It was the great Sir Isaac Newton that invented the jet-powered car. Newton forecast that one day people would travel at 50 miles an hour. In 1680 a man named Gravesande designed a car that would be powered by Newton's third law of motion - "To every action there is an equal and opposite reaction." A boiler sent out a jet of steam that pushed the car along. Of course everyone on the road behind the jet engine would have been scalded, but that's a small price to pay for progress.