Billions of particles of invisible “dark matter” are probably flying through your body right now, passing through the spaces between your atoms without a trace. According to conventional thinking, these particles should be somewhat less abundant during the winter and should peak around June 1. But a new study suggests this calculation is way off; the real peak is actually at the beginning of March.

Dark matter is thought to constitute almost 27 percent of the universe’s total mass and energy, but its nature is a mystery. One of physicists’ best guesses is that theorized particles called WIMPs (weakly interacting massive particles) make up this matter, but WIMPs have so far eluded detection. Whatever dark matter is, it appears to clump into large clouds called haloes that engulf galaxies, including our own Milky Way. As the solar system makes its regular progression around the Milky Way, it flies through this halo, causing dark matter to bombard the sun and planets with a steady “wind,” just as flies will hit the windshield of a fast-moving car. Earth, however, is also rotating around the sun. Astrophysicists have assumed that when it is moving against the direction of the dark matter wind (which happens to be during summer), we should see an uptick in dark matter particles of a few percent, and a corresponding decrease when Earth is traveling with the tide during winter.

via Dark Matter Near Earth Peaks Every March, New Study Suggests: Scientific American.