The universe is expanding faster and faster…
“Dark energy is perhaps the greatest mystery in physics” said Steve Allen of the Institute of Astronomy in Cambridge, England. Scientists suspect the there is some mysterious force behind the expansion of the universe, which seems constantly increasing. Based on the energy density that our universe has, initially scientists thought one day universe will collapse. But now it’s other way around. Galaxies are moving away and increasing the space between them.instead of being stopped by the attraction of matter or gravity.
Albert Einstein realized that empty space is not empty. In fact space itself has some interesting properties which includes the idea of creating more space. Einstein called this as the cosmological constant. However he disbanded the idea after calling it his “Biggest Blunder”. Except it seems to be pretty close to what we think now.
Another idea about dark energy is that, it’s a new kind of dynamical energy fluid-filled, like water will fill the container, the in dark energy will fill the space that in. And then it will force a container to get bigger and overflows.
Perhaps it could be the dark energy, creates a new fundamental force in the universe, that only takes effect after it reaches a certain size. Scientific theories allow for this possibility of such forces or it could happen is a very temporary force that eventually disappeared and then the universe slows and stops. But this is just grasping at ideas.
While particle physicists and cosmologists propose concrete solutions on the question of the nature of dark matter, the situation for the dark energy is considerably more difficult. To cause the accelerated expansion in the universe, its pressure must be negative. However particle physicists says, this is theoretically possible.
Based on their proposed model, certain types of postulated quantum fields, can actually create a negative pressure, which acts as repulsive gravity. Even though these theories suggested some clue, significant scope remains unexplained, due to lack of experimental evidences.