Light Cones & Causality

What can affect what

An interactive lesson with 6 steps, about 5 minutes: you predict, drag and solve, with instant feedback on every answer. It runs in your browser and needs JavaScript.

What you’ll learn

• An event’s light cone separates its future, past and “elsewhere”.
• Only timelike or lightlike separated events can be causally connected.
• Time order of spacelike-separated events depends on the observer.

Steps

1. Past, future and elsewhere
2. Could it be the cause?
3. Flip the order
4. The earliest echo
5. Out of reach
6. The cone of a lifetime