The European Space Agency's Rosetta mission landed on a comet, and we all heard the news. An interesting note not obvious in the photos from the mission is the size of the comet. It's illustrated here, actual size, compared to the city of Los Angeles.
The Rosetta spacecraft traveled some 4 billion miles on the way to the intercept. That's way more than forty times the distance from here to the sun.
It's hard to grasp such numbers in our mind picture of the mission. Maybe it would help if we visualized the earth at about the size of a VW Beetle; then you'd only have to drive 3 million miles to get to the comet. Okay, still too much, huh.
So if Earth were the size of a grape and hanging on a vine in real-size Florida, the comet would be about the size of a white blood cell floating over real-size Sydney, Australia. Now visualize people living on that grape trying to launch a pair of molecules off to Australia to land on that white blood cell that is so unimaginably far away. Never mind; I give up. And don't get me started on how far the Voyager mission has traveled.
Space missions are bizarre.