Dark Energy and Dark Matter

11:59 AM Science 0 Comments

                        The Universe always mystifies and awes us by hiding secrets in its stomach. Despite our knowledge of centuries, we have not even explored 0.1% of it. It is said that Sun can fit 1 million Earths inside it. Also, it is a rough estimation that 3.3 billion billion billion Earths can comprise our Solar System and similarly 10⁴⁶ in our Milky Way. There are innumerable such Milky Ways in our Universe. Recently, it was found by Astronomers that all this matter counts less than 4.5% of the Universe. So, what are the other constituents in it?

Supernova Explosion

                         Big Bang theory gave genuine explanations regarding the origin of the Universe. It explains that the universe is formed by the camouflage of matter and this is responsible for the continuous expansion of the universe. This shows that all the heavenly bodies should decelerate continuously and halt at a point. But, the experiment conducted by two astronomer teams in 1988 contradicted this. Three Supernovae were observed and it was found that they were accelerating instead of retarding. This led to an idea of the existence of an invisible form of energy which is allowing these celestial bodies to overcome the force of gravity. This invisible force is called DARK ENERGY.

What is Dark Energy?

                       So, what is this dark stuff  really? In simple words, it is the energy which we doesn't know. In 1917, Einstein applied his general theory of relativity to the heavenly bodies. According to him, gravity is not a force which attracts. But, it is a force which bends the space-time continuum. However, his laws doesn't seem to work well with the static universe (At that time it was unknown that the universe is expanding). So, he assumed a 'cosmological constant' to deal with his equations and it really worked very well. In 1920, when Edwin Hubble discovered that the universe is not static and it is expanding continuously. This made Einstein to think that his cosmological constant is the biggest blunder of his life. But, when Higgs Boson was discovered, this cosmological constant is proved to be correct and this explains the dark energy. It explains that dark energy remains constant in the universe and remains as it is. 

                 

                                             Dark Energy


                     Quantum Mechanics can explain almost every feature of particles, but fails at a point. It could not explain why the fundamental particles have mass? i.e, where does the mass of a particle come from? To answer this Peter Higgs, a Scottish scientist proposed a theory called Higgs field theory which explains that a particle gains mass when it gets interacted with the invisible, permeable layer called Higgs field which is spread all over the universe. The higher the mass of an object, the higher is its interaction. How is this related to Dark energy?

                   Higgs field is scalar and it permeates all over the universe same as the dark energy. The discovery of the Higgs Boson acts as a portal in coupling the other scalar fields to the fundamental particles. In the LHC, when highly accelerated particles were collided, dark energy would certainly be released and probably escaped through it. But, the energy changes before and after collision will surely reveal its presence.

                

                     The universe is expanding because the celestial bodies gain energy (this is dark energy) and halts when its energy is exhausted. Even though the dark energy comprises 70% of the total universe, the energy which is expected is nearly 10¹²⁰ times less. So, begs the question that in what form does dark energy exist? This is yet to be answered.

DARK MATTER:

                     According to the theoretical model of the universe, the dark matter accounts more than 80% of the total matter and 27% of the universe. The matter which we see today is very minute in comparison to the matter which we cannot see. This invisible matter is termed as Dark Matter. Unlike normal matter, dark matter doesn't seem to absorb, emit or reflect light and even invisible to the naked eye. We can detect its presence just by the bending positions of light. If it cannot be seen through, then how can we believe that it exists?

                             Dark Matter in a Galaxy Cluster

                       
                     The answer dates back to 1950. When cosmologists were busy in estimating the speeds of galaxies, they found amazing things. According to the law of gravity, the center should revolve with greater velocities than those at the edge. In contradiction , they found out that both the edges and center revolve with same speeds. This indicates that those galaxies comprise some invisible matter stuff which makes it possible. 

                        How can we detect this dark matter? the answer is a bit tough as dark matter is assumed to be composed of non baryons and it is hard to detect that by all the baryonic scientific equipment we have today and even this interacts weakly with the normal. However, this dark matter was detected by observing super-distant galaxies, supernovae and black holes. It is estimated that there are high chances that they are made up of Nuetralinos, particles which are far heavier and slower than Neutrons and Photinos, which are similar to that of Photons.

                  This Dark energy and Dark matter are not only important to the field of Astronomy, but also for the very existence of ours. In future, if we were able to explain the nature of this dark stuff, we would be able to unveil many secrets which were hidden in the universe.