To see the unseen

Автор: Andrew J. Butrica
Издательство: NASA History Office
Страниц: 330
Год: 1996
Размер: 10,8 МБ

Let me begin with a confession and some explanations. Before beginning this project, I knew nothing about planetary radar astronomy. I quickly realized that I was not alone. I discovered, too, that most people confuse radar astronomy and radio astronomy. The usual distinction made between the two is that radar astronomy is an "active" and radio astronomy a "passive" form of investigation. The differentiation goes much deeper, however; they represent two disparate forms of scientific research.

Radio astronomy is more akin to the methods of natural history, in which observation and classification constitute the principal methods of acquiring knowledge. Radio astronomers search the cosmos for signals that they then examine, analyze, and classify. Radar astronomy, on the other hand, is more like a laboratory science. Experimental conditions are controlled; the radar astronomer determines the parameters (such as frequency, time, amplitude, phase, and polarization) of the transmitted signals.