Last week the Kepler satellite released results indicating that the mission had discovered over 1200 planetary candidates (most of which are expected to be actual planets) orbiting stars in our neighborhood of the galaxy. In technical terms, that’s a “buttload.” A back-of-the-envelope calculation implies that there might be a million or so “Earth-like” planets in our Milky Way galaxy. A tiny fraction of the hundred billion stars we have, but still a healthy number.
In this image, the size of the dot is proportional to the size of the planet, while the distance from the center is proportional to the distance at which its orbiting its star. The color and height measure the same thing, the temperature of the planet. (Greenhouse effect not included.)
Here’s a video that offers transitions between different presentations of the data. Unfortunately, it’s kind of hard to read the labels on the various axes unless you go to the HD version.
A couple of science results pop out — you could have figured them out without the visualization, but it makes it much easier. First, most of these planets are closer to their stars than Earth is to the Sun. Second, most of the planets are equal to or a bit larger than the Earth. Both features make sense in terms of Kepler’s search technique — the mission looks for tiny dips in the brightness of stars as planets pass in front, which favors larger planets with shorter orbits. It’s unclear whether the overall planet distribution also shares these features.