Questions and Answers

Since 1995 I have received over 4000 questions and previously posted the answers to all of them at The Astronomy Café.  Here are Top-100 most popular questions I have encountered over the years! I will be updating these FAQs over the next few weeks as the interest level for this resource increases.




Solar System


Black Holes

The Universe

Space Travel

Check out my two books on interstellar and interplanetary travel from an astronomer’s point-of-view! They cover destinations, what we will do when we get there and, of course, ideas about propulsion and hazards along the way.

Gravity and Space

Everything Else!

Ask the Astronomer – The Top-100 most frequently asked questions at Ask the Astronomer from 1995 to 2015! Over 10 million requests for these FAQs. What is Dark Matter? Will Betelgeuse become a supernova? Can a planet ever explode? And many others!!! ($9.26; 10 tables; 156 pages)  Purchase book at