Astronomers and physicists are in a hurry to find more elements that should help them put together the pieces of the colossal cosmic puzzle that the dark matter represents.

Astronomers now believe with a certain degree of certitude that the so-called “visible Universe” is just a tiny portion of the complex Universe we live in, the rest being “filled” by the unfathomable dark matter and dark energy.

The mysterious dark force (attributed to the dark matter) that “glues” galaxies and keeps them relatively close together has eluded until now scientists’ efforts to put it under theoretical scrutiny, although there’s strong evidence that scientists are not chasing an illusion.

Just as planets and even entire galaxy clusters get sometimes discovered in the far reaches of the Universe through the so called “gravitational lens” effect (meaning that we cannot actually see the celestial body, be it a planet or a galaxy, but we can infer its existence by the effects it produces on nearby objects), so does the dark matter: its presence is deduced indirectly from the motions of astronomical objects, specifically stellar, galactic, and galaxy cluster/supercluster observations.

For each of the stellar, galactic, and galaxy cluster/supercluster observations the basic principle is that if we measure velocities in some region, then there has to be enough mass there for gravity to stop all the objects flying apart. When such velocity measurements are done on large scales, it turns out that the amount of inferred mass is much more than can be explained by the luminous stuff. Hence we infer that there is dark matter in the Universe.

One of the most puzzling characteristics of the elusive dark matter is its “incapacity” to interact with “regular” matter, avoiding detection because it emits no light and no heat. It is now believed that dark matter makes up 25% of the Universe. By comparison, the “usual” matter we can see is believed to make up no more than 5% of our Universe.

There are currently two types of “candidates” for what dark matter is made of, but recent research shows that the exotic state of aggregation could be even more complex. The “usual suspects” include baryonic and non-baryonic particles, differentiated by their masses and speeds. The world of physics, which has also come up with some weird names for known elementary particles (like top, down, charm, or strange quarks- the term “quark” itself being borrowed from a famous novel of James Joyce), is separating the non-baryonic dark matter particles in “cold” and “hot”, the cold having slow speeds or pressure, while the hot moving at high speeds.

Generally speaking, these are called WIMPS (weakly interacting massive particles) and they are the premier suspects when astronomers search for evidence of dark matter. However, recent studies put another candidate into the spotlight.

In the PVLAS experiment, which is located at Italy's Legnaro National Laboratory, researchers created a vacuum in a chamber, applied a strong magnetic field to the chamber using powerful magnets, and directed a beam of light into one end. They observed that the light coming out spun around as if it had passed through a crystal.

“We propose that the intense magnetic field causes light to mix with certain hypothetical particles, which are called pseudoscalars,” explained corresponding scientist Pankaj Jain, a physicist at the Indian Institute of Technology in Kanpur, to PhysOrg.com. “Essentially, light gets partially converted into these particles, which then convert back after a short time interval. The interaction of these particles with light and other known particles is very weak. Hence they could be candidates for dark matter.”