Discover the Ladder Paradox, relativity's greatest thought experimentEsther Inglis-Arkell8/30/13 4:30pmFiled to: physicssciencerelativitythe ladder paradox1576EditPromoteShare to KinjaToggle Conversation toolsGo to permalinkThe Ladder Paradox is a famous thought experiment that shows you why you can fit objects into spaces that are too small for them. And also why you can't, depending on your perspective.AdvertisementRelativity does a real number on our faith in reality. Although we can think of reality as objective, there are some special cases that prove it's nothing of the kind. Different people have their own reality, and these realities are, sometimes, incompatible. One particularly nagging problem is known as the Ladder Paradox, or the Barn-Pole Paradox.Let's say you have a ladder and you have a garage. You've never put the ladder in the garage because the ladder is too long. You'd either have to open the front door and let the end of the ladder hang out into your driveway, or the back door, and let the other end of the ladder spill out into your back yard. One day, your friend Albert says that he can put your ladder inside your garage, albeit briefly. You see, as objects approach relativistic speeds, they undergo length contraction. So if you're sitting in your garage, and Albert - who's an old guy but has a good set of legs - runs through, the ladder will appear to be shorter than it is when it's standing still. If you have a garage door opener that closes both doors simultaneously (and quickly), the ladder will fit inside.