# Illustration Simultaneous events on parallels to the spatial axis in the Minkowski diagram

A one-dimensional Minkowski diagram ($$c\,t$$-$$x$$ coordinate system) with sketched simultaneous events for the coordinate system. The simultaneous events are always parallel to the spatial axis of this rest frame of reference.
• $$\class{red}{E_0}$$ and $$\class{red}{E_1}$$ happen at the earlier time $$c \, \class{red}{t_1}$$ in the rest frame.
• $$\class{blue}{E_2}$$, $$\class{blue}{E_3}$$ and $$\class{blue}{E_4}$$ happen at the later time $$c\,\class{blue}{t_2}$$ in the rest frame.