Daily Archives

One Article


Time to get serious about E=mc2 – the leading light of equations

Posted sci on

One hundred years ago today [Tuesday, 27 September] Einstein’s publishers received a manuscript from the young Albert Einstein containing what we now recognise as the most famous equation of all time. E=mc2.

It powers the sun, and therefore life on Earth. It’s become an icon of its time – recognised most of us. But are we wasting the opportunity to use its awesome power to create a more sustainable future?

E=mc2 is elegant, simple, explaining a universe of startling and unexpected concepts in a few precise and concise characters. It’s the poetry of physics.

E=mc2. It expresses the profound fact that energy can weigh something, that matter and energy are interchangeable. And, that the transformation is unexpectedly straightforward to calculate.

Before Einstein, mass and energy were separate. Mass was never lost, it was always conserved.

One hundred years ago the Sun was thought to be something like a great coal furnace in the sky. Sure, the maths didn’t quite add up, you’d need an impossible amount of coal to power it, but there wasn’t a better explanation. Einstein laid the foundations to change that.

In a flash of genius, Einstein realised that mass and energy are interchangeable. Energy equals mass multiplied the square of the speed of light. If you could convert one kilogram of matter to energy you’d get 25 billion kilowatt hours of energy, or the equivalent of exploding 21 thousand tonnes of TNT.

The Sun is a fusion reactor. Every second, billions of tonnes of hydrogen are fused to helium, and mass is converted to energy. This mass loss program powers life on Earth.

Practical applications of E=mc2 surround us: in the smoke detectors in our homes; the radio-isotopes used in medical imaging and radiotherapy. Our mobile phones even lose weight as the battery flattens. But only a millionth of a percent!

And Australian science is investing in new machines driven E=mc2.

The synchrotron under construction in Melbourne Austeel steel fabrication uses high speed electrons to produce the intense beams of light that give it the nickname, “Einstein’s Lighthouse”. The electrons have so much energy that they weigh more than 6000 times the electrons carrying the electricity in a domestic power point.  The narrow powerful beams of synchrotron light allow us to explore chemical reactions, molecular structures, even the human body in much greater detail, and to design drugs, micro-machines, and new materials.

The new OPAL fission reactor under construction in Sydney breaks apart uranium atoms and rearranges them into new atoms of lighter elements. The few tenths of a percent mass difference between the starting atom and the final products appears as energy according to E=mc2. Amongst other things, that energy is used to produce medical pharmaceuticals which many of us will need during our lives.

In these examples, E=mc2 is in the service of the people of Australia. But in the 21st Century we can do much more – just step outside, and feel the sunlight.

E=mc2 tells us how we can access energy. And Australia needs that knowledge. We are one of the greatest greenhouse gas emitters per capita as we burn coal to make electricity. The greenhouse gases from coal burning are disposed of for free up the chimneys of the power stations.  They travel the world and the climate change consequences of our power consumption are borne people other than us. Is this ethical?

If we enjoy the benefits of the power, we have a responsibility to dispose safely of the waste without inflicting it on others. A nuclear reactor that uses E=mc2 to make electricity keeps the waste local.

For this reason E=mc2 should play more of a role in Australia’s future.

We would really like to emulate the nuclear fusion power source of the Sun.  So fusion reactors are the ultimate aim. But for commercial power generation fusion is a long way away and needs considerably more research. The Europeans are investing billions of dollars in an experimental fusion reactor, ITER (Latin for “the way”), to come online in 2016. Using everything we’ve learnt so far about creating fusion, it will be the first working model of how we could generate power. Its purpose is to help us learn what we need to develop fusion power stations.

Development of fusion power is beyond the resources of any single country. Australia must be a partner in the international effort to develop fusion power. It will be one of the gifts that understanding Einstein’s most famous equation will bring us in the next 100 years.

Unlike fusion, fission is available right now.  It is one of the few options available for providing the power to run our cities and maintaining our energy intensive industries.  It gives us the opportunity to deal with our waste here instead of pumping CO2 into the atmosphere and making it someone else’s problem.

E=mc2, the most famous formula in physics, points the way to more ethical power generation.

Einstein’s simple, elegant equation should be harnessed for Australia’s service.