Two Snowflakes May Be Alike After All

An anonymous reader writes "LiveScience is reporting that it may be possible for two snowflakes to be alike after all. For anyone who studies probability, this seems reasonable, given that the article mentions that 10^24 snowflakes fall in any given year. The article contains links to fascinating snowflake pictures. From the article: 'A typical snow crystal weighs roughly one millionth of a gram. This means a cubic foot of snow can contain roughly one billion crystals ... "It is probably safe to say that the possible number of snow crystal shapes exceeds the estimated number of atoms in the known universe," Nelson said. Still, while "no two snowflakes are alike" might hold true for larger snowflakes, Nelson figures it might ring false for smaller crystals that sometimes fall before they have a chance to fully develop. "How likely is it that two snowflakes are alike? Very likely if we define alike to mean that we would have trouble distinguishing them under a microscope and if we include the crystals that hardly develop beyond the prism stage--that is, the smallest snow crystals," Nelson said.'"

Birthday attack

[setagllib (753300)]

So now we have a way to link snowflakes and cryptography.

Re:Birthday attack

[x_MeRLiN_x (935994)]

Am I the only person to think this guy has too much time on his hands?

Re:

[Cimon Avaro (1022609)]

As stupid as it sounds, original submission is entirely redundant, as one scientist already found matching snowflakes. And the scientist wasn't even a guy but a woman scientist. Yes, Virginia, there really is serious study on the shapes of snowflakes.

Uhhhh, ... no

[Gription (1006467)]

[sarcasm]
. . .
[/sarcasm]
Leave the snowflakes alone, try to research if we can get something to fuel our cars after a decade or two or try to find the cure for utter stupidity. Hearing something useful coming out from science is rather rare these days, probably because really interesting stuff is not published or wouldn't interest the business giants like oil producers.
. . .

This is the same attitude that generates the idea that the manned space program of the 60s was a waste of money.

Believe it or not the largest payout from research is generally not directly the target of the research. We call this serendipity .

Off the top of my head the study of this subject would require the researcher to apply his efforts (described here as apparently useless) on the details of crystal formation, manipulating factors of said formation, crystalline structure, and the statistical analysis of crystal formation, besides who knows how many other details that we will never know because we weren't involved.

Let me see if I can come up with some "useless" applications for knowledge in this research track. How about crystalline formation in metals? I bet the aerospace industry has no need for this type of knowledge as they try to come up with ways to grow single crystal blocks of titanium to form turbine blades or anything else that requires insanely high strength. As an example (from memory): the tensile strength of cast iron is a little more then 10,000 psi. The tensile strength of iron formed as a single crystal is somewhere around 100,000 psi! If I remember correctly, the single crystal tensile strength of carbon is 500,000 psi. The reason for these amazing numbers is that the primary weakness is always the crystalline boundaries. (reference: http://en.wikipedia.org/wiki/Single_crystal [wikipedia.org] )

Another "useless" application of this type of research is crystalline formation as it relates to pharmaceutical research. Did you know that the (apparently unimportant and profitless) pharmaceutical companies actually sent an experiment up into orbit just so they could see how crystals grow in zero G? That sounds like it must be an incredibly lavish waste of their shareholder's money (by one of the greediest industries in the world (personal opinion)).

Fun facts:
- When you analyze a crystal you can tell the strength of the gravity field it was formed under.
- Crystalline formation is a state change and controlling this can allow you to do all sorts of interesting things from scalding the hell out of yourself heating water in a microwave, to creating so called meta materials.(reference: http://en.wikipedia.org/wiki/Meta_materials [wikipedia.org] )
- And finally: Utter stupidity is often caused by not looking any deeper then the surface of a subject. (reference: http://www.suck.com/daily/97/11/12/1.html [suck.com] )

Re:

[by Anonymous Coward]

This isn't news. No truism is 100% true.

Re:Birthday attack

[no reason to be here (218628)]

This isn't news. No truism is 100% true.

including that one?

Re:

[PieSquared (867490)]

Nuke 'em from orbit. Then you (a population living off the earth) win.

Re:

[pluther (647209)]

Plus, it's the only way to make sure.

Re:Birthday attack

[teknomage1 (854522)]

So collisions in snowflake based hashing algorithms would be instances of a SnowCrash?

Re:

[KUHurdler (584689)]

I'm afraid I'm going to have to ask to see these two snowflakes.

Number of atoms in the universe

[antic (29198)]

"It is probably safe to say that the possible number of snow crystal shapes exceeds the estimated number of atoms in the known universe..."

This sort of thing does my head in. Anyone else trying to keep up?

Re:Number of atoms in the universe

[FallLine (12211)]

"It is probably safe to say that the possible number of snow crystal shapes exceeds the estimated number of atoms in the known universe..."

This sort of thing does my head in. Anyone else trying to keep up?

Makes sense to me. The operating word is possible, as in the number of possible arrangements of unique snow crystal shapes likely exceeds the estimated number of actual atoms in the universe that we know of. This isn't terribly different than saying that number of possible lego combinations exceeds the number of legos in the world (well, I don't really know how many lego combinations are possible.... but you get my point). Though IANAA & IANAM :-)

Re:Number of atoms in the universe

[C_L_Lk (1049846)]

So how does the number of possible snowflake configurations compare with the number of possible IPV6 addresses? Can we assign a unique address to every snowflake and then just see if we get an address conflict somewhere?

Re:Number of atoms in the universe

[MrNemesis (587188)]

The problem is that once you've done a ping sweep of the IPv6 network, the first lot of snowflakes have melted (along with the DHCP server).

Re:Number of atoms in the universe

[melikamp (631205)]

how many lego combinations are possible

To simplify the question, we could consider just these classic [wikimedia.org] bricks. By different combinations we'll understand fully connected arrangements, with no regard to combinations of colour, rotations, or symmetries. I suppose that Legos can connect with a single corner, correct me if I am wrong.

Le(1) = 1

Le(2) = 17

Then, for one of the combinations in Le(2), there are 18 ways to add the third piece. The problem seems to be barely tractable now without the aid of at least lego pieces and a piece of paper, but I'll make bold assumptions. If Le(n) grows at least as fast as 10^n (and my gut tells me that it grows much faster), then measly 100 pieces will give you a quantity that dwarfs the number of particles in the known universe [wikipedia.org].

Re:Number of atoms in the universe

[jd (1658)]

It's to do with exponentials. Let's say that a particular snow crystal can form in one of fifteen ways. ((That's all the possibilities depicted on this chart) [caltech.edu]. Then, two such crystals covers 225 possibilities (minus those that simply can't be joined for whatever reason). A snowflake with a hundred crystals would have fifteen to the hundred (ie: one googol) possible permutations.

However, is our starting number of 15 reasonable? The standard snowflake crystals are all formed at temperatures just below freezing under fairly normal conditions. The rate at which the water cools will have a major impact, as will any airborne particles around which the snow crystals can condense. (Particles may cause a break in the symmetry or may force the ice to contain patterns that simply aren't possible when only hexagonal ice crystals are present.) There again, anything dissolved in the water will change the chemistry as well. As not everything freezes at the same temperature, it is entirely possible for snowflakes to acquire bubbles and other oddities where something has remained liquid even as the water froze.

Then, there are the exotic states of frozen H2O which are not considered "ice", per se. Water that has frozen under really strange pressures or at extreme rates will not form regular ice crystals, but form other solid states instead. Slashdot has covered a few of these in the past. Is it possible to have a snowflake form from such states? Maybe. Then you add a whole new set of possibilities to the mix, although it would be unlikely that you could get a mixture of regular ice and these exotic states. (Not impossible, though. If the higher-level clouds chucked down snow in the exotic states, which then got added to by regular snowflake crystals, then you could indeed have a mixture. Not sure this could happen on Earth, but there may be planets where this is common.)

My definition of "alike"...

[catbutt (469582)]

...would be more along the lines of "as alike as any two arms of a typical snowflake are"

Since we generally assume snowflakes to be radially symettrical, that implies a degree of "alikeness" within the snowflake. Intuitively, that is what would make two snowflakes alike (to me)....if you could look at their individual arms (i.e. 1/6th of the snowflake) and not be able to match them up to the correct snowflake.

If you were just talking about atom-to-atom alikeness, given that snowflakes are far from pe

My mom said you were wrong.

[by Anonymous Coward]

I am special. And I'm going to be famous.

Re:

[Alwin Henseler (640539)]

You must be a new snowflake here.

Years ago...

[dpbsmith (263124)]

...and of course, I can't find it... a scientist published a picture of two identical snowflakes in, I'm almost sure, Science or Nature. And, no, I'm not talking about Snowflake Bentley. It was a byproduct of some kind of meteorological research, they were flying a plane through clouds where snow was being formed, and, as you'd expect, if two flakes of snow form under virtually identical conditions you end up with two virtually identical flakes.

I think this was in the 1990s.

It made the mainstream news at the time.

Nancy Knight, 1988

[by Anonymous Coward]

Nancy Knight, 1988

"The old saw that no two snow crystals are identical was disproved in 1988, when National Center for Atmospheric Research scientist Nancy Knight found two that apparently were. The twin crystals were found by accident when Knight was examining samples collected at 6 kilometers (20,000 feet) over Wisconsin for a cloud-climatology study. Thick, hollow, and columnar, the crystals seem to have been Siamese twins that grew attached to each other. No satisfying explanation has yet been found." -

http://www.proquestk12.com/curr/snow/snow395/snow3 95.htm [proquestk12.com]

Picture of Identical Snowflakes

[Whiney Mac Fanboy (963289)]

The National Centre for Atmospheric Research (NCAR) has a pic of the identical (attached) snowflakes [ucar.edu] on their kid's page.

They look more like nanopumps than snowflakes to me!

Re:Years ago...

[Whiney Mac Fanboy (963289)]

as you'd expect, if two flakes of snow form under virtually identical conditions you end up with two virtually identical flakes.

From snowflake chemistry [about.com]

Is it true that no two snowflakes are identical?

Yes and no. No two snowflakes are exactly identical, down to the precise number of water molecules, spin of electrons, isotope abundance of hydrogen and oxygen, etc. On the other hand, it is possible for two snowflakes to look exactly alike and any given snowflake probably has had a good match at some point in history. Since so many factors affect the structure of a snowflake and since a snowflake's structure is constantly changing in response to environmental conditions, it is improbable that anyone would see two identical snowflakes.

Depends on what you call "alike"

[Moraelin (679338)]

If the only thing that makes two things different is that one contains an extra H2O2 molecule instead of a H2O, then that's already breaking even the original metaphor. You can find bigger differences than that in machine-stamped assembly-line-produced pieces, hence the concept of "tolerance" or the six sigma hype. Yet noone would consider them unique. I've yet to hear anyone say "I'm unique like a standardized run-of-the-mill 5mm radius, 31 teeth, brass cog." And if you heard someone saying that, you'd thi

Not quite impossible

[Mrs. Grundy (680212)]

I've always wondered what physicists were doing when they were busy not discovering cold fusion. Seriously though, what I got from this was that while still incredibly unlikely it is possible for two snowflakes to be the same. Just like everything else that is extremely unlikely but not quite impossible.

Would these be REALLY GOOD random number seeds?

[TibbonZero (571809)]

I was actually thinking about this a few days ago. Would snowflakes be good for use in encryption somehow, since they are (infrequently at best) alike? I know one of the harder things to do is get a random seed for your number generators. Would these be potentially a good source of random information?

Re:

[Manchot (847225)]

I'm sure you could, but why do that when you can buy an off-the-shelf quantum RNG [idquantique.com]? It's so much easier, and probably much more reliable. Furthermore, since it relies on quantum effects, it is 100% random. (Actually, manufacturing irregularities probably bias it slightly in favor of one state. Even if that's the case, it's still non-deterministic, unlike all software implementations.)

If you need only a few random numbers, I'd suggest using this website [randomnumbers.info], which relies on the aforementioned product. To prove

Any other handy aphorisms we'd like to test out?

[haakondahl (893488)]

What goes up must come down. (suspected true)

Lightning doesn't strike the same spot twice. (obviously false (ouch!))

A watched pot never boils. etc...

This is like numerology. You take a bunch of squishy data (aphorisms) and attempt to rigorously evaluate them.

I am reminded of Charlie Brown's answer to the question "How many angels can dance on the head of a pin?" His answer: Eight if they're skinny, four if they're fat.

By what argument could they NEVER be the same?

[vistic (556838)]

I don't see why this is a surprise. Snowflake formations are realistically independent of each other, so if it's possible for one it should be possible for any other. The odds of randomly selecting two that are exactly the same may be very small, but...

What possible argument could even exist as to how no two could EVER be the same, ever?

Magical snowflake factory in heaven that molds each flake, and after each flake they break the mold, never to use it again? Or what?

Re:Any other handy aphorisms we'd like to test out

[Perseid (660451)]

A watched pot never boils, eh? I never tried that one. But I have watched enough eMule downloads to know that a watched progress bar never fills. It always stops at 99% with 30K left and sits there for a few days.

Re:Any other handy aphorisms we'd like to test out

[darkonc (47285)]

What goes up must come down. (suspected true)

Oh yeah... tell that to Voyager.

Lightning doesn't strike the same spot twice. (obviously false (ouch!))

Well after lightning strikes the first time, that place (ouch) is never going to be the same again.

A watched pot never boils. etc...

There's actually some truth to that... If you take the lid of a pot that you're trying to boil, the escaping steam carries away heat and helps to cool the pot -- It also lowers the vapour pressure of the steam, which allows more steam to be generated (allowing the water in the pot to cool faster).
That way, a watched pot boils a lot slower than an unwatched pot -- and if t

Re:Any other handy aphorisms we'd like to test out

[DrVomact (726065)]

How about "no two fingerprints are alike". I've always wondered about that one. How do you prove or disprove it? Does it mean no two fingerprints can be alike, or that it's extremely unlikely? How unlikely? What are the criteria for "alike"? How do we eliminate artifacts of the fingerprinting process? What about the normal wear and tear that abrades the skin, and changes everyone's fingerprints slightly over time?

Another one is the belief that the rifling pattern engraved on a fired bullet can be used to

So?

[camperdave (969942)]

Myth Busted?

A typical snow crystal weighs roughly one millionth of a grama cubic foot of snow can contain roughly one billion crystals...
Most snowflakes are less than one-half inch across. The smallest may be only about one-tenth of a millimeter across...

I think, if you're talking about the myth that Americans do science in metric, then yes: Myth Busted.

identical fingerprints too!

[bodrell (665409)]

"How likely is it that two snowflakes are alike? Very likely if we define alike to mean that we would have trouble distinguishing them under a microscope and if we include the crystals that hardly develop beyond the prism stage--that is, the smallest snow crystals,"

In other news--it is very likely that two people will have identical fingerprints. If by fingerprints we mean the part of the fingerprint that cannot even be distinguished as a whorl. That is, a couple of cells constituting a tiny fold of skin.

In other news...

[yali (209015)]

If someone tells you "You're one in a million," there are 6,571 people exactly like you.

Let's disprove it empirically

[Esion Modnar (632431)]

We need to find the exception which negates the rule. I propose we spend some tax dollars to find the matching pair of snow flakes.

Interesting science...

[MavEtJu (241979)]

A typical snow crystal weighs roughly one millionth of a gram. This means a cubic foot of snow can contain roughly one billion crystals ...

Who made one cubic foot equal to 1000 grams? I'll smash him with one cubic foot of lead!

(ps for the metric vs imperial system: one cubic decimeter of water is one liter, and one liter of water weights one kilogram, so one cubic decimeter of water weights one kilogram :-)

Re:

[ThePopeLayton (868042)]

Who made one cubic foot equal to 1000 grams? I'll smash him with one cubic foot of lead!

Well if you take the weight of one snowflake and divide it by the volume of one snowflake you get the density of a snow flake. If you then multiply 1 cubic foot by the density of a snow flake you get the weight of a "cubic foot of snow flakes".
If you are looking for someone to blame that one cubic foot of snow flakes weights 1000 grams, i guess you could blame science or god, its really your choice.

Re:Interesting science...

[Deadstick (535032)]

Oohhh-kay...one cubic decimeter is about 0.016 cubic feet, so one cubic foot of snow weighs about 1000/0.016 = 62500 grams.

Freshly-fallen snow is roughly 1/10 to 1/5 as dense as liquid water, so one cubic foot of snow weighs about 6250 to 12500 grams. At one million crystals per gram, that's -- guess what -- about 0.625 to 1.25 billion crystals per cubic foot.

Who made one cubic foot equal to 1000 grams?

Mother nature. Air is part of her recipe for snow.

rj

Re:

[Deadstick (535032)]

Oopsie...substitute liquid water for snow in the first line.

rj

next up...

[10100111001 (931992)]

proving that a watched pot does indeed boil

Hoorah for science!

Yup, it's true

[muffel (42979)]

Check out the flake in pic #8.
Last winter, I saw one just like that. I swear!

So...

[Kohath (38547)]

So you're saying all snowflakes are exactly the same?

They don't taste the same.

Re:

[Mozk (844858)]

Typically I eat snow by sticking my tongue out, not by eating what's on the ground, so I'd be a little surprised (and worried) to find a yellow snowflake flying through the air. I try not to stand under animals pissing from trees when I eat my snowflakes.

Re:okay, smarty-pants...

[NiteShaed (315799)]

Now how many angels can dance on the head of a pin?

...you might just as well ask how many demons can dance on the head of a pin. They're of the same original stock, after all. And at least they dance. [Footnote: Although it's not what you and I would call dancing. Not good dancing anyway. A demon moves like a white band on "Soul Train."]

-- Neil Gaiman and Terry Pratchett, Good Omens

how many can have a snowball fight?

[EmbeddedJanitor (597831)]

keep on thread!

Re:

[UtucXul (658400)]

It's finally snowing in DC. I'm psyched. 2 inches...is not much. (I used to live in upstate NY...) But it's something.

Yeah, after a few years in upstate NY, the lack of snow and they way people deal with the little we get near DC still amazes me.

Re:

[nwbvt (768631)]

Hey, thats nothing. I'm from DC and now I live in NC. Down here people start panicking when we get a tenth of an inch. And thats not an exaggeration, two years ago we got something like that during the day and the entire region ground to a halt, and it took me three hours to get home. Then last week we got half an inch which turned to rain within a few hours and again, everyone panicked. It wasn't as bad since this time it happened at night and people could just stay home, but those who tried to drive

Re:

[rapidweather (567364)]

Last time I remember it snowing here with large flakes that had some discernible pattern to them was nearly 40 years ago.
The snowflakes were big, nearly 2.5 - 3 inches in diameter, and fell slowly from the sky.
Impossible to hold onto a few of them and see if any matched. Didn't try, really.

Re:What the **** is wrong with Slashdot moderators

[apharmdq (219181)]

Since threads are moderated by many people, it's likely that some threads will be moderated as "Trolls" or in a negative fashion early on, by moderators who do indeed consider it to be a Troll thread. However, as time goes on, more moderators will pass by and in the end the person will receive the rating/label that they deserve.

Also note that while there may be moderators that go out and toss around negative mods freely, their decisions get moderated through meta-moderation. In other words, meta-moderator