Black Hole Photon Paths (IMAGE)
Caption
Due to gravitational lensing, the photons from a single flash of light near a black hole follow winding paths. Some follow the trajectory of the blue line, where they take a direct path to the observer. Others orbit around the black hole once, following the path of the red dashed line. Others still orbit the black hole twice following the green dashed line. Because the different paths all have different time delays, the photons arrive one after another in sequence, and the original flash of light will appear to echo.
Credit
George N. Wong
Usage Restrictions
No restrictions.
License
Public Domain