Audi just created diesel fuel from air and water

Audi is looking to fuel the future without fossil fuels. One of the company's pilot plants in Germany has just produced the first batches of a synthetic diesel made using only water and air. The company's pilot plant, which is operated by German startup Sunfire, produced its first batches of the "e-diesel" this month. German Federal Minister of Education and Research Johanna Wanka put a few liters of the fuel in her work car, an Audi A8, to commemorate the accomplishment.

Avenue Trucks adds suspension to existing skateboards

Although we've seen at least one off-road skateboard with built-in suspension, aftermarket suspension systems for more traditional boards are few and far between. The designers at California-based Avenue Trucks, however, are out to change that. They claim that their suspension trucks should improve the skateboarding experience in several key ways. 

Implantable device could allow for better-targeted cancer treatment

While there are a large number of approved cancer treatments, identifying which drugs are best suited to individual patients is extremely difficult for doctors. A team of MIT researchers has developed a small, implantable device that aims to change this by allowing scientists to measure the effectiveness of different drugs, on a patient-by-patient basis.

Transparent butterfly wings could inspire low-reflectivity displays

Researchers from the Karlsruhe Institute of Technology (KIT) in Germany have studied the wings of glasswing butterflies in an effort to determine what causes their low-reflective nature. It's believed that the findings of the study could lead to less reflective screens on mobile phones, tablets and other devices.

Best Buy to accept Apple Pay for purchases

Best Buy shoppers can now use Apple Pay to complete purchases made through the electronics retailer's app, a coup of sorts for Apple in the intense mobile-payments business.

For now, Apple Pay transactions are limited to Best Buy's app, but the companies expect consumers to be able to use the mobile payment method for in-store purchases later this year, the retailer announced Monday. Best Buy was a major supporter of the Merchant Customer Exchange, or MCX -- a consortium of retailers led by Walmart that has developed a competing mobile-payments system.

"Today's consumers have many different ways to spend their money and we want to give our customers as many options as possible in how they pay for goods and services at Best Buy," Best Buy said in a statement announcing the partnership.

Apple Pay, which launched in October on theiPhone 6 and 6 Plus, is a key feature of the new Apple Watch, which hit the market last week. Its NFC technology allows users to tap their devices at payment terminals in stores to buy merchandise and pay for services.

Apple faces stiff competition from other companies that offer similar mobile payments services. Samsung offers its new Samsung Pay feature on the new Galaxy S6 and Galaxy S6 Edge and has unveiled a mobile payments service called Android Pay. PayPal, the digital payments unit being spun off from eBay later this year, plans to acquire Paydiant, a startup that helps companies such as Subway and Capitol One build mobile payments options.

Best Buy is one of several retailers part of MCX, which aims to challenge Apple Pay with its own CurrentC mobile-payments system. Apple Pay had opposition from a large group of MCX merchants early on, with some members of the consortium deciding to disable consumers' ability to use Apple Pay, in anticipation of the launch of MCX's alternative payments service.

The group denied encouraging the Rite Aid and CVS drugstore chains to block Apple Pay by disabling NFC terminals. CurrentC, which now uses QR codes instead of NFC, is expected to launch widely later this year.

MCX said Monday afternoon that Best Buy remains an MCX partner and supporter of CurrentC.

"We understand -- and strongly support -- our merchant partners' quest to do what's best for their customers," Scott Rankin, MCX's chief operating officer, said in a statement. "As we have stated in past, we are of the firm belief that there need to be at least 2 to 3 major players within the mobile payments ecosystem for it to succeed."

Apple first introduced the capability with about 500 financial-institution partners and 220,000 US merchant locations that take mobile payments via NFC's short-range, secure wireless capabilities. In its first three months on the market, Apple Pay expanded to availability in more than 700,000 locations, Apple CEO Tim Cook said last month.

Earlier Monday, the credit card Discovery announced that its 61 million card holders would be able toadd their Discover card to the Apple Pay system later this year, giving Apple access to a large pool of potential Apple Pay customers. With the announcement, Discover joins previous partners Visa, MasterCard and American Express, giving Apple a lock on all four major credit cards in the US.

Facebook Messenger app adds free video calls, works over both LTE and W-Fi

Facebook is now going after Skype.

The social network has launched a free video calling feature for Messenger, allowing you to have face-to-face conversations with your friends from across the world. Just tap the video icon in the top-right corner within an existing Messenger conversation to start a video call. The free feature, which works over both LTE and Wi-Fi, will directly rival not only Skype, but also Google Hangouts and Apple's FaceTime.

"Video calling in Messenger is available for calls made from a mobile phone to another mobile phone, even if one person is on iOS and the other person is on an Android device," explained Facebook in a blog post published on 27 April. "It’s fast, reliable and high quality."

Facebook introduced desktop video calling in 2011 via a Skype partnership, but it has since built its own voice-over-internet infrastructure. Video calling is now available within the Messenger for iOS and Android apps in the following countries: Belgium, Canada, Croatia, Denmark, France, Greece, Ireland, Laos, Lithuania, Mexico, Nigeria, Norway, Oman, Poland, Portugal, UK, US, and Uruguay.

Facebook promised to expand video calling to other regions over the coming months.

NASA is about to solve a major mystery about dwarf planet Ceres

Back in January astronomers got one of their first close-up glimpses of dwarf planet Ceres, and they were baffled.

The tiny planet is the largest chunk of rock in the asteroid belt that hangs between Mars and Jupiter, and those close-up images, captured by NASA's Dawn spacecraft, revealed two huge, and hugely mysterious, bright spots on the surface.

The problem is that no one knows what in the world they are — and the more we observe and photograph them, the more complicated and confusing they get.

And people have some crazy theories about what they might be.

Maybe they're some kind of hybrid water volcano: