这束射线具体来自来自银河系之外哪里，依然是谜，它可能来自虚空。
The exact origins of these high-energy particles still aren’t clear. They are thought to be related to the most energetic phenomena in the universe, such as those involving black holes, gamma-ray bursts and active galactic nuclei, but the biggest discovered so far appear to originate from voids or empty space — where no violent celestial events have taken place.