But there was a talk by SETI Institute science team leader Jill Tarter on another proposed super-telescope -- a ground-based radio telescope.

The Square Kilometer Array -- which she hopes will be built within a decade, using $500 million in private contributions -- would, as its name suggests, use computerlized interferometry to combine the signals from a huge number of smaller radio antennas to simulate the signal from a single dish antenna with a full square kilometer of area.

It would be 100 to 1000 times more sensitive than any radio telescope today, combing a very wide viewfield, a spatial resolution better than the Hubble Telescope, and a vast frequency range. And, being made of a flock of separate small antennas, it could be expanded indefinitely -- and different subsets of its antennas could constantly be used for a wide variety of different observations simultaneously, including by far the most thorough search ever for radio signals from alien civilizations.

The "Phoenix Project" currently searching for such signals could cover 100 times more stars at a time than it now does -- and do so both with far greater sensitivity, and at a far greater range of frequencies (especially high ones).

The U.S., Canada, the Netherlands, South Africa, China and Australia have all expressed interest in serving as its site (and all of them, predictably, have radically different design concepts for it).

But to build it, we must be able to reduce its construction cost to $500 per square meter of antennna area -- and we don't yet have the technologies for that.

However, there's an intermediate step: the "One Hectare Telescope" planned by the University of California at Berkeley and the SETI Institute, which -- starting in 2004 or 2005 -- would combine the input from 500 five-meter satellite TV dishes to provide 10,000 square meters of antenna area for only one-third the cost of a comparable single-dish radio telescope, and test the feasibility of the design which the U.S. proposes for the Square Km Array.

The One Hectare Telescope would be the first radio telescope ever to devote most of its time to the SETI search for alien radio broadcasts, allowing Project Phoenix to observe several hundred thousand stars.

In fact, the very first step in the development of this telescope was completed and turned on two weeks after the Conference: the "Rapid Prototype Array", which combines seven 3.6-meter dishes to test the new computing techniques necessary to combine the outputs from the One Hectare Telescope's 500 dishes.

This completes my series of reports on the First Astrobiology Science Conference.

Given the wildly enthusiastic reception that the Conference got from the scientific community, the Second Conference -- probably in 2002 -- is a virtual certainty.

National Astrobiology Institute Director Baruch Blumberg announced in his opening speech that there will soon be an editorial in "Science" and a special issue of the "Proceedings of the National Academy of Sciences" on astrobiology, and a post-doctoral fellowship program run by the National Research Council.

As he noted, astrobiology seems to have a remarkable ability not just to attract the interest of the general public, but that of scientists -- and to allow those in different fields to combine their expertise in ways that aren't often seen in today's scientific world.

I firmly intend to be there for that second Conference, and to report to you on its results.