ASTRONOMERS like to think they know where the stars are. They can point to them in the night sky: there's Polaris, there's Vega, there's Adhara... We've had the night sky mapped for millennia now. But how do we know the maps are right? After all, no one has been out to check that the stars really are where we think they are.
Our celestial maps are based on the assumption that photons of light almost always travel from the stars to our telescopes on Earth in a straight line. Is that a fair assumption? Maybe not. "The universe is roughly 13 billion years old: a lot of things could have happened to photon trajectories in that time," says Akhlesh Lakhtakia.
It is an unusual claim from someone in his job. Lakhtakia is not an astronomer, but an electrical engineer based at Penn State University in University Park, Pennsylvania. Nonetheless, working ...
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