Light from a distant source passing near a neutron star bends like a flashlight beam in a funhouse mirror. Astrophysicists ran a numerical experiment: they traced rays backward from the observer to the star and looked at what picture a telescope would see. Inside the star, matter is compressed so much that its behavior is described by a simple equation — the stronger the compression, the stiffer the resistance.
As the compression parameter increases, the star becomes more massive, larger in size, and denser. This changes its optical appearance. If the star is illuminated by a spherical light source, a bright ring appears around it, like a rim around a shadow. The stiffer the star, the wider the ring. If a thin disk of gas swirls around the star, the light from the disk is always brightest right at the star's surface.
The viewing angle matters: when viewed from the side, the star's outline stretches into the letter D, and the left side glows noticeably brighter than the right. This is because matter on one side moves toward us, and on the other side away from us. Light from approaching matter shifts slightly blue, and from receding matter shifts red. At small inclinations, gravitational redshift dominates; at large inclinations, blueshift from motion dominates.
Comparison with a black hole of the same mass shows that a neutron star looks different. It has no black shadow, and its glowing edge is more sharply outlined. So future high-resolution telescopes will be able to tell one from the other just from the image, and also refine how matter behaves under unimaginable pressure.
Light passing near a neutron star's surface is bent so strongly that you could see the back of the star: its far side.