Solar System Gravity Wells

On Monday (December 28), Randall Munroe released an XKCD comic on gravity wells. It's a funny, but accurate, way to look at and compare the sizes and masses of the bodies in the solar system. So what exactly is a gravity well?

Sagan-Man!

Today's XKCD comic depicts a fictional superhero: Sagan-Man, a crime fighter who uses inspiration about space to conduct his superhero tasks. Carl Sagan was a very famous astronomer, particularly well known by how he popularized astronomy. I myself was very inspired by his TV show, Cosmos, which explained often seemingly mysterious cosmological concepts with wonder, excitement, and always a great deal of curiosity.

However, Carl Sagan passed away in 1996, and there have really been no other highly inspirational astronomers that can completely fulfill his talent of passing down curiosity about our universe to others. Astronomy would benefit greatly from an advocate like Sagan-Man, as the alt text of the comic says, "They laugh now, but within 10 years the city's entire criminal class will have quit to work on space research."

Comic: Randall Munroe, XKCD


Astronomy and Space Celebrates International Year of Astronomy 2009