YAHOO UK - Dark matter, the invisible substance believed to account for over 80 percent of the universe's mass, is not an easy thing to detect. We can see its gravitational pull on visible matter, however — which makes hydrogen, as the most common element out there, a prime candidate to watch for those interactions.
Taking advantage of this, a team of researchers have analyzed how hydrogen absorbs the light from distant sources like galaxies in an effect known as the "Lyman-Alpha Forest," and have applied this in a series of simulations to map the distribution of dark matter throughout the cosmos.
Their resulting study, published in the Journal of Cosmology and Astrophysics, confirms that there's a discrepancy between our observations of the universe and our predictions about its structures — and possibly points to the existence of a never-before-seen type of particle.
The universe is filled with hydrogen atoms, often in clouds of neutral hydrogen which make up most of the interstellar medium. In a spectrum of distant light sources like galaxies and quasars — whose structures are thought to be governed by dark matter's gravity — the areas where hydrogen absorbs the light along its journey to Earth show up as a staggered series of spiked lines that look like a forest.
"These are the atoms and molecules that the light has encountered along the way," said study coauthor Simon Bird, an associate professor of physics and astronomy at the University of California, Riverside, in a statement about the work. "Since each type of atom has a specific way of absorbing light, leaving a sort of signature in the spectrogram, it is possible to trace their presence, especially that of hydrogen, the most abundant element in the universe."