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Enlarge (credit: By Diego Delso, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=74486418)

Hand axes are fairly common finds at sites dating between 2 million and 1 million years old. These sturdy tools have two sides (also called faces) and a sharp edge at one end. But hand axes are usually made of stone, so archaeologists working at the Konso Formation in southern Ethiopia were surprised to find a hand axe worked from a large chunk of bone buried in a 1.4 million-year-old layer of sediment. When Tohoku University archaeologist Katsuhiro Sano and his colleagues compared the bone to a collection of bone samples from large mammals, they found that their ancient hand axe had once been part of a hippopotamus femur (thigh bone).

From hippopotamus to hand axe

The Konso find is only the second bone hand axe archaeologists have ever found, and one of just a handful of bone tools from sites older than 1 million years. Based on fossils found at Konso, the hominin who flaked off a chunk of hippo femur and worked it into a nice, sharp hand axe was probably a Homo erectus. Members of the species walked upright and were built a lot like modern humans, and they eventually spread from Africa, across Europe and Asia, and all the way to modern Indonesia.

At least one member of this species left behind a 13cm-long hand axe that is, according to Sano and his colleagues, an excellent piece of craftsmanship. The toolmaker apparently flaked a large, flattish piece of bone off the side of a hippo femur; you can still see the outer surface of the bone on one side of the hand axe. That fits the standard Acheulean approach to making hand axes and other tools; the first step is to make a large “blank” in the right general shape, then gradually flake off smaller pieces to shape the finished product.

Enlarge / This isn't the relationship you want to see between a company with access to your private data and its affiliates. (credit: Camerique / Getty Images)

When we covered subscription-based search engine startup Neeva in June, most reader focus wasn't on the search engine itself so much as its privacy policy, which left much to be desired—particularly given the option Neeva gives its users to search their email via the service. Shortly after publication, Neeva CEO Sridhar Ramaswamy reached out to Ars to discuss what went wrong and how the company planned to fix it.

Updated privacy policy

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  The especially noxious Affiliates and Advertising Partners sections of Neeva's original Privacy Policy have been entirely removed. [credit: Jim Salter ]

Ramaswamy told Ars that the company's intention was to provide a secure and privacy-respecting platform from the start. But, he added—and we're paraphrasing here—"lawyers will be lawyers," and it was "on him" that he had not inspected the policies drafted by the company's legal counsel closely enough. He told us that he heard our readers' feedback loud and clear, and he pledged to overhaul the policy to bring it in line with the company's actual vision.

The gallery above displays the three areas in the policy that have changed since the call with Ars. Both references to third-party advertising—and tracking technologies associated with such advertising—have been entirely removed. The major impact here lies in expectations for third-party intrusions into the Neeva site itself, and it's an important one—there isn't much point in paying a monthly subscription in return for privacy if your search metadata might be leaking to the public giants you're trying to avoid in the first place.

Enlarge / Gotta catch 'em all while not catching coronavirus (TM). (credit: Niantic / Aurich Lawson)

Since its launch in 2016, the premise of mobile titan Pokémon Go has centered on roaming the outdoors in search of mystical little creatures. As a result, it’s a game that’s particularly ill-suited to pandemic-derived restrictions on movement.

In an attempt to remedy this, Pokémon Go developer Niantic has rolled out regular updates to make the game more quarantine-compatible in recent months. This has led to a new era of play among many in the Pokémon Go scene. Call it “stay-at-home, play-at-home.”

Such a systemic change in the way Pokémon Go is played was likely necessary for the game to survive in an era where many (if not most) players were unable or afraid to travel and gather together for their usual raids. By providing players with a way to play from home, Niantic is effectively removing the golden geese taunting them from the park across the road.

Enlarge / What if we spread finely crushed basalt—or even cement—on cropland? (credit: AgriLife Today)

Eventually (ideally sooner rather than later), efforts to reduce greenhouse gas emissions are going to have to be joined by a technology that actively removes CO₂ from the atmosphere. There are a number of options—from re-growing forests to burning biofuels in power plants that capture the emitted CO₂—and we'll probably need several of them to get us to net zero emissions. Some of these options involve agriculture, and a new feasibility study suggests that one of them—spreading crushed rock on farm fields—deserves serious consideration.

The study was led by the University of Sheffield’s David Beerling; it estimates both the potential for this method of carbon capture in each country and the cost required to do so.

Carbon crush

Using crushed rocks isn't a new idea. Some common minerals react with water and CO₂ as they weather, converting CO₂ from the air into bicarbonate dissolved in water. That bicarbonate may hang out in groundwater or make its way into the ocean. And along the way, it can also turn into solid carbonate. Whatever route it takes, it’s no longer a greenhouse gas in the air.