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16 Cool Facts About Glaciers

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istock

The world today would look very different were it not for glaciers, the icy bulldozers that—over many thousands of years—carved out landforms such as fjords and America's Great Lakes. As it turns out, those impressive claims to fame are just the tip of the iceberg. Here are a few more fascinating facts about the massive bodies of ice and snow.

1. There's a size requirement.

Proper glaciers must be a minimum of .1 square kilometers—that's almost 25 acres, or nearly 19 football fields!

2. The Largest Glacier on Earth is 60 Miles Wide and Around 270 Miles Long.

That would be Antarctica’s Lambert glacier, named after former Australian director of national mapping Bruce P. Lambert, who helped chart out the area during the late 1950s.

3. They Behave Like Really, Really, REALLY Slow-Moving Rivers.

Like the mighty Mississippi, glacial ice—which is driven by gravity—flows from high to low elevations. In the process, it often removes and transports chunks of rock (called “glacial erratics”), sometimes across a few hundred miles.

4. They’re Formed by Snowflakes and Time.

The most vital ingredient for glacier-making is a location where snow stays put year-round. When new layers arrive each winter, they start to crush existing blankets. All that weight distorts the snow crystals that make up the older layers, turning them into sugar-like grains. As time passes, these grains get bigger and denser until, eventually, genuine glacial ice is produced.

5. Glaciers Contain an Estimated 69 Percent of the World’s Fresh Water Supply.

By comparison, lakes, rivers, swamps, and similar bodies can only claim a combined 0.3 percent.

6. There are around 100,000 in Alaska.

These cover some 28,000 square miles of the 49th state. Provided they have the right permit, Alaskans are legally allowed to harvest glacial ice.

7. If Every Glacier and Ice Sheet on Earth Suddenly Melted, Global Sea Levels Would Rise by Over 260 Feet.

Hasta la vista, LA and London! Also, parts of southern Missouri might become great locations for beachside condos.

8. Glaciers Can Move At a Rate of Over 50 Feet Per Day.

In the summer of 2012, the Jakobshavn Glacier in Greenland set a new world record by traveling an impressive—by glacial standards, at least—150 feet per day.   

9. There Are Two Main Types.

Alpine glaciers flow downwards from mountaintops and slide through valleys. Continental glaciers, on the other hand, are large, horizontal expanses that aren’t seriously affected by the hills or mountains they cover. They generally dwarf their alpine counterparts.

10. During the peak of the Last Ice Age, Glaciers Covered About a Third of Earth's Land.

Over the past two billion years, our little blue planet has withstood at least five main ice ages. The latest one has spanned from 2.6 million years ago to the present day (yup: according to some experts, we're currently living through another).

11. Contrary to Popular Belief, You Won’t See Frozen Mammoths Suspended in Glaciers.

The mummified bodies of these great, extinct mammals are usually only found covered under frozen sediment and not—as many assume—floating inside glaciers.

12. Not All Glaciers Dwell Near the Poles.

Glaciers can be found on every continent but Australia (although New Zealand has some) and many “live” closer to the equator than one might expect—Mexico’s elevated areas are home to 24 [PDF] while the Ecuadorian Andes also have a few.

13. We Can Thank Glaciers for Something Called “Rock Flour.”

Fairsing, Wikimedia Commons // Public Domain

This stuff generally looks like earthy sawdust. As glaciers grate along the earth’s surface, they’ll grind bedrock into a fine, powdery substance. When this rock flour enters a lake, something magical takes place. Since it’s too fine to sink, the material may get suspended and turn the water turquoise blue.

14. Some Glaciers Look Blue Because That’s the Only Color Glacial Ice Can’t Absorb.

Unlike red and yellow lightwaves, blue light can penetrate snow and ice, thus creating that cool shade of winter wonderland azure.

15. Ancient Glaciers May Have Once Dotted Mars.

The red planet’s surface is rife with canyons, but did long-gone glaciers have anything to do with their creation? Some scientists think so. Last year, their theory got a major boost when a mineral called jarosite was identified along the walls of an enormous canyon known as Ius Chasma. On Mars, jarosite is created by reactions with water, usually through evaporation. But there was no way that a puddle was evaporating 3 miles up a cliff face. It’s believed that a glacier picked up some sulfur, and then as the sun melted the ice along the edges, the water reacted with the sulfur to produce jarosite.

16. Glaciers Occasionally Form Over Active Volcanoes.

In 1996, the Grímsvötn volcano of Iceland violently erupted despite the fact that it had been buried by roughly 2000 feet of glacial ice. Upon melting through this, a flood of epic proportions was triggered—one that caused $50 million in damages.

All images courtesy of iStock unless otherwise noted.

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iStock // Ekaterina Minaeva
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Man Buys Two Metric Tons of LEGO Bricks; Sorts Them Via Machine Learning
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iStock // Ekaterina Minaeva

Jacques Mattheij made a small, but awesome, mistake. He went on eBay one evening and bid on a bunch of bulk LEGO brick auctions, then went to sleep. Upon waking, he discovered that he was the high bidder on many, and was now the proud owner of two tons of LEGO bricks. (This is about 4400 pounds.) He wrote, "[L]esson 1: if you win almost all bids you are bidding too high."

Mattheij had noticed that bulk, unsorted bricks sell for something like €10/kilogram, whereas sets are roughly €40/kg and rare parts go for up to €100/kg. Much of the value of the bricks is in their sorting. If he could reduce the entropy of these bins of unsorted bricks, he could make a tidy profit. While many people do this work by hand, the problem is enormous—just the kind of challenge for a computer. Mattheij writes:

There are 38000+ shapes and there are 100+ possible shades of color (you can roughly tell how old someone is by asking them what lego colors they remember from their youth).

In the following months, Mattheij built a proof-of-concept sorting system using, of course, LEGO. He broke the problem down into a series of sub-problems (including "feeding LEGO reliably from a hopper is surprisingly hard," one of those facts of nature that will stymie even the best system design). After tinkering with the prototype at length, he expanded the system to a surprisingly complex system of conveyer belts (powered by a home treadmill), various pieces of cabinetry, and "copious quantities of crazy glue."

Here's a video showing the current system running at low speed:

The key part of the system was running the bricks past a camera paired with a computer running a neural net-based image classifier. That allows the computer (when sufficiently trained on brick images) to recognize bricks and thus categorize them by color, shape, or other parameters. Remember that as bricks pass by, they can be in any orientation, can be dirty, can even be stuck to other pieces. So having a flexible software system is key to recognizing—in a fraction of a second—what a given brick is, in order to sort it out. When a match is found, a jet of compressed air pops the piece off the conveyer belt and into a waiting bin.

After much experimentation, Mattheij rewrote the software (several times in fact) to accomplish a variety of basic tasks. At its core, the system takes images from a webcam and feeds them to a neural network to do the classification. Of course, the neural net needs to be "trained" by showing it lots of images, and telling it what those images represent. Mattheij's breakthrough was allowing the machine to effectively train itself, with guidance: Running pieces through allows the system to take its own photos, make a guess, and build on that guess. As long as Mattheij corrects the incorrect guesses, he ends up with a decent (and self-reinforcing) corpus of training data. As the machine continues running, it can rack up more training, allowing it to recognize a broad variety of pieces on the fly.

Here's another video, focusing on how the pieces move on conveyer belts (running at slow speed so puny humans can follow). You can also see the air jets in action:

In an email interview, Mattheij told Mental Floss that the system currently sorts LEGO bricks into more than 50 categories. It can also be run in a color-sorting mode to bin the parts across 12 color groups. (Thus at present you'd likely do a two-pass sort on the bricks: once for shape, then a separate pass for color.) He continues to refine the system, with a focus on making its recognition abilities faster. At some point down the line, he plans to make the software portion open source. You're on your own as far as building conveyer belts, bins, and so forth.

Check out Mattheij's writeup in two parts for more information. It starts with an overview of the story, followed up with a deep dive on the software. He's also tweeting about the project (among other things). And if you look around a bit, you'll find bulk LEGO brick auctions online—it's definitely a thing!

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iStock
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Why Your iPhone Doesn't Always Show You the 'Decline Call' Button
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iStock

When you get an incoming call to your iPhone, the options that light up your screen aren't always the same. Sometimes you have the option to decline a call, and sometimes you only see a slider that allows you to answer, without an option to send the caller straight to voicemail. Why the difference?

A while back, Business Insider tracked down the answer to this conundrum of modern communication, and the answer turns out to be fairly simple.

If you get a call while your phone is locked, you’ll see the "slide to answer" button. In order to decline the call, you have to double-tap the power button on the top of the phone.

If your phone is unlocked, however, the screen that appears during an incoming call is different. You’ll see the two buttons, "accept" or "decline."

Either way, you get the options to set a reminder to call that person back or to immediately send them a text message. ("Dad, stop calling me at work, it’s 9 a.m.!")

[h/t Business Insider]

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