A visualization of a black hole passing across Baltimore's Inner Harbor
This scientific visualization demonstrates the visual distortion known as gravitational lensing. A black hole, with roughly the mass of the planet Saturn, is imagined to pass over the Inner Harbor in Baltimore, MD. The view of the buildings on the far side of the harbor are distorted using the calculated effects of Einstein's general relativity.
A black hole warps the space around it. Light that passes near a black hole will follow curved paths and can create multiple images and other visual artifacts. Note that the sky can sometimes be seen by looking below the black hole. These distortions are similar to what can be produced using glass lenses, and are produced by similar optics equations. The effects are called gravitational lensing - lensing that redirects light using mass instead of glass.
The calculations for the visualization use a planar approximation that assumes the buildings are all at the same distance, but are otherwise accurate. Note also that foreground objects, like the boat mast, were not isolated and removed from the image before distortion. In a fully accurate visualization, foreground objects would not be distorted.