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What Killed the Neanderthals?

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Neanderthals, our closest extinct relatives, roamed the Earth for about 300,000 years. They hunted, made tools, and lived amongst one another in complex social groups. But about 40,000 years ago, they disappeared.

What killed them has been a topic of tense debate for some years. “The issue of Neanderthal extinction is very complex, and very little is agreed upon,” Anna Goldfield, a doctoral candidate in archaeology at Boston University, told LiveScience. Was it climate change? Or a volcanic eruption? One theory even suggests that Neanderthals’ big eyes are to blame for their downfall.

But most researchers agree that modern humans had something to do with it. Indeed, within just 5,000 years of our arrival, Neanderthals had vanished. A new theory suggests that our mastery of fire is the key to why we thrived while they did not. “Fire use would have provided a significant advantage for the human population,” Goldfield said at the annual meeting of the Society for American Archaeology. 

leted, Flickr // CC BY-NC 2.0

Aside from keeping us warm, fire allowed us to cook food, which has huge benefits, according to The Economist

“Cooking alters food in three important ways. It breaks starch molecules into more digestible fragments. It ‘denatures’ protein molecules, so that their amino-acid chains unfold and digestive enzymes can attack them more easily. And heat physically softens food. That makes it easier to digest, so even though the stuff is no more calorific, the body uses fewer calories dealing with it.”

It’s not that Neanderthals didn’t use fire — some of them did. Despite their historical portrayal as dimwitted cavemen, these hominids were masters of tool use, and archaeologists think they created sparks by striking flint against iron pyrite. And they did use fire to heat some of their meals. They even cooked with herbs

But Neanderthals may not have made use of flame as regularly or as efficiently as our ancestors did, according to archaeologist Dennis Sandgathe. Early modern human bodies were smaller and more efficient, which meant that cooked food was more beneficial for them. And the more that modern humans utilized the power of flame, “the more likely the human population was to increase slightly.” Over time, this disadvantage may have sealed the Neanderthals' fate.

As archaeologists continue to investigate, we’ll learn more about what really killed off our hominid relatives. “I suspect genetics will help,” says Richard Wrangham, an anthropologist at Harvard. “If we can pin down the genes underlying the adaptation to cooked food, we may be able to date the control of fire close enough to settle the big question.” Either way, the next time you turn your oven on to cook dinner, give thanks to the first modern humans for keeping the fire burning.

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Space
Look Up! The Orionid Meteor Shower Peaks This Weekend
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Ethan Miller/Getty Images

October is always a great month for skywatching. If you missed the Draconids, the first meteor shower of the month, don't despair: the Orionids peak this weekend. It should be an especially stunning show this year, as the Moon will offer virtually no interference. If you've ever wanted to get into skywatching, this is your chance.

The Orionids is the second of two meteor showers caused by the debris field left by the comet Halley. (The other is the Eta Aquarids, which appear in May.) The showers are named for the constellation Orion, from which they seem to originate.

All the stars are lining up (so to speak) for this show. First, it's on the weekend, which means you can stay up late without feeling the burn at work the next day. Tonight, October 20, you'll be able to spot many meteors, and the shower peaks just after midnight tomorrow, October 21, leading into Sunday morning. Make a late-night picnic of the occasion, because it takes about an hour for your eyes to adjust to the darkness. Bring a blanket and a bottle of wine, lay out and take in the open skies, and let nature do the rest.

Second, the Moon, which was new only yesterday, is but a sliver in the evening sky, lacking the wattage to wash out the sky or conceal the faintest of meteors. If your skies are clear and light pollution low, this year you should be able to catch about 20 meteors an hour, which isn't a bad way to spend a date night.

If clouds interfere with your Orionids experience, don't fret. There will be two more meteor showers in November and the greatest of them all in December: the Geminids.

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science
11-Year-Old Creates a Better Way to Test for Lead in Water
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In the wake of the water crisis in Flint, Michigan, a Colorado middle schooler has invented a better way to test lead levels in water, as The Cut reports.

Gitanjali Rao, an 11-year-old seventh grader in Lone Tree, Colorado just won the 2017 Discovery Education 3M Young Scientist Challenge, taking home $25,000 for the water-quality testing device she invented, called Tethys.

Rao was inspired to create the device after watching Flint's water crisis unfold over the last few years. In 2014, after the city of Flint cut costs by switching water sources used for its tap water and failed to treat it properly, lead levels in the city's water skyrocketed. By 2015, researchers testing the water found that 40 percent of homes in the city had elevated lead levels in their water, and recommended the state declare Flint's water unsafe for drinking or cooking. In December of that year, the city declared a state of emergency. Researchers have found that the lead-poisoned water resulted in a "horrifyingly large" impact on fetal death rates as well as leading to a Legionnaires' disease outbreak that killed 12 people.

A close-up of the Tethys device

Rao's parents are engineers, and she watched them as they tried to test the lead in their own house, experiencing firsthand how complicated it could be. She spotted news of a cutting-edge technology for detecting hazardous substances on MIT's engineering department website (which she checks regularly just to see "if there's anything new," as ABC News reports) then set to work creating Tethys. The device works with carbon nanotube sensors to detect lead levels faster than other current techniques, sending the results to a smartphone app.

As one of 10 finalists for the Young Scientist Challenge, Rao spent the summer working with a 3M scientist to refine her device, then presented the prototype to a panel of judges from 3M and schools across the country.

The contamination crisis in Flint is still ongoing, and Rao's invention could have a significant impact. In March 2017, Flint officials cautioned that it could be as long as two more years until the city's tap water will be safe enough to drink without filtering. The state of Michigan now plans to replace water pipes leading to 18,000 households by 2020. Until then, residents using water filters could use a device like Tethys to make sure the water they're drinking is safe. Rao plans to put most of the $25,000 prize money back into her project with the hopes of making the device commercially available.

[h/t The Cut]

All images by Andy King, courtesy of the Discovery Education 3M Young Scientist Challenge.

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