Why is it that no two snowflakes are exactly alike?
397420
I had written a detailed answer here, and Answers lost it for me, so I'll try once more and make it a bit shorter.\n\nThe snowflake phenomenon occurs because of the interaction of a microscopic unstable dynamic system (the formation of dendrites on a free-floating ice crystal) and a macroscopic one (turbulent motion in the atmosphere).\n\nThe microscopic system balances surface tension against heat diffusion; the combination of forces amplifies the tendency of water molecules to organize themselves in six-sided crystals to the point that it is visible at the snowflake scale (around a millimeter).\n\nIt takes about an hour for the typical snowflake to form. During this time, the branches of the flake go through various temperatures and zones of humidity. The variations of freezing caused by these differences don't vary enough across the scale of the forming snowflake to make the branches grow differently, so we get a hexagonally-symmetric crystal at the end, whether a flake, a needle, or a plate.\n\nEach snowflake is being blown around and up and down in the macro-scale turbulence of the atmosphere while the snow is falling; because no two snowflakes are at all likely to follow the same path through the exact same temperature and humidity gradients, the likelihood of duplicate snowflakes is pretty much zero.
1132995
they are both the same
435134
So, I don't think we have the technology to actually know if two atoms are identical.  Right now, we just think they are based on various observations.  It could turn out that each atom is actually a mini solar system like you suggested or it could turn out to be just identical atoms.  Science is just a series of guesses based on our current observations.  It changes all the time.
795499
Seems like an unfair comparison
980180
I don't get why you would think they were similar at all. This is a weird question.
1098665
Many people think that snow is just frozen rain that falls to the ground. The true process occurs in the clouds, when ice crystals form from the water vapor. This process is called sublimation and describes the solid form of snow forming directly from the vapor phase of water, without passing through the liquid water phase (rain).\n\nIt turns out that "pure" snow is made up of snowflakes, which are made up of 2 to 200 separate snow crystals. Snow crystals are crystals that have formed around tiny bits of dirt that have been carried up into the atmosphere by the wind. \n\nThe type of crystals depends on the amount of humidity and temperature present when they are forming. When cloud temperature is at freezing or below and the clouds are moisture filled, snow crystals form. The ice crystals form on dust particles as the water vapor condenses and partially melted crystals cling together to form snowflakes. As the snow crystals grow, they become heavier and fall towards Earth.\n\nAs the snowflakes move throughout the cloud, it crystallizes in different ways producing unpredictable shapes and sizes. When it’s very cold and snowing, the flakes are small, and when it’s closer to 32 degrees Fahrenheit, the flakes are larger.
260474
aren't they the same person?
198684
Most of the differences are behavioral more than just "looks." But there are differences that cannot be detected by human eye. There are computer programs to determine the differences between faces for example and research done in Britain showed that except a couple of them, all of the twins can only match up to 30%, most of the twins were way lower than that around 10%; meaning they look same to your eye, but actually they are not the same at all, not even close.
1029226
Because one of them follows the general guidelines of scientific theory and one of them doesn't.  One of them can be backed up by thousands of documents of supporting evidence, the other ends with "faith" as the answer.  Trying to equate the two is silly.
53136
Because each snowflake is actually many, many ice crystals combined.  The probability of having to pseudo-randomly arranged crystal structures being the same is very small. So it goes to say the chances of two snow flakes being made of both the same crystal structures AND arranged in the same order is so astronomical, that it can be stated with mathematical certainty that it cannot exist (i.e no two snowflakes can be the same).
837832
no\nthey are not the same
51113
Yes. It's only true that the chances of any two snowflakes being identical are extremely low, and nobody's checking and cross-referencing them all to see.\n\nIf two identical seed particles took two identical journeys to the ground, you'd have two identical snowflakes. There's no mystical law stopping this from happening apart from the sheer weight of different possibilities available.
369640
As many snowflakes as there have been, they still add up to a finite number. There is an infinite amount of possible questions.
1061455
well, thats the thing... the only way to prove that they're all different is to check every single one since the dawn of time. and they melt instantly, so you cant check them. theres not any proof that they're all different. i dont know where that idea comes from.
978852
they are the same  thing.\n!
35621
The phrase "twice as cold", has no meaning.\nYou could argue that one temperature is twice as warm as another, if they were measured from absolute zero.
249340
I think it is more that they tend to fall into the same trends and will share the same lifestyle so other things start to look similar.  I don't think they actually look alike so much as fall into a similar type of look.