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Camera images from the drone ship show the Falcon 9 first stage coming in on target April 8. (credit: SpaceX)

SpaceX launched its Falcon 9 rocket into space on April 8, and after the first stage delivered its payload, the vehicle descended back to Earth and landed on an autonomous drone ship in the Atlantic Ocean.

Now the company hopes to repeat that sea-based feat under more dynamically challenging conditions. The launch earlier this month carried a Dragon spacecraft, destined for the International Space Station about 400km above the surface. With a launch tentatively set for May 3 during the early morning hours, SpaceX plans to deliver a Japanese broadcast satellite into orbit 22,000km above the planet's surface.

This means that the first stage will accelerate to a greater velocity, moving almost parallel to the surface and away from the launch site, before it releases the second stage and the primary payload. This trajectory will leave the vehicle with far less fuel to arrest this horizontal motion, and to control its descent to the barge waiting below.

CJ Wilson Racing

This is the real #35 Cayman GT4 Clubsport.

5 more images in gallery

If you're an up-and-coming racing team, and you want to make new fans, what better way than to set up an e-sports series featuring a digital version of your real race car? The team in question is CJ Wilson Racing, which has partnered with Logitech and The Online Racing Association (TORA) to run the CJ Wilson Racing Cayman Cup—a 10-race series that gets underway on April 27th. We spoke to some of the people involved in order to find out more, particularly about how they arrived at their Forza Motorsport 6 version of the real race car.

The e-racing community might not have the same following—or prize fund—as something like Dota 2. But e-sports are being taken more and more seriously by the people that run real-word racing. As far back as 2008, Nissan and Sony in Europe were using Gran Turismo tournaments to find promising young racing drivers. TORA was officially recognized by the UK's Motor Sports Association in 2010, and even the FIA (which runs international motorsport) recently announced it would sanction a new series in the next Gran Turismo game.

How accurately racing games recreate the experience of driving the real thing is a topic we've tackled a few times. For 2016, CJ Wilson Racing switched cars, from the Mazda MX-5s it had been running in the Continental Tire Sportscar Challenge to a pair of Porsche Cayman GT4s. The Cayman GTS just came back to Forza 6, but there isn't actually a Cayman GT4 in the game. So, we wondered, how did the team recreate it?

"The tunnel entrance to the North American Air Defense (NORAD) Space Command Cheyenne Mountain Complex." Utah Mining, the company that excavated Cheyenne Mountain, also built a civilian tunnel going from Denver to Idaho Springs. The dimensions of that tunnel entrance are similar to the dimensions of this tunnel entrance. (credit: Department of Defense)

COLORADO SPRINGS, CO—Across the highway from the US Air Force Academy is a tiny cluster of buildings that represents one of Colorado Springs' earliest claims to fame: mining.

The Western Museum of Mining and Industry (WMMI) looks out onto a glorious expanse of the Rocky Mountains and is home to all manner of antique equipment that extracted minerals from those mountains.

But on a balmy April night, as a spring snowstorm rolled in from the west, Ars attended a lecture at the museum about a nearby mining marvel that was not intended to extract riches, but to bury something more valuable beneath the unyielding rock—knowledge.

Chromecast Audio! Identical size to the standard 2015 Chromecast. Those vinyl-like grooves are purely intentional. (This one also requires power via a USB mini cable.) (credit: Sam Machkovech)

I received my Google Chromecast Audio for review at the end of September, and I buried my impressions of it in an article about the Chromecast's 2015 refresh. Not a ton to say, really: it provides Chromecast-like functionality... but only for audio. Chromecast Audio. Got it.

However, Google didn't really tell critics about the Chromecast Audio's most interesting feature, possibly because it wasn't yet ready or tested. Roughly a month after its October launch, Google rolled out a "group" synced-audio update. The update wirelessly daisy-chains an unlimited number of Chromecast Audio dongles so that their audio is synced across an entire house. For $35 a pop, you can turn an old speaker with a 3.5mm audio jack into an audio repeater.

It's too late for super-fresh impressions, but my month of Chromecast Audio has proven so fruitful, I wanted to share my experience and offer recommendations so that you too can rock a party-ready house like mine.

Oceanic crust sometimes ends up on land—like the Ingalls Peak area in Washington. This stuff pulls carbon dioxide out of the atmosphere as it weathers. (credit: brookpeterson)

Earth’s climate has stayed within a pretty narrow range of temperatures over its history if you compare it to the inhospitable heat and cold found elsewhere in our Solar System. This relative stability has been maintained by an intricate system of interactions. On geologic timescales, the chemical commerce between the atmosphere and the rock of Earth’s crust acts as a thermostat. The weathering of common minerals includes a reaction that removes CO₂ from the atmosphere. High temperatures (caused by higher CO₂) mean faster weathering, which gradually brings CO₂ and temperature back down. It’s a moderating influence.

But plate tectonics also fiddle with the dial on that thermostat. Arcs of volcanoes along subduction zones (where one plate dives beneath the other) provide a constant source of CO₂, and subduction zones come and go over time. Research using tough zircon crystals as records of volcanic arcs has found a correlation with climate over geologic time. In fact, a new study published this week in Science extends that comparison over the last 720 million years by finding evidence that volcanic activity rises and falls with the great swings in Earth’s climate.

A second study—published in the Proceedings of the National Academy of Sciences and led by MIT’s Oliver Jagoutz—looks at the flip side of the equation: the ability of plate tectonics to strengthen the weathering feedback that eats CO₂. Although climate change can increase or decrease the rate of weathering, the amount of exposed and easily weatherable rock makes a huge difference. The igneous rocks that make up oceanic crust, for example, make excellent CO₂ sponges—or at least they would, if they weren’t at the bottom of the sea.