Thread by @1goodtern

The guy who told me that covid had to obey the laws of physics has been sick for eight weeks straight this winter.

He's right though.
Covid does have to obey the laws of physics.

Covid has to obey the laws of physics, and not the laws of wishful thinking.

His law of wishful thinking at the time (he said that to me in 2021) was that covid particles would drop out of the air within one or two metres.

He wasn't alone in wanting to think that.
Whole governments and societies wanted to believe that shit.

But Covid doesn't obey the laws of wishful thinking.
It obeys the laws of physics.

Have you ever stood on a beach when there's a strong wind blowing in off the sea and tasted the salt in the air?
That's salt obeying exactly the same law of physics as covid.

You can even see it sometimes as the wind moves over the surface of the water, whipping spray up and carrying it.

That's the process that goes on inside you every second as the air you breathe in and out passes into and out of the minute tubes that compose your lungs.

You don't even need to be coughing or sneezing.
The air in those tiniest passages - less than a millimetre in diameter - goes *whistling* in and out of there, across moist surfaces, and the effect is the same as that wind across the sea.

As the air blows fast across those moist surfaces, it whips up a fine mist of water, and it's what's in the water that's the problem.

Because during an infection, Covid, using the laws of physics, breaks into the cells that line those tubes of the lungs, the epithelial cells.

Then it kills those cells, spilling out thousands of new covid viral particles into the midst lining of the lungs, where that wind rushes through... and out.

You don't need to be coughing.
You don't need to be sneezing.
You don't need to be singing.
You don't need to be shouting.

Don't get me wrong, all of those things help expel viral particles, but you don't need to be doing them to exhale a fine mist of infectious covid.

It's just Covid obeying the laws of physics.

And then what happens to it outside your lungs?

Well, it continues to obey the laws of physics.

Think of a bank of fog.
Or a cloud in the sky.

It obeys the laws of physics, like everything has to.
It doesn't float there by magic.
It doesn't ignore gravity.

Fog isn't made of droplets, it's made of dropletlets.

Okay, it is made of droplets, but they're really tiny ones.
So tiny that they can just sort of bob around on the air, kept aloft by the tiniest of breezes.

Smoke particles observe the same laws.

A few months ago here in England we could taste the Canadian wildfires on the breeze.

Just smoke obeying the laws of physics.

Covid particles use the laws of physics to enter your body's cells, then use the laws of physics to replicate themselves inside your cells, then use the laws of physics to kill your cells, then use the laws of physics to get out, then use the laws of physics to float on the air.

The laws of physics are on our side here too, if we want to use them.

Whenever there's lots of something in one place in a gas or liquid, the laws of physics want to disperse it (unless it's stuck together).

So as soon as a concentration of gas or liquid is outside of its earlier containment, it starts to thin out to become evenly distributed in its new location.

So smoke *disperses* obeying the rules of drift diffusion.
And so does covid.

What comes out of someone's mouth as a concentrated stream of air carrying moisture carrying viral particles, disperses rapidly into the air.

But the longer they do it for, and the smaller the area they are in... the more the concentration of particles floating on the air builds up, ready to be inhaled by the next person.

So covid, obeying the laws of physics, builds up in concentration in spaces like rooms where the air is trapped.

Ventilation can help that problem.
Because Covid obeys the laws of physics, it is carried on the air.
If you introduce fresh air *into* the room, it blows some of the covid smoke air *out* of the room.

And because those covid particles floating on the air obey the laws of physics, you can use clever methods to trap them.

Have you ever rubbed a balloon on a woolen jumper and then felt the static charge build?

When you do that, have you noticed that the balloon can attract to itself a fine layer of dust?
It's just the balloon and the dust obeying the laws of physics.

The same effect can be reproduced using fine layers of fibre glass or synthetic fibres woven together.
When air blows through them, that's like rubbing the balloon on the wool.

And then if any particles enter the web of fibres, they are electrostatically drawn to the fibres and stick there, obeying the laws of physics.

That's a hepa filter.

Or a respirator.

Using the laws of physics to trap viral particles and remove them from circulation.

This isn't mystery, it's not magic, it's just the laws of physics.

Airborne transmission is not superstition or fearmongering or miasma theory, it's just Covid obeying the laws of physics.

And mitigations like ventilation and filtration, whether it's on your face or in a box, are not subject to the laws of opinion, they just obey the laws of physics.

You can't, as the Scotsman says, change the laws of physics.

And neither can covid.