Earth may have ‘hair’ of dark matter, says NASA scientist

Earth may have long filaments or "hair" of dark matter coming out of it, a new study by a NASA scientist has suggested.

Dark matter is the invisible, mysterious substance that makes up about 27% of all matter and energy in the universe. Visible matter, which makes up everything we can see around us, is only 5%.

The rest of the universe, roughly 68%, is made up of dark energy, a little-known phenomenon associated with the acceleration of our expanding universe.

The study was published recently in Astrophysical Journal by Gary Prézeau of NASA's Jet Propulsion Laboratory in California.

Over the last decade, calculations and simulations have shown that dark matter forms "fine-grained streams" of particles that move at the same velocity and orbit galaxies such as ours.

"A stream can be much larger than the solar system itself and there are many different streams crisscrossing our galactic neighbourhood," says Prezeau.

He likens this to mixing chocolate and vanilla ice cream. Swirl a scoop of each together a few times and you get a mixed pattern, with the individual colours standing out.

According to Prézeau's simulations, when such a stream passes through Earth, gravity would focus and bend it into a narrow, dense hair. He feels that there should be many such hairs sprouting from our planet.

The hairs would have "kinks" in them that correspond to the transitions between the different layers of Earth -- the core, the mantle and the crust.

When particles of a dark matter stream pass through the Earth's core, they focus at the "root" of a hair, where the density of the particles is about a billion times more than average.

Send probes to 'hair' root, say scientists

The root of such a hair should be around one million km away from the surface, or twice as far as the moon.

The stream particles that graze the Earth's surface will form the tip of the hair, about twice as far from the Earth as the hair's root.

"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," Prezeau suggests.

A stream passing through Jupiter's core would produce even denser roots: almost 1 trillion times denser than the original stream, he says.

Charles Lawrence, chief scientist for JPL, adds that roots of dark matter hairs would be an "attractive place to look", given their density.

Such a probe could help understand the secrets of the mysterious matter which makes up nearly 27% of our universe.

( with inputs from agencies)