Welcome to Cloud City: The case for going to Venus, not Mars

NOTE FOR 2020 READERS: This is the 12th in a series of open letters to the next century, now just 80 years away. The series asks: What will the world look like at the other end of our kids' lives?

Dear 22nd Century,

Is there life on Mars?

Human life, I mean. Or does a pioneering percentage of you have your heads in the...