lunes, 17 de octubre de 2011

Beyond Drake's Equation --New Views on the Search for ET Intelligence

Drake-equationThe SETI project – Search for Extra-Terrestrial Intelligence – has been in existence in one form or another for several decades, dating back to Frank Drake’s first SETI experiment named Project Ozma. SETI is basically the search for intelligence through listening for radio waves of another civilization. For Drake back in the 1960’s, this was no doubt the sign of a technologically prevalent society, and the smartest means to search for life.

However, one can only look at that decision and see it as a mistake. At least, that is what some scientists and others connected to the field of extra-terrestrial search feel, such as George Dvorsky, who serves on the Board of Directors for the Institute for Ethics and Emerging Technologies. Recent insights in such fields as cosmology, astrobiology have changed our perception of the cosmos and the ways in which advanced life might develop.
In the early days of SETI its astronomers predicted a steady rise in radio traffic, as populations and technology advanced. But the reverse has happened. Point to pint communications have become dominated by low-powered satellites directing their signals Earthward while the bulk of telecommiunications shifted away from radio to buried fiber optics for cable TV and Internet traffic. In another hundred years there will be no substantial radio output from Earth.
Another key weakness is Fi -the fraction of those Earthlike planets (10,000 was Drakes estimate in the Milky Way) on which intelligence evolves. To date, there isero evidence that there is a "life principle" directing primal chemical soups towards the glory of a homo sapiens-like species. Until we find strong evidence for life on an etra-solar planet, Fi remains moot.
The Drake Equation does not take into consideration such factors as the age of the Galaxy, when intelligence first emerged, or the presence of physiochemical variables such as the presence of metals necessary for the presence of life and the formation of planets. The equation, Dvorsky emphasizes, assumes "a sort of cosmological uniformity rather than a dynamic and ever changing universe."
The equation asks us to guess the number of Earth-like planets, but it does not ask us to estimate when Earth-like planets -intelligence itself may have been present as long as 2 to 4.5 billion years ago.

The Galaxy’s extreme age and the potential for intelligence, which may have been present as long as 2 to 4.5 billion years ago, to have emerged at disparate points in time leaves an absurdly narrow window for detecting radio signals.

The Drake Equation, Dvorsky believes,  does not tell us about exponential civilizational growth on account of Von Neumann probe disbursement. "It does not tell us where advanced ETI’s may be dwelling or what they’re up to (are they outside the Galaxy? Do they live inside Jupiter Brains? Do they phase shift outside of what we regard as habitable space? ).

This is a serious shortcoming because the answers to these questions should help us determine not just where we should be looking, but they can also provide us with insight as to the makeup of advanced intelligence life and our own potential trajectory."

In other words, Dvorsky concludes, post-Singularity machine-based intelligence may represent the most common mode of existence for late-stage civilizations. And that’s who we should be looking for rather than radio transmitting civilizations.

Since 1992 astronomers have been finding more and more exoplanets and as of today close to 1300 exoplanets are confirmed. The number of Sun-like stars with planets is believed to be around 40% or higher. Currently most of the planets found are massive and orbit very close to their stars (they’re called Hot Jupiters), but as detection techniques improve scientists think many more planets will be found of different sizes and orbits.

Research of the apst two decades have shown that literally billions of planets in the Milky Way might have niches that would support at least a level of life represented by Earth's extremophiles.

Drake's Equation says that the number of intelligent alien civilizations in our galaxy is = the rate at which stars form in our galaxy (around seven per year).

x the % of stars with planets
x the % of these planets in a habitable zone
x the likelihood of life emerging
x the likelihood of intelligent life evolving
x the number of intelligent civilizations that emit signs of their existence (like radio waves)
x the average length of time intelligent civilizations survive

The Drake Equation is of seminal importance because it orders our thinking. This one equation forms the backbone of astrobiology as a science. Carl Sagan was inspired that the Drake Equation showed the chances of intelligent alien life were high but he alos added that extraordinary claims require extraordinary evidence.
Image credit: With thanks to
Source: The Daily Galaxy

No hay comentarios:

Publicar un comentario