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Nature’s Ultra-Rare Isotopes Can’t Hide from this New Particle Accelerator

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A new particle accelerator at Michigan State University is producing long-awaited results. It’s called the Facility for Rare Isotope Beams, and it was completed in January 2022. Researchers have published the first results from the linear accelerator in the journal Physics Review Letters.

 

Physicists sometimes describe isotopes as different flavours of the same element. An atom of any element always has the same number of protons in its nucleus, but the number of neutrons can vary. Atoms of the same element with different numbers of neutrons are called isotopes. Carbon, for example, always has 6 protons, and its atomic number is 6. But there are different isotopes of carbon, each with a different number of neutrons, varying from 2 to 16.

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There are only two long-lived and stable isotopes of carbon: carbon-12 (12C) and carbon-13 (13C). Neither one decays, while all other carbon isotopes do. Some carbon isotopes last only a few thousand years; others exist for only the briefest moments. It’s the same with isotopes of other elements. And whether an isotope lasts for trillions of years or a trillionth of a second, its existence plays a role in nature.

Isotopes are essential in understanding many things in nature, including astrophysical objects like neutron stars and the nature and history of our Solar System. Scientists compare isotope ratios in different objects to see how they might be related. Scientists sometimes call the different ratios “fingerprints” because they fulfill a similar evidentiary role. For example, scientists measured the isotope fingerprints of Earth and compared them to Apollo lunar samples to understand how the Moon formed.

Physicists have been studying and identifying isotopes for over a century. With the advent of more powerful particle accelerators, researchers have identified isotopes that exist only for nanoseconds. It takes extremely high energy levels to produce these elusive atoms and sophisticated detectors to measure them. This is where the Facility for Rare Isotope Beams (FRIB) comes into play.

The Facility for Rare Isotope Beams is a linear accelerator shaped like a paper clip. The powerful accelerator propels atoms to speeds greater than 50% of the speed of light. Image Credit: FRIB/MSU.

Only about 250 isotopes of all types of atoms exist naturally on Earth. But theory predicts the existence of 7,000 of them, and researchers have already found about 3,000. FRIB is designed to close the gap between those numbers. Calculations predict that the accelerator will find 80% of all theorized isotopes. When its work is completed, the Chart of the Nuclides will list about 6,000 isotopes.

FRIB is made of three segments totalling 488 meters (1600 feet long), folded into a paper-clip shape. In the first stage, stable atoms of selected elements pass through a gas of electrons. The gas strips electrons from the atoms, leaving positively charged ions.

FRIB accelerates stable atoms through a gas of electrons that strip the electrons from the atom, leaving a positive ion. Image Credit: FRIB/MSU.
FRIB sends stable atoms through a gas of electrons that strips electrons from the atoms, leaving positive ions. Image Credit: FRIB/MSU.

Then FRIB accelerates the positive ions to about half of the speed of light before directing them into their target. As the stream of ions strikes the target, the collision makes the ions lose or gain protons and neutrons. That makes them unstable, producing thousands of rare isotopes, some of which last for only brief moments.

Before they can decay, the isotopes pass through a series of magnets acting as separators. They filter out isotopes by momentum and electrical charge. What remains are the isotopes desired for a particular experiment, which reach FRIB’s suite of instruments that measure the nature of the particles.

After colliding with the target, the rare and unstable isotopes pass through a series of magnets that filter out unwanted isotopes. Image Credit: FRIB/MSU.
After colliding with the target, the rare and unstable isotopes pass through a series of magnets that filter out unwanted isotopes. Image Credit: FRIB/MSU.

Researchers can’t direct FRIB to produce specific isotopes. It’s all based on probabilities. Scientists say that creating the rarest of isotopes in FRIB faces long odds: 1 in 1 quadrillion. But FRIB produces so many collisions and isotopes in a single run that 1 in 1 quadrillion isn’t insurmountable. The mass production of collisions and isotopes led to the prediction that the accelerator could produce 80% of all theorized isotopes.

FRIB has already run two experiments. The first was run at only 25% of the accelerator’s full power. It created a beam of Calcium-48 and directed it into a beryllium target. This resulted in about 40 different isotopes reaching the detectors. By measuring the time of arrival, what isotope it was, and how long it took to decay, the experiment detected five new half-lives for exotic isotopes of phosphorus, silicon, aluminum, and magnesium. Measuring these half-lives provides insights into different models of the atomic realm.

Researchers from multiple institutions took part in the first experiment. The lead spokesperson for the first experiment is Heather Crawford, a physicist at Berkeley Lab. A new paper in the Physical Review Letters presented the results.

“This is a basic science question, but it links to the bigger picture for the field. Our aim is to describe not only these nuclei, but all kinds of nuclei. These models help us fill in the gaps, which helps us more reliably predict things we haven’t been able to measure yet.”

Heather Crawford, Berkeley Lab staff scientist, Nuclear Science Division

The second experiment was directed at understanding neutron stars. Neutron stars are stellar remnants, the collapsed cores of stars that exploded as supernovae. Neutron stars are made of extraordinarily dense matter and no longer undergo fusion. There’s still a lot going on in neutron stars, and there’s much theorizing about how they function. Scientists know that neutron stars contain rare isotopes of scandium, calcium and potassium.

In this experiment, researchers produced a beam of selenium-28 to produce the same rare scandium, calcium, and potassium isotopes. This experiment began in June, and the results haven’t been published yet. But it shows how FRIB can address fundamental questions about some of nature’s most extreme objects.

FRIB can address other questions, not all related to astrophysical objects. Some of its research should shed light on more practical concerns.

In the past, research into nuclear science has produced results that have reduced suffering and shaped people’s lives. Medical imaging technologies like Magnetic Resonance Imaging (MRI) and Positron Emission Tomography (PET) are the results of basic research into nuclear physics. So are smoke detectors, something so simple, effective, and inexpensive they can easily be taken for granted. It’s impossible to calculate how many lives smoke detectors have saved and how much tragedy they’ve prevented. Same with MRI and PET.

Scientists are hopeful that research at FRIB can make similarly valuable contributions to society. History shows us that we can’t always predict the practical benefits of basic research like this but that civilization would look very different without it.

When American physicist Isidor Isaac Rabi developed a way to measure sodium atoms’ movement and magnetic properties, he wasn’t thinking about imaging the insides of human bodies. But as his work and the work of other scientists continued, scientists understood that they could use these measurements and other advances to eventually detect cancer. This work led to the development of MRI, a commonplace medical technology in our world. (Rabi eventually won the Nobel Prize in Physics for his discovery of nuclear magnetic resonance.)

Is it too much to hope that FRIB can somehow contribute to medical science? Not at all, though there are no specifics right now. But the history of one type of cancer treatment is another case study of how research into nuclear physics has reduced suffering. It’s called proton beam therapy.

Proton beam therapy allows for higher doses of radiation to be given to children and sensitive tissues like livers, eyes, and optic nerves. It can target cancer cells more precisely and avoid damaging healthy cells.

It stems directly from research at the Harvard Cyclotron Laboratory in the 1940s. In fact, the first proton beam therapy was given to patients with particle accelerators built for research, not medicine. Now proton beams are regularly used to remove eye tumours, among other things.

Will FRIP eventually treat patients? No. That’s highly unlikely.

But history shows that if we want to make advances that reduce suffering, facilities like FRIP can play a significant role.

FRIP was built to learn about some of nature’s most fascinating objects, like neutron stars. Our understanding of physics is incomplete, and researchers at FRIP intend to fill in some of the blanks. The rest of us get to come along for the ride, and that’s a win for intellectually curious people everywhere.

And if some of what we learn is applied to our everyday lives, that’s a win, too.

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New AI algorithm helps find 8 radio signals from space

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A new artificial intelligence algorithm created by a Toronto student is helping researchers search the stars for signs of life.

Peter Xiangyuan Ma, a University of Toronto undergraduate student and researcher, said he started working on the algorithm while he was in Grade 12 during the pandemic.

“I was just looking for projects and I was interested in astronomy,” he told CTV News Toronto.

The idea was to help distinguish between technological radio signals created by human technologies and signals that were potentially coming from other forms of life in space.

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“What we’re looking for is signs of technology that signifies if the sender is intelligent or not. And so unsurprised to us, we keep on finding ourselves,” Ma explained. “We don’t want to be looking at our own noisy signals.”

Using this algorithm, Ma said researchers were able to discover eight new radio signals being emitted from five different stars about 30 to 90 light years away from the Earth.

These signals, Ma said, would disappear when researchers looked away from it, which rules out, for the most part, interference from a signal originating from Earth. When they returned to the area, the signal was still there.

“We’re all very suspicious and scratching our heads,” he said. “We proved that we found things that we wanted to find … now, what do we do with all these? That’s another separate issue.”

Steve Croft, Project Scientist for Breakthrough Listen on the Green Bank Telescope, the institute whose open source data was the inspiration for Ma’s algorithm, said that finding radio signals in space is like trying to find a needle in a haystack.

“You’ve got to recognize the haystack itself and make sure that you don’t throw the needle away as you’re looking at the individual pieces of hay,” Croft, who collaborated on Ma’s research, told CTV News Toronto.

Croft said algorithms being used to discover these signals have to account for multiple characteristics, including the position they are coming from in the sky and whether or not the transmission changes over time, which could indicate if it’s coming from a rotating planet or star.

“The algorithm that Peter developed has enabled us to do this more efficiently,” he said.

The challenge, Croft says, is recognizing that false positives may exist despite a signal meeting this criteria. What could be signs of extraterrestrial life may also just be a “weirdly shaped bit of a haystack,” he added.

“And so that’s why we have to go back and look again and see if the signal still there. And with these particular examples that Peter found with his algorithm, the signal was not there when we pointed the telescope back again. And so we sort of can’t say one way or another, is this genuine?”

Researchers have been searching the sky for technologically-generated signals since the 1960s, searching thousands of stars and galaxies for signs of intelligent life. The process is called “SETI,” or “the Search for Extraterrestrial Intelligence.”

But interference from our own radio signals has always proven to be a challenge. Croft says most pieces of technology have some kind of Bluetooth or wireless wave element that creates static, resulting in larger amounts of data needed to be collected.

“That’s a challenge but also computing provides the solution,” he said.

“So the computing and particularly the machine-learning algorithms gives us the power to search through this big haystack, looking for the needle of an interesting signal.”

Ma said that while we may not have found a “technosignal” just yet, we shouldn’t give up. The next step would be to employ multiple kinds of search algorithms to find more and more signals to study.

Peter Ma

While the “dream” is to find evidence of life, Ma says he is more focused on the scientific efforts of actively looking for it.

This sentiment is echoed by Croft, who said he is most fascinating in working towards answering the question of whether humans are alone in this universe.

“I don’t show up to work every day, thinking I’m going to find aliens, but I do show up for work. So you know, I’ve got sort of some optimism.”

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How to spot the green comet in Manitoba

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Space enthusiasts in the province will get the chance to potentially see a rare green comet over the next couple of days.

The comet was discovered by astronomers in southern California last year and it was determined the last time it passed Earth was around 50,000 years ago.

Mike Jensen, the planetarium and science gallery program supervisor at the Manitoba Museum, said the time between appearances and the colour of the comet makes this unique compared to others.

“The last time it would have appeared anywhere within the region of visibility to Earth, we’re talking primitive humans walking the Earth,” said Jensen. “And then yes, its colour. Most people associate comets, they’re often referred to as ghosts of the night sky because they often have a bit of a whitish-blue appearance. This one’s got a bit of green to it. Comets are all made up of different types of material, this just happens to have a bit more of some carbon elements in it.”

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Jensen notes the green tint on the comet will be subtle, comparing it to the subtle red that surrounds Mars in the night sky.

Wednesday and Thursday are the best days to see the comet as Jensen said that’s when it will be closest to Earth – 42 million kilometres away.

“That proximity to us means it does get to its best visibility for us. The added advantage is it’s also appearing sort of high up in the northern sky, which puts it amongst the circumpolar stars of our night sky. In other words, the stars that are circling around the North Star.”

Now, just because the comet is close enough to be visible doesn’t mean it will be the easiest to see in the night sky according to Jensen. He said there are a few factors that play into having a successful sighting.

First, he suggests getting out of the city and away from the lights, noting, the darker it is, the better. If people head outside city limits, Jensen recommends people dress warmly, saying comet watching in the winter is not for the “faint of heart.”

Secondly, he said even though it might be possible to see the comet with the naked eye, he still suggests bringing binoculars to improve people’s chances. He also recommends checking star maps before leaving to get the most accurate location of where the comet may be.

Lastly, even if all of that is achieved, Jensen notes people will have to battle with the light of the moon, as it is close to a full moon.

“I’m not trying to dissuade anybody from going out to see it, but certainly, there’s going to be some hurdles to overcome in order to be able to spot it on your own.”

If people don’t want to go outside to see it, he said there are plenty of resources online to find digital views.

 – With files from CTV News’ Michael Lee

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Is there life on Mars? Maybe, and it could have dropped its teddy

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Larger than the average bear: there’s a 2-kilometer-wide bear’s face on the surface of Mars, space scientists say.

Yogi, Paddington and Winnie the Pooh, move over. There’s a new bear in town. Or on Mars, anyway.

The beaming face of a cute-looking teddy bear appears to have been carved into the surface of our nearest planetary neighbor, waiting for a passing satellite to discover it.

And when the Mars Reconnaissance Orbiter passed over last month, carrying aboard the most powerful camera ever to venture into the Solar System, that’s exactly what happened.

Scientists operating the HiRISE (High Resolution Imaging Science Experiment), which has been circling Mars since 2006, crunched the data that made it back to Earth, and have now published a picture of the face.

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“There’s a hill with a V-shaped collapse structure (the nose), two craters (the eyes), and a circular fracture pattern (the head),” said scientists at the University of Arizona, which operates the kit.

Each one of the features in the 2,000-meter (1.25-mile)-wide face has a possible explanation that hints at just how active the surface of the planet is.

“The circular fracture pattern might be due to the settling of a deposit over a buried impact crater,” the scientists said.

“Maybe the nose is a volcanic or mud vent and the deposit could be lava or mud flows?”

HiRISE, one of six instruments aboard the Orbiter, snaps super-detailed pictures of the Red Planet helping to map the surface for possible future missions, either by humans or robots.

Over the last ten years the team has managed to capture images of avalanches as they happened, and discovered dark flows that could be some kind of liquid.

They’ve also found twirling across the Martian surface, as well as a feature that some people thought looked a lot like Star Trek’s Starfleet logo.

One thing they have not found, however, is the little green men who were once popularly believed to inhabit the planet.

© 2023 AFP

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Is there life on Mars? Maybe, and it could have dropped its teddy (2023, January 31)
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