Maybe it wasn't light, but some special type of radiation - or, there are infinite possibilities.

Do you know about the different types of radiation?

Later, he had developed a device that could reproduce this new type of radiation.

What they do not say is that the screens are effective only against certain types of radiation.

All three types of radiation occur naturally in certain elements.

These three types of radiation interact with the specimen in different ways.

The natural source of both types of radiation is sun.

However, lead is not effective against all types of radiation.

It all depended on the environment, especially the type of stellar radiation they received.

Other types of radiation, such as infrared could also be used.