When it comes to dark matter, Earth is a hairy beast

24 Nov 2015

While it remains an ever-elusive and mysterious substance, dark matter surrounds us all and, according to new research, might be covering Earth in thick ‘hairs’ that reach out from our planet’s surface.

Despite completely evading detection to-date, astrophysicists do actually know some information about dark matter, such as it being found in 27pc of all matter and energy in the universe, more so than the 5pc of familiar matter that we observe every day.

While we have never observed the process in scientific analysis, however, we have observed its enormous gravitational pull on objects in our universe, and one particular way that it does interact with regular matter is seen very close to home.

Based off theories proposed in the 1990s, dark matter forms into ‘fine-grained streams’ of particles that follow identical orbits to galaxies, such as our Milk Way, some reaching sizes bigger than our entire solar system, which creates an incredible effect when interacting with a planet, according to NASA.

In a study published this week in the Astrophysical Journal, a team led by Gary Prézeau of NASA’s Jet Propulsion Laboratory said that when one of these strands goes through a planet, the stream particles focus into an ultra-dense filament, or ‘hair,’ of dark matter.

Dark matter hairs

An illustration of the dark matter ‘hairs’ that surround Earth. Image via NASA/JPL-Caltech

If one of these streams were to hit Earth, for example, Prézeau says, it would react to our planet’s gravity and bend the stream of dark matter particles into a narrow, dense hair.

These hair-like strands even have roots of-sorts where the dark matter concentration is highest, and tips at the end of the strand. When they pass through the Earth and hit its core, they focus at the root over one billion times more than the average density.

Each of these roots would be at a distance of 1m kilometres from the surface of the Earth, with the tip of the hair being two times further out again.

“If we could pinpoint the location of the root of these hairs, we could potentially send a probe there and get a bonanza of data about dark matter,” Prézeau said of the discovery’s potential.

An added bonus discovery that has been made with simulations on these dark matter hairs suggests that as they travel through a planet’s different cores they develop ‘kinks’, which, the research team says, could help scientists determine accurate depths of oceans on distant icy moons.

Hairs image via Shutterstock

Colm Gorey was a senior journalist with Silicon Republic