Other researchers, however, point out that the spread effect could have a different cause. Another spread-out signal that radio telescopes have picked up is the peryton. But these bursts definitely don't come from other galaxies, or even other planets. Instead of coming from a single point in the sky, a peryton signal looks like it's coming from all over, a sure sign that its source is very local. Some blame perytons on atmospheric lightning, radio interference, or even telescope glitches. Unfortunately, perytons look pretty similar to FRBs, so they throw doubt on the idea that the bursts are coming from far away. Some astronomers even think FRBs are just another form of perytons, a false signal rather than an extragalactic one.