This is a marble. It's small. It's light. It's only a few grams.It's quite harmless in my hand. But if we were to place this marble in orbit, it would suddenly gain 8 kilometers per second of speed. That's 8 kilometers per second.Think about it. That's around 20 times faster than a bullet. It will take this marble less than 10 minutes to travel from London to New York.And even something this tiny and innocent could cause a disaster. Why. Well, at those speeds, it's not only about the size. It's also about t ...