In Space at the Speed of Light: The History of 14 Billion Years for People Short on Time, she guides you through fundamental questions, both answered and unanswered, posed by space scientists. Why does gravity matter? How do we know the big bang happened? What is dark matter? Do aliens exist? Why is the sky dark at night? If you have ever looked up at night and wondered how it all works, you will find answers - and many more questions - in this pocket-sized tour of the universe!