UPDATE (2 a.m. EST, Dec. 10): Circumstantial evidence is mounting that the phenomenon was caused by a malfunctioning suborbital rocket, possibly a Bulava ICBM launched from a Russian submarine in the White Sea. A Navtex no-fly alert was issued for the White Sea on Dec. 9th, and photographers have recorded what appears to be the initial boost phase of a launch beneath the spiral (see inset). A rocket motor spinning out of control could indeed explain the spiral pattern, as shown in this video of a Trident II missile launched from a US submarine in 2007. The Russian rocket hypothesis is plausible, but it has not yet been confirmed.