I've always loved a good scientific graph. I own three of Edward Tufte's books on the visual display of quantitative information. I have a particular fondness for graphs where a mass of points, each point representing one entity (one sample, one asteroid, one event), displays structure that emerges from the patterns of points' presence and absence on the plane.

So I picked one of these charts to use in a reply to Jessie. I know other scientists are attached to their graphs, too, so I challenged my followers to share their favorites with the hashtag #FaveAstroPlot on Twitter. I got dozens of replies and Storified them here. I understood some of the plots that were tweeted in reply, but found some impenetrable, and in most cases I knew that there was more to a plot than I could see myself. So I emailed a bunch of scientists to ask them about their plots -- what they say, and how they're used in the scientists' subfields. Almost everybody sent me back a blog-length reply! So this is the first in what will be a long series of posts about favorite plots in planetary science.

The plot that I chose compares two properties of the orbits of asteroids: the semimajor axis and the eccentricity. I downloaded my plots from the Minor Planet Center, which provides a variety of other kinds of plots of asteroid orbital characteristics and absolute magnitudes.