Distant radio-wave pulses spotted

Signals could help astronomers understand universe's mass

It may have taken billions of years for them to get here from deep space, but four recently detected radio signals disappeared only milliseconds after arriving at Earth. The fleeting signals, only the second detection ever of radio bursts emanating from beyond the Milky Way, could help scientists understand the vast unexplored areas that separate galaxies.

Picked up by an international team of astronomers at the Parkes Radio Telescope in Australia, the powerful radio pulses emanate from sources 5 billion to nearly 11 billion light years away, the researchers report in the July 5 Science. The nature of these sources remains a mystery, says Benjamin Stappers of the University of Manchester in England, but “clearly they’re very energetic events, probably cataclysmic.”

One-time radio pulses have been hard to detect because today’s telescopes capture radio waves from such a small fraction of the sky, and the instruments lack the ultrafast time resolution required to pinpoint the short-lived bursts. The four new blips may add weight to the only other extragalactic radio burst ever witnessed, reported seven years ago by Duncan Lorimer at West Virginia University in Morgantown and his team. “We only had one burst,” Lorimer says. “So always in the back of our minds, we wondered whether it was some weird artifact.”

Now Lorimer is convinced that extragalactic radio bursts are a bona fide phenomenon. Stappers’ team estimates that 10,000 occur every day. Radio wave bursts get scattered by electrons floating in interstellar space, so Stappers envisions using them as tools to measure the mass of those electrons between galaxies.

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