Scientists propose that the planets in the solar system might be growing dark matter “beard,” making the cosmic neighborhood likely hairier than previously thought.
The new study, published in the Astrophysical Journal, proposed that there are long filaments of dark matter – might as well be called “hairs” – existing and sprouting from Earth.
Making up an estimated 27 percent of all matter and energy found in the universe is the invisible and mysterious dark matter, which has been implicated in the acceleration of the expanding universe. Regular matter, on the contrary, makes up everything one can see around, but is only a mere 5 percent.
Both dark matter and dark energy are yet to be directly found, but experiments are underway to unlock their mystery, such as dark matter from space or the planet’s deep underground.
Charles Lawrence, chief scientist at NASA’s Jet Propulsion Laboratory’s astronomy, physics and technology directorate, said that dark matter had evaded over 30 years worth of investigation.
“The roots of dark matter hairs would be an attractive place to look, given how dense they are thought to be," he said.
While a tough nut to crack, dark matter has indirect proof found in the entire cosmos. While it cannot interact through the electromagnetic force as a “non-baryonic matter” – it is “cold” or does not really move around that much, and “dark” or does not emit nor interact with light – it has a potent gravitational pull in action.
Galaxies are thought to form due to fluctuations in dark matter density, with gravity gluing both visible and dark matter together. Dark matter is believed to make up “fine-grained streams" of particles moving at the same velocity and orbit the galaxies.
Study author Gary Prézeau said the stream can even be much larger than the solar system. "When gravity interacts with the cold dark matter gas during galaxy formation, all particles within a stream continue traveling at the same velocity," he explained.
The researcher from JPL used computer simulations to analyze what happens when one of the streams approaches Earth. The results: when a stream of dark matter goes through a planet, the particles focus into “hair” or a hyper-dense filament of dark matter. Earth’s gravity would bend the stream into narrow and dense hair, based on simulations.
These hairs have roots and tips, too: the root should be about 600,000 miles away from Earth’s surface, while stream particles grazing the same surface will form the tip, estimated to be twice as far from the planet as the root.
The hairs have “kinks” as well, corresponding to transitions among the Earth layers or the core, mantle, and crust.
Prézeau is hopeful they can gather “a bonanza of data” about the elusive dark matter once they are able to point out where the root of the hairs is located.
Information on dark matter could be used for various scientific endeavors such as mapping out the layers of planetary bodies and probing the oceanic depths on icy moons.