Fast Radios Bursts (FRBs) show large dispersion measures (DMs), suggesting an extragalactic location. We analyze the DMs of the 11 known FRBs in detail and identify steps as integer multiples of half the lowest DM found, 187.5cm$^{-3}$ pc, so that DM
s occur in groups centered at 375, 562, 750, 937, 1125cm$^{-3}$ pc, with errors observed <5%. We estimate the likelhood of a coincidence as 5:10,000. We speculate that this could originate from a Galaxy population of FRBs, with Milky Way DM contribution as model deviations, and an underlying generator process that produces FRBs with DMs in discrete steps. However, we find that FRBs tend to arrive at close to the full integer second, like man-made perytons. If this holds, FRBs would also be man-made. This can be verified, or refuted, with new FRBs to be detected.
Learned et. al. proposed that a sufficiently advanced extra-terrestrial civilization may tickle Cepheid and RR Lyrae variable stars with a neutrino beam at the right time, thus causing them to trigger early and jogging the otherwise very regular phas
e of their expansion and contraction. This would turn these stars into beacons to transmit information throughout the galaxy and beyond. The idea is to search for signs of phase modulation (in the regime of short pulse duration) and patterns, which could be indicative of intentional, omnidirectional signaling. We have performed such a search among variable stars using photometric data from the Kepler space telescope. In the RRc Lyrae star KIC 5520878, we have found two such regimes of long and short pulse durations. The sequence of period lengths, expressed as time series data, is strongly auto correlated, with correlation coefficients of prime numbers being significantly higher ($p=99.8$%). Our analysis of this candidate star shows that the prime number oddity originates from two simultaneous pulsation periods and is likely of natural origin. Simple physical models elucidate the frequency content and asymmetries of the KIC 5520878 light curve. Despite this SETI null result, we encourage testing other archival and future time-series photometry for signs of modulated stars. This can be done as a by-product to the standard analysis, and even partly automated.
We document the presence of a few Cepheid and RR Lyrae variable stars with previously unrecognized characteristics. These stars exhibit the property of a period ratio of main pulsation divided by secondary pulsation P1/P2 very close to sqrt(2). Other
stars of these types have period ratios which do not show clustering with a close association and a single remarkable non-harmonic number. Close examination reveals a deviation of multiples of a few times ~0.06% for these stars. This deviation seems to be present in discrete steps on the order of ~0.000390(4), indicating the possible presence of a sort of fine structure in this oscillation.
