Where Does Outer Space Start?

And other Interesting Questions

Back when I worked at the planetarium at CU, I used to do a lot of lectures for school kids. I’d always invite questions at the end of the session, and some of them were really quite good. For instance, after a talk about stargazing and the planets, I had one kid ask, “Where does outer space start?”

Instead of trying to answer right away, I asked the student, “Where do YOU think it starts?”  The whole class got in on it, and eventually we came up with an answer that it probably starts just above our planet’s atmosphere. They figured that out themselves, with a little prompting from me.  And, I could pull up images of Earth on the dome and we could talk about the “top” of the atmosphere by looking at it. Chalk one up for the use of a planetarium in education! (The commonly held definition is that space starts about 100 kilometers (about 60 miles) above our heads.)

Another time, I had a student ask about why we see stars at night but not during the day.  Of course, I did remind him that there IS one star we can see during the day, the Sun. But, he had a good question and once again, I asked him to think about reasons why we don’t see stars during the day.  Eventually we worked it out by going outside and talking about what it was that kept us from seeing the stars during daylight.

One of the most memorable question “events” I had was with a little girl who waited until the very end to ask her question. Just as I was about to end the Q&A period, she timidly raised her hand. I called on her and she asked, “What’s it like inside a black hole?”

Before I could answer, her teacher said, “Don’t ask stupid questions!”  (The same teacher had been silent when the boys in her class who had been giggling and goofing off during the whole lecture had asked me some really stupid questions like “How do you pronounce Uranus?” and acted quite silly when I seriously explained the proper pronunciation).

The little girl sort of wilted in her seat, but I wasn’t going to let her question go unanswered. First I mentioned that in science there’s no such thing as a stupid question, but that as some of the other students had demonstrated, there are silly questions. I explained that a question about black holes and their insides is a very good one that scientists speculate about all the time. By the time I got through with my answer, the little girl was smiling, the teacher was glowering, and the boys had stopped fooling around and began thinking of follow-up questions.

Science starts with questions like “what is this?” and “Why does it do that?”  and “How far away is it?” and “What’s it like on—?”  If you walk outside at night and look up at the stars, I guarantee that you’ll have questions about what you’re seeing. And, that the answers will always amaze you. And if they amaze YOU, think of what they’ll ignite in a child’s mind!