Milky Way Is Warped, Like a Beer Bottle Cap - Technology Review

Milky Way Is Warped, Like a Beer Bottle Cap - Technology Review: The new evidence that Dame and Thaddeus have accumulated shows the existence of a new arm on the other side of the Milky Way, but further from the centre than we are. The new arm is 18 kpc long and so stretches some 50 degrees across the sky...
But why has it taken astronomers so long to find the end of this arm? The reason, says Dame and Thaddeus, is that this arm is bent. Sot it's not in the galactic plane but slightly above it.