Zero, My Hero

On the way to work this morning Spencer was expounding on the importance of zero. The number. The concept. He remarked that we could not have gotten to the moon if we did not have zero. I do not understand specifically how zero makes space travel possible. And yet, I was reluctant to ask him how zero helped us reach the moon. I am pretty sure he expects me to know the answer and he expects me to have the ability to explain it to him. After a minute, I began to feel guilty. I thought I should try to explain. A little. I began, haltingly, by stating that zero as a concept is important to math (hoping he would not ask me why). I went on to explain that math skills were involved in designing rockets. Spencer took in those remarks without a direct reply, commenting instead that zero was also important to the invention of new technologies. Ok. Now I am stumped. I do not know how zero is involved with designing anything. Luckily, that was all Spencer had to say on the concept of zero. His next comment was "oh, that's a very lovely patio" as we drove by what I can only assume was a house with a very lovely patio.