  The Unruh effect -- according to which linearly accelerated observers with
proper acceleration a= constant in the (no-particle) vacuum state of inertial
observers experience a thermal bath of particles with temperature $T_U = a
\hbar / (2 \pi k_B c)$ -- has just completed its 40$^{th}$ anniversary. A
'direct' experimental confirmation of the Unruh effect has been seen with
concern because the linear acceleration needed to reach a temperature $1 K$ is
of order $10^{20} m/s^2$. Although the Unruh effect can be rigorously
considered as well tested as free quantum field theory itself, it would be
satisfying to observe some lab phenomenon which could evidence its existence.
Here, we propose a simple experiment reachable under present technology whose
result may be directly interpreted in terms of the Unruh thermal bath. Then,
instead of waiting for experimentalists to perform the experiment, we use
standard classical electrodynamics to anticipate its output and show that it
reveals the presence of a thermal bath with temperature $T_U$ in the
accelerated frame. Unless one is willing to question the validity of classical
electrodynamics, this must be seen as a virtual observation of the Unruh
effect. Regardless of doubts still raised by some voices, the Unruh effect
lives among us.
