I touched briefly upon the subject of astrobiology in my history of geology, Earth science and planetary science, but I will expand upon this here. The best-explored planet next to our own is without doubt Mars, which has been visited by several orbiters as well as by a number of robotic probes on the surface. The most successful ones to date have been the twin Mars Exploration Rovers Spirit and Opportunity from the United States. Originally intended for just a 90-day mission, the rovers landed on opposite sides of the planet in January 2004, but were still exploring the Martian surface as of 2010. The Jet Propulsion Laboratory (JPL), a division of the California Institute of Technology in the USA, manages the rovers on behalf of NASA.- - - - - - - - -
Next to Mars, the most promising candidates for primitive life in our immediate neighborhood might not be the planets but rather some of their natural satellites. Jupiter’s huge moon Ganymede is the largest moon in our Solar System. Like Saturn’s moon Titan it is larger in diameter than the innermost planet Mercury but has less mass. Ganymede is the only natural satellite in the Solar System known to possess a magnetosphere, which is suspected to be generated through convections within a liquid, iron-rich core, not too different from the Earth.
While it is the least massive of Jupiter’s major Galilean moons, Europa is one of the most interesting bodies in the entire Solar System for astrobiologists and is strongly suspected to harbor a subsurface liquid water ocean. The same could be true of Ganymede and possibly Callisto, although this is considered less likely. If water contains a little bit of ammonia this has an antifreeze effect that could enable liquid water to exist at temperatures significantly below those of liquid freshwater or even seawater here on Earth. With a diameter of over 4,800 km, Callisto is almost the size of Mercury. Unlike Io, Europa and Ganymede, Callisto does not experience much tidal heating and orbits beyond Jupiter’s main radiation belts. “ It is thought to be a long dead world, with a nearly complete absence of any geologic activity on its surface.” Any heat generated within it would have to come from radioactive decay alone.
In contrast, the gravitational influence of Jupiter squeezes Europa as it orbits from one side of the planet to the other. This “tidal flexing” should keep its core molten and result in volcanic activity, just like at its neighbor Io which is closer to Jupiter. The downside is that Europa orbits within the unfriendly radiation environment of its planet’s powerful magnetosphere.
Io, the innermost of the Galilean moons, is the most volcanically active body in the Solar System, with volcanoes spewing out sulfur and sulfur dioxide (SO2) to a height of hundreds of kilometers. The heat is caused by massive tidal forces generated by Jupiter and its moons. Volcanism exists on other bodies, too, but not necessarily in the form of molten rock (lava).
The American probes Pioneer 10 and Pioneer 11, launched in 1972 and 1973, were the first spacecraft to visit Jupiter and Saturn in the Outer Solar System. NASA’s Galileo spacecraft orbited Jupiter from 1995 to 2003, sent pictures and data back to the Earth and dropped a probe into the Jovian atmosphere to sample its composition. It also found evidence of what could be an ocean on Europa. New research suggests that there may be plenty of oxygen available there, possibly great enough to support not only microorganisms but perhaps also “macrofauna,” or more complex organisms like fishes. Maybe Europa has hydrothermal vents like the ones we know from the ocean floors of our planet, although this remains pure speculation. Some scientists think the origin of life on Earth occurred at such volcanic vents.
Read the rest at Vlad Tepes.
9 comments:
The reason that life on other planets is such a popular topic in journals (and not just science fiction) is due to the mathematical impossibility of its naturalistic genesis on earth. Given what we now know of earth's early atmosphere, "panspermia" (such as a life form riding in on a comet) is the only recourse for the naturalist. Thus the push to find water elsewhere, as if that's enough for life. The Fjordman excerpts are entertaining, but represent little more than the long discredited theory of spontaneous generation.
Mr. Evanston there has an attitude that is just as corrosively destructive as anything Islam can produce. Mathematical impossibility? Where exactly was this proof published? Dismissing a discussion of SOME of the potential prerequisites for life as a "long discredited theory"? This is on exactly the same level as Muhammad riding a rocket ship and all modern technology being predicted in the Koran.
What is going on here is a desperate, desperate fear.
This is a side of the West that SHOULDN'T be saved, because it hates knowledge and hates attempts to expand knowledge. It prefers to replace questions with mysteries, because mysteries can't ever be answered, and ensure that men remain slaves, forever.
It is evil.
It is most important that the search for extraterrestrial life be carried out passively only. The case put forward in "Mars Attacks" is completely valid, if tongue-in-cheek. Or why should an alien race necessarily be more merciful than the human race?
I'll always remember an article that Carl Sagan wrote for Parade magazine many years ago. As I recall, Sagan was a disbeliever in ET life. He compared the current human belief in aliens to the former human belief in witches.
Sagan contended that if aliens were to come to Earth, the aliens would conquer humans because history shows us that a more advanced technological civilization always seeks to conquer and exploit a less advanced technological civilization.
Sagan's observation is interesting in light of Islam, a less advanced technological civilization, making inroads against the West, a more advanced technological civilization.
Here's the real kicker: Islam in Saudi Arabia still has literal and figurative witch trials, too. Google "Saudi Arabia witch trials" to see for yourself.
Rollory, thank you for reading my comment. Read books on Intelligent Design (ID), if you're really open-minded, for the mathematical odds of forming the molecules essential to life. These cite articles by non-ID (or if you prefer, "real") scientists regarding current knowledge in microbiology. Most of what I was taught in high school has since been proven false, including the experiments to create RNA & DNA in labs. No one can create even the basic building blocks of life given the conditions on a primeval earth. At the risk of repeating myself, this is why scientists like Crick pursued the panspermia theory and the money continues to flow. And yes, spontaneous generation is "long discredited." Hey, why don't you take some water, add an "organic" compound (which means anything that contains carbon, nothing more) in a vacuum and wait a few eons for something to happen. Your statement that these things are "potential prerequisites for life" shows the weakness of this position.
I am willing to pursue knowledge wherever it takes us. I do not live in fear of the results. The Big Bang, for example, was suppressed because it apparently supported Genesis. It was only when the evidence became undeniable that the steady state theory was abandoned.
You are the one holding on to the past. Discoveries in astronomy, microbiology/chemistry, and archaeology have discredited materialistic assumptions. The existence of the material universe is due to an amazing amount of fine-tuning of basic physical laws; the "simple cell" that Darwin started with is anything but; likewise the archaeological record has disproved the constant flow of transitional forms that Darwin postulated.
I believe in the scientific method, and it'd be cool with me if your point of view were verified by the evidence. Really. Sincerely. It's ironic that you're the one asserting that my lack of credulity is "evil."
Yes, much of what used to be taught is false. That applies to every area of human knowledge. We haven't tossed geology or physics out the window because of it.
The question of how life started is not one that has been answered. Anybody who says that they know how life can start through entirely natural means is overstating their case. This does NOT mean it is impossible. Unlikely is an entirely different thing. This is a very large universe, and rather old. In a large enough possibility space, anything will happen at least once.
A question remaining, then, is: did it?
A related question: if there is a God, and he did cause life to begin, what methods did he use to do so? Did he just point his finger and go 'ZAP'? Or did he use methods already existing within the context of the universe he created and inherent in its nature?
You can say "it rains because God makes it rain". That's the answer some classmates gave in a skiing lesson when I was 8 years old or so. It's a true answer, so far as it goes. It's not however a complete one. Some people are content with "because God makes it happen". They however are blind to the actual underlying workings of the system, missing out on knowledge that is there for the finding if one simply works at it.
The creation of life is fundamentally a question of the same nature. Life is a process that is as much a part of this universe and subject to its laws as the hydrologic cycle. There has been as yet no aspect of the functioning of this universe that is outside the bounds of rational investigation - which incidentally is what one would expect from a universe created by a God that is lawful and just; a universe bounded by and governed by absolute laws. To pick one particular area of investigation and say "it's impossible for us to know how this works and we shouldn't even try" without an ironclad proof of that impossibility - yes, that's evil.
That the specific naturalistic methods for producing life have not yet been explained and we are only at the point of identifying some of the necessary prerequisites does not invalidate the entire area of investigation. Labelling it as invalid - yes, that's evil.
If and when it is proven that one cannot start with entirely inanimate matter and artificially assemble it into a living organism, THEN the "no natural genesis" argument will have a case. If such IS possible - and I expect the molecular geneticists to answer the question definitively in the next hundred years or so - then the only remaining question is one of intermediate steps, the likeliness of those intermediate steps, and if any of them is impossible without deliberate conscious intervention. If and when such an impossibility is identified, THEN your statement is justified. In the absence of such proof? Yes, it is evil.
The motivation behind that sentiment does tend to be a fear that scientific explanations make faith-based ones less necessary. I stand by that, I've seen it too often.
Life is an entity that can reproduce itself. The earliest life forms were probably akin to prions, the pathogen of JC disease. It has no DNA, no cell structure, only the ability to modify already existing molecules into its own configuration. It is not difficult to envisage that such an entity can come into existence by chance.
Evanston, the steady state theory was admitted as false by those who proposed it and it is proven false. The universe is indeed expanding. Now, the big bang theory doesn't explain how the big bang started, why it did it, just like evolution doesn't explain the creation of the first living cells. They explain just how we got here. If God exists he created the world and live through the big bang and evolution.
Rollory, you've asked for "ironclad proof" of impossibility (that is, to "prove a negative"). That would require omniscience. Are you asking me to be God? If the term "evil" has any meaning in a materialistic context, your request is such...
...because there are scientific standards for "mathematical impossibility." These were created and employed long before Intelligent Design was formulated. Articles defining such "impossibility" are referenced in ID literature, along with the chemistry required for even the most basic building blocks of life. The "proof" may not be "ironclad" but you're free to examine the equations: they provide proof that even the most primitive compounds required for life could not have lasted on earth.
MRiggs' comment regarding prions is germane. The reason that researchers are postulating such non-DNA/RNA, non-cellular (and simply self-replicating) forms of "life" is that prevailing assertions of the origin or life have been proven false. MRiggs is free to "envisage" and I encourage him to do so. Even better would be to prove, in a lab, that such "life" is more "alive" than a self-replicating crystal. Surely something that the accident of "chance" (with enough time) can create can be created with modern chemistry by someone, right? We're talking Nobel Prizes here...
RebelliousVanilla, I hope I was clear regarding the Big Bang. I agree, it's quite evident (red shift, etc.) today. But what do you mean by "evolution?" If you include "macroevolution" (that is, gradual change from one species to another) it's one thing to assert that "They explain how we got here." It's another to prove it, even remotely. The fossil record is lacking in "transitional forms" when it should be littered with them. Instead, theories regarding the "Cambrian explosion" and "punctuated equilibrium" have been invented because macroevolution (again: gradual change over time leading to new species) does not match the fossil record. New species appear abruptly, in whole, and then are stable for (what is claimed by archaeologists) to be millenia.
Gents, I have no problem with your skepticism. I urge you to increase it. Anthropogenic Global Warming was "settled science" 2 years ago. A "gay gene" is settled science now though no one can point to one. In such a context, it's amusing that I am evidently the proponent of "evil."
Post a Comment