Will we ever be able to control gravity?

Image: Black Hole – Space Engine, by WakupFreeman on Flickr (Licensed under Creative Commons)

The universe as we understand it is governed by four fundamental forces: the electromagnetic force, strong nuclear force, the weak nuclear force, and the gravitational force.

Of these four, one is proving to be the most difficult to understand, yet mysteriously it is the one we have known about for the longest; Gravity.

As humans we develop an innate understanding of gravity – it is the force we battle when we take our first steps, it tells us which way is up and which is down, so it’s strange that it is the least understood of all the four forces.

But that is all starting to change.

On the 14th of September 2015, we made our first detection of a gravitational wave – a ripple in the fabric of spacetime itself. This discovery, while small, marks an important milestone: the first step towards control over gravity.

This may sound like an absurd statement, but the path to controlling one of the four fundamental forces is one we have walked before. I’m talking, of course, about electricity.

This may sound like science fiction, but in fact it is simply recognition of history.

Mastering Electromagnetism

We have already learned to control one of the universe’s four fundamental forces, in the forms of electricity and magnetism.

Just as we have developed an innate understanding of gravity, many cultures throughout history noticed electrical and magnetic phenomena in the world around them.

Just as we have a primitive understanding of gravity, many cultures throughout history had a practical understanding of electrical and magnetic phenomena in the world around them.

The ancient Egyptians understood the strange abilities of electric eels, Mediterranean cultures noticed that rubbing amber with cat’s hair made it attract light objects (via build-up of static electricity), and the magnetic effects of lodestones (naturally occurring magnetite) were used as basic compasses for millennia.

Amber has been used historically to build up static electricity
so that it attracts light objects like feathers and straw.

Amber, by Hans Spitner on Flickr (Licensed under Creative Commons)

These phenomena were studied for many years until our early theories of electricity were formed, and from these theories came experiments to help better understand the mechanisms which governed electricity.

Perhaps the turning point was Benjamin Franklin’s famous 1752 experiment, where he reportedly attached a metal key to a kite and flew it in a lightning storm. From our primitive understanding, we managed to prove that one of earth’s most awe-inspiring natural phenomena – lightning – is in fact simply a manifestation of a force which we can understand and quantify.

Following these early developments came the great thinkers and inventors – Thomas Edison, Nicola Tesla, Albert Einstein, who helped develop such a sophisticated understanding of electromagnetism that we can communicate instantaneously with almost any other human being on the planet, with a device that fits in our pocket.

In the space of 400 years, we went from total ignorance about electric phenomena, to creating one of the most powerful scientific theories in human history.

We are walking the path towards mastery over gravity.

Just as our first understandings of electricity were gleaned from amber and lodestones, Kepler and Newton gave us our first mathematical understandings of gravity by watching the orbits of the stars.

These theories were refined by Albert Einstein in the early 1900’s, creating a theory of General Relativity which described gravity not as a push or a pull, but as a curve of the fabric called spacetime in which our universe sits.

And on the 14th of September 2015, we made our first detection of gravitational waves.

The Laser Interferometer Gravitational-Wave Observatory, or ‘LIGO’ (below) is the most
precise ruler ever created, measuring minute changes in distance over its 4km arm span.

LIGO, by Richard Droker on Flickr (Licensed under Creative Commons)

Two black holes, titans in their own right, weighing over 30 times the mass of our sun, collided with each other in another galaxy 1.3 billion light years away.

Just as a stone creates ripples across a lake, this collision sent ripples through spacetime. These ripples stretch and contract the space they travel through, sliding objects closer together or floating them further apart as they propagate through space.

This effect is exactly what was measured. Using LIGO, the most accurate ruler ever created, we measured a change in the length of spacetime a thousand times smaller than the width of a proton. For scale – if a proton was as big as a basketball, our ruler measured a change in length equivalent to half the width of a human hair.

The detection of gravitational waves is the ‘kite in the thunderstorm’ moment for gravity.

We have proven that one of the most powerful and awe-inspiring events in the entire universe – the collision of two black holes – is simply a manifestation of a force which we are beginning to understand and quantify.

This discovery may be the most significant measurement ever made in all human history past and present, as it confirms our current theories of gravity and paves the way for a new era of experimentation and technology.

All historical precedent indicates that gravity is a force that we will inevitably learn to control, and when we do so, it will mark a new age in the evolution of human civilisation.

2 Responses to “Will we ever be able to control gravity?”

  1. Matt says:

    Thanks for the kind words Eilish, it means a lot 🙂

  2. Eilish Roberts says:

    You did a really good job of making a rather abstract and complex topic easy to understand. Great read!