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Jesse Allen/NASA Earth Observatory

Antarctica Is Covered in Rivers, Lakes, and Waterfalls. That Might Not Be Good.

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Jesse Allen/NASA Earth Observatory

The floating ice shelves that buttress Antarctica are less icy than we thought, it turns out. They’re filled with flowing water. New research published in the scientific journal Nature maps the extensive network of meltwater from Antarctica's ice sheets and found that, contrary to previous understanding, lakes and rivers—even waterfalls—created by melting have been common for at least seven decades.

Two new papers analyze satellite imagery of Antarctica dating back to 1973 and aerial photography dating back to 1947 for evidence of meltwater. Warming oceans melt ice shelves around from the bottom up, while warming air temperatures melt them from the top down, creating pools and rivers of liquid water on the continent's surface.

Researchers found that over the last 70 years, a system of meltwater drainage has transported water from the continent of Antarctica across the floating ice shelves that surround it, traveling up to 75 miles and creating ponds up to 50 miles long.

This isn’t great news for the stability of the ice shelf. Water is heavy, and the weight can cause the ice below these lakes to crack. As glaciologist Alison Banwell wrote in a separate analysis of the studies for Nature, “If a lake suddenly drains through a crevasse to the ocean below, the load deficit from the ice shelf’s surface can induce more crevasses, potentially triggering a chain reaction” of draining lakes. “This process might have been responsible for the large-scale break-up of Antarctica’s Larsen B Ice Shelf in 2002, when more than 2000 lakes drained in just a few days.”

All that water ends up in the ocean, contributing to rising sea levels. As NASA geophycisist Ala Khazendar told NPR in January, "Ice shelves are very important. They are the gates of Antarctica in a way, and the gatekeepers of Antarctica." The National Snow and Ice Center estimates that if the Antarctic Ice Shelf—which covers 98 percent of the continent—melted, sea levels would rise by as much as 200 feet.

All that makes meltwater a little worrisome for climate scientists, but there may be a silver lining, at least according to one of the published papers.

One river network the researchers studied ends in a 427-foot-wide waterfall that can empty the entire amount of meltwater produced by the ice shelf annually in just seven days. That may make the ice shelf more stable, since the meltwater gets funneled into the ocean immediately instead of building up on top of the ice shelf and cracking the ice below. “Export of meltwater by surface rivers may buffer the impact of warming temperatures,” the researchers wrote. At least when it comes to breaking up ice sheets. Unfortunately, those drainage systems are still really effective at sloughing off water into the ocean, which will still affect sea level rise.

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iStock // Ekaterina Minaeva
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Man Buys Two Metric Tons of LEGO Bricks; Sorts Them Via Machine Learning
May 21, 2017
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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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May 23, 2017
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