December 31, 2012
Always a fascinating subject.
Though "...from the stars comes only silence."
Greg Easterbrook's comprehensive analysis: Are We Alone?
...Scientists assume that contact with any extraterrestrial civilizations that may exist is most likely to occur by radio; therefore SETI is primarily a vocation of radio astronomy. But because it is possible to monitor only a small portion of the vast number of space radio frequencies, those who wish to tune in the heavens must select a channel. In 1959 Philip Morrison and Giuseppe Cocconi, two physicists at Cornell University, argued that because hydrogen is the most common substance in the universe and naturally emits radio waves in a relatively noise-free portion of the radio spectrum, it would be logical to listen there for a signal from intelligent beings. Most SETI researchers have accepted this reasoning and, since the frequency of the hydroxyl radical, which combines with hydrogen to make water, is close to the hydrogen frequency, this prime search area was later dubbed "the water hole." Paul Horowitz's superanalyzer listens to several frequency bands in the water hole.
...Needless to say, there is no way to know if the waterhole frequencies, which seem to us a logical place to direct our efforts, would seem logical to anyone else. Some have suggested that SETI listen on the frequencies of tritium, an isotope used in thermonuclear bombs which is quite rare and thus is associated with technological advancement. Horowitz, frustrated by five years of cosmic silence, recently switched the Harvard receiver over to the second harmonic of hydrogen -- a frequency that has no natural counterpart, and so is free of background noise. Any signal logged there would almost have to be artificial.
...Some astronomers doubt that planets pre-dating Earth are likely, however. Most of the heavy elements necessary to form planetary core and mantle are thought to have been produced not during the Big Bang but by the detonation of supernovas: observations of supernova 1987A appear to confirm this. The primordial cosmos was rich with supernovas, but just how many had to explode before space contained enough metallic elements to forge planets is a matter of conjecture. So, too, are related issues -- for example, how much time passed before matter accumulated in our galaxy and others structured like it.
...Hart's most unnerving calculation involves what he calls the "continuously habitable zone." Had Earth spun in an orbit only five percent closer to the sun, Hart says, it would have experienced a runaway greenhouse effect, creating unbearable surface temperatures and evaporating the oceans. Venus provides evidence for this: 28 percent closer to the sun, that planet has a nearly opaque atmosphere high in carbon dioxide and 900-degree surface temperatures. And had Earth been positioned just one percent farther out, Hart believes, it would have experienced runaway glaciation, locking its surface water in ice for eternity. Recently other scientists have endorsed Hart's concept of such a zone but have proposed that it must be wider, perhaps extending as far as the orbit of Mars for an Earth-like planet.
...Carbon has a subatomic quirk that allows it to form astonishingly complicated molecules that happen to be excellent for storing detailed information such as the secrets of life. The helical strands of human DNA have more than six billion distinct molecular components, each composed of carbon assemblies that are themselves complex. Amino acids, sugars, fats, and other building blocks of organic life also rely on carbon's quirk.
Below freezing, carbon-based molecules cannot obtain the liquid water they need to operate biologically. And above a few hundred degrees Fahrenheit, the precious life-coding chains break down; eventually they burn. So carbon can probably be the chemical foundation of life only under conditions approximating Earth's.
Now, here's the rub. There are very few elements like carbon. Silicon has the same subatomic quirk, which is why science-fiction writers speculate about silicon-based life. But silicon, like carbon, could form sophisticated information-storing molecules only under a fairly narrow range of temperatures and pressures. All remaining elements with the quirk seem to be quite uncommon in the universe, compared with carbon and silicon.
"...HERE, then, are the possibilities with respect to life on other worlds:
We have company. The scientific search for extraterrestrial beings, which is mathematically unlikely to succeed in a short time, may simply not have looked in the right place yet ....
...We had company. Perhaps thinking beings are common, but so is the sorrow that civilizations acquire weapons more readily than wisdom. Life comes and goes ....
...We are alone in this galaxy. Maybe the skeptics are right: the odds against life are so fantastic that one viable planet per galaxy is the best that can be hoped for ....
...We are alone, period. Perhaps there is no sound of breathing on any other world, no matter how many stars stretch out to the barricade of existence. And there never will be ....
...We are the first. Because the universe is ancient, man assumes he must be a latecomer. We expect that other beings could be to us as the greatest teacher is to the lowliest student. But by its own measure, creation glistens with morning dew. Stars are still forming ....
Christian Science Monitor - Study: If aliens exist, they probably want to destroy us.
When considering the prospect of alien life, humankind should prepare for the worst, according to a new study: Either we're alone, or any aliens out there are acquisitive and resource-hungry, just like us.
These two unpalatable options are pretty much the only possibilities, according to the new study. That's because evolution is predictable, and alien biospheres should thus produce intelligent creatures much like us, with technological prowess and an ever-increasing need for resources.
But the fact that we haven't run across E.T. yet argues strongly for the latter possibility — that we are alone in the universe's howling void, the study suggests.
The Daily Galaxy - Humans May be the First Generation of Advanced Life in the Milky Way.
Sasselov believes that life is probably common in the universe. He said that he believes life is a natural "planetary phenomenon” that occurs easily on planets with the right conditions. "It takes a long time to do this,” Sasselov said at a 2011 Harvard conference. "It may be that we are the first generation in this galaxy.”
Though it may be hard to think of it this way, at roughly 14 billion years old, the universe is quite young, he said. The heavy elements that make up planets like Earth were not available in the early universe; instead, they are formed by the stars. Enough of these materials were available to begin forming rocky planets like Earth just 7 billion or 8 billion years ago. When one considers that it took nearly 4 billion years for intelligent life to evolve on Earth, it would perhaps not be surprising if intelligence is still rare.
If life did develop elsewhere, adds Andrew Knoll, the Fisher Professor of Natural History using the lessons of planet Earth to give an idea of what it might take to develop intelligence. "Of the three major groupings of life: bacteria, archaea, and eukaryotes," he said, "only the eukaryotes developed complex life. And even among the myriad kinds of eukaryotes, complex life arose in just a few places: animals, plants, fungi, and red and brown algae. Knoll said he believes that the rise of mobility, oxygen levels, and predation, together with its need for sophisticated sensory systems, coordinated activity, and a brain, provided the first steps toward intelligence."
Offered without additional comment.
November 29, 2012
Is "it" possible? What is "it"? - Glad you asked.
The idea came to White while he was considering a rather remarkable equation formulated by physicist Miguel Alcubierre. In his 1994 paper titled, "The Warp Drive: Hyper-Fast Travel Within General Relativity," Alcubierre suggested a mechanism by which space-time could be "warped" both in front of and behind a spacecraft.
...But, as Dvorsky explains, White has recently come up with a new design for a warp drive, one that, theoretically, would require way, way less energy. "I suddenly realized," he told Dvorsky, "that if you made the thickness of the negative vacuum energy ring larger -- like shifting from a belt shape to a donut shape -- and oscillate the warp bubble, you can greatly reduce the energy required -- perhaps making the idea plausible."
White believes that with his new design, warp drive could be achieved with the power of a mass that is even smaller than Voyager 1's.
I'm not going to pretend that I have the faintest clue how this would work or how NASA would conceivably build such a thing, but the idea that physicists at NASA are even toying with it gives me hope that interstellar travel could one day be possible, even if this isn't how it is ultimately accomplished.
November 20, 2012
Posting primarily because this is my take-away from the election loss. And I think it well-put.
@neo-neocon : at 6:03 pm What Republican but an egomaniac would consider running after this, with so much arrayed against him/her? (Actually, I wondered that already back in 2008, when I saw the feeding frenzy against Palin).
I would add to that a bit to ask "Will the RNC ever advance the hoary chestnut again that the most important political attribute of a ‘viable' candidate's selection in the primary consists of the RNC's affirmation of said candidate's general campaign ‘electability', after failing disastrously with probably the very best candidate to run on that vacuous canard in the past 40 years”?
…this asked by someone who came to like and admire …and deeply respect (and agreed, as I learned more about him, that he was a good choice) …Romney (but also someone who was livid throughout most of the primaries).
Romney was all about his so-called "electability” in the primaries; his supporters hammered us about that time-and-again. And I haven't forgotten that.
Are we finally going to reject some vacuous claim of "electability” in the future as the incredibly weak sauce that it proved to be (i.e., when we nominated a candidate based 9 parts precisely on the nostrum of electability)?
Electability be damned.
My two bits.
Yeah. Color me bitter.
…as for Palin, that's about the exact same time I came to find the Left not merely wrong, but despicable-bordering-on-evil. All of ‘em.
I've now added inbred-Darwin-Award-fodder to that judgment's description. And have included vast swathes of the Democrat base to the group.
…let me clarify in far fewer, and plainer, words:
Electability as prognostication of electoral outcome is utter bullshit as a valid argument OR valid predictor.
November 19, 2012
Maybe this is what is going to happen? Soon?
More on Kondratieff waves here.
Musings by the inestimable Sarah Hoyt:
I’ve said before that the only way I think we beat the civilization-killing mess we’re in is technology. For one, tech in the last twenty years is the sort of tech that empowers the individual, from news to entertainment — the fields I know.
A commenter asked about nanotech — a field I don’t know — and M. Simon promised to write something about it. He did:
I think we are in a short pause between Kondratieff Waves. In my opinion, the time between waves is getting shorter, so we will not have too long to wait before the next wave takes off. My estimation is that we will see macro economic results in five to ten years. An eternity if the present economic cycle is causing you a lot of suffering but in historical terms a fraction of an eye blink.
October 25, 2012
...on the genetic rise of lactose tolerance.
In an evolutionary eye-blink, 80 percent of Europeans became milk-drinkers; in some populations, the proportion is close to 100 percent. (Though globally, lactose intolerance is the norm; around two-thirds of humans cannot drink milk in adulthood.) The speed of this transformation is one of the weirder mysteries in the story of human evolution, more so because it's not clear why anybody needed the mutation to begin with. Through their cleverness, our lactose-intolerant forebears had already found a way to consume dairy without getting sick, irrespective of genetics.
...There are no written records from the period when humans invented agriculture, but if there were, they would tell a tale of woe. Agriculture, in Jared Diamond's phrase, was the "worst mistake in human history.” The previous system of nourishment—hunting and gathering—had all but guaranteed a healthy diet, as it was defined by variety. But it made us a rootless species of nomads. Agriculture offered stability. It also transformed nature into a machine for cranking out human beings, though there was a cost. Once humans began to rely on the few crops that we knew how to grow reliably, our collective health collapsed. The remains of the first Neolithic farmers show clear signs of dramatic tooth decay, anemia, and low bone-density. Average height dropped by about 5 inches, while infant mortality rose. Diseases of deficiency like scurvy, rickets, beriberi, and pellagra were serious problems that would have been totally perplexing. We are still reeling from the change: Heart disease, diabetes, alcoholism, celiac disease, and perhaps even acne are direct results of the switch to agriculture.
I thought this rather timely.
30 queries taking 0.0374 seconds, 82 records returned.
Powered by Minx 1.1.6c-pink.