Main division would be between the "hard" sciences such as physics or biology and the "softer" sciences, sometimes called the social sciences such as economics or psychology.

Planetary astronomy

Imke De Pater has written:

'Planetary sciences' -- subject(s): Planetology

A planetary geologist needs to have at least a master's degree, and for most jobs a PhD is required. It's necessary to complete courses in geology, physics, chemistry, and other applicable sciences.

Jeffrey B. Plescia has written:

'A bibliography of planetary geology principal investigators and their associates, 1981-1982' -- subject(s): Bibliography, Space sciences, Planets, Geology

'A bibliography of planetary geology principal investigators and their associates, 1982-1983' -- subject(s): Bibliography, Space sciences, Planets, Geology