Recently I started reading about relativity and found this flaw like thingy. I asked a friend of mine who studied physics and he came with the unsatisfying answer: 'at speeds like that everything kind of blurrs so the spearman wont crash into the door'. Is the following correct and a paradox or not? There is a spearman, with a spear of 7 meters long, who is running at 0.9c. He wants to run trough a room which is also 7 meters long. In the room is a man who has 2 buttons: one to open the first door and one to open the second door. However that man wants to keep out the draft and only wants to open 1 door. Will the spearman crash into the door or not? The Doorman will see the spearman contracted to 3.05 meters so according to him the spearman will fit perfectly. However the spearman will see the room contracted to 3.05 Meters so it wont fit according to him. Who is right? And why? I'm kind of confuzzled by this. Thanks in advance for anybody helping me.