Difference between revisions of "The speed of atoms"

Revision as of 16:21, 21 August 2018

Air molecules as fast as bullets

Or: How every human on earth is hit by the the equivalent of a relentless non stop barrage of handgun bullets from birth to death.

As we all know being hit by a bullet from a handgun is not good for health. But what if you split the bullet into many many small pieces and let them hit you with the same speed but now evenly distributed from all sides (assuming no breaking through air resistance)? Would you dare to try this?
What if I tell you that you already did this for your whole life.

When we assume that:

• the bullet is split up into all its individual atoms such that there now is plenty of space between them
• the bullet is converted into a spherical shell of dispersed atoms
  (a shell with of about a thousandfold volume and a thousandth of the density of the original bullet)
• the shell is concentrically coming at you and hitting you with the original non-reduced speed

then you probably would not even notice being hit.
Baffling?

What the split up atoms of the bullet bullet would do to you is actually very similar to what the molecules of the air do to you.

If one looks at free flying atoms (or very small molecules) like the ones one finds in air, then their speed of motion lies around the speed of sound. That is the main constituents of our earth's atmosphere (dinitrogen N₂ and dioxygen O₂ zip around with speeds that average out at about 340m/s (at normal conditions). This is about the speed of a bullet of a hand gun.

In contrast to the bullet air molecules do hit you permanently and relentlessly instead of just for roughly 30 microsceconds. 30 microseconds is the time it takes for a 1cm long (hopefully atomically dispersed) bullet to hit you tip to tail. Well since this "impact" would be atop normal air pressure you would experiences doubled air pressure for these 30 microseconds. But 30 microseconds are so short that due to the inertia of mass of your skin there will barely be any effect.

How "speed" is "faster" when you are smaller as observer

Being smaller makes motions with same speeds seem to be faster. Driving an 1:10 RC car with FPV (first person view) remote vision at about 10m/s=36km/h feels like driving with 100m/s=360km/h but in reality it is still the 10m/s=36km/h. What we actually experience as "speed" is the frequency with which we are passing some stuff in the environment.

The speed of sound air molecules fly around with is pretty fast even for macroscale observers, So how fast will this feel if you scale yourself down to the nanoscale. Or reversely (more practically archivable) scale the nanoscale up to your size.

Halve the speed of light when atoms get scaled up enough to become visible to good eyes

Scaling up just size by an ideal scaling factor of 500.000 (See: Magnification theme-park) and leaving time unchanged as-is leads to a scale-up of speeds too. The speeds of real size air molecules then go from "only" ~340m/s at 1:1 scale up to an experienced pseudo-speed of scaled up air molecules of about 170.000.000 m/s at the new 500.000:1 scale. This is a bit more than halve the speed of light.

There is absolutely no way to intuitively ascertain that. Now add all the inter-atomic collisions and you end up with a mind bogglingly ridiculous pinball motion.

This has pretty wild consequences. Among others is provides the explanation why life could emerge just by accident. Why evolution works.

Keping "speed" equally "fast" when getting smaller as observer

Cinematic slow-motion by using the one special time scale factor that naturally suggests itself

To have a more natural feel for the speeds at the nanoscale, speeds must be scaled in the opposite direction. One wants to scaling ... time to keep operation frequencies natural when transferred to the model scaled up in size Using this approach still leaves us with hair diameter model air molecules bouncing around at the speed of sound ~340m/s while now for every real second to pass we need to wait 500.000 seconds (almost 6 days) in the model for the real second to pass.

So a we have a model-molecule (scaled up to hair diameter) bouncing around with the speed of sound. in a densely populated molecular environment (scaled up a heap of beard stubbles) for about six days that is thereby emulating just one real second. Just one. Let that sink.

Ok, this is not very intuitive. Now we have distributed one totally and utterly unintuitive and unimaginably big quantity (halve the speed of light) into two still quite unintuitive and unimaginably large quantities (speed of sound and a quite big stretching of time). This is not much better than before, if even, isn't it? Well yes.

Where this scaling method that also scales time not only space will become more useful for an attainment of an intuitive feel is when it comes to parts that are just a slightly bit bigger than molecules (nanomachinery crystolecules). Such parts already move quite a bit slower than single molecules. In fact usually slow enough that they can conveniently be traced around by eye. With our intuitivity preserving "magnification factor" of 500.000 typical nanomachinery operation frequencies e.g. 1MHz will get downscaled to just 2Hz.