  We revisit the familiar scenario involving two parties in relative motion, in
which Alice stays at rest while Bob goes on a journey at speed $\beta c$ along
an arbitrary trajectory and reunites with Alice after a certain period of time.
It is a well-known consequence of special relativity that the time that passes
until they meet again is different for the two parties and is shorter in Bob's
frame by a factor of $\sqrt{1-\beta^2}$. We investigate how this asymmetry
manifests from an information-theoretic viewpoint. Assuming that Alice and Bob
transmit signals of equal average power to each other during the whole journey,
and that additive white Gaussian noise is present at both sides, we show that
the maximum number of bits per second that Alice can transmit reliably to Bob
is always higher than the one Bob can transmit to Alice. Equivalently, the
energy per bit invested by Alice is lower than that invested by Bob, meaning
that the traveler is less efficient from the communication perspective, as
conjectured by Jarett and Cover.
