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In a Weird Twist, Scientists Discover Venus Flytraps Generate Little Magnetic Fields

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The Venus flytrap (Dionaea muscipula) is already a fascinating enough plant, but scientists have discovered something else amazing about it: It generates measurable magnetic fields as its leaves snap shut.

 

And going way beyond D. muscipula, the latest research could teach us a lot about how plant life uses magnetic field signalling to communicate and as an indicator of disease (something we also see in human beings and other animals).

It’s well known that plants use electrical signals as a sort of nervous system, but capturing biomagnetism has been tricky.

A 2011 study attempted to detect a magnetic field around a Titan arum (Amorphophallus titanium) – that large, very smelly plant – using atomic magnetometers that are able to detect the smallest of fluctuations.

That study revealed that the plant generated no magnetic field greater than a millionth of the strength of the magnetic field surrounding us on Earth, resulting in the experiment being considered a failure.

The researchers involved in the 2011 study said their next steps, if they were to take any, would be to focus on a smaller plant.

For the new study, a different group of researchers did indeed go smaller. 

“We have been able to demonstrate that action potentials in a multicellular plant system produce measurable magnetic fields, something that had never been confirmed before,” says physicist Anne Fabricant, from the Johannes Gutenberg University of Mainz (JGU) in Germany.

Putting Venus flytraps under observation. (Anne Fabricant)

These “action potentials” are quick bursts of electrical activity, and the Venus flytrap can have multiple triggers: If the plant is touched, injured, affected by heat or cold, or loaded with liquid, then action potentials can be set off.

Here the researchers used heat stimulation to activate the electrical activity, and a glass cell magnetometer to measure magnetic disturbances. This approach not only kept background noise down to a minimum but had advantages over other techniques in that it could be miniaturised and didn’t require cryogenic cooling.

 

The magnetic signals measured went up to an amplitude of 0.5 picotesla, comparable to nerve impulses firing in humans and millions of times weaker than the Earth’s magnetic field – a small ripple, but a detectable one.

“You could say the investigation is a little like performing an MRI scan in humans,” says Fabricant. “The problem is that the magnetic signals in plants are very weak, which explains why it was extremely difficult to measure them with the help of older technologies.”

Besides MRI scans, other techniques such as electroencephalography (EEG) and magnetoencephalography (MEG) are used to measure magnetic fields in humans, potentially identifying problems without any invasive procedures.

With the help of this current research, the same sort of scanning might now be possible with plants too: crops could be scanned for temperature shifts, chemical changes or pests without having to damage the plants themselves, for example.

And we can add the findings to our growing knowledge about how plants send signals both internally and externally, communicating via a hidden network that scientists are only just beginning to properly explore.

“Beyond proof of principle, our findings pave the way to understanding the molecular basis of biomagnetism in living plants,” write the researchers in their published paper.

“In the future, magnetometry may be used to study long-distance electrical signaling in a variety of plant species, and to develop noninvasive diagnostics of plant stress and disease.”

The research has been published in Scientific Reports.

 

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Report: NASA’s only realistic path for humans on Mars is nuclear propulsion

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Enlarge / NASA originally studied nuclear thermal propulsion in the 1960s. Here is concept art for the Nuclear Energy for Rocket Vehicle Applications (NERVA) program.

NASA

Getting humans to Mars and back is rather hard. Insanely difficult, in fact. Many challenges confront NASA and other would-be Mars pioneers when planning missions to the red planet, but chief among them is the amount of propellant needed.

During the Apollo program 50 years ago, humans went to the Moon using chemical propulsion, which is to say rocket engines that burned liquid oxygen and hydrogen in a combustion chamber. This has its advantages, such as giving NASA the ability to start and stop an engine quickly, and the technology was then the most mature one for space travel. Since then, a few new in-space propulsion techniques have been devised. But none are better or faster for humans than chemical propulsion.

That’s a problem. NASA has a couple of baseline missions for sending four or more astronauts to Mars, but relying on chemical propulsion to venture beyond the Moon probably won’t cut it. The main reason is that it takes a whole lot of rocket fuel to send supplies and astronauts to Mars. Even in favorable scenarios where Earth and Mars line up every 26 months, a humans-to-Mars mission still requires 1,000 to 4,000 metric tons of propellant.

If that’s difficult to visualize, consider this. When upgraded to its Block 1B configuration, NASA’s Space Launch System rocket will have a carrying capacity of 105 tons to low-Earth orbit. NASA expects to launch this rocket once a year, and its cost will likely be around $2 billion for flight. So to get enough fuel into orbit for a Mars mission would require at least 10 launches of the SLS rocket, or about a decade and $20 billion. Just for the fuel.

The bottom line: if we’re going to Mars, we probably need to think about other ways of doing it.

Going nuclear

A new report from the National Academies of Sciences, Engineering, and Medicine offers some answers about two such ways. Conducted at the request of NASA, a broad-based committee of experts assessed the viability of two means of propulsion—nuclear thermal and nuclear electric—for a human mission launching to Mars in 2039.

“One of the primary takeaways of the report is that if we want to send humans to Mars, and we want to do so repeatedly and in a sustainable way, nuclear space propulsion is on the path,” said Bobby Braun, director for planetary science at the Jet Propulsion Laboratory and co-chair of the committee that wrote the report, in an interview.

The committee was not asked to recommend a particular technology, each of which rely on nuclear reactions but work differently. Nuclear thermal propulsion (NTP) involves a rocket engine in which a nuclear reactor replaces the combustion chamber and burns liquid hydrogen as a fuel. Nuclear electric propulsion (NEP) converts heat from a fission reactor to electrical power, like a power plant on Earth, and then uses this energy to produce thrust by accelerating an ionized propellant, such as xenon.

“If you look at the committee’s recommendations for NTP, we felt that an aggressive program, built on the foundational work that’s been accomplished recently, could get us there,” Braun said of the Mars 2039 goal. “For NEP, we felt that it was unclear if such a program could get us there, but we did not conclude that it could not get us there.”

Nuclear propulsion requires significantly less fuel than chemical propulsion, often less than 500 metric tons. That would be helpful for a Mars mission that would include several advance missions to pre-stage cargo on the red planet. Nuclear propulsion’s fuel consumption is also more consistent with the launch opportunities afforded by the orbits of Earth and Mars. During some conjunctions, which occur about every 26 months, the propellant required to complete a Mars mission with chemical propellants is so high that it simply is not feasible.

A plan for NASA

If NASA is to use nuclear propulsion in human missions during the 2030s, it must get started on technology development immediately, the report says. So far, the agency has been somewhat reticent to move quickly on nuclear propulsion. This may be partly due to the fact that the space agency is so heavily invested in the Space Launch System rocket and chemical propulsion needed for the Artemis Moon Program.

In recent years, therefore, NASA has not asked for nuclear propulsion funding. Congress has appropriated money for the effort anyway. In the fiscal year 2021 budget bill, NASA received $110 million for nuclear thermal propulsion development.

Braun said it would cost substantially more—at least an order of magnitude—for NASA to work with the Department of Energy and other parts of the government to develop this technology and begin cargo flights to Mars in the mid-2030s. However, he said this is the kind of project that NASA would be well positioned to undertake.

“It’s the kind of technology challenge that NASA was built for, and it’s the kind of technology challenge that our nation expects NASA to be able to overcome,” Braun said. “You know, going all the way back to the Apollo program, this is the kind of thing NASA was created for. So, I think they could do it.”

Starship

And what of the Starship concept that SpaceX is building to send humans to Mars? The project seeks to address the problem of needing a lot of chemical propellant by developing a low-cost, reusable launch system. SpaceX engineers know it will take a lot of fuel to reach Mars, but they believe the problem is solvable if Starship can be built to fly often and for relatively little money. The basic concept is to launch a Starship to orbit with empty tanks and transfer fuel launched by other Starships in low-Earth orbit before a single vehicle flies to Mars.

Braun said SpaceX is developing a plan to send humans to Mars with different assumptions than NASA. “I think there’s a fundamental difference in the assumptions that NASA tends to make for what kind of infrastructure is needed at Mars,” he said.

That’s not to say Starship cannot work. However, it does illustrate the challenge of mounting a mission to Mars with chemical-only propulsion. To use traditional propulsion, one needs to push the boundaries of reuse and heavy lift rockets to extreme limits—which is precisely what SpaceX is trying to do with its fully reusable launch system.

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Early humans in China: DNA analysis points to later arrival than previously thought

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It suggested that Homo sapiens were in China at least 20,000 years earlier than early modern humans had been previously believed to have left Africa and spread around the world. It also tantalizingly hinted at the possibility that a different group of early humans could have evolved separately in Asia.

Not so fast, says the science in 2021. New research published Monday has suggested perhaps we shouldn’t be so eager to rewrite the time line on human origins.

DNA analysis of two human teeth found in the same cave, called Fuyan, plus teeth and other fossilized remains from four other caves in the same region, suggested that it was unlikely early modern humans were in China so early.

“Our new research means it is very unlikely that Homo sapiens reached China before 50,000 years ago. It is always possible that our species reached the region more than 100,000 years ago, but we would have to say that there is no convincing evidence in favor of this at present,” said Darren Curnoe, an associate professor at the Australian Museum Research Institute in Sydney and coauthor of the paper that published in the journal PNAS on Monday.

The researchers were able to extract DNA from 10 human teeth and establish the age of other materials in the caves, such as charcoal and animal teeth, using a range of different methods. The team found that the teeth were at least 16,000 years old, while the other materials were less than 40,000 years old.

“The 2015 study relied heavily on the results of a single dating method which determined the age of cave materials (flowstone) lying above and below the sediments containing the human teeth,” he said via email. Flowstone is a sheetlike deposit of rock formed by flowing water.

“It is well understood that the most reliable dates come directly from the materials of interest to archaeologists, in this case, the human teeth. Our new (dates), including direct ages, are far younger than previously suggested.”

The 2015 study measured the radioactive decay of uranium within cave deposits, not DNA.

Chris Stringer, research leader for human evolution at the Natural History Museum in London, said that the dates of Chinese fossilized teeth had always stood out and it was right to investigate them further using different methods.

However, he said the study, while interesting, didn’t definitively rule out early modern humans in China before 50,000 years ago.

Complex family tree

Untangling human ancestry is a complicated business, and recent research has indicated the human family tree is much more bushy and less linear than the traditional “Out of Africa” narrative, which suggested modern humans originated in Africa and made their first successful migration to the rest of the world in a single wave between 50,000 and 70,000 years ago.

Many different ancient hominins existed and coexisted before Homo sapiens emerged as the lone survivor, and there was interbreeding between different groups of early humans.

Some of these groups — like Neanderthals — are easily identified through the fossil record and archaeological remains, but others — like the Denisovans — have been largely identified by their genetic legacy.

Maria Martinón-Torres, director of the National Research Center on Human Evolution in Spain and an author of the 2015 study, said she welcomed the new data on the early presence of modern humans in China.

However, she noted that the two teeth from Fuyan Cave were uncovered in 2019 and didn’t belong to the original sample her team studied and published in 2015.

“The precise data about the location and morphology of the sample is crucial, but it is not provided in the paper,” she said.

“I agree that we should be working in improving the dates of all sites of interest, especially with direct dating when possible. However, at the moment, there is an increasing number of samples that would support the presence of H. sapiens outside Africa before 50 ka (50,000 years ago),” she said via email.

She noted that there are other discoveries in Saudi Arabia, Israel, Sumatra and Laos, and another site in China where a jawbone has been found, that support the presence of Homo sapiens outside Africa before 50,000 years ago.

One of the main factors supporting the idea that early modern humans left Africa around 50,000 years ago is that there is a strong signal in the genes of present-day human populations.

“We would say that Out of Africa after 70,000 years ago seems to be the dominant picture. We can’t preclude earlier dispersals in other regions, but certainly southern China seems to have been settled in this Out of Africa wave after 50,000 years ago,” Curnoe said via email.

However, Martinón-Torres said this doesn’t rule out the possibility that earlier groups of Homo sapiens wandered around Asia earlier — just as groups of other early humans like Neanderthals and Denisovans did.

“We had no expectations about the dating of these fossils and sites and would have been pleased if we had confirmed an early dispersal. It would certainly have made the history of our species much older than generally believed, and perhaps more interesting,” Curnoe said.

“Sadly, this seems not to be the case, at the least for southern China, according to our work.”

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There Is One Way Humans Could ‘Safely’ Enter a Black Hole, Physicists Say

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To solve the mysteries of black holes, a human should just venture into one.

However, there is a rather complicated catch: A human can do this only if the respective black hole is supermassive and isolated, and if the person entering the black hole does not expect to report the findings to anyone in the entire Universe.

 

We are both physicists who study black holes, albeit from a very safe distance. Black holes are among the most abundant astrophysical objects in our Universe.

These intriguing objects appear to be an essential ingredient in the evolution of the Universe, from the Big Bang till present day. They probably had an impact on the formation of human life in our own galaxy.

A person falling into a black hole and being stretched. (Leo Rodriguez/Shanshan Rodriguez/CC BY-ND)

Two types of black holes

The Universe is littered with a vast zoo of different types of black holes.

They can vary by size and be electrically charged, the same way electrons or protons are in atoms. Some black holes actually spin. There are two types of black holes that are relevant to our discussion.

The first does not rotate, is electrically neutral – that is, not positively or negatively charged – and has the mass of our Sun. The second type is a supermassive black hole, with a mass of millions to even billions times greater than that of our Sun.

Besides the mass difference between these two types of black holes, what also differentiates them is the distance from their center to their “event horizon” – a measure called radial distance.

A person falling into a supermassive black hole would likely survive. (Leo & Shanshan Rodriguez/CC BY-ND)

The event horizon of a black hole is the point of no return. Anything that passes this point will be swallowed by the black hole and forever vanish from our known Universe.

At the event horizon, the black hole’s gravity is so powerful that no amount of mechanical force can overcome or counteract it. Even light, the fastest-moving thing in our Universe, cannot escape – hence the term “black hole”.

The radial size of the event horizon depends on the mass of the respective black hole and is key for a person to survive falling into one. For a black hole with a mass of our Sun (one solar mass), the event horizon will have a radius of just under 2 miles (3.2 kilometres).

A person approaching the event horizon of a a Sun-size black hole. (Leo and Shanshan Rodriguez/CC BY-ND)

The supermassive black hole at the center of our Milky Way galaxy, by contrast, has a mass of roughly 4 million solar masses, and it has an event horizon with a radius of 7.3 million miles or 17 solar radii.

Thus, someone falling into a stellar-size black hole will get much, much closer to the black hole’s center before passing the event horizon, as opposed to falling into a supermassive black hole.

 

This implies, due to the closeness of the black hole’s center, that the black hole’s pull on a person will differ by a factor of 1,000 billion times between head and toe, depending on which is leading the free fall.

In other words, if the person is falling feet first, as they approach the event horizon of a stellar mass black hole, the gravitational pull on their feet will be exponentially larger compared to the black hole’s tug on their head.

The person would experience spaghettification, and most likely not survive being stretched into a long, thin noodle-like shape.

Now, a person falling into a supermassive black hole would reach the event horizon much farther from the the central source of gravitational pull, which means that the difference in gravitational pull between head and toe is nearly zero.

Thus, the person would pass through the event horizon unaffected, not be stretched into a long, thin noodle, survive and float painlessly past the black hole’s horizon.

Other considerations

Most black holes that we observe in the Universe are surrounded by very hot disks of material, mostly comprising gas and dust or other objects like stars and planets that got too close to the horizon and fell into the black hole.

These disks are called accretion disks and are very hot and turbulent. They are most certainly not hospitable and would make traveling into the black hole extremely dangerous.

 

To enter one safely, you would need to find a supermassive black hole that is completely isolated and not feeding on surrounding material, gas, or even stars.

Now, if a person found an isolated supermassive black hole suitable for scientific study and decided to venture in, everything observed or measured of the black hole interior would be confined within the black hole’s event horizon.

Keeping in mind that nothing can escape the gravitational pull beyond the event horizon, the in-falling person would not be able to send any information about their findings back out beyond this horizon. Their journey and findings would be lost to the rest of the entire Universe for all time. But they would enjoy the adventure, for as long as they survived … maybe ….

Leo Rodriguez, Assistant Professor of Physics, Grinnell College and Shanshan Rodriguez, Assistant Professor of Physics, Grinnell College.

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

 

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Neanderthals interbred with modern-day humans, analysis of teeth from Jersey reveals | Science | News

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Although closely related to the modern-day man, the Neanderthal was a separate species of prehistoric human.

Neanderthals are believed to have existed between 600,000 and 40,000 years ago across parts of Europe and Central Asia.

Unfortunately for the Neanderthal and a handful of other hominins, such as the Denisovans or Homo Floresiensis, it was Homo Sapiens that won the evolutionary race.

But there is a growing body of evidence to show modern humans mingled and interbred with their close relatives.

According to the new research published today in the Journal of Human Evolution, the Jersey teeth lack certain characteristics typical of Neanderthals while somewhat resembling in shape the teeth of modern humans.



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Female physicist invents fusion rocket that may take humans to Mars

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Female physicist invents new fusion rocket that could take the first humans to Mars 10 TIMES faster than space-proven thrusters

  • A new fusion rocket concept could one day take humans to Mars
  • It uses magnetic fields to shoot plasma particles out of the rocket
  • Current space-proven fusion rockets use electric fields to propel the particles
  • The new design lets scientists tailor  the amount of thrust for a mission

By Stacy Liberatore For Dailymail.com

Published: | Updated:

Dr. Fatima Ebrahimi has invented a new fusion rocket that could one day take humans to Mars

Dr. Fatima Ebrahimi, who works for the US Department of Energy’s Princeton Plasma Physics Laboratory (PPPL), has invented a new fusion rocket that could one day take humans to Mars.

The device uses magnetic fields to shoot plasma particles from the back of the rocket and propel the craft through space. 

Using magnetic fields allows scientists to tailor the amount of thrust for a particular mission and astronauts change the amount of thrust while piloting to distant worlds.

Ebrahimi’s innovation would also take space fairing heroes to the Red Planet 10 times faster than current rocket thrusters that use electric fields to propel the particles.

‘I’ve been cooking this concept for a while,’ said Ebrahimi.

‘I had the idea in 2017 while sitting on a deck and thinking about the similarities between a car’s exhaust and the high-velocity exhaust particles.’

‘During its operation, this tokamak produces magnetic bubbles called plasmoids that move at around 20 kilometers per second, which seemed to me a lot like thrust.’

Fusion is the power that drives the sun and stars, and combines light elements in the form of plasma.

The device uses magnetic fields to shoot plasma particles from the back of the rocket and propel the craft through space

Plasma is the hot, charged state of matter composed of free electrons and atomic nuclei that represents 99 percent of the visible universe – and is capable of generating massive amounts of energy.

Scientists have been working around the clock to replicate fusion in a lab with the hopes of harnessing its power to produce electricity for rockets traveling through deep space.

Current plasma thrusters that use electric fields to propel the particles can only produce low specific impulse, or speed.

But computer simulations performed on PPPL computers and the National Energy Research Scientific Computing Center, a DOE Office of Science User Facility at Lawrence Berkeley National Laboratory in Berkeley, California, showed that the new plasma thruster concept can generate exhaust with velocities of hundreds of kilometers per second, 10 times faster than those of other thrusters.

That faster velocity at the beginning of a spacecraft’s journey could bring the outer planets within reach of astronauts, Ebrahimi said.

‘Long-distance travel takes months or years because the specific impulse of chemical rocket engines is very low, so the craft takes a while to get up to speed,’ she said.

Using magnetic fields allows scientists to tailor the amount of thrust for a particular mission and astronauts change the amount of thrust while piloting to distant worlds. 

‘But if we make thrusters based on magnetic reconnection, then we could conceivably complete long-distance missions in a shorter period of time.’

Although using fusion to power rockets is not a new concept, Ebrahimi’s thruster differ from leading devices in three ways.

The first is that changing the strength of the magnetic fields can increase or decrease the amount of thrust, which will allow better maneuvering through the dark abyss that is space.

‘By using more electromagnets and more magnetic fields, you can in effect turn a knob to fine-tune the velocity,’ Ebrahimi said.

Second, the new thruster produces movement by ejecting both plasma particles and magnetic bubbles known as plasmoids.

The plasmoids add power to the propulsion and no other thruster concept incorporates them.

However, the last difference between Ebrahimi’s concept and other ones is that hers uses magnetic fields to shoot particles of plasma out from the back of the rocket – space-proven devices using electric fields.

Using magnetic fields may be a game changer, as It allows scientists to tailor the amount of thrust for a particular mission.

‘While other thrusters require heavy gas, made of atoms like xenon, in this concept you can use any type of gas you want,’ Ebrahimi said. Scientists might prefer light gas in some cases because the smaller atoms can get moving more quickly.

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Big Ben-sized space rock among FIVE headed this way, as scientist proposes humans COLONIZE asteroid belt itself — RT World News

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While NASA warns of another five space rocks headed towards the Earth, one Finnish astrophysicist is proposing human colonization of the asteroid belt itself within the next 15 years.

As the Earth lurches out of month one of 2021, NASA has issued a brief, advising that five more asteroids that are potentially between 25 and 100 meters (82 and 98 feet) in diameter are due for close flybys before the month is up. 

On Tuesday, the 25-meter asteroid 2021 BD3, with a diameter roughly half that of the Arc de Triomphe’s height, will pass the planet at a safe distance of 3.9 million km (3.9 million miles). A short time later, an object dubbed 2021 AL, which measures 40m in diameter or roughly five London buses end-to-end, will whizz past at a distance of 4.1 million km.



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Next up, on Thursday January 28, will be the 40-meter space rock 2021 BZ, which will shoot past at 2.1 million km.

To round up a rocky start to the year, on January 29, asteroids 2021 AG7, which could be up to 100m in diameter or the same size as London’s Big Ben, and the 30-meter 2021 AF7 will pass the Earth at 4.2 million km and 6.8 million km, respectively.

Meanwhile, one forward-thinking astrophysicist proposes that, rather than asteroids coming to us, humans should instead colonize the asteroid belt, in as little as 15 years. 

Dr. Pekka Janhunen, an astrophysicist at the Finnish Meteorological Institute in Helsinki, has proposed the construction of habitable floating “mega-satellites” orbiting the dwarf planet Ceres, some 523 million kilometers from Earth, among the asteroid belt between Mars and Jupiter. 



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Like something plucked straight from modern science fiction series, these disk-shaped settlements, linked by powerful magnets, would boast thousands of cylindrical structures which could house a total of 50,000 people who would all benefit from artificial gravity generated via floating cities’ slow rotation. 

Janhunen also proposes space mining from Ceres as a means by which to set up an economy and make colonization profitable and sustainable, making use of space elevators to carry resources back to the pods and potentially back to Earth for processing. 

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