Mysterious dark matter may interact with Earth’s upper atmosphere, generating telltale radio waves, according to new theoretical research.
Auroras occur in Earth’s ionosphere, where charged solar particles collide with atmospheric atoms. New research suggests this may also be the best place in the universe to find elusive dark matter. (Image credit: NASA Goddard)
New research hints that Earth might be swimming through an ocean of dark matter, and waves in this invisible ocean could produce detectable radio waves in our upper atmosphere. This could provide crucial evidence for this mysterious component of the universe.
Astrophysical and cosmological evidence strongly supports the existence of dark matter, from galaxy rotation curves to the growth of cosmic structures. Alternative theories of gravity have failed to explain these observations, leading most astronomers to conclude that dark matter is an unknown form of matter that rarely interacts with light or normal matter.
While dark matter may consist of massive particles, searches have yielded no results. An intriguing alternative is that dark matter is exceptionally light, potentially in the form of “axions” or exotic photons with a bit of mass.
This ultralight dark matter would act strangely, behaving like large waves rather than individual particles. A recent study on arXiv explored models of ultralight dark matter interacting very rarely with normal matter, producing detectable radio waves in rare cases.
This interaction occurs when dark matter waves align with plasma waves, amplifying the interaction and producing radio waves. Previous research focused on environments like the solar corona or interstellar medium. However, this new study identified Earth’s ionosphere as a potential interaction point.
The ionosphere, a thin layer of charged particles in Earth’s upper atmosphere, naturally has waves sloshing through it. Researchers found that these waves could interact with hypothetical dark matter waves, producing barely detectable radio waves. Using a carefully tuned radio antenna to search for a specific frequency over a year could potentially detect these waves.
This approach has advantages: the ionosphere reflects many radio waves from deeper space, reducing contamination, and is already well-studied and monitored. While this dark matter form is highly theoretical and the technique would take years to perfect, it could provide groundbreaking insights into one of the universe’s most mysterious elements.
