Astronomy: At the farthest end of universe — the quasars
AS I race towards the farthest edges of the universe, some 12-15 billion years in the past, (as of now the exact time/distance is elusive) much faster than the speed of light — which as you know is about 186,000 miles, or 300,000 km per second — I confront something I did not imagine before. Nor did I ever know that it existed in the first place.
I keep getting closer, as much as I can for it is getting hotter by the moment; hot at first, searing hot now and the gravity is catching on and pulling me hard towards the objects — the mysterious quasars. I am told that these brightest of bright objects came into being, soon after the Big Bang, so that, helped by other factors, we can make a safe estimate of their age.
When the universe came into being, there were no galaxies, no stars yet, but soon there were quasars, short for quasi-stellar radio sources. Most of them are rather small, about twice as big as the entire Solar System. But they are the earliest ware on the rack. These brilliant and extremely hot objects are like the first child in the family. Nothing is older, brighter or hotter than the quasars. Small though they evidently are, yet there may be some as big as a small galaxy and there may be as many as 2,000 of them, you never know.
Racing along at 240,000 km per second (80 per cent the speed of light), they are little galaxies unto themselves, discovered in the 1960s, they came into being soon after the universe did, preceding all else. Therefore, they are billed as the earliest of galaxies that came into being long before anything else did.
Along the way, in the course of my imaginary journey, I happened to pass by many items of absolute startling nature. These include the earliest, better known as proto galaxies.
Galaxies, I notice, come in all shapes and sizes. Some shaped like many mundane things, seen from the Earth through telescopes. These may resemble a sombrero, a dark cloud here, a bright cloud there, but most of them as pin wheels, or elongated wagon wheels.
Also, many nebulae appear in interesting forms and shapes, like a horse head or flower petals, in all the exotic colours. And then those loose chunks of pebbles in all sizes. Then those stars, some half the size of our Sun, some others even smaller, but more of them stood out in great dimensions, being a million times bigger, and hotter than the Sun, and naturally, more luminous. Maybe these are the future black holes, or black holes in the making, especially those at the centre of a galaxy. Some stars are blue, red or orange in colour and hues. Some others are called red giants, or even white dwarfs; then, there are the Black Holes all over the place.
Often we had to circuit around them to ‘save our souls’. As you are aware, a Black Hole sucks in all material lying nearby. On the contrary, a quasar may only be spewing out material for new galaxies. As if it was not enough, I encountered many wispy clouds that from our home base looked like densely packed opaque cloud systems; some others in exquisite rainbow colours. I am reminded that the opaque objects are, sort of, satellite galaxies, with stars studded in them.
Then I was shown nurseries for the baby stars, also called nebulous clouds, with stars just emerging from the cosmic cradle.
After them, I saw the remnants of what used to be blooming, shimmering stars until a few million years back. They are now dead and have since burst open in one great smash and spread in all directions for billions upon billions of miles (in fact trillions of miles). These are called, novas (better known as novae). Their debris will pick itself up once again to create yet another star, or many more of them in due course (like Cassiopeia, or Seven Sisters). That sounds like our own fabled bird, Phoenix, reputed to recreate itself from its own ashes.
Next, I passed through many satellite galaxies. Whereas, a nova only turns into a star or two, a satellite galaxy, having come into being from a few nebulae, may be also from the residual material of the galaxy itself. It is a city of stars in the making. I was told that it hangs around a full galaxy, like our own, and never leaves the side of its mother galaxy. Hence the name, satellite galaxy: like the large and small Magellanic clouds, along with its millions of stars.
The strange thing I see next is a large group of stars huddled together in a warm celestial embrace. They are gravitationally bound and stick together. Then I see many ‘twins’ and some ‘triplets’ and even quadruples circling around each other, almost defying the laws of gravity. I understand that it is because of their high speed of rotation that keeps them from falling into each other, or a unique centre of gravity (called barycentre), I immediately recall how I learned to ride a bicycle, or play the whirling top way back.
At this point in time I need to know my bearing, or direction in the sky. But I am instantly reminded that there are no directions in outer space. No direction at all. Nor up and down, neither before nor after. This place is all crazy. Nobody seems to be ‘at rest,’ nothing ever goes to sleep in this place. It’s all lighted up, bright and blazing.
I was at my wit’s end until I saw a huge cloud of tenuous gas and dust. As I approached it, it grew wispy and tenuous but not colourful like the earlier ones. It is sort of black, made from gas and little pebbles. I at once suspected that it could only be the Dark Matter and nothing else.
It was diffuse, gathering, converging, and spread all around. They say that it is laid out between stars and adds into their mass with the passage of time, but I was not sure. For sure, however, it is very, very hot! Hotter than the surface of the Sun! How it came to be so hot, the very thought drove me crazy.
What beauty all around! On the Earth I never imagined that the universe could be so beautiful, hauntingly beautiful, I must add. Poincare was absolutely right.
Then, galaxy after galaxy full of stars; in all shapes and colours, and furious activity galore like there is no tomorrow!
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