The brain is made up of an estimated 100 billion brain cells or neurons. An astronomically large number, you might think. But think again. This number pales in comparison to the number of stars in the Milky Way galaxy. In fact, there are about three to four times more stars in our galaxy than there are neurons in our brain. Don’t get me wrong here. I’m not trying to belittle this amazing and complex computer we call the brain. Just the sheer quantity of stars in the Universe is a mind-boggling number. It is difficult to conceive of the incredibly large number of stars shining above our heads. Yet, we have managed to map billions upon billions of them.
In our galaxy alone there are about 300 billion or so stars. But this is not as big as it gets. 300 billion is just a fraction of the number of stars in the Andromeda galaxy, for example. But even Andromeda is dwarfed by the size of other supermassive galaxies that bear about 50 to 100 times more stars. Now, thus far we are only considering the number of stars. Already we are dealing with extremely huge numbers. Those stars live in groups called galaxies which themselves exist in vast numbers. There are probably more than 170 billion galaxies in the Universe. I say ‘probably’ because this is, at least, what we can potentially observe. There could be even more!
With 170 000 000 000 galaxies and about 600 000 000 000 stars in each of them, we’re talking of a total 100 000 000 000 000 000 000 000 stars or so! Don’t despair if you’re lost in a sea of zeros. Astronomy is rife with large numbers. And yet, even if it may be a daunting concept, to realise that we live in such a complex world is an equally awe-inspiring and humbling experience. So, if each neuron was a star, say, then there would be about a thousand billion brains in the Universe! A thousand billion… This is 142 times more brain than there currently is on Earth (with an estimated 7 billion people)!
To quote Einstein, “The most incomprehensible thing about the world is that it is comprehensible.” The Universe is the most complex entity. This might sound tautological but this is more than just stating the obvious. Yes, our brains are complex but these very brains are a product of the evolution of the Universe. And this is the point I would like to emphasise. There is a level of complexity in the Universe which comes full circle. Not only has the Universe evolved to produce myriads of stars but also planets. And upon at least one of these planets, remnants of stars (in the form of chemical elements such as oxygen and carbon) have coagulated and changed over billions of years to form life. And life has produced a whole plethora of beings, from the simple unicellular organisms to a variety of plants and animals. And, eventually, animals with complex brains have come unto the scene. The human brain is so complex that it can marvel at the very thing which brought it into existence; it can marvel at the Universe; it can ponder on its long evolutionary process right from the Big Bang, nearly 14 billion years ago, to the present and even going further and dreaming of future possibilities. This Universe, despite its overwhelming complexity, is something comprehensible. And Science is the key to understanding and appreciating this elegant Universe in all its glory.