Until 10 years ago, radio astronomers thought they had assembled an essentially complete picture of the sky. In this view, with telescopes attuned to radio waves rather than visible light, the solar system’s brightest radio sources—the sun and Jupiter—would pale against the Milky Way’s splendor. Aglow with radio emissions from sizzling supernovae debris, gas-shrouded stellar nurseries and the metronomic flashes of pulsars, our galaxy would dominate the vista overhead. Beyond that the entire sky would be speckled with steady, starlike points of luminosity from radio-belching supermassive black holes at the centers of distant galaxies.
It turns out, however, those astronomers had missed something big. The heavens also sparkle with something entirely unexpected: fast radio bursts, or FRBs—flashes of radio waves as “bright” as a half-billion suns, which flare from seemingly random locations and fade in just milliseconds. Because most radio telescopes can only survey small patches of sky for short periods, the phenomenon had gone unnoticed for decades.
Even now, with the study of FRBs becoming the most vibrant subfield of radio astronomy, the phenomenon remains unexplained, and observers have reported detecting less than two dozen in all. But extrapolating those meager results to the entire celestial sphere suggests the radio sky should twinkle with perhaps hundreds of FRBs per day. Astronomers regularly quip that there are more theories for the phenomenon’s physical sources than actual observed FRBs. These range from exploding suns to colliding neutron stars to evaporating black holes—or perhaps even chatty aliens.
To read more, click here.