Dark matter is an obscure, yet important component of our overall structure that makes up most of the universe. Although scientists have seen the general gravitational effects of dark matter since early years, researchers still remain baffled about its nature.
What is dark matter, and how does it affect the structure of the entire universe?
Astronomers have spotted many compact dark matter clusters within clusters of galaxies. The largest such structure is the Virgo cluster, which is composed of over half a million stars. Another example is the Beta Lupis, which consists of over one hundred and fifty galaxies. These clusters are thought to be held together by their very own gravity, and are therefore extremely heavy, making them very cluster-like in structure. Scientists have used gravitational lensing to estimate the mass of these structures, and have thus come up with a very precise value.
There are two different theories on what dark matter consists of.
One of them is completely electromagnetic, and involves the existence of several satellites or spinning satellites orbiting the earth. The other theory involves the idea of a “normal” matter which exists in an extremely dense arrangement, but has remained virtually invisible to us. This “normal matter” is made out of very heavy quarks, like protons, electrons, and mesons. This type of dark matter poses a great challenge to conventional telescopes.
Astronomers also use a relatively new technique called gamma ray tomography.
It works on the following theory: gamma rays emitted from explosions in outer space are absorbed by matter which is located very close to the explosion. The dark matter particle that was initially responsible for the explosion is thus pushed into the black hole, while the gamma rays travel through the tunnels created by the holes, and reach the detectors. By measuring the amount of light emitted from the dark matter, scientists can determine its composition. If it is made up mostly of dark matter, then they will be able to map the location of the holes.
A new theory regarding dark matter was recently proposed by scientists working at CERN (European Organization for Nuclear Research).
The new theory suggests that dark energy is caused by another force, one which accounts for the repulsion and attraction of objects. The strength of this other force could be measured with the help of satellites in orbit around the earth. If it is found to be stronger than the force that accounts for dark energy, it means that it pushes and pulls on objects, including stars. These results will be helpful in determining the location of dark energy factories.
Another way to verify the presence of dark matter is to look at the distribution of missing mass in our galaxy. The largest galaxy known as the Milky Way has about half a million galaxies, and most of these are either close to empty, or have a slight amount of missing mass. We can estimate the amount of missing mass by looking at the motion of stars in the nearby galaxies.
What is Dark Matter made up of?
It was discovered that the majority of galaxies contain a lot of cold atomic nuclei, while the dark matter makes up about 70%. Cold atomic nuclei are very similar to ordinary matter, but are much colder. Because of their cold nature, they can only be created in very low temperatures inside dwarf galaxies, like the Milky Way, which is why we cannot see these rare elements in the so-called ‘cometary gases’ of these smaller galaxies.
However, the existence of this rare type of matter is inferred from the motion of baryonic hydrogen atoms, which are found in all nuclei and produce baryonic matter, in a similar fashion to what happens when a nucleus emits a particle as soon as it decays.
The existence of dark matter particles was confirmed through the detection of a variety of phenomena.
It is possible to test its existence using the Cosmic microwave background (CMC), which is the oldest radiation in the cosmos. It is also detectable in satellite surveys of space and in radio waves from space, such as those coming from galaxy clusters.
Apart from these, there are several theories that suggest the presence of dark matter particles in the form of relic radiation, which originated from very ancient explosions that occurred in the past. The detection of this radiation supports the general theory of relativity (Gravitation), which states that the cosmos is governed by a constant wind of invisible matter that permeates the entire Universe, bringing about the structures we observe.