TL;DR: At a distance, like hexagons. Close up they look like beautiful and complex mathematical shapes.
If we could perceive the universe as it truly is, everything would appear as nets of buzzing atoms. Every time you touch your screen, they bend like a trampoline. Every time you run your hand through your hair, it captures and carries off their electrons. Every interaction on Earth, from picking up a coffee cup to hitting a baseball, involves atoms.
Atoms are one of the most fundamental concepts in the universe, but only very recently has our technology been able to see them, and very few people can tell you what they actually look like. This article is about what an atom looks like.
In school we’re shown this diagram:
But it is about as different to an actual atom as a kid’s drawing of a bus is to an actual bus.
It gets the point across but its point has never been to be accurate.
The most colourful description of the world of the atoms that I’ve ever read comes from the writer Stephen King:
“The pencil point is not solid; it is composed of atoms which whirl and revolve like a trillion demon planets. What seems solid to us is actually only a loose net held together…” Stephen King, The Dark Tower
An impossible picture
For a long time, we thought that diagrams and imagination were as close as we were ever going to get because seeing an atom was something that science considered to be impossible.
When you see an everyday object like a baseball or coffee cup, what you are looking at is the reflection of trillions of light particles that have bounced off their surface. But light particles reflect off objects much larger than an atom. It was thought that no microscope would ever be able to see an atom directly, as the resolution it would need was beyond the limit of what light could reflect. It’s like trying to image a baby using an ultrasound wand the size of a beach ball.
That was until two scientists made a breakthrough. Gerd Binnig and Heinrich Rohrer changed the game by inventing a new type of microscope using electrons instead of light, which have a much greater resolution. For the first time in human history, we could look at individual atoms. It was called the ‘Scanning Tunnelling Microscope,’ and it won them a Nobel Prize in 1986.
Below is the surface of a thin sheet of gold that was put in one of their microscopes. Every tiny hexagon here is an individual atom of gold.
Wikipedia, Atomic resolution AU100
The technology has only been getting better. A few decades later scientists captured atoms on video. This is a real-time look at a layer of carbon atoms just one atom thick, showing atoms actively dancing around a puncture hole in the material.
In 2013, scientists at UC Berkley took the idea even further. They watched a small molecule undergo a chemical change. In this picture, each corner of the hexagons is an atom, and the glowing lines between them are the chemical bonds holding the atoms together.
It’s astounding just how close our diagrams were to reality, considering they were created long before we could see atoms. But as we zoom in even closer to an individual atom, a strange thing starts to happen. The closer you get, the more the strange rules of Quantum Mechanics begin to take over.
We know from our diagrams that there are clouds of electrons buzzing around an atom. But when we try to see the clouds using our microscopes, we inevitably interfere with it. If anything at all, including light and electrons, hits the electrons and changes the clouds. For this reason, many scientists believe that peering any closer at an atom is impossible. So once again we have to rely on diagrams to show us what an atom looks like up close.
We can use our data to create what are known as ‘wave functions’, which is like a map of where the electrons in the cloud should be. When you put the wave function into special software, it will generate for you what an atom would look like if only we could see it.
The results are astonishing. Atoms are far more varied and mathematically beautiful than what we could have imagined. The atom below is a hydrogen atom, with the red area being its nucleus, and the light blue area is its electron cloud.
At this level, strange patterns in the electron cloud become prominent – and they are shaped not like individual particles like in the diagram, but as a series of buzzing clouds shaped into strange mathematical designs called ‘orbital shapes’. Below is a hydrogen atom showing off a bunch of different orbital shapes.
Wikipedia, Hydrogen Density Plots
For our microscopes this is the end of the line, for now.