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Early modern humans cooked starchy food in South Africa, 170,000 years ago – Phys.org

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Border Cave excavation. Credit: Dr. Lucinda Backwell

“The inhabitants of the Border Cave in the Lebombo Mountains on the Kwazulu-Natal/eSwatini border were cooking starchy plants 170 thousand years ago,” says Professor Lyn Wadley, a scientist from the Wits Evolutionary Studies Institute at the University of the Witwatersrand, South Africa (Wits ESI). “This discovery is much older than earlier reports for cooking similar plants and it provides a fascinating insight into the behavioural practices of early modern humans in southern Africa. It also implies that they shared food and used wooden sticks to extract plants from the ground.”

“It is extraordinary that such fragile plant remains have survived for so long,” says Dr. Christine Sievers, a scientist from the University of the Witwatersrand, who completed the archaeobotanical work with Wadley. The underground food were uncovered during excavations at Border Cave in the Lebombo Mountains (on the border of KwaZulu-Natal Province, South Africa, and eSwatini [formerly Swaziland]), where the team has been digging since 2015. During the excavation, Wadley and Sievers recognised the small, charred cylinders as rhizomes. All appear to belong to the same species, and 55 charred, whole rhizomes were identified as Hypoxis, commonly called the Yellow Star flower. “The most likely of the species growing in KwaZulu-Natal today is the slender-leafed Hypoxis angustifolia that is favoured as food,” adds Sievers. “It has small rhizomes with white flesh that is more palatable than the bitter, orange flesh of rhizomes from the better known medicinal Hypoxis species (incorrectly called African Potato).”

The Border Cave plant identifications were made on the size and shape of the rhizomes and on the vascular structure examined under a scanning electron microscope. Modern Hypoxis rhizomes and their ancient counterparts have similar cellular structures and the same inclusions of microscopic crystal bundles, called raphides. The features are still recognisable even in the charred specimens. Over a four-year period, Wadley and Sievers made a collection of modern rhizomes and geophytes from the Lebombo area. “We compared the botanical features of the modern geophytes and the ancient charred specimens, in order to identify them,” explains Sievers.

Hypoxis rhizomes are nutritious and carbohydrate-rich with an energy value of approximately 500 KJ/100g. While they are edible raw, the rhizomes are fibrous and have high fracture toughness until they are cooked. The rhizomes are rich in starch and would have been an ideal staple plant food. “Cooking the fibre-rich rhizomes would have made them easier to peel and to digest so more of them could be consumed and the nutritional benefits would be greater,” says Wadley.

<div data-thumb="https://scx1.b-cdn.net/csz/news/tmb/2020/1-earlymodernh.jpg" data-src="https://scx2.b-cdn.net/gfx/news/hires/2020/1-earlymodernh.jpg" data-sub-html="Hypoxis angustifolia growth habit. Credit: Prof. Lyn Wadley/Wits University”>

<img src="https://scx1.b-cdn.net/csz/news/800/2020/1-earlymodernh.jpg" alt="Early modern humans cooked starchy food in South Africa, 170,000 years ago" title="Hypoxis angustifolia growth habit. Credit: Prof. Lyn Wadley/Wits University”>
Hypoxis angustifolia growth habit. Credit: Prof. Lyn Wadley/Wits University

Wooden digging sticks used to extract the plants from the ground

“The discovery also implies the use of wooden digging sticks to extract the rhizomes from the ground. One of these tools was found at Border Cave and is directly dated at circa 40,000 years ago,” says co-author of the paper and co-director of the excavation, Professor Francesco d’Errico, (Centre National de la Recherche Scientifique (CNRS), Université de Bordeaux, France and University of Bergen, Norway). Dr. Lucinda Backwell (Instituto Superior de Estudios Sociales, ISES-CONICET, Tucumán, Argentina) also co-authored the paper and was a co-director of the excavation.

The plants were cooked and shared

The Hypoxis rhizomes were mostly recovered from fireplaces and ash dumps rather than from surrounding sediment. “The Border Cave inhabitants would have dug Hypoxis rhizomes from the hillside near the cave, and carried them back to the cave to cook them in the ashes of fireplaces,” says Wadley. “The fact that they were brought back to the cave rather than cooked in the field suggests that food was shared at the home base. This suggests that the rhizomes were roasted in ashes and that, in the process, some were lost. While the evidence for cooking is circumstantial, it is nonetheless compelling.”

Early modern humans cooked starchy food in South Africa, 170,000 years ago
Border Cave entrance in the Lebombo Mountains, South Africa. Credit: Ashley Kruger

Discoveries at Border Cave

This new discovery adds to the long list of important finds at Border Cave. The site has been repeatedly excavated since Raymond Dart first worked there in 1934. Amongst earlier discoveries were the burial of a baby with a Conus seashell at 74,000 years ago, a variety of bone tools, an ancient counting device, ostrich eggshell beads, resin, and poison that may once have been used on hunting weapons.

The Border Cave Heritage Site

Border Cave is a heritage site with a small site museum. The and museum are open to the public, though bookings are essential [Olga Vilane (+27) (0) 72 180 4332]. Wadley and her colleagues hope that the Border Cave discovery will emphasise the importance of the site as an irreplaceable cultural resource for South Africa and the rest of the world.

About Hypoxis angustifolia

Hypoxis angustifolia is evergreen, so it has visibility year-round, unlike the more common deciduous Hypoxis species. It thrives in a variety of modern habitats and is thus likely to have had wide distribution in the past as it does today. It occurs in sub-Saharan Africa, south Sudan, some Indian Ocean islands, and as far afield as Yemen. Its presence in Yemen may imply even wider distribution of this Hypoxis plant during previous humid conditions. Hypoxis angustifolia rhizomes grow in clumps so many can be harvested at once. “All of the rhizome’s attributes imply that it could have provided a reliable, familiar food source for early humans trekking within Africa, or even out of Africa,” said Lyn Wadley. Hunter-gatherers tend to be highly mobile so the wide distribution of a potential staple plant food would have ensured food security.


Explore further

Archaeologists and anthropologists peer into original homes of the past to see what made us who we are today


More information:
L. Wadley el al., “Cooked starchy rhizomes in Africa 170 thousand years ago,” Science (2019). science.sciencemag.org/cgi/doi … 1126/science.aaz5926

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A TV satellite is about to explode following 'irreversible' battery damage – Space.com

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Following an unexplained accident, a satellite built by Boeing and operated by DirecTV is at risk of exploding in the coming weeks. To mitigate potential damage to other satellites, the U.S. government will allow the satellite TV provider to move the doomed craft to a higher orbit ahead of schedule.

The satellite, called Spaceway-1, has been orbiting some 22,000 miles (35,400 kilometers) above Earth since 2005, providing high-definition television coverage for many years before being demoted to a backup satellite. (Currently, it is not providing any coverage for customers.) 

In December 2019, the craft experienced a “major anomaly” that resulted in “irreversible thermal damage” to its batteries, DirecTV officials wrote last week in a filing to the U.S. Federal Communications Commission (FCC). While Spaceway-1 has relied on its solar panels for power in recent months, the craft will soon enter its “eclipse season” — a period when the satellite hovers in Earth’s shadow — and the batteries must be activated. When this season begins on Feb. 25, company representatives wrote, the damaged batteries will likely explode upon activation, destroying the satellite and putting other nearby satellites at risk. 

Related: The Top 10 Greatest Explosions Ever

The satellite follows a geostationary orbit (meaning it appears to stay put over one particular part of Earth as it rotates), which is the highest orbit possible for in-use satellites. Because of the craft’s high location, redirecting the craft downward — where other in-use satellites are circling — so that it may eventually burn up in the atmosphere is not a viable option. Instead, on Jan. 19, DirecTV requested that the FCC allow the company to relocate the satellite to a higher orbit known as the “graveyard orbit,” roughly 185 miles (300 km) above its current path, where, hopefully, Spaceway-1 can explode in peace.

Normally, decommissioning a satellite involves releasing all of the satellite’s remaining propellant — a process that can take months, depending on how much fuel is left in the tank. Spaceway-1 doesn’t have months to spare; according to the FCC filing, there’s only enough time to release a “nominal” amount of the satellite’s remaining fuel if the craft is to be moved to that great graveyard in the sky before exploding.

The FCC approved DirecTV’s request to decommission Spaceway-1 ahead of schedule and gave the company a waiver to ignore the propellant-depletion rule. According to AT&T, the parent company of DirecTV, the soon-to-explode satellite “is a backup and we do not anticipate any impacts on consumer service as we retire it.” 

RIP, Spaceway-1. May your broken body rust in peace in the quiet of space.

Originally published on Live Science.

Want more science? Get a subscription of our sister publication “How It Works” magazine, for the latest amazing science news.  (Image credit: Future plc)

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Stennis Space Center sets stage for Artemis testing in 2020 – Space Daily

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All eyes are on south Mississippi with this month’s delivery and installation of NASA’s Space Launch System (SLS) rocket’s first core stage to Stennis Space Center for a milestone Green Run test series prior to its Artemis I flight.

The Green Run testing will be the first top-to-bottom integrated testing of the stage’s systems prior to its maiden flight. The testing will be conducted on the B-2 Test Stand at Stennis, located near Bay St. Louis, Mississippi, and the nation’s largest rocket propulsion test site. Green Run testing will take place over several months and culminates with an eight-minute, full-duration hot fire of the stage’s four RS-25 engines to generate 2 million pounds of thrust, as during an actual launch.

“This critical test series will demonstrate the rocket’s core stage propulsion system is ready for launch on missions to deep space,” Stennis Director Rick Gilbrech said. “The countdown to this nation’s next great era of space exploration is moving ahead.”

NASA is building SLS as the world’s most-powerful rocket to return humans to deep space, to such destinations as the Moon and Mars. Through the Artemis program, NASA will send the first woman and next man to the Moon by 2024. Artemis I will be a test flight without crew of the rocket and its Orion spacecraft. Artemis II will carry astronauts into lunar orbit. Artemis III will send astronauts to the surface of the Moon.

The SLS core stage, the largest rocket stage ever built by NASA, stands 212 feet tall and measures 27.6 feet in diameter. It is equipped with state-of-the-art avionics, miles of cables, propulsion systems and propellant tanks that hold a total of 733,000 gallons of liquid oxygen and liquid hydrogen to fuel the four RS-25 engines during launch. The core stage was designed by NASA and Boeing in Huntsville, Alabama, then manufactured at NASA’s Michoud Assembly Facility in New Orleans by lead contractor Boeing, with input and contributions from more than 1,100 large and small businesses in 44 states.

“Delivering the Space Launch System rocket core stage to Stennis for testing is an epic historical milestone,” said Julie Bassler, the SLS stages manager. “My team looks forward to bringing this flight hardware to life and conducting this vital test that will demonstrate the ability to provide 2 million pounds of thrust to send the Artemis I mission to space.”

The stage was transported from Michoud to Stennis aboard the specially outfitted Pegasus barge. It arrived at the B-2 dock on Jan. 12 and was rolled out onto the test stand tarmac that night. Crews then began installing ground equipment needed for lifting the stage into a vertical position and onto the stand.

The lift was performed Jan. 21-22, which provided optimal weather and wind conditions. Crews now will fully secure the stage in place and to stand systems for testing.

NASA completed extensive modifications to prepare the B-2 stand for the test series. The stand has a notable history, having been used to test Saturn V stages that helped launch astronauts to the Moon as part of the Apollo Program and the three-engine propulsion system of the space shuttle prior to its first flight.

Preparing the stand for SLS core stage testing required upgrades of every major system on the stand, as well as the high pressure system that provides hundreds of thousands of gallons of water needed during a test. It also involved adding 1 million pounds of fabricated steel to the Main Propulsion Test Article framework that will hold the mounted core stage and extending the large derrick crane atop the stand that will be used to lift the SLS stage into place.

Once installed on the stand, operators will begin testing each of the stage’s sophisticated systems. Among other things, they will power up avionics; conduct main propulsion system and engine leak checks; and check out the hydraulics system and the thrust vector control unit that allows for rotating the engines to direct thrust and “steer” the rocket’s trajectory.

They also will conduct a simulated countdown, as well as a “wet dress rehearsal,” in which propellants are loaded and flow throughout the stage system. The rehearsal exercise will end just prior to engine ignition, with the full four-engine hot fire to come in subsequent days.

After the hot fire test, crews plan to perform refurbishment work on the stage and inspect and configure it for shipment to Kennedy Space Center. The stage will be removed from the stand, lowered to its horizontal position on the tarmac and reloaded into Pegasus for the trip to Florida.

At Kennedy, the stage will be joined with other SLS elements and prepared for launch. The next time its four RS-25 engines fire, Artemis I will be taking flight.

Related Links

Space Launch System,

Rocket Science News at Space-Travel.Com


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ROCKET SCIENCE
Russia to supply US with six RD-180 rocket engines this year

Moscow (Sputnik) Jan 23, 2020


Russian rocket engine manufacturer NPO Energomash plans to ship six RD-180 rocket engines to the United States this year, government procurement website data shows.

The RD-180 engines will be used to power the first stage of the Atlas V launch vehicles.

In December, Energomash said that it shipped a total of six RD-180 rocket engines to the United States in 2019.

In October, Roscosmos subsidiary Energomash was preparing to deliver three more RD-180 engines for use with Atlas V launch v … read more


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IceCube rules out last Standard Model explanation of ANITA's anomalous neutrino events – Tdnews

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IceCube rules out last Standard Model explanation of ANITA’s anomalous neutrino events

The IceCube Neutrino Observatory is possibly the strangest telescope on Earth. From its home at the South Pole, it sits and waits for fundamental particles called neutrinos to pass through its 5,160 optical detectors buried in the ice. When a neutrino interacts with a hydrogen or oxygen atom in the ice, it produces a signal that IceCube can detect.

But IceCube isn’t the only neutrino experiment in Antarctica. There is also the ANITA (the ANtarctic Impulsive Transient Antenna) experiment, which flies a balloon over the continent and points radio antennae toward the ground. ANITA searches for radio waves because extremely high-energy neutrinos—those hundreds of times more energetic than the ones that IceCube commonly detects—can produce intense radio signals when they smash into an atom in the ice.

From its balloon flights, ANITA claimed to have detected a few events that appear to be signals of these extremely high-energy neutrinos, so the IceCube Collaboration decided to investigate. In a paper submitted today to The Astrophysical Journal, they outline their search for an intense neutrino source in the direction of the events detected by ANITA. The collaboration found that these neutrinos could not have come from an intense point source. Other explanations for the anomalous signals—possibly involving exotic physics—need to be considered.

When ANITA reported signals that looked like extremely high-energy neutrinos, physicists were puzzled. These neutrinos had arrived at an angle that suggested they had just traveled through most of the planet, which is not expected for neutrinos at these energies.

“It’s commonly said that neutrinos are ‘elusive’ or ‘ghostly’ particles because of their remarkable ability to pass through material without smashing into something,” says Alex Pizzuto of the University of Wisconsin–Madison, one of the leads on this paper. “But at these incredible energies, neutrinos are like bulls in a china shop—they become much more likely to interact with particles in Earth.”

Many scientists have since come up with potential explanations for these weird signals, and one possibility is that a really intense neutrino source produced them. After all, if a source produced huge numbers of neutrinos, it is more plausible that one or two made it to ANITA.

So Pizzuto and his collaborators decided to see whether there was an intense neutrino source shooting a beam of neutrinos toward Earth—a point source. To do this, the researchers took eight years of IceCube data and looked for correlations between the locations of the ANITA events and the locations of the IceCube events.

Since the researchers could not know how long a potential point source might have been emitting neutrinos, their analyses used three different and complementary approaches equipped to find coincidences on different timescales. Their analyses also had to account for uncertainty in the ANITA events’ directions because the events do not have definite positions on the sky.

Once they had addressed those challenges, the researchers simulated neutrinos passing through Earth to see how many incident neutrinos would be necessary for ANITA to see one event, and they then did the same for IceCube.

In all three searches, they found no evidence for a neutrino source in the direction of the strange ANITA events. This is particularly intriguing because, due to a process called tau neutrino regeneration, the extremely high-energy events that don’t make it all the way to ANITA should still be detectable by IceCube.

“This process makes IceCube a remarkable tool to follow up the ANITA observations, because for each anomalous event that ANITA detects, IceCube should have detected many, many more—which, in these cases, we didn’t,” says Anastasia Barbano of the University of Geneva in Switzerland, another lead on this paper. “That means that we can rule out the idea that these events came from some intense point source, because the odds of ANITA seeing an event and IceCube not seeing anything are so slim.”

When the ANITA events were detected, the main hypotheses were an astrophysical explanation (like an intense neutrino source), a systematics error (like not accounting for something in the detector), or physics beyond the Standard Model. “Our analysis ruled out the only remaining Standard Model astrophysical explanation of the anomalous ANITA events,” says Pizzuto. “So now, if these events are real and not just due to oddities in the detector, then they could be pointing to physics beyond the Standard Model.”

Ibrahim Safa of UW–Madison, another lead on this paper, says that while it has been an exciting time for physicists trying to explain these events, “it looks like we’ll have to wait for the next generation of experiments, which will increase exposure and sensitivity, to get a clear understanding of this anomaly.”

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