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A meteor streaks across the sky during the annual Perseid meteor shower on Friday, Aug. 12, 2016 in West Virginia. Image credit: Bill Ingalls, NASA

The 2020 Perseid meteor shower peaks tonight

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<p>There were nights every August and November when I couldn’t sleep.</p><p>My dad would bundle me in my sleeping bag—a forest green junior rendition of his own—and carry me to a lawn chair outside. He’d put a cup of steaming hot chocolate in my hand. Together, we’d wait for the show to begin.</p><p>These nights were not<a href="https://www.pbs.org/wgbh/nova/article/sleep-deprivation-anxiety/"> bouts of insomnia</a> fought off with fresh air. My six-year-old self and my dad <i>chose</i> to stay up until the early hours of the morning. In November, when the <a href="https://solarsystem.nasa.gov/asteroids-comets-and-meteors/meteors-and-meteorites/leonids/in-depth/">Leonid meteor showers</a> were in full bloom, I’d sleep from 3-6 a.m. and scramble off to school red-eyed. In August, after watching the Perseids perform for hours, I’d sleep in like a teenager.</p><p>I credit these spectacles, put on by the cosmos twice a year, for my unending passion for science and understanding the world around us.</p><p>I may not be alone. The Perseid meteor shower, which peaks overnight from 2 a.m. to dawn local time, is one of the most popular of the year, Rachel Treisman<a href="https://www.npr.org/2020/08/11/901094691/perseid-meteor-shower-peaks-after-midnight-nasa-says-its-one-of-the-best"> reports for NPR</a>: Warmer summer temperatures and high rates of meteors are hard for astronomy aficionados to resist. If you’re able, find a spot away from city lights, lie on your back or sit in a camping chair, and gaze toward the night sky. Meteors will appear like faint streaks of light that gradually fade within moments.</p><p>Meteors form when meteoroids, objects in space that range in size from dust grains to about 80-foot asteroids, <a href="https://www.pbs.org/wgbh/nova/article/cone-meteorites/">enter Earth’s atmosphere</a> at high speed and burn up.</p><p>Debris left behind by the ancient <a href="https://solarsystem.nasa.gov/asteroids-comets-and-meteors/comets/109p-swift-tuttle/in-depth/">comet Swift-Tuttle </a>creates the Perseid meteors. Every year in August, Earth ventures through trails of this debris. “NASA says it's ‘one of the best’ meteor shows of the year. That's because of the sheer number of meteors<b>—</b>50 to 100 meteors to catch per hour as well as their <a href="https://solarsystem.nasa.gov/asteroids-comets-and-meteors/meteors-and-meteorites/perseids/in-depth/">fireballs</a>—larger, brighter explosions of light and color that last longer than an average meteor streak,” Treisman writes.</p>
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<p>Unfortunately, this year’s shower will be somewhat impeded by the Moon, which is currently in its last quarter phase. This will limit observers’ view of the shower peak, “reducing the visible meteors from over 60 per hour down to 15-20 per hour,” Emily Clay<a href="https://blogs.nasa.gov/Watch_the_Skies/2020/08/06/perseids-peak-watch-best-meteor-shower-of-the-year/"> reports for NASA</a>. “But the Perseids are rich in bright meteors and fireballs, so it will still be worth going out in the early morning to catch some of nature’s fireworks.”</p><p>With<a href="https://www.space.com/comet-neowise-is-dimming.html"> Comet NEOWISE</a> now making a 6,800-year exit from our solar system and a global pandemic still very much underway, any meteor shower spectacle is better than none. I think my six-year-old self would agree.</p>
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<p>Here’s how to watch and what you’ll see.</p>

Members of the Iowa Air National Guard remove trees limbs near downed power lines in Cedar Rapids, Iowa on August 18, 2020, eight days after a powerful derecho hit the Midwest. Image credit: Senior Master Sgt. Vincent De Groo, U.S. Air National Guard

Inside the derecho that pummeled the Midwest

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<p>A global pandemic. Forest fires in the West. And now a derecho.</p><p>On the evening of Monday, August 10, a weather complex known as a “derecho” sent intense winds and thunderstorms over a 700-mile stretch from Nebraska to Indiana. In Iowa, the hardest-hit state, <a href="https://apnews.com/d44fdc171bf64a11981cec69e39390a9">three deaths have been reported</a> so far and hundreds of thousands of people went without power for days. More than 40% of the state’s corn and soybean crop, the core of Iowa’s economy, was severely damaged by the storm, whose winds reached 110-140 mph, equivalent to those of a Category 3 or 4 hurricane. Patrick Marsh, science support chief at the National Weather Service’s Storm Prediction Center in Norman, Oklahoma compared it to the devastating <a href="https://www.spc.noaa.gov/misc/AbtDerechos/casepages/may82009page.htm">“Super Derecho” of 2009</a>, which extended from Kansas to Tennessee.</p><p>Destruction to Iowa’s homes, farms, businesses, livestock, and crops translates to a $4 billion hit, Donnelle Eller reports for the <a href="https://www.desmoinesregister.com/story/money/agriculture/2020/08/17/derecho-damage-homes-farms-push-higher-than-iowas-4-billion-estimate/5598590002/">Des Moines Register</a>.</p><p>Cedar Rapids was one of the hardest hit cities in the state. More than 800 buildings suffered partial collapse of the roof, walls, ceiling, or floors, and more than 20 schools sustained damage, Cedar Rapids Fire Chief Greg Smith tells CNN.</p><p>“Nearly every home has damage. Most big trees in the city fell. Most local businesses are closed. Every business is damaged. Most roads are impassable,” <a href="https://medium.com/@bjkap/its-worse-in-cedar-rapids-than-you-know-33b4c9b9c7fe">writes Cedar Rapids resident</a> Ben Kaplan on Medium.</p><p>“Our city of Cedar Rapids has been destroyed by a Derecho, a term for a type of storm I’ve never heard of and never want to hear of again,” one <a href="https://twitter.com/WadeNJerry/status/1295434198485000196">Iowa resident tweeted</a>.</p><p>Though derechos are often referred to as “inland hurricanes” because of their extreme rainfall and winds that can exceed the hurricane threshold of 74 mph, “that is where the similarities end,” Marshall Shepherd, director of University of Georgia’s Atmospheric Sciences Program <a href="https://www.forbes.com/sites/marshallshepherd/2020/08/18/a-derecho-is-not-an-inland-hurricane-but-does-it-matter-what-people-call-it/#36b40a10199a">writes for Forbes</a>.</p><p>The National Oceanic and Atmospheric Association <a href="https://www.nssl.noaa.gov/education/svrwx101/wind/types/">defines a derecho</a> as a widespread, long-lived wind storm associated with a band of rapidly moving showers or thunderstorms. Though the damage they can create can be similar to damage inflicted by tornadoes, there’s a key difference: Unlike the spiraling winds and winding paths of twisters, derechos tend to move in one direction along a relatively straight line. Thus their path of destruction is also relatively linear.</p><p>“Meteorologists like me will often refer to this hazard as ‘straight-line wind damage,’”<a href="https://www.forbes.com/sites/marshallshepherd/2020/08/10/what-is-a-derecho/#32c400593b8e"> Shepherd writes</a>. Much like blizzards, he adds, derechos are defined by very specific criteria. For a storm to be considered one, it must have wind gusts at or greater than 58 mph, pockets of 75 mph or greater gusts, and cause a band of wind damage that is greater than 250 miles long.</p><p>In the Eastern half of the United States, one derecho is expected to occur between every .75 and 4 years, depending on the location. Researchers aren’t yet sure whether climate change is affecting derechos or the frequency at which they occur. Warming global temperatures may actually inhibit the cooler temperature gradients that derecho-producing thunderstorms need to grow. What’s more certain, NOAA states, is that climate change is causing the jetstream to move toward the pole. So it’s likely that derechos will shift poleward in a warming world, too.</p>
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<img alt="" class="richtext-image full-width" src="https://www.pbs.org/wgbh/nova/media/images/Derechoclimo.width-990_NY9HfyR.png"/>
<figcaption><p>Derecho frequency for the lower 48 United States. Derechos in North America form predominantly from April to August, peaking in frequency from May into July. Image credit: Wikimedia commons</p>
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<p>The storms associated with derechos can be arranged in a line and be accompanied by squalls of high wind and heavy rain (a “squall line”) or like the curve of a boomerang (a “bow echo”), Shepherd writes. Collectively, squall lines, bow echoes, and other types of thunderstorms that act as a single system are called “<a href="https://www.nssl.noaa.gov/education/svrwx101/thunderstorms/types/">mesoscale convective systems</a>.”</p><p>On August 10 in Iowa, swaths of 90 to 100 mph winds may have been between 30 and 50 miles wide at times, radar signatures indicate. In Marshalltown, a community of 27,000 people northeast of Des Moines, a personal weather station measured a 106-mph gust of wind, Matthew Cappucci <a href="https://www.washingtonpost.com/weather/2020/08/12/iowa-derecho-corn-damage/">reports for the Washington Post</a>; in Midway, a town just north of Cedar Rapids, winds clocked in at an alarming 112 mph.</p><p></p>
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<p>Thousands of Iowans remained without power and dozens were in shelters as of Thursday, August 20. And then there’s the damage to Iowa’s agriculture, which approximately 90% of the state’s land is dedicated to. Iowa has been the number-one corn producer in the United States for the past 26 years, and experts can’t yet tell the extent of the derecho’s destruction to this year’s crop. “A lot of the corn is in the later development stages,” Keely Coppess, communications director for the Iowa Agriculture Department, tells the Washington Post. “Some is at a 45-degree angle, but it may attempt to stand back up. But it’s really too soon to tell.”</p><p>Now, volunteers are now traveling from out of town to assist with cleanup efforts in Cedar Rapids. Among the volunteers are Dave and Diane Lobermeier from Amherst, Wisconsin, about 300 miles away.</p><p>“We’re retired so we decided we’ll take some time and pack up and come,” Diane tells Cedar Rapids’ local news station KCRG, adding that it’s “the right thing to do.” She and her husband Dave came armed with donations and a chainsaw.</p><p>“They found Pete Martin, from North Liberty, wanting to help, too,” Aaron Scheinblum<a href="https://www.kcrg.com/2020/08/17/volunteers-traveling-from-out-of-town-to-help-cleanup-efforts-in-cedar-rapids/"> reports for KCRG</a>. “‘I feel like we all have a part to make a difference and help recover from this, so this is what I’m going to do,’ Martin said.”</p>
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<p>On August 10, a weather complex known as a “derecho” sent intense winds and thunderstorms over a 700-mile stretch from Nebraska to Indiana. Now, Iowa works to recover from its damage.</p>

Chadwick Boseman speaks at the 2017 San Diego Comic Con International for "Black Panther." Boseman died of colon cancer on August 28, 2020 at age 43. Image credit: Gage Skidmore

Chadwick Boseman and the rise of colon cancer in young adults

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<p>On Friday, August 28, actor Chadwick Boseman died at age 43 of colon cancer.</p><p>Perhaps best known for his role as King T’Challa in “Black Panther,” the actor starred in numerous other Avengers movies, “21 Bridges,” “Da 5 Bloods,” and a not-yet-released adaptation of “Ma Rainey’s Black Bottom.” This “superstar run” of back-to-back productions “seems all the more miraculous in light of the knowledge that Boseman pulled it off while quietly undergoing many surgeries and rounds of chemotherapy,” David Sims<a href="https://www.theatlantic.com/culture/archive/2020/08/chadwick-boseman/615868/?utm_source=feed"> writes for The Atlantic</a>.</p><p>The cancer that killed Boseman is the second-leading cause of cancer deaths in the United States after lung cancer. And although the majority of colon cancer cases are found in older adults, rates are rising among young people.</p><p>In July 2019, University of Texas at Austin researchers reported that “the proportion of newly diagnosed colorectal patients under age 50 <a href="https://onlinelibrary.wiley.com/doi/full/10.1002/cncr.32347">rose from 10 percent in 2004 to 12.2 percent in 2015</a>. Younger patients were also likely to have advanced cases more often than older patients,” Knvul Sheikh <a href="https://www.nytimes.com/2019/07/31/health/colon-cancer-young.html">writes for the New York Times</a>. (Colorectal cancer includes illness in which tumors are present in the rectum or the colon.) According to the <a href="https://www.cancer.org/latest-news/colorectal-cancer-rates-rise-in-younger-adults.html">American Cancer Society</a>, about 18,000 people under 50 will be diagnosed with colon cancer in 2020.</p><p>Data from Canadian national cancer registries illustrate a similar trend in colorectal cancer rates in younger adults. Colorectal cancer rates increased by 3.47% among Canadian men under age 50 between 2006 and 2015, and by 4.4% among Canadian women under age 50 from 2010 to 2015.</p>
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<img alt="" class="richtext-image full-width" src="https://www.pbs.org/wgbh/nova/media/images/Sessile_Serrated_Polyps.width-990_gKqMmGj.jpg"/>
<figcaption><p>Micrograph of a colorectal sessile serrated lesion, which is most commonly seen in the cecum and ascending colon, and has the potential to lead to colorectal cancer. Image credit: Nephron, Wikimedia Commons</p>
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<p>While older patients undergo regular screenings like colonoscopies, which help flag the disease in its early stages so that doctors can remove polyps before cancer develops (colorectal cancer rates have been declining among people over 65, likely because of more regular screenings), neither younger adults nor their healthcare providers are actively on the hunt for colon cancer, Kat Eschner<a href="https://www.popsci.com/story/health/colon-cancer-young-people/"> reports for Popular Science</a>. Therefore, younger patients are often diagnosed at the later stages of the disease and are more likely to die from their illness, whether or not their cancer is more aggressive than an older patient’s.</p><p>Experts aren’t yet sure why colon cancer rates are increasing among younger Americans and Canadians, but lifestyle changes may be a contributor. “Obesity and sedentary lifestyles, for example, are linked to colorectal cancer, as are poor diets low in fiber,” Sheikh writes. But experts are not entirely convinced these are the only factors at work. Trends in obesity among people of different ethnic and racial backgrounds don’t always correspond to an increase in colorectal cancer, Rebecca Siegel, an epidemiologist at the American Cancer Society Patients, told Sheikh.</p><p>Patients with <a href="https://www.gastrojournal.org/article/S0016-5085(11)00170-3/fulltext?referrer=https%3A%2F%2Fwww.ncbi.nlm.nih.gov%2F">chronic inflammation</a> or <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5392343/">Type 2 diabetes</a> have also been found to be at increased risk for colon cancer. According to the National Institutes of Health, because of genetic traits, insulin resistance, and the prevalence of obesity—explained at least in part by<a href="https://www.pbs.org/wgbh/nova/article/racism-stress-covid-allostatic-load/"> systematic racism and allostatic load</a>—African Americans have a<a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1743410/"> high risk for type 2 diabetes</a>.</p>
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<p>As a Black man, Boseman belonged to the demographic of people who have the highest rates of colorectal cancer. In another major healthcare inequity, African Americans, particularly men, are more likely to be diagnosed at a younger age relative to other diagnoses, Eschner writes for Popular Science. And Black Americans are less likely to be screened early and are more likely to die of the disease, research <a href="https://www.asge.org/docs/default-source/education/practice_guidelines/piis0016510717318059.pdf?sfvrsn=0">shows</a>.</p><p>At the Center for Young Onset Colorectal Cancer at Memorial Sloan Kettering Cancer Center, which was opened in 2018 to treat younger patients and study the reasons for their diagnoses, Co-Director Dr. Robin B. Mendelsohn and her colleagues “are exploring whether diet, medications like antibiotics, and the microbiome — which have all changed significantly for generations born in the 1960s and later — might be contributing to the cancer in younger people,” Pam Belluck<a href="https://www.nytimes.com/2020/08/29/health/colon-cancer-chadwick-boseman.html"> writes for the New York Times</a>.</p><p>As experts attempt to elucidate why colon cancer rates are increasing among young people, physicians should monitor their younger patients for symptoms that might suggest colorectal cancer, Nilofer Azad, a professor of gastrointestinal oncology at Johns Hopkins University, tells Popular Science. In this population, Eschner writes, symptoms like bloody stool, unexpected weight loss, and prolonged cramping can be overlooked or misdiagnosed as conditions like hemorrhoids.</p><p>Moving forward, better understanding and detection of colon cancer are crucial. But Boseman’s story and his legacy—an incredible collection of films created in a mere 7 years—also illustrate something else: a continued need to address systemic inequities in health care and beyond.</p>
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<p>Colorectal cancer is the second-leading cause of cancer deaths in the United States. Boseman’s case illustrates the importance of more screening—and addressing systemic inequities in health care.</p>

A close-up of Ingenuity taken on April 5 by Mastcam-Z, a pair of zoomable cameras aboard the Perseverance rover. Credit: NASA/JPL-Caltech/ASU.

What to expect during NASA’s first-ever Mars helicopter flight

<p>NASA has delayed the first flight of its Ingenuity Mars helicopter, announcing that it expects to set a new date next week.</p><p>The helicopter, which arrived on the red planet tucked inside <a href="https://www.pbs.org/wgbh/nova/article/nasa-perseverance-mars-rover-landing-success/">the Perseverance rover</a> in February, was initially set to fly on Sunday, securing its position as the first rotorcraft to lift off on another world. Late on Friday night, however, a high-speed test of Ingenuity’s rotors <a href="https://mars.nasa.gov/technology/helicopter/status/291/mars-helicopter-flight-delayed-to-no-earlier-than-april-14/">ended early</a>: As the helicopter’s command sequence tried to transition the flight computer from “preflight” to “flight” mode, engineers were alerted to a potential problem. The team has decided to update Ingenuity’s flight control software before attempting a maiden flight.</p><p>During this first flight, the Ingenuity Mars helicopter will lift off, hover 10 feet above the Martian surface, take pictures, and touch back down—all in a period of about 40 seconds. Meanwhile, some 200 feet away, the Perseverance rover will snap pictures and videos of its companion’s brief voyage.</p>
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<p>This first flight will be a modest beginning of a much more ambitious task: In the next 30 days, the Ingenuity team at NASA’s <a href="https://www.jpl.nasa.gov/">Jet Propulsion Laboratory</a> will attempt a total of five flights, each longer and more technical than the last.</p><p>“Each world only gets one first flight,” Ingenuity Project Manager MiMi Aung said during a press conference on Friday. It’s a “historic moment that has analogues in 1903,” NASA’s Associate Administrator for Science Thomas Zurbuchen added, referring to the year the <a href="https://www.pbs.org/wgbh/nova/article/unlikely-inventors/">Wright brothers</a> became the first in the world to fly a motor-operated airplane—after two failed liftoffs.</p><p>“History tells us that Orville and Wilbur took this setback like true engineers,” confirming that their fundamental understanding of flight was correct and going back and making subtle changes, Aung said during Friday’s press conference. Aung believes she and her team have become similarly well-versed in the unique challenges of flying a hovercraft on another planet and are aware that despite years of preparation, something could go wrong when it’s time for the first attempt. “I want to be conservative,” Aung said on Friday, adding the Ingenuity team had yet to celebrate the Mars helicopter’s achievements.</p><p>Perhaps the greatest challenge the team will face is the <a href="https://www.pbs.org/wgbh/nova/video/mars-facts-red-planet/">Martian atmosphere</a>. Made up of mostly carbon dioxide, Mars’ atmosphere is a mere 1% as thick as our own planet’s, which is primarily nitrogen. Its thinness makes it the equivalent of flying at three times the height of Mount Everest, Ingenuity chamber test engineer Amelia Quon said on Friday.</p><p>Rotorcrafts, including helicopters, fly by generating lift. As their blades spin, they push the air and this lifts the craft up, Aung explains. In a thin atmosphere, she says, there are fewer molecules to push, “so you need to spin much faster to get lift,” she says. While the blades of most Earthly helicopters operate at around 450 to 500 revolutions per minute, Ingenuity’s will move at 2,400 rpm.</p><p>Ingenuity’s rotors “are not something off the shelf; they’re really fine-tuned to maximize lift in a really thin atmosphere,” Aung said. Weighing in at about 35 grams, the rotors have a foam core for lightweightedness and are covered in carbon fiber, laid out in a grid, for optimal stiffness and strength.</p><p>Like its blades, the body of the Mars helicopter is also lightweight, at less than four pounds. “We couldn’t make this happen” with technology that existed 10 or 15 years ago, Aung said.</p><p>Mars’ strong winds also pose a challenge. If gusts become too strong before Ingenuity is scheduled to fly, there’s no way of automatically postponing or canceling the flight through Perseverance, Ingenuity Operations Lead Tim Canham explained during Friday’s press conference. This is because the Perseverance rover’s weather-determining system has no connection to Ingenuity. And Ingenuity has no way to right itself; if it fails to land right-side-up during any of its flights, its mission on Mars would end.</p>
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<p>But there’s good news: Martian weather is easy to predict. “Weather on Mars tends to stay the same over a period of sols,” Canham explains. (At 24 hours, 39 minutes, and 35 seconds, a Martian sol is slightly longer than a day on Earth.) The Ingenuity team initially chose 12:30 p.m. Martian time Sunday, the equivalent of 11:00 p.m. EDT, for a potential first liftoff because the team calculated that’s when Ingenuity would have the most charged battery and Mars would have the calmest skies.</p><p>The team started testing in 2014 whether Ingenuity could successfully fly on another planet. We “made Mars on Earth,” Quon said, referring to NASA’s Jet Propulsion Laboratory’s 25-foot space simulator thermal vacuum chamber, which Voyager 1 and 2 were tested in before making their way into space and out of our solar system.</p><p>First, the team used a flight model to illustrate that lift is possible—picture a couple of hops and a crash landing—in a Martian-like environment. Then, in 2018, the team had the model spin up three feet in the air and turn. In 2019, NASA scientists took data from previous tests and applied them to testing the actual Ingenuity Mars helicopter.</p><p>If all goes well, during its first sol after taking to the sky, Ingenuity will transmit its black-and-white photos and flight summary data to Perseverance, which will transmit the data to scientists on Earth. In the following days, scientists expect to receive color imagery and more complex data from the flight.</p>
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<img alt="" class="richtext-image full-width" src="https://www.pbs.org/wgbh/nova/media/images/Perseverance_Selfie.width-990_aHdZNGv.jpg"/>
<figcaption><p>NASA’s Perseverance Mars rover took a selfie with the Ingenuity helicopter, seen here about 13 feet (3.9 meters) from the rover in this image taken April 6, 2021, the 46th Martian day, or sol, of the mission. Image Credit: NASA/JPL-Caltech/MSSS</p>
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<p>Canham is also eager to hear the sound of Ingenuity’s liftoff: Perseverance is equipped with a microphone specifically designed to survive on Mars—and capture the <a href="https://www.scientificamerican.com/article/perseverance-mars-rover-records-sound-of-rock-zapping-laser1/">snaps, crackles and pops of its sizzling stones</a>. It’s possible for the microphone to capture Ingenuity’s liftoff, but given its somewhat significant distance (more than 200 feet) from the helicopter, there are no guarantees. It’s “very touch and go on whether we’ll get anything,” Canham said on Friday. “But who knows.”</p><p>What’s more certain is that Perseverance will capture its own photos of Ingenuity’s first flight.</p><p>Before, during, and after Ingenuity’s 40-second airtime, Perseverance will snap six to seven photos a second using its onboard <a href="https://mars.nasa.gov/mars2020/spacecraft/instruments/mastcam-z/">Mastcam-Z cameras</a>, one with zoomed-in perspective and the other a zoomed-out perspective. (You can view images as they come in on <a href="http://go.nasa.gov/perseverance-raw-images">NASA’s website here</a>.)</p><p>The Ingenuity team expects its second flight to happen four days after its initial flight. And if that one goes well—the goal being to have the helicopter fly up to 15 feet—the team will move to an every-three-day flight cadence.</p><p>“We want to have fun” with the fourth and fifth flights, Aung said, suggesting that the team may venture at least 150 feet out and back from the helicopter’s takeoff site, possibly into never-before-seen territory. “This is all about the future. This is all about being a pathfinder,” she said, explaining that Ingenuity can inform how future space helicopters, which will be bigger and heavier, should function.</p><p>Like NASA’s <a href="https://www.nasa.gov/mission_pages/mars-pathfinder">first Mars rover</a>—the modest 23-pound microwave-sized Sojourner, which touched down on the red planet in 1997—Ingenuity is a “tech demonstration,” explained Zurbuchen, NASA’s Associate Administrator for Science. Similar to Sojourner’s brief mission on Mars, Zurbuchen believes, decades from now, we’ll look back on Ingenuity’s month of flight with awe and fondness.</p><p>“Ingenuity’s month will be an aggressive demonstration of what it can possibly do,” he said. And, teammate Elsa Jensen added, “Big Sister”—Perseverance—“will be watching.”</p>
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<p>Want to fly a rotorcraft on another planet? Here’s what it takes.</p>

Ingenuity’s first black-and-white picture from the air. Image credit: NASA/JPL-Caltech

Victory! Ingenuity conducts its first powered flight on Mars

<p>When a diminutive 4-pound helicopter lifted off over a red landscape on Monday morning, it became the first craft to achieve controlled, powered flight on a planet beyond Earth.</p><p>At approximately 6:15 a.m. EDT on Monday, NASA’s Ingenuity Mars helicopter team—along with eager viewers from across the globe—watched live as data from the red planet arrived to Mission Control via a <a href="https://www.nasa.gov/directorates/heo/scan/services/networks/deep_space_network/about/">Deep Space Network antenna</a>. The data signified that Ingenuity’s flight, which occurred approximately four hours earlier, had been a success.</p><p>“Sometimes we have to do something just to show that we can do it,” NASA’s Associate Administrator for Science Thomas Zurbuchen said during <a href="https://www.youtube.com/watch?v=p1KolyCqICI">NASA’s livestream</a> of the event. “When the Wright brothers flew for the first time, they flew an experimental aircraft. And in the same way, the Mars helicopter is designed to show that we can fly a powered helicopter flight in the Martian atmosphere.”</p>
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<p><a href="https://www.pbs.org/wgbh/nova/article/nasa-ingenuity-mars-helicopter-first-flight/">Getting Ingenuity to fly</a>, Ingenuity Project Manager MiMi Aung added, “was the unwavering dream of our team since day one.”</p><p>On Monday, downlink lead Michael Starch, clad in an orange Ingenuity team polo, studied his computer screen in the helicopter control room. “This is downlink. Early indications,” he said, looking up from the monitor. “Data products look nominal.”</p><p>Sitting close by was Aung, who visibly grinned under her mask.</p><p>“This is downlink,” Starch repeated. “We’ve pulled in data products from Mars 2020.” He pauses for 39 seconds. The room was silent. “This is downlink,” he said again. “Confirming we received Mars 2020 telemetry. Confirming we received Mars 2020 event. Confirming we received helicopter data products.” Starch nodded his head up and down.</p><p>Silence once again fell over the control room. Aung twiddled her fingers. Some teammates nodded. Others glanced at their laptops and then back at their anxiously-awaiting colleagues.</p><p>“This is downlink,” Starch said. “Confirming we have helicopter data products, helicopter telemetry, helicopter event… battery data has been received.”</p>
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<img alt="NASA JPL's Ingenuity Mars helicopter team" class="richtext-image full-width" src="https://www.pbs.org/wgbh/nova/media/images/25819_4-PIA24585-web.width-990_lltuX2v.jpg"/>
<figcaption><p>Members of NASA’s Ingenuity helicopter team, including MiMi Aung (front), in NASA JPL’s Space Flight Operations Facility prepare to receive the data downlink showing whether the helicopter completed its first flight on April 19, 2021. Image Credit: NASA/JPL-Caltech</p>
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<p>Starch handed it off to Flight Control, which gave its announcement: “Ingenuity is reporting having performed spin-up, takeoff, climb, hover, descent, landing, touchdown and spin-down.”</p><p>Aung gave two thumbs up and then waved her fists. The control room erupted with clapping, originating from both mask-wearing team members in person and those watching over Zoom.</p><p>“Altimeter data confirmed,” Flight Control said. Cheers exploded from the control room. The altimeter plot of the flight, mechanical engineer Taryn Bailey explained during NASA’s livestream, indicates a peak. It starts off with a flat line, showing that Ingenuity is grounded, has a steep incline, indicating that the helicopter has spun up and risen, a dwell, showing that Ingenuity is hovering, and then another steep decline to the ground representing Ingenuity’s touchdown.</p><p>“Confirmed that Ingenuity has performed its first flight of a powered aircraft on another planet,” Flight Control said.</p>
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<p>As the cheers and fist pumps continued, the team received its first picture from the mission: a black and white photo that Ingenuity snapped while hovering over the Martian surface, its shadow—four rotors, four legs, and a tissue box-like body—cast beneath it.</p><p>Getting Ingenuity to fly on Mars was no easy feat. This first flight, initially scheduled for Sunday, Apr. 11, was delayed after team engineers identified a potential problem. (The team decided to update Ingenuity’s flight control software before attempting a maiden flight.) And years of preparation back on Earth was necessary.</p><p>Starting in 2014, before testing Ingenuity, the team used helicopter models to simulate flight on Mars. These models were the precursors to Ingenuity and “went through extensive environmental and aerodynamic testing,” Bailey said.</p><p>To properly test these models and then Ingenuity beginning in 2019, “We had to simulate a Mars-like atmosphere,” which is 1% the density of Earth’s, Bailey explained. The team did this by using NASA’s Jet Propulsion Laboratory’s 25-foot space simulator thermal vacuum chamber, which allowed the team to control temperature and pressure to simulate Mars’ atmospheric density. The team also used a gravity off-load system to compensate for the difference in gravity between Earth and Mars, Bailey said.</p><p>After these tests “We said, ‘The next time we fly it’ll be on Mars,’” Aung said during a press conference on Apr. 9.</p>
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<figcaption><p>The first flight of NASA’s Ingenuity Mars Helicopter was captured in this image from Mastcam-Z, a pair of zoomable cameras aboard NASA’s Perseverance Mars rover on April 19, 2021. Image Credit: NASA/JPL-Caltech</p>
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<p>At four pounds, Ingenuity was built to be both light and fast, bolstering its ability to soar in Mars’ incredibly thin atmosphere. Despite its small size, the helicopter’s wingspan is 4 feet tip-to-tip: “super large for something that’s essentially carrying [a vehicle] the size of a tissue box,” Bailey said.</p><p>Each of its four blades is made of a lightweight but strong composite material and weighs less than 2 ounces—the equivalent of four empty soda cans. To generate lift in an incredibly-thin atmosphere with few molecules to push around, Ingenuity’s blades move at an average speed of 2,500 rotations per minute. (Helicopters used on Earth typically operate at 450 to 500 rpm.)</p><p>While Ingenuity’s first flight was modest—a 10-foot hover above the red planet’s surface and a touchdown—its upcoming four flights will increase in technical difficulty. The team hopes to eventually explore parts of Mars’ terrain that it can’t navigate with terrestrial rovers like <a href="https://www.pbs.org/wgbh/nova/article/nasa-perseverance-mars-rover-landing-success/">Perseverance</a>. “The rover has to navigate around a lot of obstacles on the ground that the helicopter can fly around,” Bailey said.</p><p>“We’ve sent five rovers to Mars and now we have an aerial dimension, which...elevates the next stage of space exploration,” she added. Ingenuity and its eventual successors may also allow for more collaboration and eventually open the doorway for human exploration of other worlds, Bailey said.</p><p>Though the Ingenuity team already received still images of the helicopter’s maiden flight from both Ingenuity and Perseverance, it expects to get video footage and more high-resolution images in the next couple of days. You can view these on <a href="https://mars.nasa.gov/mars2020/multimedia/raw-images/">NASA’s website here</a>.</p>
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<p>The 4-pound helicopter just became the first craft to achieve controlled, powered flight on a planet beyond Earth.</p>

Depending on how you feel about squirrels, you might delight or despair to hear that we've got a lot in common with these woodland wunderkinds. Image Credit: Dgwildlife, iStock

The 10 most popular NOVA stories of 2019

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<h3>10. FDA approves first major new depression treatment in decades</h3><p>In March, the U.S. Food and Drug Administration approved a drug called esketamine, the first major new depression treatment to hit the market in decades. The drug is designed specifically for people suffering from the most extreme forms of treatment-resistant depression and is administered only in certified treatment centers via a nasal spray (rather than an oral pill). Esketamine is specifically for patients who have tried two other antidepressants with no success. </p><p>Janssen Research &amp; Development, the developer of the drug, hopes that by targeting the neurotransmitter glutamate, esketamine can offer rapid antidepressant effects, much like its cousin ketamine does. Experts’ opinions on the new drug, however, are split.</p><p><a href="https://www.pbs.org/wgbh/nova/article/fda-approves-first-major-new-depression-treatment-in-decades/">Read the full article</a>.</p><p></p>
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<figcaption><p>The Milky Way's population of Cepheid stars suggests that our galaxy is a twisted disk. Image Credit: J. Skowron / OGLE / Astronomical Observatory, University of Warsaw</p>
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<h3>9. A new 3D map of the Milky Way flaunts our galaxy’s warped shape</h3><p>If you ever thought the Milky Way was a flat, featureless pancake, think again. This summer, we learned that the Milky Way is bent out of shape. In fact, it seems to be warped into a wave much like a beach towel being shaken free of sand.</p><p>Finding definitive proof of the Milky Way’s warp was no simple task. While astronomers have gotten pretty good at snapshotting galaxies in more distant regions of the universe, here on Earth we don’t have the best vantage point to get a birds-eye view of the celestial structure that surrounds us: Just imagine trying to map a forest by being dropped down into its center.</p><p><a href="https://www.pbs.org/wgbh/nova/article/milky-way-3d-map-cepheids/?linkid=71919590">Read the full article.</a></p><p></p>
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<figcaption><p>Microwaving grapes is a surefire way to get your hands on some plasma—and an elevated risk of burning down your apartment. </p>
<div class="credit"><p>Image Credit: Hamza K. Khattak, Trent University; PNAS</p></div>
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<h3>8. How does microwaving grapes create plumes of plasma?</h3><p>If you’ve been tempted ever to create some plasma—and potentially burn down your home in the process—we learned this year that grapes and a microwave are the ticket. </p><p>Or, alternatively, you can turn to YouTube and (safely) watch researchers as they puzzle out the physics behind DIY plasma. Spoiler: The result is a swarm of subatomic particles that clash and collide, often emitting roiling blobs of light and heat that can resemble molten fire.</p><p><a href="https://www.pbs.org/wgbh/nova/article/how-does-microwaving-grapes-create-plumes-plasma/">Read the full article</a>. </p><p></p>
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<figcaption><p>European robins make harrowing, cross-continental migrations to escape harsh winters. To guide their way, these birds and others may use quantum entanglement to "read" Earth's magnetic field. Image Credit: Frank Vassen, flickr</p>
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<h3>7. A bird’s eye view of quantum entanglement</h3><p>Every year, billions of birds make harrowing, cross-continental migrations. But how do they know where to go?</p><p>Scientists have known for a while that Earth’s magnetic field lends a helping hand. But this year, some researchers gleaned insight into how, suggesting that at some point in history, avian evolution tapped into quantum mechanics.</p><p><a href="https://www.pbs.org/wgbh/nova/article/birds-quantum-entanglement/?linkid=69249680">Read the full article</a>.</p><p></p>
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<figcaption><p>An artistic three-dimensional representation cyclo[18]carbon, a ring of 18 carbon molecules. Image Credit: IBM Research</p>
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<h3>6. A new form of carbon is born—on a bed of salt</h3><p>In August, a new molecule called cyclo[18]carbon officially joined the carbon club. The creation, imaging, and analysis of cyclo[18]carbon helped settle decades of debate on the structure and properties of the molecule, which some researchers doubted could even be stably made in a laboratory setting.</p><p>Historically, researchers’ attempts to generate cyclocarbons in the lab resulted in volatile gas, too ephemeral to rigorously study. But the recent breakthrough shows that cyclocarbons can be generated by pruning carbon and oxygen atoms off a more complex molecule at extremely cold temperatures. Starting with a molecule made up of 24 carbons linked to six oxygens, researchers at IBM Research and Oxford University were able to generate a final structure of 18 carbons—the smallest possible ring of carbons predicted to be stable by theoretical models. </p><p><a href="https://www.pbs.org/wgbh/nova/article/cyclo18carbon/">Read the full article</a>.</p>
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<figcaption><p>A wild silver-backed chevrotain appeared! Image Credit: SIE/GWC/Leibniz-IZW/NCNP Copyright holder: Andrew Tilker</p>
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<h3>5. Feast your eyes on the first-ever photos of a silver-backed chevrotain in the wild</h3><p>Once upon a time, there was a fanged, cat-sized deer-like creature with a glossy silver back. Then, like many legendary beasts, it was “lost to science.”</p><p>Until this November, that is. Though Western researchers have known about the skittish silver-backed chevrotain for more than a century, they’ve only managed to collect five specimens, all corpses obtained from hunters in Vietnam. The last of these appeared nearly three decades ago. But this year, with the help of local knowledge and a cluster of well-placed camera traps, Global Wildlife Conservation biologist Andrew Tilker and his team snapped the first-ever photos and videos of the silver-backed chevrotain in the wild.</p><p><a href="https://www.pbs.org/wgbh/nova/article/silver-backed-chevrotain-rediscovered-vietnam/?linkid=76835332">Read the full article</a>.</p><p></p><p></p>
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<figcaption><p>As Alzheimer's disease progresses, communication between brain cells breaks down. New research suggests that one possible cause for this deterioration may be a brain infection by <i>Porphyromonas gingivalis, </i>a bacterium known for causing gum disease. Image Credit: National Institute on Aging/NIH, flickr</p>
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<h3>4. Could Alzheimer’s begin with bacteria that cause gum disease?</h3><p>In individuals affected by Alzheimer’s disease, communication between brain cells breaks down over time. Early this year, a study suggested one peculiar potential cause for this deterioration: a brain infection by a bacterium known for causing gum disease.</p><p>In January, researchers reported that the bacterium, <i>Porphyromonas gingivalis</i>, might be capable of traversing the path from mouth to brain, where it can trigger chemical changes that damage cognitive function. These findings suggest that some cases of Alzheimer’s might have an infectious cause—and a new drug that blocks this process is now in clinical trials.</p><p><a href="https://www.pbs.org/wgbh/nova/article/alzheimers-bacteria-gum-disease/?no-cache=&amp;linkid=62727014">Read the full article</a>.</p><p></p><p></p>
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<figcaption><p>A complex tangle of social factors may encourage girls to prioritize verbal skills from a young age. But being excellent at reading doesn’t make a person bad at math—no matter their gender. Image Credit: Imgorthand, iStock</p>
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<h3>3. Girls’ superb verbal skills may contribute to the gender gap in math</h3><p>Being excellent at reading doesn’t make a person bad at math—no matter their gender.</p><p>According to previous studies, including <a href="https://psycnet.apa.org/doiLanding?doi=10.1037%2Fa0021276">a meta-analysis</a> that probed gender differences in recent studies of mathematics performance, girls are just as good at math as boys are. But a complex amalgam of social factors may encourage girls to prioritize verbal skills from a young age, a study published in July suggests.</p><p>Drawing on data from more than 300,000 high school students from 64 countries, the study found that because girls’ verbal skills outshine their already high marks in math, many who do every bit as well as their male peers in mathematics still choose more humanities-centric careers.</p><p><a href="https://www.pbs.org/wgbh/nova/article/gender-gap-math-comparative-advantage/">Read the full article</a>.</p><p></p><h3>2. Six stupendous reasons to appreciate the heck out of squirrels</h3><p>Beady eyes, bushy tails, can’t lose: We’re talking squirrels. And whether you love these nut-crazed rodents or not, there’s no denying that despite being zany, squirrels are also aerodynamic and brainy.</p><p>On January 21, for Squirrel Appreciation Day, <i>NOVA</i> published a roundup of six squirrel facts—and it quickly became a fan favorite. So if you’re still in the dark about squirrel-induced electrical power outages, squirrels eating spring rolls, the power of squirrel memory, and how squirrels can give investment bankers a run for their money, here’s your ticket out.</p><p><a href="https://www.pbs.org/wgbh/nova/article/six-snippets-squirrel-science/">Read the full article</a>.</p><p></p><p></p>
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<figcaption><p>Now that's a purrfect pair. Image Credit: AkilinaWinner, iStock</p>
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<h3>1. Study finds kittens bond with their human caregivers like babies do</h3><p>Sorry, dogs: You may not be humans’ only faithful companions. Though cats have their critics, it turns out that they can be extremely social with other felines and humans alike.</p><p>In September, researchers revealed that much like human infants, cats are “attached” to their caretakers (and like babies, felines have different ways of expressing their attachment). When analyzing humans, dogs, and cats, the research team found that roughly 60 percent of infants or pets are “secure,” meaning they appear to use their caregivers as a safe base from which to explore their surroundings. Of the felines that seemed, well, insecure, fewer acted aloof or avoidant than one might expect.</p><p><a href="https://www.pbs.org/wgbh/nova/article/cats-secure-attachment/">Read the full article</a>.</p>
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<p>We’ve counted down our ten most-read articles of 2019 and found that health and medicine, physics—and of course animals—were fan-favorite topics this year.</p>

Human fossil footprints at White Sands National Park in New Mexico. Image Credit: Courtesy of the National Park Service

Human tracks may be earliest evidence of people in North America

<p>In southern New Mexico lies the Tularosa Basin, an oblong bowl that’s home to a natural sandbox: White Sands National Park.</p><p>In 2005, David Bustos came to White Sands to work as a National Park Service biologist. The following year, he took notice of odd animal footprints that would appear only when the ground was wet. (The first of these footprints was reported in the 1930s.) The markings, which would disappear as the earth dried up, became known as ghost tracks.</p><p>Then in 2009, Bustos came across tracks he thought belonged to ancient humans walking alongside mammoths. But few scientists agreed, he says, rebutting with “No, no, those are the prints of camels that were slipping in the mud,” referring to now-extinct North American camels. And the tracks would disappear with changes in the weather. Heavy rainfall drowned them; periods of drought dried them up. It would take more than a decade—and cooperative weather—for scientists to agree that the tracks belonged to humans. </p><p>Then, says U.S. Geological Survey (USGS) Research Geologist Kathleen Springer, “What everyone was asking is, ‘How old are these things, really?’”</p>
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<p>In September 2021, Bustos, Springer, and a group of other researchers published their findings in the journal Science: The team identified 61 human tracks within multiple levels of earth belowground, and between layers of these tracks were seeds from an ancient aquatic plant. Analyses of these seeds—and the footprints they were embedded within—are now challenging scientists’ understanding of when and how people arrived in the Americas.</p><p>Archaeologist Joe Watkins, who was not involved in the study, believes the findings have potentially massive implications. “I think, outside the next big migration of going to the Moon or Mars, the migration to the Americas was the last great migration humanity had,” he says. Upending the timeline of this journey could have implications for both science and Native American cultures, Watkins, who is a member of the Choctaw Nation of Oklahoma, believes.</p><h3>Visiting the tracks</h3><p>At first light on a cold January morning in 2020, Bustos set out with Springer and her USGS colleague Jeff Pigati on all-terrain vehicles to visit White Sands’ ancient tracks. The team wore parkas to keep warm amid a prevailing wind. Springer recalls the hour-and-a-half journey through the dunes being like a “Disney ride.” It was the “funnest thing in the world,” she says. “Just being out there is surreal.”</p><p>Eventually, after passing through a large swath of national park that borders the site of the first atomic bomb test, Springer, Pigati, and Bustos fell upon thousands of tracks. They belonged to packs of dire wolves, giant sloths, 13-foot-tall mammoths, and other animals. And, Springer says, “there’s a person track right smack dab in the middle of them.”</p>
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<figcaption><p>Gypsum sand dunes at White Sands National Park, New Mexico. Image Credit: NOVA/GBH</p>
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<p>“When Dave showed us these things and we had our eyes trained on them, we were almost afraid to step down,” Pigati says. “It looks like a painting in some places.”</p><p>Bustos recalls the conditions that day being perfect for identifying tracks. The trio saw human footprints going underneath the sediment in places, illustrating that there was more than a surface layer of them. “We were seeing seed layers popping out all over the place,” Bustos says. To determine how old the footprints were, Springer and Pigati’s team would collect these ancient seeds from different layers of footprints. The overwhelming evidence of ancient plant life excited Bustos.</p><p>About 36,000 to 19,000 years ago, lakes filled the Tularosa Basin. The largest of these was Lake Otero, which fluctuated in size and activity based on rainfall. Plants like spiral ditchgrass (<i>Ruppia cirrhosa</i>), whose seeds are now embedded in layers of earth, grew along Otero’s edges. About 23,000 years ago, the southwestern U.S. became drier and the lake shrank. This exposed a large area of land that was once underwater, whose clays and silts became overtopped by gypsum sand and silt. People began walking around these surfaces, which “were kind of squishy in some areas,” Springer explains. And the people weren’t alone: The impressions from mammoths, ground sloths, and camels, sit alongside—and sometimes right on top of—human prints. </p><p>“This can only happen if they are in the area at the same time,” Pigati said in an email. “Exactly how they may have interacted in the vicinity of our [research site] is unknown, but there is definitive evidence that humans were harassing or stalking a giant ground sloth on the west side of the basin.”</p><p>In many other cases, interactions between humans and animals seem peaceful. “What’s interesting to me,” Bustos says, “is it’s not just a mammoth and a hunter. It’s families. You see a baby mammoth turning around and spinning. We have the juvenile and adult megafauna prints with the babies and adult [humans].”</p>
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<figcaption><p>A footprint from a Harlan's ground sloth at White Sands National Park. Image Credit: Courtesy of the National Parks Service</p>
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<p>Having about 10 hours of daylight, the team got to work “trenching” the human footprints, Springer says. With ground-penetrating radar, they were able to determine that footprints were present within layers of sediment. They then dug a trench to view the layers in cross-section. If Springer and Pigati’s cross-section was a sandwich, the footprints would be the filling and the dateable material around the footprints would be the bread. </p><p>Dating tracks only at the surface would yield inaccurate results, Pigati explains. “You can look in every direction and there are trackways everywhere in every horizon,” he says. But if you calculate the age of these footprints on the surface layer of earth only, you’ll just find that they’re younger than the ground they’re upon, he says. By looking at layers of sediment below the surface, the team set out to document how many layers contained footprints and find datable material above and below each layer. Each of these layers would contain footprints from a unique time period, the team posited. “The footprints are imprinted at the top of a given layer of sediment—they don’t really pass through the layers,” Pigati wrote in an email.</p><p>As the sun rose higher in the sky, the white sand reflected a near-blinding light, and the day quickly grew warm. The researchers shedded their parkas and worked in t-shirts until the January sun fizzled and it was time to ride back through the dunes, chunks of sediment layers in hand.</p><p>The team later extracted 40 to 60 ditchgrass seeds from every level of footprints in every sample. In a USGS lab in Golden, Colorado, they cleaned each set of seeds with a chemical treatment and began combusting them.  </p><p>The combustion process, automated by a machine in the lab, didn’t obliterate the seeds but turned them into a gas. From this gas, a machine turned the once-seeds back into solids: graphite pellets about the size of a pencil tip. This technology of making “graphite targets” dates back to the 80s, Pigati says. “Every lab does it the same way in the world.”</p><p>The team then took these pellets, tapped them down into cartridges, and sent them off to a lab to measure the amount of a radioactive isotope of carbon, called carbon-14, they contained. Then they waited for results.</p><h3>What the tracks mean</h3><p>Months later, they came. The seeds revealed that the footprints they were embedded within are between 21,000 and 23,000 years old—thousands of years older than what scientists generally consider to be the earliest evidence of people in the Americas.</p><p>“For forever, people thought Clovis were the first people to cross over [the Bering Strait] about 13,000 years ago,” Pigati says, referring to the commonly-held view among archaeologists. As the story goes, ice sheets in what is now Canada blocked passage between what is now Alaska and the rest of the Americas. Once these ice sheets began retreating, people came south through an ice-free corridor, Pigati explains. His team’s findings now challenge this belief. Carbon dating of the seeds within the White Sands footprints suggest that people were in the Americas while ice sheets still covered much of northern North America. “A lot earlier” than previously thought, Pigati says. </p><p>“When we got the final dates back, it was very…” Springer pauses over Zoom, choosing her words carefully. “The arrows were going to start flying. We knew we needed an [evidence-supported] explanation why these findings were really robust.”</p>
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<p>Archaeologist Joe Watkins says that if the dating of the seeds, and therefore footprints, is correct, “it puts us at 20% older than the dates we have from the rest of America.” Therefore, ages of other important archaeological sites like Meadowcroft Rockshelter in Pennsylvania, where scientists have found 16,000-year-old evidence of human life, may need to be reconsidered. (In 2014, Nikhil Swaminathan <a href="https://www.archaeology.org/issues/145-1409/features/2369-peopling-the-americas-meadowcroft-rockshelter">wrote for Archaeology Magazine</a> that Meadowcroft Rockshelter is “the longest-occupied site in the Americas.”)</p><p>Watkins first heard about the White Sands tracks years ago while working in Washington D.C. as the chief of the Tribal Relations and American Cultures Program of the National Park Service. But he didn’t see them until after he’d retired, visiting White Sands during a NOVA shoot for the film “<a href="https://www.pbs.org/wgbh/nova/video/ice-age-footprints/">Ice Age Footprints</a>.” Seeing human footprints intermingling with those of ground sloths was overwhelming and “tremendously exhilarating,” he says.</p>
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<figcaption><p>Watkins pictured with a replica Clovis point. His interest in archaeology was piqued at 10 years old when he found an archaic point on his family’s Oklahoma homestead. Watkins, who’s now 71, showed the point to his grandmother. The artifact didn’t come from modern Choctaw, but was much older, she explained in her native language. From that moment, Watkins became “more interested in looking into the unwritten past,” and, with his grandmother’s support, began pursuing a career in archaeology, a field he recognizes isn’t always “in advantage to the Native American community,” he says. Image Credit: NOVA/GBH</p>
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<p>But Watkins cautions that, with no other aspects of culture present but footprints, scientists like him can only speculate how ancient humans were using the land. “Were they just walking? Were they hunting? Did they have a camp nearby?” he asks. Archaeology may not hold all the answers to these questions: “I do think it’s important for American Indians to be involved so they can offer their insights so we can better understand who these people were,” Watkins says, reflecting on his own Choctaw roots.</p><p>As Native American identity is tied to the land, Watkins believes, “the Native peoples will say we’ve always been here,” he says. “I usually say [the first Americans] weren’t Native Americans. They weren’t Siberians. They were whatever they called themselves.” Combining this philosophy with science is a way to integrate belief systems, he says.</p>
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<p>The White Sands findings, Watkins says, “forced us to reconsider the most cherished ideas of the people of North America.”</p>
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<p>Watkins recites his people’s story about two stiff-legged bears that meet in a black-loam prairie and have a battle. Only one survives; it becomes the last of its species. “Some Choctaw interpret ‘stiff-legged bear’ as being a mammoth,” Watkins says. If humans did once walk alongside mammoths in New Mexico’s Tularosa Basin 20,000 years ago, he adds, there’s a chance these people gave birth “to any number of tribal people across the U.S.” </p><h3>Racing against time</h3><p>Bustos, Springer, Pigati, and fellow researchers visited the ghost tracks again in January and April 2022. They extended their trench, identifying more footprints from potentially before and after the original set they excavated. To bolster their findings, Bustos explains, the team won’t rely solely on dating seeds. They’ll date pollen, too. “This work is not done,” Pigati says. “We have a window from 21,000 to 23,000 [years]. We don’t know if people were here before then.” </p><p>But the clock is ticking. Erosion in White Sands is exposing and destroying the tracks, Springer says. Though the Tularosa Basin has been eroding for nearly 12,000 years, climate change is likely exacerbating erosion today, she explains. “The layers, they’re finite,” Bustos adds. “We’re losing thousands of tracks to erosion. It’s a race to document them before they’re gone.”</p><p>Already, some tracks reveal clues about ancient daily life in the Tularosa Basin.</p><p>“There’s something about the children,” Bustos says. “You see these toddlers running and jumping, and the story really comes alive.” Watkins agrees. “When we look at the tracks of children playing in perhaps puddled water surrounded by ground sloths,” he says, “it takes us back to childhood memories of children playing in puddles all around the world.”</p>
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<p data-block-key="arqov">Footprints in New Mexico’s White Sands National Park challenge scientists’ timeline of when humans first came to North America.</p>

Sukee Bennett

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