Video: The Mysterious Return Of NASA’s Centaur Rocket

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

Photos: Incredible Science: PERSEVERANCE KICKS OFF ELABORATE EFFORT TO BRING MARS ROCKS TO EARTH

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.”

Mars Soil Collection TubesA 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 Drills For a Rock SamplePerseverance 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.

Transfer of Rock on MarsA 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.

Rocket Launched From MarsNASA’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.

Mars Ascent VehicleThe 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

NASA’S HELICOPTER INGENUITY WILL ATTEMPT THE FIRST FLIGHT ON MARS

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 and IngenuityPerseverance 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.

Examining IngenuityNASA 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 Species of Human Once Walked Earth. Now There’s Just One. Did We Kill The Rest?

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)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.The Conversation

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

Science: The Origin of Modern Humans Cannot Be Traced to Any One Single Point in Time or Space

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

Some Scientists Believe All Life Started on Mars

Some scientists believe life came from Mars.

If life spread from somewhere else in our galaxy, it’s likely to have gotten to Mars first.

Scientists hope to find DNA scraps on samples of material from Mars.

Could life as we know it have begun on Mars instead of Earth? A handful of scientists believe so, and even more think we should at least consider the possibility.

This special case of the overall theory of panspermia, where life on Earth began somewhere else and traveled or was planted here, has some prominent supporters. In a new Salon article, these proponents say the theory makes intuitive sense based on what the two planets are like.

Let’s review the facts. First, no one knows for certain where and how life began. We can backform theories based on what we know now, and what life is like throughout the fossil and carbon record on Earth.

Researchers also study unique qualities that Mars and Earth share compared with the other planets in our solar system, and Mars is, in many ways, a smaller, older Earth that “burned out” its natural resources and electromagnetic core sooner. (This, too, makes intuitive sense. A smaller ice cube melts faster, and a smaller piece of hot food cools more quickly.)

Scientists study genomics as a way to extrapolate the origins of life. The order in which building blocks like RNA and DNA emerged can be cross-referenced with, for example, the many dozens of Mars-based meteorites that are known to have hit the Earth over time.

This idea coalesces around the last universal common ancestor (LUCA), meaning the single cell from which all the rest of the cells on Earth descended. All living things have some most recent common ancestor—think about humans and, say, horses, whose most recent common ancestor might be some extinct third mammal species.

LUCA is different, requiring a lot more backtracking to a much further past. Could the last universal common ancestor be from genetic material that came from Mars?

Scientists believe the first life on Earth came just 200 million years after the first liquid water—and Mars panspermists point out that Mars likely had surface water before Earth based on the two planets’ makeups.

“Let’s say you expect life to be flourishing whenever a planet cools down to the point where it can start to have liquid water,” Erik Asphaug, a professor of planetary science at the University of Arizona, told Salon. “But just looking at our own solar system, what planet was likely to be habitable first? Almost certainly Mars.”

He continued:
“If life was going to start anywhere it might start first on Mars. We don’t know what the requirement is—you know, if it required something super special like the existence of a moon or some factors that are unique to the Earth—but just in terms of what place had liquid water first, that would have been Mars.”

If pieces from Mars were knocked off via “ballistic” panspermia, where an impact breaks off pieces that fly and strike another planet, they could have landed and flourished in the right puddle on Earth.

Astronomers say the likelihood is greater for life to have traveled to Mars before it traveled to Earth, for very prosaic reasons. Earth is closer to the sun, and anything trying to reach us would have to avoid the sun’s enormous gravity, for example. Something traveling from outside our solar system could also be slingshotted by Jupiter’s gravity directly into Mars, for example.

Intelligent Life Can’t Exist Anywhere Else
One way to test this theory is to study every sample from Mars for the presence of DNA. This is the latest installment in a long, twisting narrative arc for the idea of life on Mars, from astronomer Percival Lowell’s insistence that Mars was covered in engineered canals, to the present, where we know there’s some frozen water on the Red Planet after all.

Either way, Mars’s once-molten core slowed and solidified, reducing the planet’s gravity and atmosphere to nearly nothing and removing essential protections for any life form of which we know. But cellular matter could still exist, dormant in the cold yet there to find.

Source: https://www.popularmechanics.com/space/moon-mars/a35450915/did-life-start-on-mars/?source=nl&utm_source=nl_pop&utm_medium=email&date=021021&utm_campaign=nl22896716&utm_content=A&utm_term=AAA%20–%20High%20Minus%20Dormant%20and%2090%20Day%20Non%20Openers

Video: Science/Astronomy: The First Real Images Of Europa (Jupiter-Moon) – What Have We Discovered?

In the world of astronomy, the great spotlight sometimes falls on the famous planets of our solar system. What we quickly forget, however, in view of the numerous reports about Mars, Saturn and Co., is the fact that the natural satellites of those celestial bodies also exert a great fascination. It is not without reason that the first manned moon landing in 1969 is still considered one of the greatest milestones in the history of space exploration. Today we would like to take you on a journey to another, no less impressive moon. Our contribution today is dedicated to one of the most famous natural satellites in our planetary network: Jupiter’s moon Europa. We will explain to you what characterizes the celestial body, which missions have been carried out to study the moon, and we will go into some breathtaking real images of Europa.

View the video here: https://www.youtube.com/watch?v=wOG2iLYd4a4

SCIENTISTS HAVE TAUGHT SPINACH TO SEND EMAILS AND IT COULD WARN US ABOUT CLIMATE CHANGE

It may sound like something out of a futuristic science fiction film, but scientists have managed to engineer spinach plants which are capable of sending emails.

Through nanotechnology, engineers at MIT in the US have transformed spinach into sensors capable of detecting explosive materials. These plants are then able to wirelessly relay this information back to the scientists.

When the spinach roots detect the presence of nitroaromatics in groundwater, a compound often found in explosives like landmines, the carbon nanotubes within the plant leaves emit a signal. This signal is then read by an infrared camera, sending an email alert to the scientists.

This experiment is part of a wider field of research which involves engineering electronic components and systems into plants. The technology is known as “plant nanobionics”, and is effectively the process of giving plants new abilities.

“Plants are very good analytical chemists,” explains Professor Michael Strano who led the research. “They have an extensive root network in the soil, are constantly sampling groundwater, and have a way to self-power the transport of that water up into the leaves.”

“This is a novel demonstration of how we have overcome the plant/human communication barrier,” he adds.

ENVIRONMENTAL POTENTIAL

While the purpose of this experiment was to detect explosives, Strano and other scientists believe it could be used to help warn researchers about pollution and other environmental conditions.

Because of the vast amount of data plants absorb from their surroundings, they are ideally situated to monitor ecological changes.

In the early phases of plant nanobionic research, Strano used nanoparticles to make plants into sensors for pollutants. By altering how the plants photosynthesized, he was able to have them detect nitric oxide, a pollutant caused by combustion.

“Plants are very environmentally responsive,” Strano says. “They know that there is going to be a drought long before we do. They can detect small changes in the properties of soil and water potential. If we tap into those chemical signalling pathways, there is a wealth of information to access.”

When it’s not busy emailing researchers, spinach seems to also hold the key to efficiently powering fuel cells too.

Scientists from the American University have found that when spinach is converted into carbon nanosheets, it can function as a catalyst to help make metal-air batteries and fuel cells more efficient.

“This work suggests that sustainable catalysts can be made for an oxygen reduction reaction from natural resources,” explains Professor Shouzhong Zou, who led the paper.

Metal-air batteries are a more energy efficient alternative to lithium-ion batteries, which are commonly found in commercial products like smartphones.

Spinach was specifically chosen because of its abundance of iron and nitrogen, which are important elements in compounds that act as catalysts. The researchers had to wash, juice and grind the spinach into a powder, turning it from its edible form into nanosheets suitable for the process.

“The method we tested can produce highly active, carbon-based catalysts from spinach, which is a renewable biomass," adds Zou. "In fact, we believe it outperforms commercial platinum catalysts in both activity and stability.”

Source: https://www.euronews.com/living/2021/02/01/scientists-have-taught-spinach-to-send-emails-and-it-could-warn-us-about-climate-change