Stephen Hawking Knew What He Wanted Written On His Gravestone


A uniquely brilliant mind right up until the end, Professor Stephen Hawking knew precisely what he wanted inscribed on his gravestone.

Of course, as a theoretical physicist with levels of ingenuity and personal determination we may never witness again, it is impossible to describe him in words alone.

Which is why it makes perfect sense for the Cambridge professor’s gravestone inscription to include the most important equation of his life, in accordance with his wishes.

Known as the Hawking’s equation – or the Bekenstein–Hawking entropy formula – this solution wraps the key points of his career-defining discovery.

Over four decades ago Hawking shook the world of cosmology by announcing how – rather than being completely black – black holes actually emit a ‘glow’. This glow is now referred to as the Hawking radiation.

In a discovery which would change the way scientists view the universe forever, the ingenious academic noted how black holes leaked radiation and particles, before exploding and disappearing.

Hawking realised black holes create radiation, while slowly losing mass. This is because of the quantum effects close to the black hole’s edge; within a region known as the event horizon.

The S is entropy, which is a complex yet important part of black holes. This S can be read as a measurement of how much disorder is within the system. Sometimes, this letter can be written alongside a small ‘BH.’

These letters stand for Professor Hawking and Jacob Bekenstein, another scientist who contributed towards our understanding of black holes.

The rest of the equation includes important numbers needed in order to calculate the entropy. The h refers to the Planck constant, a vital part of quantum mechanics. The G represents Newton’s constant, for the purpose of comprehending gravity.

The A symbolises the area within the event horizon. The c refers to the speed of light, brought to attention through Einstein’s formula. The k references Boltzmann’s constant, a means of understanding the relationship between energy and temperature.

According to The Independent, the great professor made his wishes clear in 2002, reflecting on his discovery as he celebrated his 60th birthday:

In particular, I wondered, can one have atoms in which the nucleus is a tiny primordial black hole, formed in the early universe?

To answer this, I studied how quantum fields would scatter off a black hole. I was expecting that part of an incident wave would be absorbed, and the remainder scattered.

But to my great surprise, I found there seemed to be emission from the black hole. At first, I thought this must be a mistake in my calculation.

But what persuaded me that it was real, was that the emission was exactly what was required to identify the area of the horizon with the entropy of a black hole.

Hawking added:

I would like this simple formula to be on my tombstone.

Speaking with the BBC in 2017, Hawking revealed how he wanted his legacy to be this incredible discovery:

I never expected to reach 75, so I feel very fortunate to be able to reflect on my legacy.

I think my greatest achievement will be my discovery that black holes are not entirely black. Quantum effects cause them to glow like hot bodies.

He added:

This result was completely unexpected and showed theorists a deep relationship between gravity and aero-dynamics.

I think this will be key to understanding how paradoxes between quantum mechanics and general relativity can be resolved.

Watch Hawking reflect on his astronomical legacy below:

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Hawking died peacefully at his home, surrounded by family, in the early hours of Wednesday March 14.

His children, Lucy, Robert and Tim, made the following announcement:

He was a great scientist and an extraordinary man whose work and legacy will live on for many years.

He once said, ‘It would not be much of a universe if it wasn’t home to the people you love.’

We will miss him forever.

Our thoughts are with Professor Stephen Hawking’s family and friends at this difficult time.