Theory suggests that "hairs" of dark matter may exist around planets
A new theory from NASA's JetPropulsion Laboratory (JPL) in Pasadena, California, suggests thatdark matter may interact with planets, forminglong filaments or "hairs" of invisible particles. Studying thesehairs could be scientifically fruitful, deepening our knowledge ofthe elusive matter, and even using them to analyze distant planetarybodies.
Dark matter is extremely prevalent,with current theories estimating that it makes up around 27 percentof all matter and energy in the entire Universe. It's a very common and extremely important area of study, with past research examining everything from its very nature to how it might play a role in mass extinction events.
The other big characteristic of dark matter is that it's extremelydifficult to detect. While the effects of its gravitational pullmake us certain that it exists, we've never actually successfullyobserved it.
So, why is it so hard to detect? Well,current theories suggest that it doesn't move around as much asnormal matter, and that it's "dark" in that it doesn't interactwith or produce any light at all.
Despite its illusive nature, darkmatter is thought to have a huge impact on the Universe. The visiblematter that makes up stars, planets and entire galaxies forms as areaction to fluctuations in the density of dark matter, while gravityholds the visible and invisible matter together.
Decades-old calculations suggested thatdark matter forms streams of particles all moving at the samevelocity. These streams can be huge – as large as entire solarsystems – and are laced out amongst the visible matter of galaxies.
The JPL researchers used computersimulations to demonstrate what might happen when one of thesestreams interacts with a planet. While a physical object such as aplanet would stop ordinary matter in its tracks, dark matterparticles pass straight through it, affected only by the gravity ofthe object, which according to the simulations, focuses the streaminto a narrow and extremely dense filament.
These hair-like structures, many ofwhich may be present around our own planet, have "roots" wherethe dark matter is most concentrated, some billion times more thanaverage. On more massive planets the elevated density is even morepronounced. For example, the roots of the filaments around Jupiterare almost 1 trillion times denser than the original stream ofparticles.
These roots are located pretty far outfrom the objects they surround – some 600,000 miles (1 million km)in the case of Earth. If we were able to pinpoint their location thenit might even be possible to to send a probe out to attempt to gatherdata on the invisible particles.
The computer simulations revealed oneother fascinating insight into the potential behavior of dark matter,and it's one that could help us analyze distant planets. According tothe simulation, when the particles pass through a planet, the changesin density directly affect the structure of the filaments, creatingkinks at the transition points between different layers of the Earth.
As our understanding of dark matterimproves, it might one day be possible to detect those kinks,allowing astronomers to look at distant planetary bodies and map outtheir layers from afar, gaining insights into their structures andeven the depths of their oceans.