### Stephen Hawking passed away in the early hours of March 14 – leaving our lonely planet behind to reclaim his place among the stars as stardust once again.

He took the helm in the world of cosmology, producing more than 150 papers during his extraordinary life. In fact, he even held the position of Lucasian Professor of Mathematics at Cambridge University from 1979 – a position once held by Sir Isaac Newton himself.

He radiated hope, intellectual curiosity and willingness to make the most of a life that he was told he would only live two years more of, after his diagnosis with Motor Neurone Disease, or ALS, at just 21.

Over five decades later, he had become the Planet Earth’s most encapsulating theoretical scientist, best-selling author and cosmologist.

Not only this, but he advocated the importance of our struggling National Health Service, shone in the eyes of social justice, displayed what one can achieve in the face of utmost adversity and provided many with a way out of the dark black hole event horizon that is depression.

“We are just an advanced breed of monkeys on a minor planet of a very average star. But we can understand the universe. That makes us something very special” Hawking’s told *Der Spiegel*, a German paper, in 1988.

During his life, he not only made us realise the potential of our ‘minor planet’ and those that inhabit it, but he showed the world how we have the ability to comprehend how truly wonderful life is.

Remembering Stephen Hawking, a renowned physicist and ambassador of science. His theories unlocked a universe of possibilities that we & the world are exploring. May you keep flying like superman in microgravity, as you said to astronauts on @Space_Station in 2014 pic.twitter.com/FeR4fd2zZ5

— NASA (@NASA) March 14, 2018

Really, on top of his crowning achievement that is the formula describing the entropy of a black hole, he devised a formula for many of us about life. A formula on how to live.

That being our ability and fortune, as an ‘advanced breed of monkeys’, to experience life, love and most importantly – to laugh.

In his words, “life would be tragic if it weren’t funny”.

His humour allowed him to become a pop culture icon, with his IMDB page loaded with TV appearances.

In Kitty Ferguson’s 2013 biography of Hawking, it was revealed that Hawking’s biggest regret was that of ‘not having the opportunity to run over Margaret Thatcher’s toes’.

His political views against the further presence of austerity were never held back, notably his conflict with Secretary of State for Health, Jeremy Hunt.

Hawking expressed his dear feelings and thanks to the NHS, a service he argued allowed him to live the life he did.

Hawking told the Guardian: “The NHS is Britain’s finest public service and the cornerstone of our society. The NHS brings out the best in us. We cannot lose it.

“I wouldn’t be here today if it were not for the NHS. I have received a large amount of high-quality treatment without which I would not have survived.”

Hawking will be remembered not only for his scientific work, but his sheer determination to make the world a better place, make the most of what is given, and most importantly, live, love and laugh.

**IN DEPTH:**

** HAWKING’S LANDMARK FORMULA FOR BLACK HOLE ENTROPY**

His world-renowned formula describing the entropy of a black hole, developed alongside colleague Jacob Bekenstein, has become a landmark in our understanding of the black hole.

The formula may even, going by his wishes expressed in 2002, embellish his gravestone – A poignant bookend to his crowning achievement.

What is more, the very first proposer of entropy, Austrian physicist Ludwig Boltzmann, had his gravestone inscribed with his formula, thus it seems fitting that Hawking should do the very same.

The theory joins together thermodynamic quantities such as entropy, displayed in the formula as the capital ‘S’, to physical properties of the black hole itself, its area of the event horizon (a boundary in spacetime beyond which events cannot affect the outside observer), displayed as ‘A’.

The other letters in the formula are constants of the universe, ‘k’ is the Boltzmann constant (which relates the average kinetic energy of particles in a gas with its temperature), ‘c’ is the speed of light, ‘h-bar’ is the reduced Planck constant (the energy of a quantum of electromagnetic radiation divided by its frequency) and ‘G’ is the universal gravitation constant (otherwise known as Newton’s constant).

Summarily, the end result of Hawking’s formula is that a black hole radiates energy, coined ‘Hawking radiation’, while gradually evaporating and getting smaller.

ICYMI: Stephen Hawking Remembered by Neil deGrasse Tyson and More on Twitter https://t.co/AmnWI1qPbF pic.twitter.com/78WenhMvvg

— SPACE.com (@SPACEdotcom) March 15, 2018

**BREAKING DOWN HAWKING’S CROWNING DISCOVERY**

Hawking realised early on that a black hole can only ever increase in size, as nothing that gets too close can escape – therefore the black hole gains mass.

A black hole’s mass consequently determines its size, measured as the radius of the events horizon, the point at which nothing can escape. This boundary gradually expands outwards.

Hawking theorised that black holes cannot be split into two smaller holes, even if two different ones collide.

He then made another discovery, arguing that the constantly expanding event horizon and its surface area was parallel to a quantity that could only grow, according to common physics.

This quantity is known as entropy – which measures the disorder in a certain system. Atoms close together have low entropy, whilst free moving atoms in, for example, a gas, have high entropy.

Going by the second law of thermodynamics, the universe’s entropy can only increase – the universe, as it ages, gets more disorderly. Hawking then realised that the two rules of nature and physics, the increasing entropy of the universe and the surface area of a black hole, were strangely the very much the same.

Hawking revealed this to Jacob Bekenstein in 1970 – who said that maybe this was not simply a similarity – stating that the surface area of a black hole’s event horizon may be a measure of its entropy.

However, as we know, if something has entropy it must also have a temperature, and if something has such it must then radiate energy, decreasing in mass and over time size. The entire belief that nothing escapes a black hole was therefore disproved.

Hawking achieved this when trying to prove Bekenstein wrong, having combined general relativity (matter on a cosmic scale) and quantum theory (matter on anatomically small/invisible level) together.

Stephen Hawking became a pop culture icon by explaining the mysteries of the universe to a mass audience — while retaining a sense of adventure and fun: https://t.co/IArxszvj21 pic.twitter.com/YuIH2HlAmC

— CNN (@CNN) March 15, 2018

Space is not simply a smooth sheet of emptiness (general relativity), but it is filled with activity on an ‘invisible’ scale (quantum theory).

Hawking argued that a pair of subatomic particles, one positively charged and the other negatively, may be split apart if created next to a black hole’s event horizon, leaving one particle of the pair left outside, while the other one is absorbed by the black hole.

If the negative particle is absorbed by the black hole, then its mass will subsequently shrink – and the positive particle which is left outside will be flung out into space in the form of ‘Hawking radiation’.

Thus the black hole gradually shrinks whilst outputting energy. So far, this radiation has not been detected due to the extremely volatile temperature (we simply do not have the equipment to detect such).

**By Joe Locker**