1. What is a planet and how many of them can be seen in our solar system?
2. If there are yet unseen planets, how might astronomers find them?
1. What is the so-called Planet Nine or Planet X? If it existed, how big did scientists think it would be?
2. What did Chad Trujillo and Scott Sheppard report in 2014?
3. How many objects were studied in the new analysis on Planet Nine? What type of objects are they?
4. What is the “street lamp” effect and how did Kevin Napier use that analogy to describe concerns about evidence for Planet Nine?
5. When asked about whether the new analysis kills Planet Nine, what did Napier conclude?
6. What examples did Samantha Lawler give for arguing that Planet Nine would be appealing to astronomers, such as herself.
7. Konstantin Batygin claims that evidence for Planet Nine should show up “only” in what type of data?
1. Based on what you read, what do you think Planet Nine might be like (if it existed)? Might it host life? Explain your reasoning.
2. If Planet Nine exists, describe at least three of the challenges to sending spacecraft to explore it with cameras or other instruments.