Around 300 million years after the BIG BANG the early stars begin to form galaxies. Our galaxy The Milky way is thought to be one of the oldest coming started to assemble itself some 13 billion years ago. It’s roughly 6000 billion miles in diameter and contains something like 200 billion individual stars and it’s not quite sure exactly how many since they can’t all be seen from earth and anyway it take long time to count them, because all these stars were built by gravity you could say gravity is the hero of the universe. After all, it turned the meaningless soup of gas into something of beauty and power. But like all interesting heroes gravity has its dark side. Right in the center of our galaxy lays an example of what happens when gravity rules unchallenged – “A BLACK HOLE!”
How does a Black Hole form?
Physicists all over the world are studying Black Hole behavior. We now know that Black Holes are not only the fascinating in their own right, but that they play a fundamental role in the formation of galaxies they also give us the glimpse how the universe may end? A Black forms when a large star one say 20 times of our massive sun comes to the end. Such a star looks nothing like our sun because it becomes unstable convulsing violently as its death rows begin. Finally it runs out of fuel and begins to shrink getting denser and denser, hotter and hotter. But with the star this massive there is no force in the universe capable of stopping the collapse, the core is so heavy that it just keeps on folding within itself. Gravity is running wild in just 15 seconds or so the unstoppable force crushes the stars from millions of miles in diameter to is as little as 12 miles in diameter. All the mass within the star is still there but its all weight keeps forcing it down smaller and smaller, the temperature of the core source to the 100 billion degrees. The outer layers are blasted away in a massive supernova, but deep in the center the core falls down what we called a gravitational well it crushes itself into a single point a Black Hole is born.
Facts about Black Holes
Nothing nearby can escape its pull, not even light. It’s hard to imagine just how dense a Black Hole would be. Let’s try to understand this with something familiar – The Earth. Imagine piece by piece we can compress our planet and crushes it until gravity took over and it becomes a Black Hole. How small it has to be to vanish down its own gravitational well, from 8000 miles in diameter we have to crush it to the size of a pea.
In years of studying about Black Holes, one of the most unexpected discoveries is that the Black Hole can’t be perfectly Black, for much the same reason as the early universe cannot be perfectly spread out. There is no such thing as perfection. Black Holes must give of radiation, the smaller the Black Hole the greater the radiation. Even a tiny Black Hole with only the mass of a mountain range will actually shine. Outer space, most Black Holes are much larger the smaller ones have around 4 times the mass of our sun and are 50 miles in diameter. Some are much larger containing the mass of thousands of sun and then there are the really big ones Super massive Black Holes those exist the center of the galaxies like our own. This Black Hole is thought to have the mass of 4 million suns and the diameter of 11 million miles.
Bright side of Black Holes
Black Holes like these are the heavy hubs around which many galaxies including the Milky Way rotate, a kind of stabilizer that gives them form and shape. So after the 8 billion years after the big bang after a long and remarkable run of good luck we have stars and we have galaxies slowly rotating around Giant Black Holes.
Now the scene is set for something close to our hearts the formation of sun, earth and ultimately us.
As we know Nature always surprises us with its beauty and incredible treasures, Science always give us power to understand them. In next article we will discuss about the formation of earth and life.
Stay tuned.. Stay blessed! 🙂