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Boost Histories

Look for the toothpaste effect: events are stretched apart in some cases, and squeezed together in others.

Different inertial grids have different rel-coordinates for events. Here, two grids, Grid 1 and Grid 2, differ by a boost, in which Grid 2 is moving along the x-axis of Grid 1, at a speed β, with -1<β<1. The sign of β indicates if Grid 2 moves in the +x direction, or the -x direction.

Given the rel-coordinates of an event as measured in Grid 1, you use the boost transformation to find the rel-coordinates for the same event, as measured in Grid 2.

The form lets you input multiple events for each of the two separate histories. For example, this input for a history:

generates these two events:

These events are joined by a line to make a history. If you entered 3 events, then they would be joined to form a single history as well, and so on. Black dots represent the ticks of a wristwatch. The tick marks stretch out as γ increases.

The units used in this chart aren't specified. It shows values only within a certain range, about +/- 225 or so.