But they can't be coming from very far away. If they were traveling from more than 30 million light years away, they would most likely collide with other stuff such as the cosmic microwave background and slow down. By the time they reached Earth they would have much less energy than they have. But 30 million light years isn't very far, by astronomical standards. So if there's something out there stirring all this up, you would think scientists would know it was there.
Nobody knows, but when they find it, it's going to be a blast.
A former science writer for the Los Angeles Times , he now lives in Juneau, Alaska. Others have suggested they are artifacts of the earliest universe. ABC News Internet Ventures. Click here for Terms of Use and Privacy Policy and Internet Safety Information applicable to this site.