[barakm]

As other comments suggest, this is a half-truth.

Yes, if an atom was compressible to a bit, you could represent this many universes. It’s analogous to a perfect compression dictionary.

But that’s the rub: an atom isn’t compressible to a bit, at least in this universe. So you have these massive scales competing against each other. The more you say about the atom, the fewer multiverses you have (on an exponential scale!)

It’s an okay way of expressing how many states a kilobyte can take, but what that state means (is it a universe per state or an arrangement of about 1024 ascii characters?) is what’s important.

(Ninja edit: That would imply you can arrange 1024 ascii characters in that-many-universes ways! That’s also fun!)

[IncRnd]

That's not what the twitter comment was talking about. It was saying that there are more states in 1KB than the number of atoms in the universe - or 2^8192 > 10^78.

[barakm]

Which is why I support the unique strings— but as you can also tell from many comments, this is not easy for a lot of very technical folk.

What you’re saying is true— if you replace an abstract state with an atom — but the problem here is people are thinking about individual atoms, and not static arrangements of atoms in a in a universe.

Edit: Or, put another way, you changed the game. Of course there are more states in a kilobyte than the sheer number of atoms. But when you start claiming multiverses… no, it doesn’t work. Which the tweet did, and it confuses things.

[IncRnd]

I didn't change the game. That is literally what the tweet was conveying. It then expanded the first claim by what was also a correct statement that each atom could be replaced with a universe of atoms, and still that would not not exceed the number of states in a Kilobyte of memory.

What many people have done is interpret that to mean that somehow complexity theory is broken or that the tweet author was arguing for multiverses. It appears that not everyone actually read the tweet.

> What you’re saying is true— if you replace an abstract state with an atom

That is not at all what was written in my comment. There is no replacement being mentioned anywhere.

[barakm]

> and replaced it with a copy of the observable universe, and then did it again

Sorry, it was totally in the tweet. Literally used the word replaced

[Dylan16807]

> Yes, if an atom was compressible to a bit, you could represent this many universes.

That would be 2^(2^hundreds). That's not the representation that's interesting here.

The interesting comparison is 2^1024 versus the number of things that exist or ever will exist.

If a piece of information has ever been written down, or will ever be written down, you can point to the exact place and exact time in much less than a thousand bits.

[ketzu]

> Yes, if an atom was compressible to a bit

Isn't it when an atom is compressible to a kilobyte? If a kilobyte were the data, not the alphabet, it would only contain... 8096 atoms.

[barakm]

Right idea on why it’s wrong, but it’s even worse than that! The kilobyte, say all 0s, represents the state of an entire multiverse.

As my comment below, it’s maybe a couple dozen atoms, in perfect conditions (the conditions are again absurd) so this is some definite jiggery-pokery and let’s focus on what they got right? (Ie, how many states a kilobyte can take)

[charcircuit]

I don't see how you can store an atom with 1 bit. Under most models the position of an atom takes an infinite amount of bits.

[barakm]

You can’t. It’s absurd. That’s my point.

Even if you had a perfect 3D coordinate system and atoms worked on float64 boundaries, you’d still have 64 bits to represent one atom. So you could fit, at best, 128 atoms. These are the competing scales.

Unless you knew ahead of time the exact state of an entire universe, then the kilobyte would be your key into that value, as it were.

(Ninja edit again: you’d need 3 float64s! So 128/3 atoms in a kilobyte. Not much. Point stands)

[ReaLNero]

AFAIK under the current quantum model (QFT) specifying a precision finer than the Planck length will not make your predictions more accurate. So you only need a finite number of bits to describe a field over a finite volume using a 3-d matrix for each lattice point's amplitude.

[barakm]

You’re right to go to Planck length to get a number of bits to represent an atom, but here’s another angle:

To best guess, there are about 10^24 stars in the sky. That’s about 2^80.

That means you could simply, on Earth-prime, give an id to all the stars in 2^944 universes. Way way less than the multi-multiverse in question, let alone anything atomic.

[charcircuit]

Usually the volume isn't assumed to be finite. Sure there is the observable universe, but I don't think many models prohobit atoms from living outside of it.