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To Open The SkyThe Front Pages of Christopher P. Winter
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![]() The Cassini Mission to SaturnA personal viewThe Benefits of CassiniThe benefits are easy to describe. Scientists will learn a great deal about the composition of Titan and the nature of Saturn and its moons and rings. They — along with many of the rest of us — will exult at the spectacular images flowing back across a billion miles. Data on the performance of spacecraft instruments and systems will augment our engineering knowledge base. We will, in short, know more about our solar system and the worlds within it. What use is this new knowledge? I cannot say for sure. Who can, without having that knowledge? The one thing that can safely be said about the value of knowledge we haven't yet obtained is that, if we never bother to obtain it, it will be of absolutely no value. It's like the lottery: If you never buy a ticket, you'll never win a prize. (Except, of course, the "tickets" we've bought in the science "lottery" have in general paid off much better.) I will mention two examples of such payoffs. The greenhouse effect, now known to keep Earth warmer than it would otherwise be (and, if we're not careful, too warm) was first identified as the reason why Venus is so hellishly hot. And the phenomenon known as "nuclear winter" is related to planet-wide dust storms which cool a world by blocking or reflecting more sunlight than usually reaches the surface. They were first seen by the Viking probes we sent out. So, although the idea was known before then, from observations on Earth, the confirmation came from a close look at Mars. By observing and measuring conditions on two other worlds, we have proven the existence of effects that might damage our Earth. We have learned how those effects work, and how to defeat them. Sounds like a worthwhile effort to me. |