Seth Shostak

The central region of the Milky Way, known as the bulge, is stuffed with literally tens of billions of stars. And most of these are old - considerably older than our Sun or its neighbors - because this part of the galaxy formed first. Consequently, bulge stars are generally deficient in heavy elements.

Junk, redundancy, and inefficiency characterize astrophysical signals. It seems they characterize cells and sea lions, too. These biological constructions have lots of superfluous and redundant parts, and are a long way from being optimally built or operated.

Explorers tend to be the aggressive types - why else would they risk scurvy, mutiny and other bad things to go out there? So, you could say that any aliens that are actually moving and interested in going somewhere are likely to be more aggressive. But who knows?

One of the jovian moons, Europa, is coated with twice as much liquid water as is sloshing around our planet.

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?

Ever since the infamous quiz show scandals of the 1950s, the feds had insisted that TV game shows be honest - or that at least they didn't cheat. So as a 'Dating Game' bachelor, I didn't know what I was going to be asked. The other bachelors and I were required to concoct our answers in real time.

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.

Studying Sol's interior by looking for analogous patterns on its incandescent face is known as helioseismology, an active - if largely unpronounceable - research area that uses sound as a probe of our home star.

It's hard to imagine anything more interesting than learning how we're woven into the enormous tapestry of existence. Where did our universe come from? How special is our world, and how special are we? We allocate tens of billions of dollars annually to NASA, NSF and academia in search of the answers.

We haven't yet found a speck of evidence for biology on another world, so we have no objective way to judge whether life is a onetime fluke or a near-inevitable phenomenon.

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.

The math is dead simple: it seems that the frequency of planets able to support life is roughly one percent. In other words, a billion or more such worlds exist in our galaxy alone. That's a lot of acreage, and it takes industrial-strength credulity to believe it's all bleakly barren.