Astronomer blows your mind

Astronomer changes the world as we know of.

Really????? 

Newton's 3 famous laws of motion changed the way we thought of nature. Newton used the observations of Galileo Galilei, an astronomer, to formulate newton's law of universal gravitation and laws of motion.

What about finding cool things?

Its astronomers who look into deep sky, look for the smallest hint, to find origins of everything. They came up with the theory of big bang, which blows minds of millions. Even more unbelievable is the discovery of dark matter and dark energy.

How about looking into past?

If you feel like looking into past, you should become an astronomer. They are best at it.

Astronomer look billions of years into past to find how mother nature works.

How about saving our lives?

Yes, astronomers might save our lives from dangerous natural disasters. They observe asteroids in our solar system and protect us from possible asteroid attacks. They also observe the sun closely to protect the earth from dangerous solar flares. 

Gravitational Lensing : Estimating mass of Dark Matter

Introduction :-
Dark matter is (almost) like normal matter; it has mass and volume. The difference is small, but very important. Unlike regular matter, it does not scatter Electromagnetic wave, so we cannot see it with telescope.

Gravitational Lensing :-
Even though it cannot be observed directly, we can use Einstein's Theory of General Relativity to calculate the mass of Dark Matter. He stated that light follows the curvature of space-time, hence when light passes through massive object, it is bent. The angle of deflection is :

G = gravitational constant
M = mass of an object
r = distance between mass and radiation
c = speed of light

Bent rays when passed through heave mass

Recent Discoveries :-

Discovered in 2007, Luminous Red Galaxy 3-757 interacts with another much more distant blue galaxy. This galaxy was re-observed in December 11, 2011 with Hubble Space Telescope.

LRG 3-757 in front of distant blue galaxy creating Einstein Rings

Approximate Mass of Dark Matter :-
Dark matter is believed to constitute 83% of all matter in the universe, and 23% of total mass-energy in the universe. 

Sources :-
Wikipedia : Dark Matter
Wikipedia : Gravitational Lensing
NASA Picture of the Day