Dark Matter and Energy

Dark Matter and Energy


What is unseen is much more than what is seen. Dark matter and dark energy is something still continues to be a mystery, and mind you a mystery of great importance, because no scientist till date has been able to observe dark matter or energy directly. It still continues to be something that is just there and show their presence without any direct proof in hand. As apparent from the word “dark” that dark matter is something that cannot be seen by naked eyes, as this bizarre ingredient does not emit light or energy.

Dark matter is something which gives the universe its shape. To say, if you calculate mass of each and every particle in the universe then that mass is extremely less (only 5%) than the mass you would calculate using 3rd law of Kepler's planetary motion. In that case, how do you compensate that extra mass? The most accepted answer was to introduce a concept called dark matter. So, it is something which has gravitational effect but it neither interacts with ordinary matter or electromagnetic waves. Dark matter must exist to account for the gravity that holds galaxies together

Now, dark energy is different. Something Einstein called the greatest blunder! According to Hubble, universe is expanding. And everything is continuously moving away from us. Assuming that we only take matter - both dark and normal - into account, the gravity of these would pull everything closer. Basically, the force of gravity should have slowed down the expansion after the big bang and should have pulled things towards each other or have attained balance. But universe is still expanding. And not just expanding but accelerating. That energy which is causing this expansion is unknown and this 'anti-gravity' force at work is termed 'dark energy'. Universe is expanding at an accelerating rate gives the idea that dark energy must be great than dark matter. While dark energy repels, dark matter attracts.

So talking statistically 68% of the Universe is dark energy. Dark matter contributes about 27%. Remaining everything on Earth, everything ever observed with all of our instruments, all normal matter, all that is luminous that includes all the stars and planets adds up to less than 5% of the Universe. If you think of it, maybe it shouldn't be called normal matter after all! We live in a weird place called universe where hundreds of things are waiting to be unveiled.