By Seth Shostak, Senior Astronomer
Originally published on http://www.nbcnews.com/mach/space/what-s-causing-those-mysterious-burst…
They are blasts from the past, shrieks from the black abyss of the universe unlike anything ever found before. And they are deeply mysterious.
Are these some new cosmic phenomenon, an odd habit of nature that we never knew? Or could they be the deliberate wails of societies howling from the farthest corners of space?