Аннотация:Long-term observations of global oscillations of the Sun revealed the existence of the phasecoherent periodicity P0 = 160.0101 ± 0.0001 min seen in the Doppler shift of a photospheric spectral line. The true nature of the phenomenon is yet unknown. But the most intriguing aspect seems to be the recent discovery of the same periodicity in luminosity variations of several AGNs which makes the puzzle of the "ubiquitous" P0-oscillation much more mysterious. The present analysis of all available data on the rapid variability of the nucleus of NGC 4151 fully confirms the AGN P0-oscillation (with a mean amplitude 0.01 mag). It is argued that this oscillation must have a cosmological origin - due to, e.g., its independence of the AGN redshift. In terms of general relativity the P0-oscillation is treated as a characteristic time scale of metric fluctuations of the Universe. The conclusion is made that this new astrophysical phenomenon severely contradicts today's cosmological model of the Universe based on the Big Bang paradigm.