Recent controversies, particularly about evolutionary biology, obscure the nature of how scientists do their work. To understand that better, I recommend this week's podcast episode of CBC Radio's "Quirks and Quarks."
In it, you can hear about how scientists in different disciplines approach problems with particular ideas in mind. In one case (how babies learn language), the researcher was right in her hypothesis that newborn humans seem "hard wired" to learn language—but she would have been just as happy to find out she was wrong. Another scientist turned out to be wrong about whether he could identify individual loons from their calls—but that turned out to be even more interesting because loons change their calls when they move between territories, which is much more complex behaviour than anyone previously knew about. There are also two fascinating stories about climate change, demonstrating the subtleties of what often seems like a black-and-white issue.
The key is that the scientists involved want their ideas to be tested, and are willing to be wrong or to be led in new directions. They undertake remarkable intellectual exercises to design experiments or make predictions that will tease out the truth—find out, for instance, how they "ask" newborns what they're interested in, or how they determine how carbion dioxide levels changed in Europe during the Middle Ages. Scientific researchers are not, in general, as dogmatic as the stereotypes imply. Indeed, if they are they can't be very good at their jobs. Even when they are highly opinionated, as Phil Plait is on the Chris Pirillo show this week, those opinions come from trying to understand what they can about the universe, and frustration with those who would rather believe something than discover it.
Incidentally, the last half of that Pirillo Show episode gives great general advice about buying a telescope. While I'm not an astronomer, amateur or professional, my dad has been looking at the sky from a young age, and I grew up with telescopes as much a part of the house as cookware or furniture. There's good stuff in that podcast.