We present new Very Long Baseline Interferometry observations of the LINER galaxy NGC 4278 .
The observations were taken with the Very Long Baseline Array ( VLBA ) and a single antenna of the Very Large Array ( VLA ) at 5 GHz and 8.4 GHz and have a linear resolution of \lesssim 0.1 pc .
Our radio data reveal a two sided structure , with symmetric S -shaped jets emerging from a flat spectrum core .
We fit the jet brightness with gaussian components , which we identify from a previous observation taken five years before .
By comparing the positions of the components in the two epochs , we measure motions between 0.45 \pm 0.14 and 3.76 \pm 0.65 mas , corresponding to apparent velocities \lesssim 0.2 c , and to ages in the range 8.3 - 65.8 years .
Assuming that the radio morphology is intrinsically symmetric and its appearance is governed by Doppler beaming effects , we find that NGC 4278 has mildly relativistic jets ( \beta \sim 0.75 ) , closely aligned to the line-of-sight ( 2 ^ { \circ } \leq \theta \leq 4 ^ { \circ } ) .
Alternatively , the source could be oriented at a larger angle and asymmetries could be related to the jet interaction with the surrounding medium .
We also present new simultaneous VLA observations between 1.4 and 43 GHz , and a 5 GHz light curve between 1972 and 2003 .
The radio spectrum can be fit by a relatively steep power-law ( \alpha = 0.54 ) .
We find significant variability at 5 GHz .
All these arguments indicate that the radiation from NGC 4278 is emitted via the synchrotron process by relativistic particles accelerated by a supermassive black hole .
Despite a much lower power , this is the same process that takes place in ordinary radio loud AGNs .