Something in outer space is shouting at us, but astronomers are still trying to figure out the source of this cosmic “noise.” A telescope in Australia recently detected a flood of radio waves, akin to the waves that allow you to listen to the radio in your car, coming from an otherwise unremarkable area of the sky. These millisecond-long pulses of electromagnetic radiation are called fast radio bursts (FRBs). Each burst can release more energy than the Sun does in a million years. Even though almost two dozen FRBs have been observed all over the sky in the past decade, their origins remain shrouded in mystery.
One of the most perplexing aspects of this most recent FRB is that astronomers looked really, really hard for clues about its source…and found nothing. Astrophysical objects and phenomena like FRBs often emit many different types of energy at once, providing observational astronomers with a more holistic picture of what they are and how they arose. For example, insights into dust content or the hot gases that surround galaxies are informed by infrared light and X-rays, respectively. It appears that FRBs don’t have any of this “afterglow” energy to study—even our most advanced “listening” tools haven’t detected the faintest whisper.
Echoes of exploding stars? Aftershocks of colliding black holes? Messages from extraterrestrial civilizations? Some of the proposed causes of FRBs are more plausible than others, but we can’t rule anything out for now. We’ll just need to keep listening.
Acknowledgments: Many thanks to Jieun Choi, a graduate student in Astronomy at Harvard University, for providing her expertise and commentary on the topic.
Managing Correspondent: Christopher Gerry
Original Research: A polarized fast radio burst at low Galactic latitude – arXiv
Media Coverage: The Newest Cosmic Radio Burst Has Stumped Scientists – Gizmodo; Latest Fast Radio Burst From Space Adds to Their Mystery – Smithsonian