How so? The multiple tails emanating from comets are well understood. The tail pointing directly away from the sun is composed of ionized gasses sublimated off the comet’s surface and propelled by subatomic particles emanating from the sun (the solar wind), and the other tails are made up of dust, rock, and ice fragments too heavy to be affected by that process. These particles are gravitationally bound and stream behind in the comet’s wake. Due to differential composition and heating on the comet’s surface, material is liberated at varying rates and locations, so given the comet’s speed and trajectory, a number of tails may fan out from the nucleus.
Always two, one positive and one negative.