The beginning of chapter 3 has two pictures of galaxies. The study of the universe has been on-going for decades. One organization involved with this is the SETI Institute. You may remember this from the movie Contact. One area of their research is with exoplanets. Until 1995, other solar systems with planets like ours was a simple conjecture. Now, this is a very exciting field of study. To do this, the scientist gather immense amounts of data from the telescopes. For their research, the goal is to find a planet which could, in theory, support human life. In this endeavor, the scientists would not be as interested in a gas giant, e.g. Saturn or Jupiter.

If you were creating a decision tree based on the telescope observations, please describe what the root node would be, possible internal nodes, and leaf terminal nodes