Here are some of the specific areas of expertise within planetary science:

* Astrophysicists: Study the physical and chemical properties of planets, including their atmospheres, interiors, and surfaces.

* Geologists: Study the geological processes that have shaped planets, such as volcanism, tectonics, and erosion.

* Atmospheric scientists: Study the atmospheres of planets, including their composition, circulation, and climate.

* Geochemists: Study the chemical composition of planets and their rocks and minerals.

* Exobiologists: Study the possibility of life on other planets and moons.

Some famous planetary scientists include:

* Carl Sagan: Astronomer and science communicator who was known for his work on planetary atmospheres and the search for extraterrestrial life.

* Galileo Galilei: Italian astronomer who made groundbreaking observations of the planets Jupiter, Venus, and Saturn.

* Neil deGrasse Tyson: Astrophysicist and science communicator who is known for his work on the study of planets and the history of astronomy.

If you're interested in learning more about planetary science, there are many resources available online and in libraries. You can also find planetary science departments at many universities.