The fascinating journey of life-sustaining force on Earth: Water
Wonder where the water you just gulped down came from? The tap, the office water dispenser, under the earth or from the sky? Well, it actually landed on Earth from space some four billion years ago - covering an unknown journey of hundreds of millions of miles - to finally reach your kitchen.
In his quest to find about water, Alok Jha, a former reporter with the Guardian, takes the reader on a voyage trying to unravel the journey that a simple molecule - made from two atoms of hydrogen and one of oxygen - undertook in the blackness of space.
There can be no life without water. At least, no complex life as we know it. Water is the life force, the medium for sustenance and the basis for the myriad variety of life forms on this planet we call our home.
But some of our knowledge about water may have been incomplete.
In fact, the water cycle that you drew in your school notebook was never complete. Jha wonders who actually came up with the idea that the Earth's oceans and rivers were connected via the clouds.
But what is crystal clear is that the water bodies that exist today were made by bombardment of 'water-filled' asteroids and comets in the formative years of the Earth, facilitated by its position in the solar system (that makes it a habitable zone). Movement of plate tectonics and volcanoes eruptions too helped.
Water could sustain on our young planet because its temperature was just right to keep intact the vast liquid oceans and water vapour in the atmosphere that we see today.
To delve further into the deep, Jha, currently the science correspondent for ITV News, takes us on a dual journey.
Part of a group of oceanographers and other scientists on a recent and exclusive water expedition to Antarctica, he takes us through the ice fields, icebergs and world-shaping weather systems of the southern ocean.
In a parallel scientific voyage, he describes the origins of water after the Big Bang, through the beginning of life on Earth and the shaping of our civilisations as the water slowly formed our oceans and filled the aquifers beneath our feet.
Apart from the outside world, water is what keeps us alive from within too.
An average 70-kg person has 42 litres of water inside his body interacting with various molecules in a powerhouse of chemical reactions that lets him or her read, play, work, sleep and pray.
What is life if not water?
"Life is a self-sustained chemical system capable of undergoing Darwinian evolution," NASA says. But this elegant definition is incomplete without water being part of it.
The book comes at a right time when NASA and other global science institutions are scanning the universe for any signs of life - of water in any form that may have given rise to life.
The ingredients of water in us and around us existed in the first few million years after the Big Bang and they will persist long after life on Earth ends.
The distant future of water would be like this: In around one billion years, a quarter of the world's oceans will have been absorbed into the mantle.
The Sun's luminosity will steadily increase and, by the time it is 10 percent brighter than it is today, the surface temperature of the Earth will be an average of 47 degrees Celsius.
"The greenhouse conditions will make life unbearable for the most part and the highest parts of the atmosphere, the stratosphere, will contain even more water. Sunlight hitting this part of the atmosphere will split water atoms, allowing the free hydrogen to escape the Earth," Jha writes.
Over the following 100,000 years, the world's seas will disappear.
Water will still sit in pools on the surface as it is released from inside the Earth, and there might be some small lakes at the poles.
Eventually, by the time the Sun has run out of hydrogen fuel in five billion years, any remaining water on the Earth's surface would have been driven away by the extreme temperatures.
"Disassociated into its constituent elements, all the water we have ever known will be atoms, floating in the blackness of space and the clock will come full circle," Jha concludes.
So, the next time when you hold a glass of water, remember this: it did come from the heavens and your life depends on it.