In November 2007, a team of astronomers led by West Virginia researcher Duncan Lorimer uncovered a really cool, and really strange, intergalactic radio signal that they attributed to a supernova. Flash forward a few years later, and we found evidence of similar radio bursts from Parkes Observatory in New South Wales.
Swinburne University discusses the original Lorimer and Parkes bursts, and what they may mean, here:
Now the Arecibo Observatory in Puerto Rico has confirmed the signals, removing any possibility that this is a fluke.
Are we being contacted by extraterrestrial worlds? If we are, they're doing a terrible job of it—the bursts are short, fast, and not particularly complex. They're exactly the sort of thing you'd expect to see from a series of cosmic explosions 10 billion years or so ago, but they don't correspond well with what we'd ordinarily expect to find from supernovae. Which doesn't necessarily mean that they're not supernovae, since our understanding of supernovae isn't exactly comprehensive.
But more likely we're discovering a new kind of star. Some researchers have credibly speculated that what we might be picking up are the emanations of blitzars and magnetars, stars whose existence has been theorized but never observed, or the death throes of a dissolving black hole. It's all highly speculative at this point, but what we do know for certain is that the radio signals are very real, very loud, and (probably) very old and very far off.