Planet's future

The rapid growth of human civilization -in the number of people, the power of technology, and the global economy - is colliding with approaching limits to the supply of natural resources on which billions of lives depend. our consumption patterns are mocking Earth's resources. Humanity's footprint already exceeds the planet's regenerative capacity by 50 per cent

- JAYDEV JANA The writer is a retired IAS officer

Throughout the history of human civilisation, every culture has had its own idea of the future. The crushing disappointments that are so often part of the human condition have sometimes led to crises of confidence in the future, replacing hope with despair. But most have learned from their life experiences and the stories told by their elders that what we do in the present, when informed by the knowledge of the past, can shape the future in objectively better ways.

Our planet is 4.5 billion years old. While the future can't be predicted with certainty, it is certain that the future of Earth is shaped by a number of factors including the Sun's evolution as well as a variety of interconnected environmental, technological, social and economic trends.

About the evolution of the Sun renowned astrophysicist Stephen W. Hawking says in his seminal book A Brief History of Time: "A star is formed when a large amount of gas (mostly hydrogen) starts to collapse in on itself due to gravitational attraction. As it contracts the atoms of gas collide with each other more and more frequently and at greater and greater speeds - the gas heats up. Eventually, the gas will be so hot that when the hydrogen atoms collide they no longer bounce off each other, but instead coalesce to form helium. The heat released in this reaction, which is like a controlled hydrogen bomb explosion, is what makes the star shine. The additional heat also increases the pressure of the gas until it is sufficient to balance the gravitational attraction, and the gas stops contracting. It is a bit like a balloon... Star will remain stable like this for a long time, with the nuclear reactions balancing the gravitational attraction.