DARK ENERGY- CONTROL THE FUTURE OF COSMOLOGY

In the course of 20^th century we went from knowing almost nothing about the universe to knowing all its basic features. But knowing is different from understanding. That is the challenge before us right now. Cosmology, the study of comets, planets, solar system, stars, galaxies, space and entire universe. And gravitational force plays important role to keep these components of universe in balanced way. But as the gravitational force of larger body is attracts the smaller body in the universe, each body is attracted by another body, it means every components inside the universe attracting each other or concentrated at a single point or we can say universe is contracting or expanding.

According to Friedmann Lemaitre Robertson Walker metric, it can be shown that a strong constant negative pressure in the universe causes an acceleration in universal expansion if the universe is already expanding or a deceleration in universe contraction if the universe is already contracting.

A team of astronomer doing a survey of extremely distant supernovae found that they were farther away than expected. They lead to the real discovery of the universal increased expansion rate. And also the group of scientist revealed accelerating universe. So, the universe is flying apart in all direction at every increasing rate. Since 1998 when the discovery was announced, scientist have struggle to come to grief for the mysterious presence, now appears to control the future of cosmos- “Dark Energy”.

Dark energy hasn’t been “Discovered”, but instead is the name of the unknown force that seems to be causing the expansion rate of our universe to accelerate.

Best example that explains about universal expansion is related to Doppler shift which is applied to light also, if our eyes are more sensitive to colour then the car seems to be slightly blue when it approaches and very slightly red as it goes away, the same rule applied in the universe, all distant galaxies are slightly red in colour. So, by the exact piece of basic physics they must all be moving away infact the whole universe is expanding in all direction being bigger and bigger like an inflated balloon.

According to latest research, dark energy permeates space and exerts a negative pressure which would have gravitational effects to account for the differences between the theoretical and observational results of gravitational effects on visible matter. It is not directly observed but rather inferred from observations of gravitational interactions between astronomical objects, along with the dark matter. It is the most accepted hypothesis to explain observations since the 1990s that indicate that the universe is expanding at an accelerating rate. According to the Planck mission team, and based on the standard model of cosmology the total mass- energy of the universe contains 4.9% ordinary matter, 26.8% dark matter and 68.3% dark energy.

As for now many scientist are doing different researches to revel the truth behind the dark energy but till yet it is an unsolved mystery.