In an earlier article, I mentioned that at the heart of every snowflake is a speck of dust. After talking with some readers, it turns out that wasn’t so “common knowledge” as I had thought. I’m happy to say, there’s much more to that little tid-bit.

At the core of every snowflake is a speck of dust because clouds would not exist without dust. A visible cloud is a vast collection of water droplets that have individually condensed upon dust floating in the breeze. This is why the air seems clearer after rain, particularly in smoggy cities. Each rain drop will drag a bit of dust, kicking and screaming, to the ground.

When it’s cold enough, these tiny water droplets will freeze into ice crystals. At the tiniest level, a molecule of water (H₂0) has a particular rigid hexagonal honeycomb structure formed with the two hydrogen atoms for every one oxygen atom. This core hexagonal structure affects the shape of a snowflake to the point that nearly all fancy snowflakes have exactly six points or sides.

Turns out, the majority of individual snowflakes are not so pretty. The most common by far are just irregular clumps of crystals. Nothing fancy there. Like with an ugly baby, it’s best just to politely nod or not say anything at all.

However, the amazingly beautiful crystals, like the ones we try to emulate with folded and cut paper, do abide by some interesting rules. All snowflakes start with a single ice crystal which takes the shape of a hexagonal cylinder. More water droplets will attach themselves around this. The pattern of the crystals is dependent upon the humidity and precise air temperature.

The quintessential snowflake is called a Stellar Dendrite. These have six points, each with many branches. (dendrite meaning “tree like”) They are large enough, 2 to 4 mm, to be seen on the end of your mitten. The largest individual snowflakes, Fernlike Stellar Dendrites, can be over 5 mm across.

A real life snowflake, microscopically photographed. From SnowCrystals.com

Some fancy snowflakes take completely different forms. Some are flat hexagon plates with intricate ridges and markings. Others are simply elongated cylinders. Sometimes the cylinders will have caps on the end, like two wheels on an axle. Multiple flakes can join together creating intricate bi-level dendrites.

Kenneth Libbrecht is a physicist at Caltech who has studied the structure of snowflakes. In his studies he has photographed many wonderful specimens, both rare and common. He also answers the question, are there two snowflakes exactly alike? With the typical big-picture-thinking of a physicist his first response is “who would ever notice?”.

In fact, the simplest snowflakes can be exactly alike. (one hexagonal crystal) However, with calculator firmly in hand, a complex snowflake is arranged from up to 100 or more random growths. The number of possibilities (picture a 1 with 156 zeroes behind it) is so staggeringly large that an identical match seems highly unlikely to occur, let alone be observed.

At least this will give you something to think about next time you need to shovel a few thousand of these things off your walkway.

• Source: Guide to Snowflakes from Kenneth Libbrecht. Also see his book on the science and beauty of snowflakes.

How can a sea have no shores? No beaches, no coastline, and not touching any land whatsoever. It can, when that sea is in the middle of an ocean.

The Sargasso Sea floats in the middle of the Atlantic Ocean, north of the equator. The water there is the clearest in all the ocean, and the edge of this secret sea can in fact be seen from the air with a noted change in water colour to a deep blue.

The sea is created by a calmness. This expanse of water is free of ocean currents, and generally doesn’t get much wind or storms. It was named the Sargasso Sea by Portuguese sailors in the 15th century who were amazed by the massive collection of seaweed (of the Sargassum variety) that floats in the calm. It is pushed and corralled by the strong ocean currents that surround the area. (those circular currents are called a gyre, created by the Coriolis Effect)

Before modern ships, the Sargasso Sea could be hazardous to sailors. The calm ocean and weak winds could leave ships stranded on the open ocean, unable to move. This part of the world has been named the horse latitudes (between 30 and 35 degrees latitude, both north and south) after an odd sailing tradition that involved parading around the deck with a straw horse and tossing it overboard. Dumping the “dead horse” was to signify working off their debts at about that point in the journey.

Sadly, in modern times the same currents that collect the seaweed have also gathered a fair amount of pollution. There are large puddles of oil and plastic trash in the Sargasso Sea. Just the same as the more famous “plastic island” in the middle of the Pacific Ocean.

• Source: Sargasso Sea – Wikipedia
• I first heard about this when watching the documentary Turtle: The Incredible Journey (which, fair warning, has no ninjas in it)

It’s finally gotten to the point where I can lay out on the grass and stare at the sky without the risk of being covered in snow. Let’s celebrate with the game show craze that’s not exactly sweeping the nation… Name That Cloud! You’ve probably heard the cloud names before, but if you’re like me, you couldn’t accurately match them up with the real thing. (unless you’re thinking of names like “puffy” and “dark”)

Clouds are classified based on their height and structure.

Clouds below 2000 meters are called stratus.The word comes from Latin for “spread out”. The two types of cloud in this category are nimbostratus and stratocumulus. To my untrained eye, there’s not a big difference between the two, but the stratocumulus should be more lumpy and uneven. Both tend to result in those dreary grey days where it’s trying to rain but not particularly succeeding. Sometimes stratus clouds get low enough to touch… what we call fog.

Above 6000 meters are the cirrus clouds. Cirrus in Latin translates to “curl of hair”. These are the wispy clouds that are just thin lines across an otherwise blue sky. Cirrostratus (high-level, spread out) clouds are nearly invisible, as they are a sparse collection of ice crystals that stretch across wide areas. They sometimes hint at their existence by creating a halo effect around the sun or moon.

Between those two levels, clouds get dubbed “alto”. Either altrostratus or altocumulus. Altostratus (remember “spread out”) is what we call overcast. It’s a light grey covers that dulls the sun, but rarely makes for any rain. Filmmakers love this! Altocumulus clouds show up like ripples across the sky, not unlike the sandy bottom of a lake, and may foretell a coming thunderstorm.

Cumulus clouds, named from Latin for “pile up” (like accumulate), are the stereotypical fluffy cotton-ball clouds. They come and go with a lifespan of 5 to 40 minutes. Everybody loves cumulus clouds. But you do have to watch out for the evil Dr. Jekyll version called cumulonimbus. These are the gigantic, huge, towering clouds that bring powerful storms.

This all should make perfect sense… if you can speak Latin. For the rest of us, here’s the quick memonic guide to souding really smart about clouds.

Spread-out… straddling the sky… Stratus

Fluffy… piled-up… accumulated… Cumulus

Wispy… seriously thin… Cirrus (okay, that one’s a stretch, I admit)

And for those of you who can’t get enough cloud facts, many months ago I wrote a article to calculate how much a cloud weighs. (hint: it’s seriously heavy!)

• Source: Cloud classifications from the University of Illinois

Yesterday I was talking about the hypersphere as one of the proposed shapes for the universe, but I ran out of space (trying to keep things snappy) before I got to the more interesting idea. Some theories peg the universe as having no shape at all… it just goes on forever.

Have you ever heard the expression that an infinite number of monkeys banging away on an infinite number of typewriters will eventually produce the complete works of William Shakespeare? Statistically, that is a guaranteed fact. Given enough time, the “random sequence” of letters that correspond with Hamlet will eventually turn up. That’s the curious thing about infinity.

If the universe is truly infinite, that means Shakespeare was not the only Shakespeare. If you traveled far enough you would come across another galaxy, with another solar system, and another planet very much like earth. (having been formed with the same random sequence of evolutions) Walking this planet would be people very much like you and I. It may be off by a bit… Mary would actually be Sara, and with red hair rather than brown. Their pet dogs would have six legs.

Given enough distance covered in the infinite sequence, you will eventually stumble upon a place which is identical in every way to Earth, with identical people hanging around. Actually, the physicist Max Tegmark once calculated (for fun) how far away this mirror world would likely be according to the mathematics of probability:

A mere 10 to the power of 10²⁹ meters. That’s a 1 with 100 000 000 000 000 000 000 000 000 000 zeros behind it.

In fact, if the universe goes on forever then anything that you can imagine… exists. It sounds crazy, but that is actually the simplest answer regarding the universe. It’s easy to explain how everything exists. However, it’s very difficult to explain why some things would exists while others would not. The question becomes the dividing line between can exist and can’t exist. How would such a rule come about? Does that mean our “laws of nature” are not universal?

Finally we come to the theory that the universe may not be the universe, but rather one little puddle of space in the infinite multiverse. As such, each pocket universe can be distinct unto itself, mind-numbingly large, but not infinite. More interestingly, each universe can then have it’s own unique set of natural laws forged as the universe was born.

As I said in Part 1, all this is theory. There is no way for us to know things on this scale, as we cannot see that far. The speed of light and the “cosmic horizon” means we can only observe a (relatively) very small portion of space around us. But as Richard Feynman said… “It’s fun to imagine!”

• Source: All this and more covered completely in “The Goldilocks Enigma” (Amazon link)
• Also, Max Tegmark has posted many of his articles regarding the Multiverse on his website.

This post is part of “Blog Action Day“, wherein over 7000 blogs will be posting on the topic of climate change. The goal is to raise awareness of the issues and concerns of the global environment. I have a hunch that my post is not quite what they had in mind.

I’ll come right out and say it: I am not at all worried about global warming. I don’t believe it’s a crisis, or even a concern. The current state of fear and sense of impending doom has been nurtured by the media, who are just trying to sell newspapers. I don’t deny that the global temperatures are rising, but it’s not a problem. Here’s some hype-free facts about climate change…

The leading cause of global warming is the sun. The giver of all life. Obviously, it has the biggest impact on everything here on earth. Like most humongous balls of burning gas, it’s not a static thing. It moves, it changes. A scientific paper form March 2008 determined that 62% of temperature change has been the result of the sun, caused by short-term fluctuations and long-term solar cycles.

The earth also has it’s cycles. In the time of the dinosaurs, carbon dioxide levels were 2 to 4 times higher than they are now, but things have cooled off a few times since then. About 125,000 years ago, at the peak before the most recent ice age, global temperatures were much higher, and the sea level was 20 feet above current levels. Still, things froze up yet again.

We only really started keeping track of temperatures around 1850. Studies of Greenland ice cores, which offer a timeline of weather going back a few millenia, indicate that the northern hemisphere circa mid 1800s was the coldest period in about 8,000 years. So the average temperatures would have nowhere to go but up. The point being, rising temperatures are not a crisis. We’re just on a natural upswing.

In 2007 all the world heard reports about the University of Illinois study revealing that Arctic ice was at it’s lowest levels in 30 years. Nobody seemed to mention the bit in the same study that mentioned the Antarctic ice down south was at record highs.

I don’t understand why people love doom and gloom news stories so much, but I do hope I’ve encouraged you to take a peek beyond the hype. There are some serious environmental concerns we should be dealing with rather than fretting about the multi-millennial ebb and flow of climate cycles.

• Source: http://www.climatechangefacts.info/ (This is a massive resource of scientific research presented plainly. You don’t have to take my word for it.)

It’s now officially chilly around here, so my curiosity turned towards the leaves. Specifically, how and why they change to such lovely colours. Turns out, they don’t really change to yellow and orange so much as let their true colours come through. (That’s your cue, Cyndi!)

The green in leaves is due to the presence of chlorophyll. That’s the chief ingredient for the process of photosynthesis, turning sunlight, water and carbon dioxide into glucose… yummy tree food. (also good on pancakes) If you ever mow a lawn in white shoes, you know that chlorophyll is a strong green pigment, and that’s what you’re seeing when you look at a green leaf.

As the days get shorter, the trees take the hint to begin hibernating for the winter. In shutting down photosynthesis food production, the green chlorophyll drains out of the leaves and the true colour of the leaf, be it yellow, brown, orange, or some mix of the above, can now be seen. (the colour is caused by carotenoids, much like those newfangled orange carrots)

Red leaves, however, are not a natural colour but the result of specific circumstances. If the autumn days tend to be sunny, but then the nights are particularly cold (but not freezing) then we will see more vibrant red leaves. The red is caused by anthocyanins, which only enters the leaves as an elite rescue force. In such weather conditions the glucose (food) gets stuck in the leaf, unable to completely drain into the tree, and the red anthocyanins are created to recover nutrients from the leaves before they fall off.

• Source: http://dnr.wi.gov/org/caer/ce/eek/veg/trees/treestruecolor.htm

I’m declaring “casual Friday” again, and what’s more casual than a sing-along? It seems that the science-folk genre just isn’t what it used to be, so I’m bringing it back to the limelight. Back in 1959 Tom Glazer teamed up with Dottie Evans to record a series of albums called “Singing Science”. Their little ditties covered a wide range of topics from “Constellation Jig” to “A Thumbnail Sketch of Atomic Energy”.

You probably even know Tom Glazer, but you don’t know you know. His peak of commercial success came with a parody he wrote and performed entitled “On Top Of Spaghetti”, the tale of a lost meatball. The science songs were written by Hy Zaret, who brought home the bacon when he co-authored the mega-hit “Unchained Melody”. With a team like that, it’s no wonder the Singing Science albums were so awesome.

Taking inspiration from them, this morning I got out the ol’ guitar and am pleased to present, with huge apologies to Eva Cassidy, a science sing-along of my own composition…

(You can click above to play the song, or grab the MP3 file)

“Weight on the Water”

Put the water in the pot, then wait on the the water
turn on the burner so it gets hot, that’s how you boil the water

But what happens in that pan, while you wait on the water?
I’m gonna explain it the best I can about the boiling point of water

If you put some water on a plate, it will eventually evaporate
It goes from a liquid to gaseous state, just like boiling water

You see water always wants to boil, but it can’t. Its plans are foiled
by the crushing weight of the air above, that pops all the bubbles before they can get out of… the water

[insert science ramble because it's REALLY hard to make all the facts rhyme]

Now when you apply some heat, into the water
the vapor pressure and air pressure meet, as the pot gets hotter

Now the bubbles start to form, in the middle of the water
they rise up and take their vapor form, and that is boiling water

So there you have it, the facts are true, straight from a scientist, through me then to you
It’s a story of hope, of overcoming, it’s the story of boiling water

• Fact source: http://www.ccmr.cornell.edu/education/ask/index.html?quid=1316
• Thankfully, you can download (free!) many of the original Singing Science songs here: http://www.acme.com/jef/singing_science/