What snowflakes reveal about the laws that govern the Universe – 01/31/2024 – Science

Snowflakes are intricate, beautiful and mysterious.

Each flake is unique and complex. Despite being small, they contain universal laws and forces that explain how our Universe works, from the smallest to the galaxies of the cosmos.

Let’s start by explaining what exactly a snowflake is — or, to be more precise, a snow crystal.

Journey through the clouds

A snow crystal forms in clouds when water vapor encounters small particles of dust or pollen.

This leads to the formation of its small hexagonal core. Their ends stick out and are rough, which attracts water molecules, which in turn attract more water molecules. These molecules form the branches of the snowflake.

The shape and size of these branches depend on the exact temperature and humidity that the snow crystal encounters during its journey through the clouds, influenced by the force of gravity.

“Each flake follows a slightly different path, so no two snowflakes are the same,” explains physics professor and BBC presenter Brian Cox, in the video “What snowflakes tell us about our Universe” (what snowflakes tell us about our Universe).

When a snowflake reaches you, it has made its own unique journey to reach you, before melting in a matter of moments.

Kepler’s theory

In 1611, on a freezing January morning in Prague, a snowflake landed on the coat sleeve of mathematician Johannes Kepler.

This seemingly trivial event for most ordinary people led him to reflect: “Why do snowflakes have six sides?” he asked himself.

The mathematician concluded that this hexagonal pattern was the most efficient way to utilize space, whether in a honeycomb in a beehive, in a pile of cannonballs, or in a delicate and ephemeral snowflake.

It took 400 years for his theory to be proven.

What he didn’t know at the time is that each water molecule (H2O) is made up of two hydrogen atoms and one oxygen atom.

As water molecules clump together during freezing, the angle formed between the hydrogen atoms is always approximately 105°, and this is what gives us the six sides.

The center of the snowflake is always hexagonal, but it can grow into many different and extraordinary shapes.

Symmetry, gravity and electromagnetism

The snowflakes are all radially symmetrical. This means you can divide them into identical portions, just like cutting a cake.

“Shells, flowers, sea stars and even spiral galaxies, like the Milky Way, share this type of symmetry,” comments Cox.

Each snowflake is a microcosm of the laws of physics.

For starters, they are not actually white, but rather transparent. However, due to their many edges, which scatter light, this makes them appear white.

They also fall towards the ground. Even though, on their descent, they become trapped in turbulent air currents, causing a more complex sequence of fluctuations and spins, the snowflakes fall following the universal laws of gravity.

Electromagnetism determines their shape: As water molecules freeze and form ice crystals, they acquire an electrical charge that creates a magnetic field around each crystal.

And it is the interaction between the magnetic fields of adjacent crystals that influences the growth and aggregation of the flakes.

And there is the symmetry we mentioned earlier.

Ultimately, it’s similar to what happens with stars, solar systems, planets, and ourselves: by examining a snowflake in detail, you can read its unique story, but also understand how it is a microcosm that contains the universal laws of physical.

_{*This article is based on the video “What snowflakes tell us about our Universe”, produced by the BBC in partnership with The Royal Society, directed by Studio Panda and Sam Pierpoint.}