This is Scientific Americans 60 Second Science.

I'm Lee Billings.

Got a minute?

Radio waves are invisible to our eyes.

But if you could see them, the sky would dance with random tiny flashes.

Thousands of what are called fast radio bursts are estimated to occur every day.

And though each pinprick flash lasts only a thousandth of a second,

they represent a faraway source briefly shining

a billion or more times brighter than our sun.

Fast radio bursts have been known for nearly a decade, but scientists have struggled to determine exactly where they come from, and they'd like to know.

Because finding their origins would help astronomers use the bursts as probes to map the history and structure of the universe in unprecedented detail.

Now, researchers have found the source of one particular burst.

They used radio telescopes in Australia and the giant Subaru optical telescope in Hawaii

to trace a burst observed last April.

And they determined it came from an old elliptical galaxy full of exhausted dying suns

some 6 billion light years away.

The findings are in the journal Nature.

Identifying the source galaxy provides crucial clues.

For one thing, such a galaxy is short on some of the objects expected to cause bursts such as supernovae or rapidly

spinning and flaring pulsars, suggesting this burst came from something else.

And although the burst in question lasted only milliseconds,

astronomers were able to witness its faint fading radio afterglow for about six days.

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