Infrared headlights washed the terrain ahead with invisible radiation - clearly visible to him through the lenses.
But it was the invisible radiation that would kill them all in a few days.
But scientists are especially interested in certain types of invisible radiation, notably X-rays, which only recently began to reach earth.
Later versions of the system used invisible infrared radiation.
Her skin itched all over now, in waves that cascaded up and down as if she were being inundated by invisible radiation.
Galaxies when the universe was only 300 million years old would be moving so fast that all their light would be invisible infrared radiation.
This turned out to be the cosmic microwave background, invisible electromagnetic radiation left over from the explosive dawn of the universe.
Along it and around it would pour the hard, silent invisible radiation.
And invisible radiation that could kill him in an instant if his suit's protection failed.
We creamed and, despite the heat, put on enough clothing to shield us from the invisible radiation that was pouring out of the clouded sky.