A new paper proposes a fully physically realized model for warp drive.

This builds on an existing model that requires negative energy—an impossibility.

The new model is exciting, but warp speed is still probably decades or centuries away.

In a surprising new paper, scientists say they’ve nailed down a physical model for a warp drive, which flies in the face of what we’ve long thought about the crazy concept of warp speed travel: that it requires exotic, negative forces.

To best understand what the breakthrough means, you’ll need a quick crash course on the far-out idea of traveling through folded space.

The colloquial term “warp drive” comes from science fiction, most famously Star Trek. The faster-than-light warp drive of the Federation works by colliding matter and antimatter and converting the explosive energy to propulsion. Star Trek suggests that this extraordinary power alone pushes the ship at faster-than-light speeds.

Scientists have been studying and theorizing about faster-than-light space travel for decades. One major reason for our interest is pure pragmatism: without warp drive, we’re probably never making it to a neighboring star system. The closest such trip is still four years long at light speed.

Our current understanding of warp speed dates back to 1994, when a now-iconic theoretical physicist named Miguel Alcubierre first proposed what we’ve called the Alcubierre drive ever since.

The Alcubierre drive conforms to Einstein’s theory of general relativity to achieve superluminal travel. “By a purely local expansion of spacetime behind the spaceship and an opposite contraction in front of it,” Alcubierre wrote in his paper’s abstract, “motion faster than the speed of light as seen by observers outside the disturbed region is possible.”

Essentially, an Alcubierre drive would expend a tremendous amount of energy—likely more than what’s available within the universe—to contract and twist space-time in front of it and create a bubble. Inside that bubble would be an inertial reference frame where explorers would feel no proper acceleration. The rules of physics would still apply within the bubble, but the ship would be localized outside of space.

It might help to think of an Alcubierre drive like the classic “tablecloth and dishes” party trick: The spaceship sits atop the tablecloth of spacetime, the drive pulls the fabric around it, and the ship is situated in a new place relative to the fabric.

Alcubierre describes spacetime expanding on one side of the ship and contracting on the other, thanks to that enormous amount of energy and a requisite amount of exotic matter—in this case, negative energy.

Is NASA Working On a Warp Drive?

Some scientists have criticized the Alcubierre drive, however, because it requires too much mass and negative energy for humans to ever seriously construct a warp-based propulsion system. NASA has been trying to build a physical warp drive through Eagleworks Laboratories for most of the last decade, but hasn’t yet made any significant strides.

warp propulsion
This brings us to the new study, which scientists in the Advanced Propulsion Laboratory (APL) at Applied Physics just published in the peer-reviewed journal Classical and Quantum Gravity. In the report, the APL team unveils the world’s first model for a physical warp drive—one that doesn’t require negative energy.

The study is understandably pretty thick (read the whole thing here), but here’s the gist of the model: Where the existing paradigm uses negative energy—exotic matter that doesn’t exist and can’t be generated within our current understanding of the universe—this new concept uses floating bubbles of spacetime rather than floating ships in spacetime.

The EmDrive Just Won’t Die
The physical model uses almost none of the negative energy and capitalizes on the idea that spacetime bubbles can behave almost however they like. And, the APL scientists say, this isn’t even the only other way warp speed could work. Making a model that’s at least physically comprehensible is a big step.

Plus, Alcubierre himself has endorsed the new model, which is like having Albert Einstein show up to your introductory physics class.

Of course, there’s one gigantic caveat here: The concept in this paper is still in the “far future” zone of possibility, made of ideas that scientists still don’t know how to construct in any sense.

“While the mass requirements needed for such modifications are still enormous at present,” the APL scientists write, “our work suggests a method of constructing such objects based on fully understood laws of physics.”

But while a physical drive may not be a reality today, tomorrow, or even a century from now—let’s hope it’s not that long—with this exciting new model, warp speed travel is now a lot more likely in a much shorter timespan than we previously thought.

Source: https://www.popularmechanics.com/science/a35718463/scientists-say-physical-warp-drive-is-possible/?source=nl&utm_source=nl_pop&utm_medium=email&date=0

• Experts analyzed a meteorite discovered last year in the Sahara desert
• The rock weighs 70 pounds and is tan in color with green spots throughout
• It consists mostly of volcanic rock, but also silicon dioxide that is found on Earth
• Named EC 002, it is 4.6 billion years old and was once part of an early planet

An ancient, meteorite, or achondrite, was discovered in the Sahara desert last year that has now been identified as chunk from a protoplanet that formed before Earth came into existence.

The space rock, named EC 002, dates back 4.6 billion years and consists mostly of volcanic rock, leading experts to believe it came from the crust of a very early planet.

The team of French and Japanese scientists determined that the rock was once liquid lava, but cooled and solidified over 100,000 years to form the 70-pound piece that eventually made its way to our planet.

Researchers also note that no asteroids have been found with similar properties, which suggests the protoplanet it came from has since disappeared by either becoming parts of larger bodies or ‘were simply destroyed.’

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An ancient achondrite was discovered in the Sahara desert last year that has now been identified as chunk from a protoplanet that formed before Earth came into existence. The stony meteorite, named EC 002, dates back 4.6 billion years

Anchondrites originate from early planetary bodies that have reformed from molten fragments and were flung into space as a result of another collision.

These rocks also resemble those on Earth at first glance, deeming them a rare discovery in the scientific community.

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The latest anchondrite has been named after its landing site in Algeria’s Erg Chech dune sea, which consist of several meteorites that collectively weight some 70 pounds, Motherboard reports.

Only a few thousands of these have been analyzed, most of which are basaltic, but EC 002 is made mostly of volcanic rock – making it rich in sodium, iron and magnesium.

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The rock consists mostly of volcanic rock, leading experts to believe it came from the crust of a very early planet. The team describes EC 002 as ‘relatively coarse grained, tan and beige,’ noting that it was also spotted with yellow and green bits

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The latest anchondrite has been named after its landing site in Algeria’s Erg Chech dune sea, which consist of several meteorites that collectively weight some 70 pounds

With this in mind, the team says EC 002 ‘is also the oldest magnetic rock ever observed.’

Researchers determined its age by studying the rock’s magnesium and aluminum isotopes, which showed it formed about 4.566 billion years ago – while Earth is said to be 4.543 billion years old.

The team describes EC 002 as ‘relatively coarse grained, tan and beige,’ noting that it was also spotted with yellow and green bits.

They also note that when they looked at other celestial bodies, focusing on their wavelengths, they found nothing that matched the wavelength reflected by EC 002.

The meteorite is also 58 percent silicon dioxide, making it even rarer than others previously found on Earth, as this mineral is commonly found in volcanic regions on our planet.

‘Protoplanets covered by andesitic crusts were probably frequent,’ the team wrote in the study published in Proceedings of the National Academy of Sciences.

‘However, no asteroid shares the spectral features of EC 002, indicating that almost all of these bodies have disappeared, either because they went on to form the building blocks of larger bodies or planets or were simply destroyed.’

Source: https://www.dailymail.co.uk/sciencetech/article-9346939/4-6-BILLION-year-old-meteorite-discovered-Sahara-shed-light-early-solar-system.html

Scientists have peered into the heart of Mars for the first time. NASA’s InSight spacecraft, sitting on the Martian surface with the aim of seeing deep inside the planet, has revealed the size of Mars’s core by listening to seismic energy ringing through the planet’s interior.

The measurement suggests that the radius of the Martian core is 1,810 to 1,860 kilometres, roughly half that of Earth’s. That’s larger than some previous estimates, meaning the core is less dense than had been predicted. The finding suggests the core must contain lighter elements, such as oxygen, in addition to the iron and sulfur that constitute much of its make-up. InSight scientists reported their measurements in several presentations this week at the virtual Lunar and Planetary Science Conference, based out of Houston, Texas.

Rocky planets such as Earth and Mars are divided into the fundamental layers of crust, mantle and core. Knowing the size of each of those layers is crucial to understanding how the planet formed and evolved. InSight’s measurements will help scientists to determine how Mars’s dense, metal-rich core separated from the overlying rocky mantle as the planet cooled. The core is probably still molten from Mars’s fiery birth, some 4.5 billion years ago.

Compare and contrast

The only other rocky planetary bodies for which scientists have measured the core are Earth and the Moon. Adding Mars will allow researchers to compare and contrast how the Solar System’s planets evolved. Similar to Earth, Mars once had a strong magnetic field generated by liquid sloshing its core; but that magnetic field dropped dramatically over time, causing Mars’s atmosphere to escape into space and the surface to become cold, barren, and much less hospitable to life than Earth’s.

Simon Stähler, a seismologist at the Swiss Federal Institute of Technology in Zurich, reported the core findings in a pre-recorded 18 March presentation for the virtual conference. Stähler declined an interview request from Nature, saying the team intends to submit the work for publication in a peer-reviewed journal.

First ‘marsquake’ detected on red planet

The work builds on earlier findings from InSight that detected layers in the Martian crust. “Now we start to have that deep structure down to the core,” said geophysicist Philippe Lognonné in another pre-recorded talk. Lognonné, based at the Paris Institute of Earth Physics in France, heads InSight’s seismometer team.

The spacecraft, which cost nearly US$1 billion, landed on Mars in 2018 and is the first mission to study the red planet’s interior. The stationary lander sits near the Martian equator and listens for ‘marsquakes’, the Mars equivalent of earthquakes. So far, InSight has detected around 500 quakes, meaning the planet is less seismically active than Earth but more so than the Moon. Most marsquakes are very small, Lognonné said, but nearly 50 of them have been between magnitude 2 and 4 — strong enough to provide information on the planet’s interior.

Just as seismometers do on Earth, InSight measures the size of the Martian core by studying seismic waves that have bounced off the deep boundary between the mantle and the core. With information from enough of these deep-travelling waves, InSight scientists were able to calculate the depth of the core–mantle boundary and hence the size of the core. The seismic data also suggest that the upper mantle, which extends to around 700 to 800 kilometres below the surface, contains a zone of thickened material in which seismic energy travels more slowly.

In an effort to replicate the conditions inside planetary cores, other researchers have squeezed combinations of different chemical elements at high pressures and temperatures. InSight’s estimate of the Martian core density agrees with many of those laboratory-based estimates, says Edgar Steenstra, a geochemist at the Carnegie Institution for Science in Washington, DC.

Orbital extreme

InSight might be running out of time to make discoveries. Dust has been piling up on its 2-metre-wide solar panels, cutting down on the amount of power the spacecraft can generate. Mars is also moving towards the farthest point from the Sun in its orbit, which will further limit the craft’s opportunity to recharge.

“This is going to cause us to reduce our instrument usage over the next few months,” says Mark Panning, InSight’s project scientist at the Jet Propulsion Laboratory in Pasadena, California.

In January, the team already had to give up on its German-built ‘mole’, a thermal probe that was supposed to bury itself in the soil and measure heat flow, but which encountered problems with friction and couldn’t dig deep.

Drastic temperature changes on Mars that occur when day turns to night and vice versa, create noise in the signals that Insight’s seismometer collects, as the tether connecting it to the lander lays exposed on the planet’s surface. So InSight is now trying to bury the tether by scooping dirt onto it in an attempt to insulate it.

InSight detects marsquakes mostly at night, because daytime winds cause too much shaking and interfere with seismic signals. But the windy season at its landing site recently drew to an end. Team scientists are looking forward to new-found seismic quiet to catch as many marsquakes as they can before the mission has to end.

Source: https://www.nature.com/articles/d41586-021-00696-7?utm_source=Nature+Briefing&utm_campaign=02e41775a1-briefing-dy-20210318&utm_medium=email&utm_term=0_c9dfd39373-02e41775a1-46019854

I was looking for video footage of the testing of the Mars Helicopter on Earth to see how it actually performs.

https://www.youtube.com/watch?v=nAQxNd3uBN0

This contains a fascinating discussion about what happens to rockets after they’ve been fired off. I never knew that they end up returning, more or less to where they started from. Also the mention of the pressure of solar radiation on the rocket also surprised me. I was unaware the pressure had such an effect.

https://www.youtube.com/watch?v=NLKvK_S5StE

The decade-long mission requires dozens of glass tubes, two rovers and three more rocket launches, including the first from another planet

BY THERESA MACHEMER

SMITHSONIANMAG.COM | Feb. 22, 2021, 8 a.m.

The Perseverance Rover is about to gather a rock collection with no equal. On February 18, the rover landed in Mars’ Jezero Crater to gather rock samples and begin searching for signs of ancient microbial life in visible deltas where water once flowed. The rover is set to fill 38 glass tubes with samples of Mars’ surface, then send them to Earth like pebbly postcards, souvenirs to show scientists where it has been. But the samples will need to travel a complicated delivery route to get to their final destination.

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The mission, called Mars Sample Return, will require two more rocket launches from Earth, currently slated for 2026 and 2031, and one rocket launch from Mars, which could become the first launch from another planet. If the plan runs smoothly, the mission will provide the first cache of rock samples from another planet—complete with details about when, where and how they were collected. The mission will culminate with the samples crash-landing on the mudflats of the Utah Test and Training Range. Scientists on Earth will then be able to scour the samples for details about the Red Planet’s climate, geological history and even subtle signs of life.

“It’s something that the entire Mars exploration community is really excited about and looking forward to,” says David Spencer, the Mars Sample Return campaign mission manager at NASA’s Jet Propulsion Laboratory. “And Perseverance is that critical first step.”

Perseverance is loaded with scientific equipment to help it hunt for signs of life, like SHERLOC, which uses an ultraviolet laser to observe some details of minerals, and SuperCam, which can spot organic compounds at a distance. But SHERLOC is about the size of a large hardcover book, and SuperCam is the size of two stacked shoeboxes. To study a rock’s age, texture, mineral makeup or the climate that it formed under, scientists need access to equipment that’s closer to the size of a microwave or refrigerator.

“These instruments could not be on a rover, they are too large and too sensitive and too high maintenance,” writes Rutgers University planetary scientist Juliane Gross, now the deputy curator of Apollo moon samples at NASA, in an email. “But we need to use these instruments if we want to understand how these rocks form.”

A tray holding 39 sample tubes is installed into the Perseverance rover. (NASA / JPL-Caltech / KSC)

Over 30 years ago, an international panel of scientists wrote a report that first detailed their interest in a Mars sample return mission. The scientific community knew then that a quick grab-and-go mission for one sample, as has recently been accomplished from asteroids, wouldn’t be worthwhile on Mars, given the cost of an interplanetary mission. (Last July, NASA and the European Space Agency estimated it would cost about $7 billion.)

A useful sample return mission from Mars requires grabbing a bunch of samples from many scientifically interesting locations. “Rocks and minerals record the conditions of these environment from which they crystallized,” says Gross. “So, bringing back these samples that span a range in age and crystallized at different times in Mars history, we can start to answer some of these fundamental questions.”

Perseverance will spend its first Martian year, the equivalent of 687 Earth days, in Jezero crater compacting half-ounce samples of rock and regolith into some of its glass tubes. Most of the samples will be gathered in pairs. At some point during that first year, Perseverance will drop a cache of samples in Jezero crater—while keeping the second set of samples on board.

Perseverance uses its drill to core a rock sample on Mars in this illustration. (NASA / JPL-Caltech)

If the rover is still in good working order after one Martian year, then NASA will have a chance to extend the mission. The rover will roll to the edge of Jezero crater and gather more samples from both inside the crater and along its ridge, also in pairs. Once the rover fills the last of its sample tubes, it will drop a second cache on Mars’ surface—again keeping the second set of samples stowed.

When Perseverance puts sample tubes down, it can’t pick them back up. The rover will drive away, leaving glass tubes of precious geological samples laying around on the surface of a distant planet. That might sound risky, but NASA has a plan.

“Once we place them on the surface, we will thoroughly document every tube, and where it’s located relative to its surroundings,” says Spencer. NASA will use local landmarks for on-the-ground references, as well as orbital measurements, to track the tubes. “So we’ll know, down to the centimeter level, where every tube is on the surface of Mars.”

Perseverance is also responsible for scoping out the landing site for the next phase of the sample return mission, the Sample Retrieval Lander.

The Sample Retrieval Lander is slated to depart from Earth in 2026, and it will be packing the Sample Fetch Rover, which will be designed and built by the European Space Agency. The five-foot-long rover will have four wheels for speed, solar panels for power and one job: gather Perseverance’s samples to send to Earth.

The rover will drive to the coordinates of Perseverance’s caches and use machine vision and artificial intelligence technologies to recognize and collect the sample tubes on Mars’ surface autonomously using a robotic arm—which it can do even if the glass tubes are covered by several years-worth of dust.

A robotic arm transfers samples of Martian rock and soil from a fetch rover onto a lander in this illustration. (NASA / JPL-Caltech)

And if something goes wrong with the Fetch rover, Perseverance has its backup samples.

“The most challenging aspect of Mars Sample Return is just the long chain of events that all need to be successful,” says Spencer. “We’re trying to build in robustness as much as we can. One aspect of that is the Perseverance rover will be capable of delivering samples directly to the SRL [Sample Retrieval Lander].”

Once the sample tubes reach the Sample Retrieval Lander, either from Perseverance or the Fetch rover, they will be packaged into a soccer ball-sized container called the Orbiting Sample Canister. The canister will not be able to hold all of the samples collected; it can only hold one cache. Glass tubes from the second group, which will include rocks from inside and along the edge of Jezero crater, will be first in line to leave Mars because they will have a greater variety of samples and therefore more scientific value, Spencer says.

NASA’s Mars Ascent Vehicle, which will carry tubes containing rock and soil samples, is launched from the surface of Mars in this illustration. (NASA / JPL-Caltech)

The Orbiting Sample Canister will be loaded into the Sample Retrieval Lander’s Mars Ascent Vehicle, which may become the first rocket launched from a planet other than Earth. It will ferry the canister into Mars orbit, where the canister could circle the planet for up to a decade.

To finally deliver the samples to Earth, the European Space Agency plans to launch the Earth Return Orbiter mission in 2031. The agency plans to put a satellite in Mars orbit that can intercept the canister and contain it in another layer of protection, in case it’s covered in Mars dust. Then the satellite will fly back to Earth with its quarry, transfer the canister to an Earth entry capsule and drop it on Utah’s mudflats, where giddy geologists will retrieve it.

The Mars Ascent Vehicle releases a sample container high above the Martian surface. (NASA / JPL-Caltech)

NASA and the European Space Agency haven’t yet decided how they will distribute the Mars samples among the scientific community. When Apollo astronauts brought back samples from the moon, NASA took proposals from scientists around the world for moon rock-based research projects. Those projects have illuminated the life and death of the moon’s magnetic field, the formation of the moon and Earth and the history of space weathering over billions of years.

Perseverance’s primary goal is to search for signs of fossilized life on Mars, but there is a lot to learn about Earth’s planetary neighbor no matter the results. The samples could provide insights into Mars’ history and help scientists predict Earth’s distant future. And any information about the Martian environment could help the astronauts who, someday, take humanity’s first steps on the Red Planet.

“Bringing back samples to be analyzed in Earth based laboratories is crucial for our understanding of planetary processes that have shaped our corner of the universe,” Gross says. By “bringing back these samples that span a range in age and crystallized at different times in Mars history, we can start to answer some of these fundamental questions that ultimately will help us explore Mars safely in person one day.”

Source: https://www.smithsonianmag.com/science-nature/perseverance-kicks-elaborate-effort-bring-mars-rocks-earth-180977056/?utm_source=smithsoniandaily&utm_me

The official video of the touchdown on Mars:

https://www.youtube.com/watch?v=4czjS9h4Fpg&feature=emb_logo

t’s been nearly 120 years since the Wright Brothers proved that controlled, powered flight was possible on Earth. Now, NASA is set to prove that it can happen on another planet.

Ingenuity, a four-pound helicopter, will attempt the first ever flight in another planet’s atmosphere when it reaches Mars. The pint-sized helicopter is currently strapped to the underside of NASA’s Perseverance rover, which is rocketing towards the Red Planet with an expected arrival date of February 18.

The helicopter is what’s known as a technology demonstration, which means that successfully showing its capabilities in a series of test flights is its only mission. If all goes well, Ingenuity will usher in a new era of exploration of Mars’ rugged terrain—going where rovers can’t and giving some of the planet’s treacherous features, such as its huge lava tubes, a closer inspection.

If the Wright Brothers comparison seems overwrought, consider the following: no helicopter has ever flown higher than around 40,000 feet on our planet. But on Mars the air is just one percent the density of Earth’s—so thin that flying there is the equivalent of trying to take off at 100,000 feet.

“You can’t just scale a helicopter designed to fly on Earth and expect it to work on Mars,” says MiMi Aung, the project’s manager at NASA’s Jet Propulsion Laboratory (JPL).

To generate enough lift, Aung and a team of engineers led by JPL’s Bob Balaram had to redesign traditional rotorcraft down to the very shape and material of the rotor blades, while also dramatically cranking up how fast those blades spin. The final product sports two stacked rotors featuring blades roughly four feet in diameter that spin in opposite directions at 2,400 revolutions per minute.

But generating enough lift wasn’t the team’s only concern. To create a helicopter that could fly on Mars the team faced a variety of challenges, from making the vehicle almost completely autonomous to trimming the craft down to an ultralight weight.

Though Martian gravity is only around a third of what we experience on Earth, reducing Ingenuity’s weight was a constant obsession for those on the project, says Aung. No matter what, the helicopter had to weigh four pounds or less. What became the governing law of the project emerged from the need to fit Ingenuity underneath the Perseverance rover, which capped the width of Ingenuity’s rotors at four feet and in turn restricted lift.

“Everything we did to make it incredibly lightweight was countered by the need to make it strong enough to withstand launch and the trip to Mars,” says Balaram. “It’s an aircraft that also needed to be a bona fide spacecraft.”

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Perseverance drops Ingenuity off on the Martian surface in this illustration. (NASA / JPL-Caltech)

Aung recalls a full-blown argument breaking out between the normally mild-mannered Balaram and members of the telecommunications team who made the mistake of requesting an extra three grams (around 0.1 ounces) for their equipment. “He made it clear they needed to figure it out without the extra three grams,” recalls Aung.

Another big challenge the JPL team faced was making Ingenuity almost totally autonomous, because it takes a minimum of five minutes for signals to reach Mars. Designers also needed to make the helicopter would not endanger Perseverance’s $2.5 billion mission. That required safety innovations like only charging batteries to full power just before flights to ensure Ingenuity’s lithium ion batteries had no opportunities to overcharge and explode like the smartphones of yore.

Balaram first had the idea that would become the backbone of Ingenuity’s design in the 1990s. He and some colleagues proposed the idea of a Mars helicopter to NASA in the early 2000s and got a year of funding to work on it, but ultimately the money dried up and the idea was shelved.

More than a decade later, Aung says then director of JPL, Charles Elachi, saw a talk that inspired him to return JPL with a blunt question for his team: Why aren’t we flying on Mars? Somebody in the room remembered Balaram’s work and the ball started rolling again. After a fresh round of promising tests, JPL added Aung as the project’s manager in 2014.

As the project moved farther along, a new challenge forced the team to innovate in another dimension: testing. Nobody had ever tried to fly on Mars before, and so the team had to come up with ways of trying to replicate its thin air, lower gravity and even a bit of its weather

In December 2014, the team sucked almost all the air out of a vacuum chamber at JPL until it matched the density of Mars’ atmosphere. Then they spun up the blades of their prototype. The craft lifted off the ground, demonstrating for the first time that it was possible to fly in air that thin. But the joystick-controlled helicopter bobbled and bounced off the ground like a baby bird leaving the nest for the first time before crashing onto its side, sending pieces of its blades flying. The lift was there but the control was not.

In the analysis of that test, Balaram and the team realized they needed to alter the prototype’s blades. On Earth, spinning helicopter blades start to flap up and down at speed, but the air is thick enough to dampen the flapping before it gets out of hand. In the simulated Martian air however, that flapping ran amok and destabilized the young helicopter. To solve the problem the team ended up making the blades out of super-stiff carbon fiber, which is also, crucially, very light.

NASA team members examine Ingenuity. (NASA / Cory Huston)

After tackling controlled flight, the team needed to address near-total autonomy. Havard Grip, an engineer who led the project’s guidance, navigation and control team, needed to develop the right combination of sensors and algorithms to enable the helicopter to keep itself stable and on-target. In May 2016, the next big test saw the nascent Ingenuity lift off the ground and hover steadily, but the helicopter was still tethered to a power source and a computer behind the scenes by a dangling tail of wires. Over the next two years, the team packed all the parts needed to fly on Mars—solar panels, batteries, communications and processors—into a sub-four-pound package that could essentially fly itself.

That final test of the fully loaded prototype came in January 2018. Engineers crafted a flight environment even more similar to Mars. They hung a fishing line that tugged the prototype gently upwards to simulate the Red Planet’s reduced gravity and suffused the flight chamber with carbon dioxide to more closely mimic the composition of Martian air. The helicopter took off, hovered and performed a measured side to side maneuver, looking every bit like an idea that had matured into something real.

Finally, it was time for the team to assemble the real Ingenuity. That final, nerve-wracking build took place inside a clean room with meticulously sterilized equipment and parts to make sure the helicopter tagging along on a mission aimed at searching for ancient signs of life on Mars wouldn’t bring any biological contaminants with it. Now, Ingenuity is strapped to Perseverance’s undercarriage as the whole mission hurtles through space towards Mars.

On February 18, when the helicopter arrives on the Red Planet it will contend with a dry, cold environment where nighttime temperatures can plummet to -130 degrees Fahrenheit. After a few weeks of ensuring everything is working as expected, Perseverance will motor off to some suitably flat ground to drop off Ingenuity. After depositing the helicopter in the rust-colored soil, Perseverance will drive about a football field away.

Over the course of the following 30 days, Ingenuity plans to attempt up to five increasingly ambitious flights. The historic first flight on another world will be a simple hover.

“The very idea that the first flight has to work under conditions you’ve never experienced is amazing,” says Nick Roy, a researcher at the Massachusetts Institute of Technology who specializes in autonomous robots. “You can do all the testing and analysis you want but at the end of the day you’re taking off and flying in conditions we never fly in on Earth.”

If all goes well, the test flights will culminate with a 500-foot traverse of the Martian terrain. Though Ingenuity has no science objectives, it has a pair of cameras that have the potential to deliver images of the Red Planet from an entirely new perspective.

Those images may provide glimpses of how future helicopters may transform NASA’s capabilities on Mars and even other planets. “If this effort is successful it opens up a whole new method by which we can survey the Martian surface,” says Dave Lavery, the program executive for Ingenuity at NASA headquarters. “You want to know what’s over that next hill.”

Erik Conway, a historian at JPL whose job it is to catalog its triumphs and tribulations, says simply covering more ground more quickly on Mars will do wonders for our exploration of its surface. “We’ve landed less than ten things on all of Mars,” he says. “If you tried to convince me that you knew everything there was to know about Earth by landing in ten spots, I’d laugh at you.”

Balaram says future iterations of Mars helicopters could tip the scales at up to 50 pounds, including around eight pounds of scientific instruments, and might shift to become hexacopters like some drone designs already flying here on Earth.

If Ingenuity succeeds and achieves controlled flight on Mars, Lavery says it “breaks open the dam. If we can do it on Mars…we can probably do it in other places as well.” NASA already has a similar mission called Dragonfly in the pipeline that plans to fly a nuclear-powered rotorcraft on Saturn’s moon Titan where the air is thicker.

But, all these possibilities hinge on the word “if.”

“That first flight on Mars will be the ultimate, ultimate test,” says Aung. “Nobody knew if this was possible, and now we need one more flight to prove it is.”

Source: https://www.smithsonianmag.com/science-nature/nasas-helicopter-ingenuity-will-attempt-first-flight-mars-180976958/?utm_source=smithsoniandaily&utm_medium=email&utm_campaign=20210216-daily-responsive&spMailingID=44457834&spUserID=MTA2NjM3MDM1MzY5MAS2&spJobID=1941438762&spReportId=MTk0MTQzODc2MgS2

Nine human species walked the Earth 300,000 years ago. Now there is just one. The Neanderthals, Homo neanderthalensis, were stocky hunters adapted to Europe’s cold steppes.

The related Denisovans inhabited Asia, while the more primitive Homo erectus lived in Indonesia, and Homo rhodesiensis in central Africa.

Several short, small-brained species survived alongside them: Homo naledi in South Africa, Homo luzonensis in the Philippines, Homo floresiensis ("hobbits") in Indonesia, and the mysterious Red Deer Cave People in China.

Given how quickly we’re discovering new species, more are likely waiting to be found.

By 10,000 years ago, they were all gone. The disappearance of these other species resembles a mass extinction. But there’s no obvious environmental catastrophe – volcanic eruptions, climate change, asteroid impact – driving it.

Instead, the extinctions’ timing suggests they were caused by the spread of a new species, evolving 260,000-350,000 years ago in Southern Africa: Homo sapiens.

The spread of modern humans out of Africa has caused a sixth mass extinction, a greater than 40,000-year event extending from the disappearance of Ice Age mammals to the destruction of rainforests by civilisation today. But were other humans the first casualties?

Human evolution. (Nick Longrich)

We are a uniquely dangerous species. We hunted wooly mammoths, ground sloths and moas to extinction. We destroyed plains and forests for farming, modifying over half the planet’s land area. We altered the planet’s climate.

But we are most dangerous to other human populations, because we compete for resources and land.

History is full of examples of people warring, displacing and wiping out other groups over territory, from Rome’s destruction of Carthage, to the American conquest of the West and the British colonisation of Australia. There have also been recent genocides and ethnic cleansing in Bosnia, Rwanda, Iraq, Darfur and Myanmar.

Like language or tool use, a capacity for and tendency to engage in genocide is arguably an intrinsic, instinctive part of human nature. There’s little reason to think that early Homo sapiens were less territorial, less violent, less intolerant – less human.

Optimists have painted early hunter-gatherers as peaceful, noble savages, and have argued that our culture, not our nature, creates violence. But field studies, historical accounts, and archaeology all show that war in primitive cultures was intense, pervasive and lethal.

Neolithic weapons such as clubs, spears, axes and bows, combined with guerrilla tactics like raids and ambushes, were devastatingly effective. Violence was the leading cause of death among men in these societies, and wars saw higher casualty levels per person than World Wars I and II.

Old bones and artefacts show this violence is ancient. The 9,000-year-old Kennewick Man, from North America, has a spear point embedded in his pelvis. The 10,000-year-old Nataruk site in Kenya documents the brutal massacre of at least 27 men, women, and children.

It’s unlikely that the other human species were much more peaceful. The existence of cooperative violence in male chimps suggests that war predates the evolution of humans.

Neanderthal skeletons show patterns of trauma consistent with warfare. But sophisticated weapons likely gave Homo sapiens a military advantage. The arsenal of early Homo sapiens probably included projectile weapons like javelins and spear-throwers, throwing sticks and clubs.

Complex tools and culture would also have helped us efficiently harvest a wider range of animals and plants, feeding larger tribes, and giving our species a strategic advantage in numbers.

The ultimate weapon

But cave paintings, carvings, and musical instruments hint at something far more dangerous: a sophisticated capacity for abstract thought and communication. The ability to cooperate, plan, strategise, manipulate and deceive may have been our ultimate weapon.

The incompleteness of the fossil record makes it hard to test these ideas. But in Europe, the only place with a relatively complete archaeological record, fossils show that within a few thousand years of our arrival, Neanderthals vanished.

Traces of Neanderthal DNA in some Eurasian people prove we didn’t just replace them after they went extinct. We met, and we mated.

Elsewhere, DNA tells of other encounters with archaic humans. East Asian, Polynesian and Australian groups have DNA from Denisovans. DNA from another species, possibly Homo erectus, occurs in many Asian people. African genomes show traces of DNA from yet another archaic species. The fact that we interbred with these other species proves that they disappeared only after encountering us.

But why would our ancestors wipe out their relatives, causing a mass extinction – or, perhaps more accurately, a mass genocide?

The answer lies in population growth. Humans reproduce exponentially, like all species. Unchecked, we historically doubled our numbers every 25 years. And once humans became cooperative hunters, we had no predators.

Without predation controlling our numbers, and little family planning beyond delayed marriage and infanticide, populations grew to exploit the available resources.

Further growth, or food shortages caused by drought, harsh winters or overharvesting resources would inevitably lead tribes into conflict over food and foraging territory. Warfare became a check on population growth, perhaps the most important one.

Our elimination of other species probably wasn’t a planned, coordinated effort of the sort practised by civilisations, but a war of attrition. The end result, however, was just as final. Raid by raid, ambush by ambush, valley by valley, modern humans would have worn down their enemies and taken their land.

Yet the extinction of Neanderthals, at least, took a long time – thousands of years. This was partly because early Homo sapiens lacked the advantages of later conquering civilisations: large numbers, supported by farming, and epidemic diseases like smallpox, flu, and measles that devastated their opponents.

But while Neanderthals lost the war, to hold on so long they must have fought and won many battles against us, suggesting a level of intelligence close to our own.

Today we look up at the stars and wonder if we’re alone in the universe. In fantasy and science fiction, we wonder what it might be like to meet other intelligent species, like us, but not us. It’s profoundly sad to think that we once did, and now, because of it, they’re gone.

Nick Longrich, Senior Lecturer, Paleontology and Evolutionary Biology, University of Bath.

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Source: https://www.sciencealert.com/did-homo-sapiens-kill-off-all-the-other-humans

Homo sapiens today look very different from our evolutionary origins, the microbes wriggling about in the primordial mud. But our emergence as a distinct species cannot, based on the current evidence, be conclusively traced to a single location at any single point in time.

In fact, according to a team of scientists, who have conducted a thorough review of our current understanding of human ancestry, there may never even have been such a time. Instead, the earliest known appearances of Homo sapiens traits and behaviours are consistent with a range of evolutionary histories.

We simply don’t have a large enough fossil record to definitively rule on a specific time and place in which modern humans emerged.

"Some of our ancestors will have lived in groups or populations that can be identified in the fossil record, whereas very little will be known about others," said anthropologist Chris Stringer of the Natural History Museum in London in the UK.

"Over the next decade, growing recognition of our complex origins should expand the geographic focus of paleoanthropological fieldwork to regions previously considered peripheral to our evolution, such as Central and West Africa, the Indian subcontinent and Southeast Asia."

We do have some general ideas about our history. Homo sapiens diverged from archaic ancestors sometime between a million and 300,000 years ago (by which time nine distinct human species populated the planet).

Then, we know that modern human ancestries diversified in Africa between 300,000 and 60,000 years ago.

Finally, between 60,000 and 40,000 years ago, those modern humans migrated out of Africa and across the globe, interbreeding with Neanderthals and Denisovans before those two species ultimately died out.

Based on current evidence, including genomic data and the fossil record, the researchers assert, a more precise location and time in Africa for modern human diversification cannot be identified.

"Contrary to what many believe, neither the genetic or fossil record have so far revealed a defined time and place for the origin of our species," explained geneticist Pontus Skoglund of The Francis Crick Institute in the UK.

"Such a point in time, when the majority of our ancestry was found in a small geographic region and the traits we associate with our species appeared, may not have existed. For now, it would be useful to move away from the idea of a single time and place of origin."

Instead, the researchers stress the importance of trying to separate the emergence of anatomy, physiology, traits and behaviours associated with Homo sapiens from genetic ancestry. This would help separate the question of when human ancestry emerged from when human behaviour emerged.

Conflating the two, they note, risks oversimplifying what was likely a long, continuous and complex process.

"Following from this, major emerging questions concern which mechanisms drove and sustained this human patchwork, with all its diverse ancestral threads, over time and space," said archaeologist Eleanor Scerri of the Max Planck Institute for the Science of Human History in Germany.

"Understanding the relationship between fractured habitats and shifting human niches will undoubtedly play a key role in unravelling these questions, clarifying which demographic patterns provide a best fit with the genetic and palaeoanthropological record."

The research has been published in Nature.

Source: https://www.sciencealert.com/the-origin-of-modern-humans-cannot-be-traced-to-any-one-single-point