Science
Science of Simone: The forces behind her iconic Yurchenko double pike
The most decorated gymnast ever sprints down the vault runway. She tumbles gracefully onto the springboard, flings herself backward onto the vault table and pops off the surface. Soaring through the air, she folds her body in half and grabs the back of her legs for two head-over-heels flips.
The crowd erupts when Simone Biles stomps her feet into the mat.
Another successful Yurchenko double pike.
“It just makes your mouth drop open every time,” said UCLA gymnastics coach Janelle McDonald, who sat in the front row next to the vault landing area at the U.S. Olympic trials, where Biles competed her signature vault.
Of the five skills in the International Gymnastics Federation (FIG) code of points named after Biles, her most recent vault — the Yurchenko double pike — has become the most iconic.
It’s the first major leap in vault innovation for women’s artistic gymnastics in two decades. When leveling up the sky-high event used to mean extra twists, Biles flipped the game upside down. She was the first woman to attempt her double-flipping skill in competition and completed it in international competition for the first time at the 2023 World Championships, earning its name as the Biles II.
“Simone made impossible an opinion with that vault,” NBC analyst John Roethlisberger said on the telecast during the U.S. Olympic trials.
In a sport that blends power and grace, Biles’ Yurchenko double pike is at the center of its own Venn diagram: athletic feat, scientific marvel and artistic genius all in six seconds.
The entry
Biles begins with a sprint down the runway and reaches her hands toward the ground while cartwheeling her legs over her head. The roundoff turns her momentum forward to backward.
(Kenzo Tribouillard / AFP via Getty Images)
The height, the rotation and the landing earn the most gasps from the fans who follow Biles’ every move on the competition floor. But for her peers who continue to marvel at the 27-year-old’s revolutionary talent, the most impressive part of the vault happens before Biles even contacts the table.
“Your Yurchenko entry has to be so technically perfect and so consistent,” said 2016 Olympic gold medalist Kyla Ross. “You have no doubt coming off the table that you’re going to hit the double pike.”
The Yurchenko entry — a roundoff onto the springboard and a back handspring onto the vault table — is named after former Russian gymnast Natalia Yurchenko, who debuted her eponymous skill in 1982. Since the FIG replaced the vault horse — which resembled a pommel horse without handles and was about 5 feet long and 1 foot wide at the top — for a tongue-shaped vault table in 2001, the Yurchenko vault has become more common for elite female gymnasts. Athletes can still harness the power generated from the unique entry while having a larger, safer surface area for their hands.
2024 Paris Summer Olympic Games
Biles begins with a sprint down the runway and reaches her hands toward the ground while cartwheeling her legs over her head. The roundoff turns her momentum forward to backward. Slamming her feet down on the springboard, Biles compresses the springs that then uncoil and transfer energy back into her body as she reaches up and backward for the vault table.
The key to vault liftoff is how Biles contacts the equipment to transfer her momentum.
“Pre-springboard, all of their motion is forwards,” said Emily Kuhn, a physics PhD student at Yale who was a level 10 gymnast. “After the springboard, some of their motion is upwards. And so [the board is] really helpful for converting the rotational energy from that roundoff into an upwards velocity that is used to get the height on the vault.”
In an instant, Biles arches backward toward the vault table. Her body whips back in a lightning-fast handspring that leaves even the best athletes in the world in the dust.
“She gets that power because of how quick-twitched her roundoff-back handspring is, technically speaking,” said 2008 Olympic silver medalist Samantha Peszek. “No one is as quick-twitch as Simone.”
The block
During the block, the moment Biles’ hands strike the table, she extends through her shoulders in a motion that’s barely detectable in real time. The micro-movement lasts a tenth of a second as Biles applies force to the vault that is then returned in equal and opposite measure.
(Kenzo Tribouillard / AFP via Getty Images)
Aly Raisman had a front-row seat to the world’s best vaulters. The two-time Olympian watched 2012 Olympic teammate McKayla Maroney nail a nearly perfect two-and-a-half twisting Yurchenko in the team final. Raisman was also the team captain in 2016 when Biles won Olympic gold on vault. Both standouts shared a key ability that helped them soar above the competition.
“When you look at her elbows on the table, they’re always very straight,” Raisman said. “Their body was so tight when their arms hit the table that it just helps them get so much air.”
The moment Biles’ hands strike the table, she extends through her shoulders in a motion that’s barely detectable in real time. The micro-movement lasts a tenth of a second as Biles applies force to the vault that is then returned in equal and opposite measure. Keeping every muscle contracted during the split second on the table is vital to transferring energy efficiently for maximum height.
“The force gets dispersed in bad form,” said Gina Pongetti, a physical therapist with more than 20 years of experience working with college, national team and elite gymnasts. “[The muscles] are all tight at one time so that nothing gives, nothing buckles. Because of that, all of that force, or as much as possible, goes into the vault [and] goes back to her to transfer to height and rotation.”
NBC estimated that Biles’ feet reach about 12 feet in the air at the peak of her vault when she is upside down.
Former UCLA gymnast Nia Dennis knows the feeling. The three-time U.S. national team member trained a Yurchenko double tuck — with her knees bent and legs pulled toward her chest — into the foam pit during her elite career, eventually stacking up soft mats to be equal to competition height. While she is best known for her viral, energetic floor routines, Dennis loved vault the most. She still recalls the intoxicating feeling of hitting the perfect block that fired her into the air.
“I just felt like a cannon,” Dennis said.
The flips
After Biles blocks off the vault, she is just a projectile.
(Matthias Hangst / Getty Images)
Searching for ways to upgrade her vault difficulty, Dennis wanted to buck the trend of adding additional twists to her Yurchenko. She was always more of a flipper than a twister, and Dennis sometimes landed on her neck from over-rotating her warm-up drills. One day, her coach encouraged her to pull all the way around onto her feet for an additional flip.
“It was just straight power,” Dennis said. “All I had to do was run and close my eyes, for real. Just block really hard, close my eyes really hard and pull really hard.”
For Dennis, the daring skill was fun. Her former UCLA teammate Ross did not share the sentiment.
“I used to like, cry because I was so scared of it,” laughed Ross, who practiced Yurchenko double tucks into the foam pit alongside her longtime club teammate Maroney.
The second flip is what makes the vault so frightening for athletes. Gymnasts can adjust a twisting vault midair by reducing the number of revolutions by halves if they feel something gone awry. There is no safe Plan B between one and two flips.
After Biles blocks off the vault, she is just a projectile, Kuhn emphasized. At that point, there is nothing she can do to change how high she is or her path through the air.
That’s when her proprioception takes over. Biles’ air awareness is “unbelievable,” Pongetti said. The physical therapist, who specializes in treatment, diagnoses and biomechanics in gymnastics, has watched Biles train for years.
While she cannot change her flight path, Biles is an expert in making split-second decisions to rearrange her body midair to change how she will move. If she is too low, she can pull her body into a tighter shape to flip faster. If she is too high, she knows a more open shape can slow down her flip and help avoid over-rotation.
Only that caliber of spatial awareness can make the death-defying skill “safer,” Pongetti said. She would never say it’s “safe.”
“That sets apart the level 10 [gymnast] from the elite,” Pongetti said, “from the Olympian from Simone.”
The landing
Simone Biles of the United States reacts after performing a vault during the 2023 gymnastics world championships in Antwerp, Belgium.
(Tim Clayton / Corbis via Getty Images)
With five skills named for her in the code of points, Biles is at the forefront of the sport’s progression. Peszek remembers when the double-twisting, double back tucks she and 2008 Olympic teammate Shawn Johnson competed were arguably the hardest tumbling passes in the world. Now Biles casually does that skill in combination with a full-twisting front layout.
“It’s really special to see the generations pass the torch and just how they’ve been able to take this sport by storm by creating all these new elements and really pushing the boundaries,” Peszek said. “Seeing her do it so effortlessly, it’s really a work of art to see.”
The Biles II was awarded the highest-difficulty score of any vault by the FIG at 6.4. Astronomical-difficulty scores, which are combined on each event with an execution score out of 10, allow Biles to win competitions by whole numbers as most of her peers fight for half-tenths.
On vault, most of the top medal contenders have difficulty values of 5.4 for the two-and-a-half twisting Yurchenko known as an Amanar or 5.6 for a Cheng, which begins with a roundoff onto the springboard, a half turn onto the vault table and a one-and-a-half twist off.
But Rebeca Andrade could challenge Biles for the crown. The Brazilian Olympic confederation published a YouTube video that featured the Olympic and world vault champion training a triple-twisting Yurchenko. If she lands it in international competition, it will bear her name.
Biles considered the skill as the next Yurchenko progression from an Amanar but has said going for the double flip was safer for her to land. The landing on a twisting flip presents additional challenges, Kuhn said, as gymnasts must absorb rotational forces to stop the twist while also controlling the landing vertically.
A 2013 study estimated that gymnasts absorb 11 times their body weight on landings during competition. The force increases to 18 times body weight if a landing is uneven, a common consequence of twisting elements. What Biles feels when her 4-foot-8 frame is falling from more than two and a half times her height to land the Yurchenko double pike might be even greater, Pongetti said.
“Her quads and her glutes and her hamstrings [and her calves], which otherwise would work to allow her to jump high, work in reverse to slow her down,” Pongetti said. “They are her brakes. … She is so good at not being stiff-legged when she lands.”
Fans seem to hold their breath as Biles floats and flips through the air. At the moment her feet punch into the mat, the crowd exhales with a roar of applause.
Thousands in Paris’ Bercy Arena will see the vault’s official Olympic debut. Millions more will watch internationally.
They’ll see Biles push the boundaries of sport and science in a gravity-defying six-second burst.
Our universe might be chock-full of cosmic wonder, but you can observe only a fraction of astronomical phenomena with the naked eye. Meteor showers, natural fireworks that streak brightly across the night sky, are one of them.
The latest observable meteor shower will be the Lyrids, which has been active since April 14 and is forecast to continue through April 30. The shower reaches its peak April 21 to 22, or Tuesday night into Wednesday morning.
According to NASA, the Lyrids are one of the oldest known meteor showers, and have been enjoyed by stargazers for nearly 3,000 years. Their bright, speedy streaks are caused by the dusty debris from a comet named Thatcher. They appear to spring from the constellation Lyra, which right now can be seen in the eastern sky at night in the Northern Hemisphere.
The moon will be about 27 percent full tonight, appearing as a thick crescent in the sky, according to the American Meteor Society.
To get a hint at when to best watch for the Lyrids, you can use this tool, which relies on data from the Global Meteor Network. It shows fireball activity levels in real time.
And while you gaze at the heavens, keep an eye out for other stray meteors streaking across the night sky. Skywatchers are reporting that the amount of fireballs is double what is usually seen by this point in the year.
Where meteor showers come from
There is a chance you might see a meteor on any given night, but you are most likely to catch one during a shower. Meteor showers are caused by Earth passing through the rubble trailing a comet or asteroid as it swings around the sun. This debris, which can be as small as a grain of sand, leaves behind a glowing stream of light as it burns up in Earth’s atmosphere.
Meteor showers occur around the same time every year and can last for days or weeks. But there is only a small window when each shower is at its peak, which happens when Earth reaches the densest part of the cosmic debris. The peak is the best time to look for a shower. From our point of view on Earth, the meteors will appear to come from the same point in the sky.
The Perseid meteor shower, for example, peaks in mid-August from the constellation Perseus. The Geminids, which occur every December, radiate from the constellation Gemini.
How to watch a meteor shower
Michelle Nichols, the director of public observing at the Adler Planetarium in Chicago, recommends forgoing the use of telescopes or binoculars while watching a meteor shower.
“You just need your eyes and, ideally, a dark sky,” she said.
That’s because meteors can shoot across large swaths of the sky, so observing equipment can limit your field of view.
Some showers are strong enough to produce up to 100 streaks an hour, according to the American Meteor Society, though you probably won’t see that many.
“Almost everybody is under a light-polluted sky,” Ms. Nichols said. “You may think you’re under a dark sky, but in reality, even in a small town, you can have bright lights nearby.”
Planetariums, local astronomy clubs or even maps like this one can help you figure out where to go to escape excessive light. The best conditions for catching a meteor shower are a clear sky with no moon or cloud cover, sometime between midnight and sunrise. (Moonlight affects visibility in the same way as light pollution, washing out fainter sources of light in the sky.) Make sure to give your eyes at least 30 minutes to adjust to seeing in the dark.
Ms. Nichols also recommends wearing layers, even during the summer. “You’re going to be sitting there for quite a while, watching,” she said. “It’s going to get chilly, even in August.”
Bring a cup of cocoa or tea for even more warmth. Then lie back, scan the sky and enjoy the show.
Where weather is least likely to affect your view
Storm systems sweep across the country in early spring, and some will be obscuring skies tonight. But there will still be plenty of areas with clear skies, particularly in parts of the central United States.
“The best spot is going to be in the Upper Midwest,” said Rich Bann, a meteorologist with the Weather Prediction Center.
Minnesota, Wisconsin and Iowa will offer especially good sky-viewing weather and a beach on the Great Lakes could be a nice spot to look up at the stars.
But don’t expect to view the show from Chicago, as Illinois could see some thunderstorms. The weather will be better in the Northern and Central Plains, particularly the eastern Dakotas.
High, wispy clouds are expected over the Ohio and Tennessee Valleys and into parts of the Mid-Atlantic. But, Mr. Bann said, “you may be able to see some shooting stars through thin clouds.”
Clouds will be draped across much of the Southeast and the Northeast, though there could be some clearing in Florida, Georgia, the Carolinas and Virginia. Remember, the meteors could be visible all night long. If you look outside and see clouds, try again later.
Catching the spectacle will be challenging across much of the West, particularly from Washington into Northern California, where a storm system is bringing rain and snow. That system will move east overnight.
There are likely to be some pockets of clear skies at times across southern Nevada, northwest Arizona and southwest Utah, Mr. Bann said.
Amy Graff contributed reporting.
WASHINGTON — Amid growing national security concerns, the FBI said Tuesday that it has launched a broad investigation in the deaths or disappearances of at least 10 scientists and staff connected to highly sensitive research, including four from the Los Angeles area.
“The FBI is spearheading the effort to look for connections into the missing and deceased scientists. We are working with the Department of Energy, Department of War, and with our state and state and local law enforcement partners to find answers,” the agency said in a statement.
The FBI’s announcement comes after the House Oversight Committee announced that it would investigate reports of the disappearance and deaths of the scientists, sending letters seeking information from the agencies involved in the federal inquiry as well as NASA, which owns the Jet Propulsion Laboratory in La Cañada Flintridge, where three of the missing or dead scientists worked.
“If the reports are accurate, these deaths and disappearances may represent a grave threat to U.S. national security and to U.S. personnel with access to scientific secrets,” Reps. James Comer (R-Ky.), chairman of the committee, and Eric Burlison (R-Mo.) wrote in the letters.
President Trump told reporters last week that he had been briefed on the missing and dead scientists, which he described as “pretty serious stuff.” He said at the time that he expected answers on whether the deaths were connected “in the next week and a half.”
Michael David Hicks, who studied comets and asteroids at JPL, was the first of the scientists who disappeared or died. He died on July 30, 2023, at the age of 59. No cause of death was disclosed.
A year later, JPL physicist Frank Maiwald died at 61, with no cause of death disclosed.
Two other Los Angeles scientists are part of the string of deaths and disappearances.
On June 22, 2025, Monica Jacinto Reza, a materials scientist at JPL, disappeared while on a hike near Mt. Waterman in the San Gabriel Mountains.
On Feb. 16, Caltech astrophysicist Carl Grillmair was fatally shot on the porch of his Llano home. The Los Angeles County Sheriff’s department arrested Freddy Snyder, 29, in connection with the shooting. Snyder had been arrested in December on suspicion of trespassing on Grillmair’s property.
Snyder has been charged with murder.
There is no evidence at this point that the deaths and disappearances, which occurred over a span of four years, are connected.
A spokesperson for NASA, which owns JPL, said in a statement on X that the agency is “coordinating and cooperating with the relevant agencies in relation to the missing scientists.
“At this time, nothing related to NASA indicates a national security threat,” agency spokesperson Bethany Stevens wrote. “The agency is committed to transparency and will provide more information as able.”
Representatives from Caltech, which manages JPL, did not immediately respond to a request for comment.
The sun had barely risen over the Pacific Ocean when a small motorboat carrying a team of Indigenous artisans and Mexican biologists dropped anchor in a rocky cove near Bahías de Huatulco.
Mauro Habacuc Avendaño Luis, one of the craftsmen, was the first to wade to shore. With an agility belying his age, he struck out over the boulders exposed by low tide. Crouching on a slippery ledge pounded by surf, he reached inside a crevice between two rocks. There, lodged among the urchins, was a snail with a knobby gray shell the size of a walnut. The sight might not dazzle tourists who travel here to see humpback whales, but for Mr. Avendaño, 85, these drab little mollusks represent a way of life.
Marine snails in the genus Plicopurpura are sacred to the Mixtec people of Pinotepa de Don Luis, a small town in southwestern Oaxaca. Men like Mr. Avendaño have been sustainably “milking” them for radiant purple dye for at least 1,500 years. The color suffuses Mixtec textiles and spiritual beliefs. Called tixinda, it symbolizes fertility and death, as well as mythic ties between lunar cycles, women and the sea.
The future of these traditions — and the fate of the snails — are uncertain. The mollusks are subject to intense poaching pressure despite federal protections intended to protect them. Fishermen break them (and the other mollusks they eat) open and sell the meat to local restaurants. Tourists who comb the beaches pluck snails off the rocks and toss them aside.
A severe earthquake in 2020 thrust formerly submerged parts of their habitat above sea level, fatally tossing other mollusks in the snail’s food web to the air, and making once inaccessible places more available to poachers.
Decades ago, dense clusters of snails the size of doorknobs were easy to find, according to Mr. Avendaño. “Full of snails,” he said, sweeping a calloused, violet-stained hand across the coves. Now, most of the snails he finds are small, just over an inch, and yield only a few milliliters of dye.
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