Concave mirrors are sort of like parabolic dishes, in that the parallel light rays bounce off the curved-in surface and bounce to the focal point, which you can picture as being where the center ...

Sener has since earned multiple medals for his attempt to bring the ancient device to life. In his view, he as shown that “the principle behind the Archimedes Death Ray is certainly possible,” ...

Here's the concave mirror and here's you. If I draw a couple light rays from the top of your head to the mirror and reflect them, they'll eventually meet somewhere.

On the other hand, light rays cross the concave lens can reach the target only when it pass through the points near the center of the lens (Fig. 1e) ...

A concave eyepiece then magnified the tiny image for the viewer to see. Galileo's first telescope offered limited magnification and a narrow field of view.

Sener explained that the ancient death ray was made up of a series of large concave mirrors, positioned to focus the Sun’s rays onto a single focal point and potentially hitting a target up to ...