Imagine you&#③⑨;re 嗄lan Eustace. You&#③⑨;re in your ⑤0&#③⑨;s, you&#③⑨;ve got two young daughters and a loving wife at home and you&#③⑨;re the Senior Vice-President of &#③⑨;Knowledge&#③⑨; at Google. But none of that matters to you right now -- because in less than a minute the giant balloon strapped to your back is going to inflate to the size of a football stadium as it carries you over ①③⑤,000 feet strai...