You are given a passage. You need to construct a question about the information present in the passage. Construct a question in such a way that (i) it is unambiguous, (ii) its answer is the whole paragraph. Avoid creating questions that can be answered correctly without actually understanding the paragraph.
Q: Yes -- in fact you are living on one.  The earth and moon is quite unusual in being relatively the same size to earth other compared to other moons around other planets in the solar system.\n\nIn that respect you can consider the earth and moon as being twin planets.\n\nAs to how often this happens outside the solar system, you would probably have to wait a few years as we have only just started to be able to detect planets around nearby stars but currently have no real means of actually observing them.
A: 
There are traces of joint stars in Milky Way galaxy. Are there any traces of joint planets ever detected?