Hacker News Reader

Comment by jstanley | Hacker News Reader

It took me a while to understand this comment, because I imagined that scaling up a golf ball would involve creating new atoms, but what you said only makes sense if you are scaling up the individual atoms.

What you're saying is that the ratio of the size of an atom to the size of a golf ball is approximately the same as the ratio of the size of a golf ball to the size of the earth.

I'm surprised atoms are so big, I would have guessed much smaller.

View on HN

The analog is no good because it assumes people have an intuitive understanding of the volume of the Earth, which basically 0 people do because it's stupidly absurdly counter-intuitive (like volume in general). So let's go for something way smaller. Imagine we take just one little 'cube' of Earth that's just 1 mile on each side. And let's start placing boxes in it that are 1 cubic foot in size, so about the size of a micro microwave. How many of these boxes would it take to fill our little cube? The math is simple, but the answer is no less stupefying or counter-intuitive. It's more than 147 billion!!

Ok. Imagine we take those cubes that filled our 'little' cube of earth and taped them in one giant stack. That stack would not only reach to the Moon, but reach to the Moon 116 times over! In fact you'd be nearly able to reach Mars at its closest approach (34.8 million miles, vs 27.8 million miles for our box stack). And that's in 1 cubic mile of volume. The volume of Earth is about 260 billion cubic miles. To wrap up by getting back to golf balls - you can fit about 700 golf balls in 1 cubic ft.

------

Actually a somewhat macabre example came to mind. How many humans could we fit in our little cubic mile? And the answer is literally all of us, many times over in fact! And that's in just one cubic mile of the 260 billion total on Earth.

Is this going to be on the test, Professor?

We’d fit, but it sounds uncomfortable.

Hate me all you want for the last part of my comment, but I was trying to follow along. And then... non-metric :-[

> I'm surprised atoms are so big, I would have guessed much smaller.

Me too. Perhaps what we should realise is not how big atoms are, but how small we are. I wonder if life can be sustained at larger scales. Could we have galaxy-sized lifeforms that make us look like bacteria?

The relationship between time and distance is presumed to be a system constant, which we named c.

So, a galaxy-sized lifeform would take a very long time to experience stuff. It takes a tiny but measurable amount of time to go from your brain choosing "Press button" to your muscles all that distance away firing to cause the button press, and then for the button press to have effect - at galaxy scale these periods would be much larger than all of human recorded history.

It'd have to be much more distributed in its ability to react, like octopuses arms being semi autonomous. They'll continue to pass objects towards the body even after being severed.

Or consider the humongous fungus: https://en.m.wikipedia.org/wiki/Armillaria_ostoyae

Sure, but it's not clear in this case whether say the human species should also count as a single "organism". We don't understand very much about the octopus, which is a healthy reminder of why I shouldn't even speculate about alien life which would almost unavoidably be much stranger than an octopus - but we feel comfortable asserting that the "semi autonomous" limbs of the octopus are not distinct in the way that say, my friends Chris and Caroline are distinct people. So if this galaxy sized organism consisted of smaller units with similarly distinct properties, I think we'd say that's not a galaxy sized organism that's a culture of individuals.

think it's relative upward and downward in scale. an entity at universe scale might be moving similar speed to us in our 3d space

No, I assure you that the constant is not concerned with scale, we're easily able to check that. A bigger device does not make this constant larger or smaller, you may be able to get more accurate results but that scale is unaltered.

Good point. Of course this presumes that we understand the physics at that scale, and that there's nothing akin to a quantum tunneled nervous system, etc.

Not so early in the universe age, but who knows what happens in 10^10^10^10 years. Also organisms consume energy, but mechanism of consumption of some ultra massive central quasars is beyond my imagination (I know Marvel has Hunger character but thats not the level of detail and logic I mean).

Maybe as an eventually consistent life form using extremely slow message passing. Though gravity becomes a major factor that would limit the size unless it’s incredibly sparse.

One of my favorite episodes of Love, Death, & Robots is “Swarm”. Worth a watch.

There is a great classic sci-fi book that explores this: https://www.amazon.com/Black-Cloud-Fred-Hoyle/dp/0140014667

But that comment is about atoms, while ALICE is talking about nuclei, which are way smaller than atoms. Not sure what would be the analogy there.

Atoms are large enough to have noticeable Brownian motion visible with an optical microscope.

They're small but not impossibly so.

mmmm, not exactly. you cannot see atomic brownian motion with an optical microscope, what you can see is visible brownian motion of otherwise visible particles caused by their collisions with molecules/atoms. this says as much about the momentum/energy of the collisions as it does about the mass (which bears some relationship to the size which bears direct relation to optical visibility)

You are correct, but that is what I meant, even if the way I wrote it is either incorrect or somewhat unclear.

Now consider that most of that volume is empty space. Scaling up an atom such that a nucleus is the size of the Sun, you'd end up with an electron cloud about the size of the planetary solar system.

Atoms are relatively large and relatively dense in solids, atomic nuclei are small.

How do you draw a distinction? The nucleus is the part of the atom that occupies space.

The electrons are far better at occupying space. Or at least at keeping out other atoms, which is what counts.

Reply on news.ycombinator.com