Maybe the date of dark matter day involves symbolism. Also for a century ago the world was in critical state. Atomic physics, nuclear physics, and quantum theory were developing and revolutionizing the world view. There was a lot of political turmoil. October revolution in Russia took precisely 100 years ago October 25. Maybe also the results deduced from GW170817 and published during October motivated the choice of the date. The results eliminate large class of models trying to explain dark matter without dark matter.
Also I have spent a lot of time in developing a vision about dark matter as heff=n×h phases of ordinary matter. Vision involves magnetic flux tubes carrying dark matter and would apply in all scales. Also in quantum biology dark matter would play a key role. Galactic dark matter and also dark energy would reside at cosmic strings: this predicts the velocity spectrum of distant stars without any further assumptions. One also ends up to a rather detailed fractal vision about formation of galaxies and larger scale structures in terms of cosmic strings. Galaxies would be along long cosmic strings like pearls in necklace: these linear structures have been observed long time ago. Pearls could be knotted regions of this long cosmic string having constant density of dark matter indeed observed in galactic cores.
A side comment about GW170817 is in order. Neutrinos were not observed. A possible explanation inspired by SN1987A is that they move along different space-time sheets than photons and gravitational radiation. Estimating from SN1987A time lag between gamma rays and neutrinos and from the distances of SN1987A and GW170817 and assuming sama Δ c/c, one gets the first estimate that the lag is 118 days. The neutrinos would travel 4 months (of lenth 30 days) -2 days. For details see this.
If I managed to count correctly from my web calendar, the neutrino signal should arrive at December 14. It would be a nice Christmas present but is there any hope that any astrophysicists believes in Santa Claus? Or who knows: perhaps astrophysicists remember SN1987A and are eagerly waiting for the Christmas present!
October by the way "Lokakuu" in finnish. "Loka" translates to "Dirt". As an academic loser whose work fails to satisfy all imaginable criteria for science (as a couple of finnish colleagues so eloquently expressed it) I sometimes feel that my birth month was an omen. The next month is "Marraskuu". "Marras" translates to "Death"! But then comes "Joulukuu": "Joulu" translates to "Christmas". I keep fingers crossed and try to behave and I have already written to Santa Claus a letter, the contents of which should be clear from above.
For a summary of earlier postings see Latest progress in TGD.