In a new study, MIT physicists propose that if most of the dark matter in the universe is made up of microscopic primordial black holes—an idea first proposed in the 1970s—then these gravitational dwarfs should zoom through our solar system at least once per decade. A flyby like this, the researchers predict, would introduce a wobble into Mars’ orbit, to a degree that today’s technology could actually detect.

Such a detection could lend support to the idea that primordial black holes are a primary source of dark matter throughout the universe.

Beyond particles

Less than 20% of all physical matter is made from visible stuff, from stars and planets, to the kitchen sink. The rest is composed of dark matter, a hypothetical form of matter that is invisible across the entire electromagnetic spectrum yet is thought to pervade the universe and exert a gravitational force large enough to affect the motion of stars and galaxies.