Astrophysics, Space Science, Planetary Science and Cosmology

Christopher B. Siren


Astrophysics, Space Science, Planetary Science, and Cosmology

A word to the uninitiated: At first blush one might think that Astrophysics, Space Science, and Planetary Science are all pretty much the same thing, and indeed, they often wind up being lumped together under the heading Astronomy. The main differences are that Astrophysics is the study of everything outside the solar system and Space and Planetary Science are pretty much confined to the solar system. Planetary Science is the study of those solid and fluid bodies within the solar system, from the size of a small rock, to something like Jupiter or even the Sun. It has close ties to geology and meteorology. Space Science concerns itself with the seemingly empty space between the planets and sun. It is the realm of the Solar wind, charged particles and magnetospheres. All three branches overlap in the study of our closest star, the Sun.