The beauty of Eintein's general theory of relativity

                 The beauty of science

This article was written by Margaret Wertheim
from the University of Melbourne. It was originally
published by The Conversation .
One hundred years ago, an obscure German
physicist named Albert Einstein presented to
the Prussian Academy of Science his general
theory of relativity . Nothing prior had prepared
scientists for such a radical re-envisioning of
the foundations of reality. Encoded in a set of
neat compact equations was the idea that our
universe is constructed from a sort of magical
mesh, now known as 'spacetime'. According to
the theory, the structure of this mesh would be
revealed in the bending of light around distant
stars.
To everyone at the time, this seemed
implausible, for physicists had long known that
light travels in straight lines. Yet in 1919
observations of a solar eclipse revealed that on
a cosmic scale light does bend, and overnight
Einstein became a superstar.
Einstein is said to have reacted nonchalantly
to the news that his theory had been verified.
When asked how he’d have reacted if it hadn’t
been, he replied: "I would have felt sorry for
the dear Lord. The theory is correct."
What made him so secure in this judgement
was the extreme elegance of his equations:
how could something so beautiful not be right?
The quantum theorist Paul Dirac would latter
sum up this attitude to physics when he
borrowed from poet John Keats, declaring that,
vis-à-vis our mathematical descriptions of
nature, " beauty is truth, and truth beauty ".
Art of science
A quest for beauty has been a part of the
tradition of physics throughout its history. And
in this sense, general relativity is the
culmination of a specific set of aesthetic
concerns. Symmetry, harmony, a sense of unity
and wholeness, these are some of the ideals
general relativity formalises. Where quantum
theory is a jumpy jazzy mash-up, general
relativity is a stately waltz.
As we celebrate its centenary, we can applaud
the theory not only as a visionary piece of
science but also as an artistic triumph.
What do we mean by the word "art"?
Lots of answers have been proposed to this
question and many more will be given. A
provocative response comes from the poet-
painter Merrily Harpur , who has noted that "the
duty of artists everywhere is to enchant the
conceptual landscape". Rather than identifying
art with any material methods or practices,
Harpur allies it with a sociological outcome.
Artists, she says, contribute something
bewitching to our mental experience.
It may not be the duty of scientists to enchant
our conceptual landscape, yet that is one of
the goals science can achieve; and no scientific
idea has been more enrapturing than
Einstein’s. Though he advised there’d never be
more than 12 people who’d understand his
theory, as with many conceptual artworks, you
don’t have to understand all of relativity to be
moved by it.

 

In essence the theory gives us a new

understanding of gravity, one that is

preternaturally strange. According to general

relativity, planets and stars sit within, or

withon, a kind of cosmic fabric - spacetime -

which is often illustrated by an analogy to a

trampoline.

Imagine a bowling ball sitting on a trampoline;

it makes a depression on the surface. Relativity

says this is what a planet or star does to the

web of spacetime. Only you have to think of

the surface as having four dimensions rather

than two.

Now applying the concept of spacetime to the

whole cosmos, and taking into account the

gravitational affect of all the stars and

galaxies within it, physicists can use Einstein’s

equations to determine the structure of the

universe itself. It gives us a blueprint of our

cosmic architecture.

Synthesis

Einstein began his contemplations with what

he called gedunken (or thought) experiments;

"what if?" scenarios that opened out his

thinking in wildly new directions. He praised

the value of such intellective play in his

famous comment that "imagination is more

important than knowledge".

The quote continues with an adage many

artists might endorse: "Knowledge is finite,

imagination encircles the world."

But imagination alone wouldn’t have produced

a set of equations whose accuracy has now

been verified to many orders of magnitude, and

which today keeps GPS satellites accurate.

Thus Einstein also drew upon another

wellspring of creative power: mathematics.

As it happened, mathematicians had been

developing formidable techniques for describing

non-Euclidean surfaces, and Einstein realised

he could apply these tools to physical space.

Using Riemannian geometry, he developed a

description of the world in which spacetime

becomes a dynamic membrane, bending,

curving and flexing like a vast organism.

Where the Newtonian cosmos was a static

featureless void, the Einsteinian universe is a

landscape, constantly in flux, riven by titanic

forces and populated by monsters. Among

them: pulsars shooting out giant jets of x-rays

and light-eating black holes, where inside the

maw of an 'event horizon', the fabric of

spacetime is ripped apart.

One mark of an important artist is the degree

to which he or she stimulates other creative

thinkers. General relativity has been woven into

the DNA of science fiction, giving us the warp

drives of Star Trek , the wormhole in Carl

Sagan’s Contact, and countless other narrative

marvels. Novels, plays, and a Philip Glass

symphony have riffed on its themes.

At a time when there is increasing desire to

bridge the worlds of art and science, general

relativity reminds us there is artistry in

science.

Creative leaps here are driven both by playful

speculation and by the ludic powers of logic.

As the 19th century mathematician John

Playfair remarked in response to the bizzarities

of non-Euclidean geometry, "we become aware

how much further reason may sometimes go

than imagination may dare to follow".

In general relativity, reason and imagination

combine to synthesise a whole that neither

alone could achieve.