Sagan’s philosophical opus centers around Dr. Ellie Arrowway, the discovery of a radio
message from Vega, and the subsequent building of a machine in accordance with directions in
the message. A key twist in the plot requires Ellie to briefly posit time travel as the only
explanation that fits her scientific viewpoint.
You know, it’s not called a space-time continuum for nothing. If they can make tunnels
through space, I suppose they can make some kind of tunnels through time.