This artist's concept portrays the appearance of a "light echo" from a supernova that exploded in the nearby galaxy called the Large Magellanic Cloud (LMC), as seen from Earth more than two centuries after the explosion. The echo is only partly visible because it must intersect with clouds of interstellar dust far from the explosion to be seen. The dust clouds are not equally spaced in the volume the supernova light expands into.

Located 160,000 light-years away in the southern constellation Dorado, the LMC is considered the closest large galaxy to Earth.

This graphic shows the geometry of the light path that creates a supernova light echo, as if the process could be viewed from the side. An echo occurs when the Earth is at one spot in an imaginary ellipse, and the supernova remnant is at another located near dust clouds.

When light from the supernova reaches the dust clouds, it is reflected toward an observer located on Earth. To the observer, the reflection appears as an arc; this arc would be a full, circular slice through the ellipse (as viewed from Earth) if dust were equally distributed in the space the supernova light is traveling through.