Some radioactive material may be carried legally by approved operators, whilst some foodstuffs, ceramics, and other items naturally emit radiation.

Passive equipment works by detecting the faint infrared radiation naturally emitted by almost all objects.

The plutonium 238 for sale by the Russians is a radioactive isotope that naturally emits heat, which can be turned into electrical power.

That means benign items that naturally emit radioactivity - including cat litter, ceramic tile, granite, porcelain toilets, even bananas - can set off the monitors.

As we have drawn closer, we have determined that the extra electromagnetic interference that we thought was somehow being emitted naturally by the star is actually coming from the third planet of that system.

Richard Barrans Department of Physics and Astronomy University of Wyoming All bodies naturally emit radiation.

It is emitted naturally through the carbon cycle and through human activities like the burning of fossil fuels.

The joyous whoop that Sonny Terry naturally emitted between raucous harp blasts was as distinctive a signature sound as can possibly be imagined.

The electrodes pick up the low-voltage electrical signal that is emitted naturally by eye movement.

The original article states that these butterflies are able to change colour, and are luminescent, naturally emitting light from its wings.