Earth may have ‘hairy’ dark matter around it, new study suggests
A researcher from NASA’s California-based Jet Propulsion Laboratory has theorized that when dark matter forms “fine-grained streams” that go through Earth, its particles form an ultra-dense filament. In his research, scientist Gary Prezeau call those filaments “hair.”
With all this “hair” sprouting around Earth, our planet almost looks like a space sea urchin in Prézeau’s computer simulation.
"A stream can be much larger than the solar system itself, and there are many different streams crisscrossing our galactic neighborhood," Prezeau said.
It was back in the 1990s when space researchers suggested that dark matter – a mysterious, invisible substance – forms what they called "fine-grained streams" of particles, which move with the same speed and orbit galaxies such as ours.
When speaking on the nature of those streams, Prezeau likened their formation to mixing chocolate and vanilla ice cream: As you mix scoops of the two kinds, individual colors can still be seen in the swirls.
"When gravity interacts with the cold dark matter gas during galaxy formation, all particles within a stream continue traveling at the same velocity," Prezeau said.
Prezeau looked into what happens when one of those streams comes close to a planet like Earth, for example. He ended up learning that when the dark matter runs through the planet, unlike ordinary matter that can’t do so, Earth’s gravity focuses and bends the stream of dark matter particles into narrow, dense hair.
Just like our hair, Earth’s hairs would have both roots, the thickest part of the stream, and tips, the end of the stream. When particles of dark matter pierce through the Earth’s core, they converge into the root, around 600,000 miles (1 million kilometers) away from the surface. The concentrations of particles there can be about a billion times more than average.
The tip of the hair is about twice as far from Earth as the hair’s root. It is formed from the stream of particles that touch our planet’s surface.
"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 said.
He has also “taken” his computer simulation to Jupiter. It suggested that a stream going through the Gas giant would produce even denser roots: almost 1 trillion times denser than the original stream.
Prezeau also theorized that changes in density found inside Earth would be reflected in the hairs as “kinks.” They would correspond to the transitions between the different layers of Earth.
It is thought that dark matter makes up about 27 percent of all matter and energy in the universe. Yet neither dark energy nor dark matter have been directly detected.
"Dark matter has eluded all attempts at direct detection for over 30 years. The roots of dark matter hairs would be an attractive place to look, given how dense they are thought to be,” said Charles Lawrence, chief scientist for JPL’s astronomy, physics and technology directorate.
The findings made by Prezeau could help solve some of the mysteries surrounding dark matter, which despite lack of proof, scientist are sure exists. They could also help them map out the layers of any planet and assume the depths of oceans on icy moons, like those near Jupiter, for example.