Quotes from Seth Shostak

Thanks to the fact that the Earth isn't a perfect sphere, and invoking a bunch of Newtonian physics, you can deduce that our planet wobbles, too, taking roughly 26,000 years to trace out a small circle on the sky, a phenomenon known as precession.

This plucky NASA telescope is able to find planets en masse. If you compare planet hunting to prospecting for gold, then Kepler is equivalent to trading in your trusty pan for a diesel-powered sluice box.

Look, science is hard, it has a reputation of being hard, and the facts are, it is hard, and that's the result of 400 years of science, right? I mean, in the 18th century, in the 18th century you could become an expert on any field of science in an afternoon by going to a library, if you could find the library, right?

The ideas of science germinate in a matrix of established knowledge gained by experiment; they are not lonesome thoughts, born in a rarified realm where no researcher has ever gone before.

Give consideration to the fact that alien astronomers could have scrutinized Earth for more than 4 billion years without detecting any radio signals, despite the fact that our world is the poster child for habitability.

A factory that can turn carbon nanotubes into a sheet a yard wide and long enough to stretch one-fourth of the way to the moon is not something you'll find at your local industrial park. That's the show-stopper for the space elevator. The ribbon.

The stars look the same from night to night. Nebulae and galaxies are dully immutable, maintaining the same overall appearance for thousands or millions of years. Indeed, only the sun, moon and planets - together with the occasional comet, asteroid or meteor - seem dynamic.

Despite tantalizing suggestions of fossilized microbes in meteorites, puzzling and possibly biogenic methane gas in the martian atmosphere, and a long-standing controversy over the Viking lander experiments of nearly 40 years ago, there's still no Exhibit A that points unequivocally to biology in our own back yard.

The Earth has been lawned with life for something over 3.5 billion years. That's a span of time great enough to encompass some honest-to-goodness catastrophe. For example, 700 million years ago, Earth underwent a planet-wide deep freeze, with ice covering the oceans from the poles to the equator.

Any beings advanced enough to traverse interstellar distances are at least a thousand years beyond our technical level. Spending gobs of time examining our missiles is equivalent to sending the Air Force back to the Middle Ages and insisting they examine the chain mail factories.

In 1908, there was a persuasive demonstration of the power of high-speed, low-mass asteroids in rural Siberia. The Tunguska impactor iced millions of pine trees and about a zillion mosquitoes - and was no larger than an office building.

According to 'Star Trek' mythos, Starfleet Command - operational headquarters for a flotilla of craft that keep the cosmic peace - is located in San Francisco's Presidio, in the shadow of the Golden Gate Bridge (still carrying traffic, even in the 23rd century).

Forecasting Armageddon has become trendy of late, with a great deal of attention being given to an interpretation of the Mayan Calendar suggesting that Mother Earth is destined for doom in December of 2012.

We've accounted for 95 percent of all the stars in the Milky Way. The other 5 percent are big, bright stars - the kind that dominate the night sky, but are lamentably both rare and short-lived. If biology's your thing, you can forget those guys.

When was the last time you bought an American-made radio or television? If you're Gen X or younger, the answer is 'never.' Does the label on that shirt or skirt you're wearing say 'Made in the U.S.A.'? If so, you probably got it at Goodwill, or maybe at a Smithsonian garage sale.

When I graduated high school, nearly a half-million people subscribed to 'Popular Electronics' magazine. Soldering up some radio or hi-fi amplifier on the basement workbench was not just a personal passion - a lot of young people were doing the same. The magazine expired in 1999 for lack of interest.

People don't learn science in movies. You don't go to the movies thinking, 'I hope I learn some quantum mechanics this afternoon.' But on the other hand, movies are instrumental and influential in getting young people interested in science.

Estimates are that at least 70 per cent of all stars are accompanied by planets, and since the latter can occur in systems rather than as individuals (think of our own solar system), the number of planets in the Milky Way galaxy is of order one trillion.

Like prospecting in the 19th century, reconnaissance of the asteroids would of necessity take place in an arena where trouble is likely and help is distant. Heroic stories of individual triumph and failure, set on landscapes never seen by humankind, are in the cards.

A century ago, scientists believed there was only one obvious stomping ground for alien biology in our solar system: Mars. Because it was reminiscent of Earth, Mars was assumed to be chock-a-block with animate beings, and its putative inhabitants got a lot of column inches and screen time.

The Moon is a ball of left-over debris from a cosmic collision that took place more than four billion years ago. A Mars-sized asteroid - one of the countless planetesimals that were frantically churning our solar system into existence - hit the infant Earth, bequeathing it a very large natural satellite.

Very few societies on Earth developed science as we know it today. On the other hand, the number is not zero - the Greeks, the Chinese, and the Maya did, among others. Once invented, science proved so useful that it spread like mold on a petri dish.

Plate tectonics is not all havoc and destruction. The slow movement of continents and ocean floors recycles carbon dioxide dissolved in the oceans back into the atmosphere. Without this slow speed carbon cycle, Earth's temperatures would cool dozens of degrees below your comfort zone.

In days gone by, scientists would speak solemnly about our solar system's 'habitable zone' - a theoretical region extending from Venus to Mars, but perhaps not encompassing either, where a planet would be the right temperature to have liquid water on its surface.