The shape and size of the continents has changed a lot over the history of our planet. Sea levels have changed, plates have drifted, and in all the upheaval some large chunks of land have gone missing. Now geologists think they've found one -- a lost chunk of continent (otherwise known as a microcontinent) called Mauritia, which once connected India and Madagascar, before sinking deep under the Indian Ocean.

To find the continent, scientists dove deep down into the ocean and found a lost world, complete with mer-dinosaurs and other weird creatures. We wish. Actually, they analyzed some sand.

Editor’s note: The chat’s now over, but you can replay it in full.

Neal Gorenflo is the founder and publisher of Shareable, a website dedicated to promoting the sharing economy in all its forms, from car sharing to tool-lending libraries and even pet sharing. A former corporate up-and-comer, he quit his job in 2004 and vowed to “make a world where people felt like they were part of something meaningful.”

Gorenflo chatted with Grist earlier this month as part of our two-month exploration of the sharing economy -- and now, he’s offered to talk to you, too. Join us this Friday at 1 p.m. Eastern (10 a.m. Pacific), for a live chat, moderated by Grist Senior Editor Greg Hanscom.

Got something to share? Click here to join the chat.

Outlawing fracking in Fort Collins makes local business owners sad. At least, that's what liars working for the Colorado Oil and Gas Association tried to tell local lawmakers.

Anders’ Auto Glass, Meneike Car Care Center, and Computer Renaissance were among 55 businesses whose names appeared with signatures on a petition that the association submitted to Fort Collins City Council. The petition urged city councilors to vote against a proposed ban on fracking within the city.

The petition failed. Following a two-hour Feb. 19 hearing, the council voted 5-2 to ban hydraulic fracturing in Fort Collins.

But it turns out that none of those three businesses support fracking in their town, they told Fort Collins Coloradoan reporter Bobby Magill. Why on earth would they?

Are you dying to meet someone serendipitously -- perhaps glimpsing Mr. Right on a subway car going in the opposite direction, or making eyes at the girl of your dreams on the elliptical machine? Well, cartoonist Dorothy Gambrell of Cat and Girl has crunched the numbers on Craigslist "Missed Connections" ads from all over the country, and generated this map that shows you where to hang out and wait for Cupid to strike.

Public transit fans looking for love should opt for New Jersey, New York, Massachusetts, Illinois, D.C., Oregon, and Washington. If you'd rather get laid from the driver's seat, you can go to Georgia, the only state where most missed connections spot each other from their cars -- or you can head for a gas station in Colorado or a parking lot in Rhode Island. In most of the rest of the country, Walmart seems like a good bet, alas. 

Take a cloud of carbon monoxide. Mix in nitrogen oxide, sulfur oxide, and ammonia. Sprinkle it with a heap of soot.

That poisonous recipe is cooked up and released into the air when tires are burned. And it's what residents of the heavily polluted, low-income, predominantly black community of Ford Heights, Ill., have been breathing, on and off, since a tire-incinerating power plant began operating in their neighborhood in 1995.

But relief has finally arrived: Following a string of air pollution citations and a federal civil rights complaint, Geneva Energy has agreed to stop burning tires to generate electricity at the sprawling Cook County facility.

"This settlement will eliminate the source of almost 200 tons of air pollutants each year, in a community that has historically been disproportionately impacted by environmental contamination," EPA Regional Administrator Susan Hedman said in a statement on Monday.

The company began operating the incinerator in 2006. By 2010, it had been cited four times by state inspectors for pollution violations at the facility, at which point the EPA stepped in with the civil rights complaint, the Chicago Tribune reports. In 2011, the incinerator was switched off. In Monday's announcement, the EPA said that it had reached an agreement that prevents the company from switching the incinerator back on.

This is Horsetail Fall. On most days, it is a beautiful waterfall in Yosemite Valley. But once a year, if the sky is clear and the snowmelt abundant enough to pour water down the cliff, it lights up like a stream of fiery lava.

The New York Times reports that photographers have been chasing the elusive firefall since 1973:

The photographer and mountain climber Galen Rowell was driving through the park after a winter climb when he spotted the light catching in Horsetail Fall. He rushed across the valley and took what is believed to be the first image of the illuminated waterfall. ...

Someone has made a rather silly but funny video about what would happen if animals ate fast food and got all fat and useless. A very round alligator swims past a flock of flamingos, but can't manage to attack before his considerable weight pulls him underwater. A roly-poly leopard rolls out of a tree. A cheetah chases down an antelope, but as it makes the final leap towards its prey both lose their footing and end up bouncing across the savannah like two balls.

You've heard of pink slime. You know trans fats are cardiovascular atrocities. You’re well aware that store-bought orange juice is essentially a scam. But, no matter how great of a processed-food sleuth you are, chances are you've never set food inside a processing plant to see how many of these products are actually made.

Writer Melanie Warner, whose new exposé-on-the-world-of-processed-foods book, Pandora’s Lunchbox, is out this week, spent the past year and a half doing exactly that. In her quest to explore the murky and convoluted world of soybean oil, milk protein concentrates (a key ingredient in processed cheese), and petroleum-based artificial dyes, she spoke to food scientists, uncovered disturbing regulatory loopholes in food law, and learned just how little we know about many of the food products on supermarket shelves.

After reading Pandora’s Lunchbox, I sent Melanie some burning questions via email. Here is what she had to say:

Q. The term "processed food" is ubiquitous these days. The food industry has attempted to co-opt it by claiming canned beans, baby carrots, and frozen vegetables are "processed foods." Can you help explain why a Pop-Tart is years away from a "processed food" like hummus?

Imagine looking out over your city and instead of seeing a sea of brown and grey rooftops, you’re looking at reflective black, all the way to the horizon.

That’s the view Sanders Moore is trying to bring to Albuquerque. Moore is the 31-year-old state director at Environment New Mexico, an advocacy group (and part of the Environment America network) that works to get citizens to demand better environmental policy from their elected leaders. “Our goal is to get 100,000 roofs covered in solar panels by 2020,” she explains.

Here’s how a woman from Atlanta landed in the high, Southwestern desert with dreams of getting an entire state off oil and powered by the sun.

For most people affected by superstorm Sandy, the damage was plain to see: devastated homes, impossible traffic, even lost lives. But for Bruce Brownawell, the storm’s biggest consequences are buried under several meters of seawater. Brownawell is a marine scientist at SUNY-Stony Brook who has spent the last several years becoming intimately acquainted with the chemical makeup of mud on the floor of various bays, harbors, and inlets in the New York City area.

When Sandy hit, several local scientists saw opportunity: For Bruce, it was a chance to return to these areas and investigate how strong storm tides shifted mud around -- particularly in areas close to several low-lying sewage treatment plants that were knocked out during the storm and dumped raw sewage into the water for days. To do that, he and colleague Jessica Dutton of Adelphi University strapped on mud-proof waders and headed out to Hempstead Bay off the south shore of Long Island. Climate Desk crammed onto the boat for the inside dirt.