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5 Cratered Facts About Mercury

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An enhanced-color composite image of Mercury's Caloris basin. Lavas appear orange, and blue areas are likely the original basin floor. Image Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington

 

by Alex Carter

Mercury is the closest planet to the sun, and you would be forgiven for thinking it’s just a boring lump of rock. After all, there’s nothing interesting on it like aliens or places to drink. Still, Mercury is probably a more interesting place than you think...

1. IT HAS WATER ICE.

Although you would be forgiven for thinking Mercury, being the closest planet to the Sun, is one of the hottest places in the solar system, it in fact is subject to enormous temperature fluctuations. Some regions reach 800°F, but without an atmosphere to retain heat, Mercury’s poles and nightside of the planet plunge well below even the coldest temperatures recorded on Earth. With some regions never getting above -279°F, conditions are perfect for ice to form. Mercury’s regolith is home to possibly a trillion tons of ice, which would make it one of the wettest places in the solar system.

Fitting, then, that the ancient Chinese called it the Water Star.

2. IT ONCE HAD AN IMAGINARY FRIEND CALLED VULCAN.

In the 19th century, scientists were smug in the knowledge that they knew everything there was to know. There were of course a couple of curiosities that they could not understand, one being the precession in the orbit of Mercury. That is to say, Mercury goes around the Sun in an ellipse rather than in a circle, and the ellipse changed the direction it was pointing from time to time. It was thought that there must be a new planet between Mercury and the sun that was changing its orbit—the planet Vulcan. But despite trying, the planet could not be observed.

Albert Einstein eventually disproved the theory of Vulcan via the general theory of relativity. Rather than looking for an external cause, Einstein showed that Mercury was doing exactly what it should do, and that gravity was just acting in ways no one had known it could. Mercury is so close to the Sun that not only is it pulled around the Sun, space itself is too. Were it not for Mercury demonstrating this effect, Einstein probably would not have been so readily believed.

Incidentally, the other curiosity was the photoelectric effect, which needed quantum mechanics to explain. That, not relativity, was what Einstein won his Nobel Prize for.

3. IT CONTAINS THE BIGGEST HUMANMADE CRATER IN SPACE.

After six years orbiting the planet, NASA’s MESSENGER probe ran out of fuel in 2014 and could no longer correct its course. As its orbit decayed, it got closer to the planet, and much faster. The resulting crash into Mercury a year later occurred at more than 8000 mph and left a crater more than 50 feet wide. That makes it easily the biggest humanmade crater anywhere in the universe … apart from those on Earth, obviously.

4. ITS DAY IS LONGER THAN ITS YEAR.

Mercury orbits so close to the Sun that the conventional ideas of days and years don’t really make much sense. Mercury’s rotation (remember, rotation on a planet's axis causes its days) and orbit (which causes its years) are linked through gravity more tightly than Earth. In fact, Mercury rotates three times on its axis every two years. This makes each Mercury day—as in sunrise to sunset and back to sunrise—last two of its years. It’s a weird day, too: The Sun rises, goes backwards in the sky to set, rises again, then finally sets a year later. The next year, from the perspective of Mercury, the Sun would appear to move in the opposite direction.

5. IT MAY SMELL AWFUL.

Mercury’s small size means it has no permanent atmosphere, just a thin layer called an exosphere; its gravity is too weak to hold onto any gas in the wake of the strong solar wind. However, it does have a remarkably strong magnetic field, which means it keeps a hold of whatever ions come its way. There are a lot of ions in that part of space.

So while planets such as Earth are nice and oxygen filled, Mercury’s atmosphere contains the kind of things planets normally don’t hang on to, including ions of magnesium, calcium, sodium (you may remember from chemistry class that those are the ones that explode in water), as well as unusual ions of water. Mercury may smell like wet, metallic burps. 

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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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Nick Briggs/Comic Relief
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What Happened to Jamie and Aurelia From Love Actually?
May 26, 2017
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Nick Briggs/Comic Relief

Fans of the romantic-comedy Love Actually recently got a bonus reunion in the form of Red Nose Day Actually, a short charity special that gave audiences a peek at where their favorite characters ended up almost 15 years later.

One of the most improbable pairings from the original film was between Jamie (Colin Firth) and Aurelia (Lúcia Moniz), who fell in love despite almost no shared vocabulary. Jamie is English, and Aurelia is Portuguese, and they know just enough of each other’s native tongues for Jamie to propose and Aurelia to accept.

A decade and a half on, they have both improved their knowledge of each other’s languages—if not perfectly, in Jamie’s case. But apparently, their love is much stronger than his grasp on Portuguese grammar, because they’ve got three bilingual kids and another on the way. (And still enjoy having important romantic moments in the car.)

In 2015, Love Actually script editor Emma Freud revealed via Twitter what happened between Karen and Harry (Emma Thompson and Alan Rickman, who passed away last year). Most of the other couples get happy endings in the short—even if Hugh Grant's character hasn't gotten any better at dancing.

[h/t TV Guide]

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