The findings by University of Iowa scientists refute the decades-long assumption that such radio waves disperse in an ever-widening cone.

The researchers studied radio waves called the Auroral Kilometric Radiation generated by the same solar particles that produce auroral lights. The scientists said they analyzed data collected by instruments on the European Space Agency's four Cluster spacecraft.

Completing analyses of 12,000 bursts of AKR, the astronomers concluded the AKR beamed into space is confined within just 15 degrees of a narrow plane.

Knowing how AKR is transmitted is expected to give astronomers another method of finding planets in other solar systems.

"Whenever you have aurora, you get AKR," said Professor Robert Mutel, lead author of the study, who noted that aurorae and AKR have been detected from Jupiter and Saturn, the two largest gas giants in our solar system.

Once planets have been identified, astronomers will measure the frequency of AKR bursts to determine the rotational periods of the planets.

The study appears in the journal Geophysical Research Letters.