Saturday, July 30, 2011

The Uniqueness of the Earth Still A Mystery and Enigma


Our earth seems special – maybe because it is. Some astronomers are seriously considering that life might be rare or unique on our rare (or unique) planet. If so, hopes for finding sentient aliens on the celestial radio dial drop accordingly. The 50th anniversary of the first SETI search came, unfortunately for search enthusiasts, at a time when funding is harder to get.

New Scientist has been running a series called “Existence” for the purpose of examining big questions about the origin of the universe, life, and consciousness. Most of the articles try to give atheist answers to arguments of intelligent design. In “Why is the universe just right for us?” for instance, Marcus Chown tried to explain away fine-tuning arguments with responses that physical constants might be interconnected, or are not as finely tuned as they seem, or that the multiverse hypothesis provides a way out. Even so, he could not explain away the incredibly “fortuitous” dark energy parameter.

In “Where did we come from?” Stephen Hawking presented the standard big bang scenario with inflation, but admitted at the end that “many huge mysteries remain,” leaving the solution in the future.

In “Why is there a universe?” Amanda Gefter tried to explain how something can come from nothing via quantum fluctuations.

MacGregor Campbell posted a cartoony animation trying to convince puzzled readers that “nothing” and “something” might be one and the same – i.e., that our physical universe, including us, might really be nothing. At the end, though, Gefter realized this is not a satisfactory answer:

None of this really gets us off the hook, however. Our understanding of creation relies on the validity of the laws of physics, particularly quantum uncertainty. But that implies that the laws of physics were somehow encoded into the fabric of our universe before it existed. How can physical laws exist outside of space and time and without a cause of their own? Or, to put it another way, why is there something rather than nothing?

Readers of these articles might well ask how nothing could know anything.

Live Science put forth a new idea by David Spiegel [Princeton U] and Edwin Turner [U of Tokyo] that allows for sentient life being so rare that we might be alone in the universe. Using Bayesian analysis, they showed mathematically that there is no way to prefer the belief life is common over the belief life is rare, even using the famous Drake equation. When you have only one data point, “Our own existence implies very little about how many other times life has arisen.” Accordingly, it is just as scientifically reasonable to believe life is unique in the universe as to argue it must be common.

In a Nature News article, M. Mitchell Waldrop announced royally, “SETI Is dead – Long live SETI.” By that he meant that “The closure of the Allen Telescope Array shifts the search for extraterrestrial intelligence away from big science.” California’s budget crisis has shut down hopes at the Hat Creek site to scan the skies for intelligent signals. With that comes the graying of the true believers:

The melancholy vista at Hat Creek makes it easy to entertain equally melancholy thoughts about the SETI enterprise itself. It's the ultimate in high-risk, high-payoff science, pursued by only a handful of passionate researchers. In 50 years of searching, they have turned up nothing — and they can't quite shake an association in the public mind with flying-saucer sightings and Hollywood science fiction, all of which is so easy for cost-cutting politicians to ridicule that any substantial federal funding for SETI is impossible. Private support for the search is getting tighter because of the global recession. And many of the pioneers who have championed the search are now well into their 60s, 70s or 80s.

SETI Institute research head Jill Tarter remains optimistic, however, because smaller, cheaper searches are still continuing, and all searches over the past half century have only represented a tiny sample of space. Bottom line, though, is that nothing has been found, and even the most optimistic proponents cannot provide any reasonable estimate of the chances of success, despite the self-reinforcing opinions of those whose reputations depend on high hopes (see Space.com).

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