Don't know much about space Book

I like the don't know much about series. It has questions and answers. The questions are simple, but the answers are complicated. This book reveals a lot of info that I had never known. Some stars look like they are twins, but they are not binary stars! It's just like three dots almost on the same line, but the dots are very far apart. After the Hubble telescope was sent out, some scientists discovered that the main mirror had a tiny but serious error. A fraction of the width of a hair! It caused blurry vision. So in 1993, some astronauts flew to the ISS and repaired the telescope. But why do the scientists want two extra pieces of space trash after 2020------Voyager 1 and 2? Even though the spacecrafts are useful for finding aliens, after 2020, there will be two pieces of trash in space if the spacecrafts don't return.