase as CO2. While silicon can be taken up from the soil and incorporated into plant life, it simply cannot form the backbone to the the variety of bio-molecules that carbon does.

As science learns more about the complexity and versatility of carbon chemistry in carbon based life forms, it seems more and more likely that if alien life is out there (and it almost certainly is), its basic forms and biochemistry look a lot like life, at least early life, here on Earth.

[Guest]

I don't understand enough of the chemistry to have an informed judgement here, but for what it's worth my feeling is that life is probably quite a bit too rare to crop up twice in our solar system. I'm sure it exists in many other forms throughout the universe, but that's because there are just so incredibly many stars and planets out there.

My almost completely uninformed guess would be that life hits something like one planet in ten thousand. That would mean that the nearest other life might be hundreds of light years away from us, and that all of the stars we can see with the naked eye could well be lifeless. And yet it would allow millions of alien species just within our own galaxy. That's how huge a single galaxy is. And the number of other galaxies in the universe is hard to imagine.

The only thing that does inform my guess, other than a basic awe at how complex life is, is the so-called Fermi paradox, which just consists of the question, "Where is everybody?" If humans survive for even another hundred thousand years, then over all that time we will probably have sent probes to all the stars within a few dozen light years of us, at least. If life hits as many as one solar system in ten, then there must be quite a few alien life forms within that range of us, and a hundred thousand years is an eyeblink in cosmic time. One of those alien species would surely have chanced to be ahead of us in technology by at least such an eyeblink—and therefore already have visited us. So how come we haven't noticed them?

There are lots of possible ways the Fermi paradox might be resolved. One of the easiest is that life is quite rare.

I would love to be wrong about that naïve guess, because my main research goal is understanding some basic metabolic processes at the level of basic physics. I'd really like to know whether any other molecules can play the roles that are played in practically all life on Earth by DNA and ATP.

[_DrW]

I don't understand enough of the chemistry to have an informed judgement here, but for what it's worth my feeling is that life is probably quite a bit too rare to crop up twice in our solar system. I'm sure it exists in many other forms throughout the universe, but that's because there are just so incredibly many stars and planets out there.

My almost completely uninformed guess would be that life hits something like one planet in ten thousand. That would mean that the nearest other life might be hundreds of light years away from us, and that all of the stars we can see with the naked eye could well be lifeless. And yet it would allow millions of alien species just within our own galaxy. That's how huge a single galaxy is. And the number of other galaxies in the universe is hard to imagine.

The only thing that does inform my guess, other than a basic awe at how complex life is, is the so-called Fermi paradox, which just consists of the question, "Where is everybody?" If humans survive for even another hundred thousand years, then over all that time we will probably have sent probes to all the stars within a few dozen light years of us, at least. If life hits as many as one solar system in ten, then there must be quite a few alien life forms within that range of us, and a hundred thousand years is an eyeblink in cosmic time. One of those alien species would surely have chanced to be ahead of us in technology by at least such an eyeblink—and therefore already have visited us. So how come we haven't noticed them?

There are lots of possible ways the Fermi paradox might be resolved. One of the easiest is that life is quite rare.

I would love to be wrong about that naïve guess, because my main research goal is understanding some basic metabolic processes at the level of basic physics. I'd really like to know whether any other molecules can play the roles that are played in practically all life on Earth by DNA and ATP.

Most folks I know would agree that intelligent life is likely very rare in the universe. Your one in ten thousand planets estimate seems very reasonable. Considering what we know about the history of this planet, including the fortunately timed reboot enabled by an asteroid impact into the Gulf of Mexico, I would have no problem extending that estimate to one in ten thousand Goldilocks zone planets for any form of intelligent life.

As to the Fermi paradox, in a universe where space is expanding at the rate we now detect in our own, every passing year reduces the number of planets that are even theoretically within range for a sub-light-speed transit to Earth. (Our to-date fastest space vehicle, Voyager, travels at approximately 1/600th the speed of light). In any case, the amount of energy required to achieve and logistically support a near light speed interstellar mission is higher than could be foreseeably supported from Earth. Any alien civilization capable of such feats would need to be much older, wiser, and with access to a hell of a lot more critical resources and wealth than we have.

Add to that the myriad of hazards attendant to travel at anywhere near light speed, including intense hull surface heating and penetrating radiation from near light speed collisions with ubiquitous hydrogen molecules, let alone tiny solid particles of dust in interstellar space. All of these limitations would apply to interstellar voyaging aliens as well as to we Earthlings.

[_Physics Guy]

The expansion of the universe is the tendency that predominates on the largest scales. It is intergalactic space that expands. Within any galaxy the expansion of space is held in check by local gravitational attraction. So the stars within our own galaxy are not getting any farther away on average. I'm not even sure there's much problem with nearby galaxies. I believe some of them are actually getting closer.

I think you are right that even the shortest range interstellar travel is likely to be insanely hard unless there are big technology breakthroughs in future (which there could be—who knows). Fifty light years doesn't sound too bad if you think of travel at light speed, but if it's more like 1% of light speed then that's like 5000 years just to get a probe there. A big part of the explanation of the Fermi Paradox may just be that there aren't any big advances in space travel technology to be found and that interstellar travel will still be very difficult even a hundred millennia from now.

Over the very long term, inter-galactic travel may well be even more drastically limited unless we can find wormholes or something. All the farthest away places are getting farther away from us too fast for us to catch them. But the Milky Way is probably big enough to keep us busy for quite a while. I can't think of any science fiction stories that have even come close to doing justice to the enormous scale of a galaxy; I don't think anybody has needed a stage large enough to include many galaxies.

Except, apparently, Perry Rhodan. I've never read any of it but according to Wikipedia it's absurdly large-scale, and at 300,000 pages since 1961 I guess it has had to cover a lot of ground.