VISUAL ARCHIVE / IMAGE STORY
Where Cause and Effect Can Meet
A light cone marks which events can exchange a physical signal.
A light cone separates events that can participate in a chain of cause and effect from events that are too widely separated to influence one another. Relativity permits disagreements about the timing of those distant, spacelike-separated events while preserving the order of genuine causal relationships.
THE OBSERVATION
What we can actually see.
The ordering of causally connected events remains consistent for all inertial observers. Disagreement over the order or simultaneity of sufficiently separated events applies only when neither could have influenced the other.
THE ILLUSTRATION
What the artwork imagines.
The luminous cone is a spacetime diagram turned into scenery, not a physical shell in the night sky. It separates possible causal connections from distant coordinate choices.
FROM THE ILLUSTRATED ARTICLE
The story that inspired it.
The Andromeda thought experiment distinguishes the delay of light from the relativity of assigning a distant event to a local present. A light cone marks which events can exchange a physical signal.
Read There Is No Such Thing as “Right Now” Across the UniverseCHECK THE RECORD
The image interprets the research below. Follow the original work for the measurements and limits behind the scene.
Einstein Online: the relativity of the presentOTHER IMAGE STORIES
Two Ways to Draw the Distant Present
The Galaxy We See Is Already History
The Mark Shared by Titan and Pluto