Square’s Cash App has been helping people send and receive money without fees for a while now. Originally an money-by-email service, Cash App has grown into a more robust offering with its own prepaid Visa card. The company has been testing buying and selling Bitcoin via the app, as well, and has finally made it official.
Blockchaiiiiinnnnn! You can now buy and sell Bitcoin instantly with the Cash App!
The feature is available to most everyone who uses Cash App, unless they’re in New York, Georgia, Hawaii or Wyoming. The company promises that it’s working on it. This does seem to be a pretty simple way to get into owning Bitcoin, though Square warns that the cryptocurrency’s price is "volatile and unpredictable." While the company won’t add additional fees when you purchase Bitcoin through its app, it calculates the price when buying based on a quoted mid-market price and margin, which could be different when selling. You’ll also be limited to up to $10,000 worth of Bitcoin per week, so be sure to plan accordingly.
We aren’t yet rolled out in New York, Georgia, Hawaii, or Wyoming – but we’re working on it! Stay tuned.
Waymo’s vehicles drove 2 million miles in self-driving mode across 25 cities in 2017, putting its total autonomous miles to 4 million. It accelerated its testing to prepare for its ride-hailing fleet’s launch this year, allowing it to "gather as much data as possible in order to improve [its] technology." According to its annual report submitted to the government of California, Waymo drove 352,545 of those miles in The Golden State from December 2016 to November 2017. Within that period, the company reported a total of 63 disengagements (instances wherein the human test driver had to step in), which means its vehicles drove an average of 5,595 miles for every disengagement.
While its disengagement rate only fell 0.02 points from 0.20 to 0.18 over the twelve-month period, all these numbers indicate that Waymo is still ahead of its peers. It’s done the most extensive testing among all the companies with California permits, and as The Atlantic noted, only GM’s Cruise division comes close when it comes to autonomous mileage. Cruise vehicles racked up 125,000 miles on San Francisco’s streets without the help of a human driver and reported a yearly average of 1,254 miles per disengagement. We’re guessing GM also has plans to expand its testing efforts this year, considering it’s aiming to start selling cars without steering wheels in 2019.
Among all the causes of disengagement Waymo mentioned, "unwanted maneuver of the vehicle" topped the list with 19 instances, followed by "perception discrepancy" with 16. It’s worth noting, however, that most of those instances happened in the earlier part of the 12-month period, suggesting that the company’s technology improved tremendously in the second half of 2017.
On Wednesday evening, a couple of hours after the Falcon 9 rocket had successfully deployed a satellite into geostationary transfer orbit, SpaceX founder Elon Musk shared a rather amazing photo on Twitter. “This rocket was meant to test very high retrothrust landing in water so it didn’t hurt the droneship, but amazingly it has survived,” he wrote. “We will try to tow it back to shore.” In other words, a rocket that SpaceX had thought would be lost after it made an experimental, high-thrust landing somehow survived after hitting the ocean.
This was amazing for a couple of reasons. First of all, when the first stage of a rocket hits water after a launch, it typically explodes. (This can be seen in some of the early water landing attempts shown in a blooper reel released by the company). A rocket should not survive impact because it will rupture the relatively thin aluminum-lithium tanks that separate fuel and oxidizer. These tanks are built to withstand the axial force of a vertical launch, but not a crash into the ocean.
In this case, that did not happen. Perhaps the rocket descended such that the engines and lower end of the booster were submerged, before the 40-meter tall first stage tipped over—gently. Hopefully, at some point, SpaceX will release video from the on-board camera or other assets in the Atlantic Ocean that observed the landing on Wednesday evening.
Another reason to be surprised at the landing is the fact that the rocket performed a “three engine” landing burn. Normally, during the last part of a Falcon 9 landing, the central engine alone fires to slow the rocket for its final descent. (See, for example, here). In this case the rocket performed what Musk called a “very high retrothrust landing,” which means that three engines fired instead of one to triple the deceleration force.
This is significant because three engines firing instead of one greatly increases the gravitational force exerted on the structure of the approximately 27-ton rocket. Calculations by amateur enthusiasts on Reddit suggest that the Falcon 9 booster underwent approximately 10gs of force compared to the normal 3gs, in the seconds before landing. The upside of landing with three engines is that a booster only has to fire them for a short amount of time relative to a single engine deceleration burn, and therefore it uses considerably less fuel.
In 1982 the towing ship, Liberty, tows a recovered solid rocket booster from for the STS-5 mission to Port Canaveral, Florida.
NASA
It is not clear how SpaceX will attempt to tow the rocket to shore. The company’s Atlantic Ocean-based drone ship, “Of Course I Still Love You,” will be in service during the next week to catch the central core of the Falcon Heavy launch, tentatively scheduled for Tuesday, February 6. Perhaps the company will take a page from the playbook of NASA, which recovered the space shuttle’s larger solid-rocket boosters, with tugboats.
