[I have been following the topic of exo-planets – planets outside the solar system for some years now. The rate of discovery is picking up faster and faster. I suspect that when new specialised satellites get going, you'll see the pace of discoveries picking up EXPONENTIALLY FASTER. I suspect within a decade or two they'll be finding planets at insane speeds and the discoveries will run into the millions and later the billions – just like with stars. It's going to be incredible. Western science totally smokes. Jan]

The number of planets detected around other stars – or exoplanets – is set to hit the 4,000 mark.

The huge haul is a sign of the explosion of findings from searches with telescopes on the ground and in space over the last 25 years.

It’s also an indication of just how common planets are – with most stars in the Milky Way hosting at least one world in orbit around them.

That’s something astronomers couldn’t be certain of just 30 years ago.

The Extrasolar Planets Encyclopedia, run by the Observatoire de Paris, has already passed the 4,000 mark.

Dr Françoise Roques, from the observatory, who is on the scientific board of the encyclopedia, told BBC News: "The great news is that we shift from a starry sky to a planetary sky, as there are more planets than stars.

"And also that the planetary systems have great diversity of structure, with planets orbiting zero, one, two… stars, or other planets."

The Nasa Exoplanet Archive is 74 planets away from the milestone. But there are 443 planet candidates detected by Nasa’s Tess space telescope (launched in 2018) awaiting confirmation.

There are a further 2,423 candidates detected by the Kepler space telescope.

The latest exoplanet to be added to the Nasa archive was the Super Earth GI 686 b, which orbits a red dwarf star (a type cooler than our Sun) which was discovered using ground telescopes. It was added on 21 March.

The total number of confirmed planets differs between the two catalogues because of slightly different acceptance criteria – along with other factors.

The early technique of detecting new worlds by the "wobble" induced by a planet’s gravitational tug on its star yielded many giant planets known as "hot Jupiters", which orbited close to their stars. These planet types were easier to detect using the wobble method.

Nasa’s Kepler space telescope was launched in 2009; it used a different technique known as the transit method to measure the dip in brightness as a planet passed in front of its host star. Kepler discovered hundreds of Neptune-sized planets and those that fell into a category known as Super Earths (those having a mass larger than Earth’s but below those of Neptune-sized planets).

Dr Roques said it remained a difficult task to distinguish between a type of star known as a brown dwarf and giant planets.

"Four-thousand is just a number as the frontier of the planet domain is uncertain," she said.

"The brown dwarfs have been defined by the [IAU – International Astronomical
Union] as small stars, but in fact, some of them are big planets. Our database collects objects until 60 Jupiter masses and contains a mix of the planetary brown dwarfs (formed in a protoplanetary disk around a star) and starry brown dwarfs (formed by collapse of interstellar cloud).

"The only way to ensure the difference is to access its internal structure, which is a difficult/ impossible task."

The first exoplanets were found around a pulsar – a highly magnetised neutron star – in 1992 by Aleksander Wolszczan and Dale Frail.

The initial discovery of a planet around a main sequence star – those that fuse hydrogen into helium within their cores – was made in 1995 by astronomers Didier Queloz and Michel Mayor.

Dr Roque explained: "For the field of exoplanet exploration, we [are
going] from discovery projects to exploration projects, for a better understanding of the structure, formation, atmosphere and, of course habitability of exoplanets."

Source: https://www.bbc.com/news/science-environment-47681239

[This is quaint. We have pieces of rock that come into orbit and later leave. Jan]

Until recently, many of us earthlings were blissfully unaware that our planet had gained a second moon. But now 2020 CD3 has become such a superstar, we’re using giant telescopes just to catch a glimpse of it.

Part-time paparazzi, full-time astronomers at the Gemini Observatory in Hawaii snapped the stunning pictures of the car-sized carbonaceous rock using the 8-meter Gemini North telescope.

The image is actually a combination of three separate images using three different filters to capture our new natural satellite in all its glory.

"Obtaining the images was a scramble for the Gemini team because the object is quickly becoming fainter as it moves away from Earth," explains Gemini Observatory astronomer John Blakeslee, adding that the new celestial superstar 2020 CD3 is expected to leave us forever some time in April.

Fear not, as there are already rumors circulating of a new generation of mini-moons that could already be orbiting the Earth.

"We expect to find a population of these objects once the Rubin Observatory is operational," said Grigori Fedorets, the lead astronomer for the Gemini observations, referencing the Vera C. Rubin Observatory, whose sole purpose will be to scan the skies for similar, previously unknown, objects.

Source: https://www.rt.com/news/481914-astronomers-first-color-photo-minimoon/

[This is astounding. This normally is not possible. This is moving things to a whole new level as bits and pieces of older and older DNA is found … something previously impossible! So much can be learned from this. Jan]

The remnants of DNA may lurk in 125 million-year-old dinosaur fossils found in China. If the microscopic structures are indeed DNA, they would be the oldest recorded preservation of chromosome material in a vertebrate fossil.

DNA is coiled inside chromosomes within a cell’s nucleus. Researchers have reported possible cell nucleus structures in fossils of plants and algae dating back millions of years. Scientists have even suggested that a set of microfossils from 540 million years ago might hold preserved nuclei.

These claims are often controversial, because it can be hard to distinguish a fossilized nucleus from a random blob of mineralization created during the fossilization process. In the new study, published Sept. 24 in the journal Communications Biology, researchers compared fossilized cartilage from the feathered, peacock-size dinosaur Caudipteryx with cells from modern chickens; they found structures in the fossils that looked much like chromatin, or threads of DNA and protein.

"The fact that they are seeing this is really interesting, and it suggests we need to do more research as to what happens to DNA and chromosomes after cell death," said Emily Carlisle, a doctoral student who studies microscopic fossils and their preservation at the University of Bristol in England but was not involved in the new research.

To answer the obvious burning question: No, we’re nowhere close to resurrecting dinosaurs from their fossilized DNA.

"If there is any DNA or DNA-like molecule in there, it will be — as a scientific guess — very, very chemically modified and altered," Alida Bailleul, a paleobiologist at the Chinese Academy of Sciences who led the new research, wrote in an email to Live Science.

However, Bailleul said, if paleontologists can identify chromosome material in fossils, they may someday be able to unravel snippets of a genetic sequence. This could reveal a little more about dinosaur physiology.

But first, researchers have to find out if the DNA is even there. Until recently, most paleontologists thought that rot and decay destroyed the contents of cells before fossilization could take hold. Any microscopic structures inside cells were considered collapsed cell contents, such as organelles and membranes, that had rotted before mineralization, Carlisle told Live Science. More recently, though, paleontologists have found legitimate cell structures in a few fossils. For example, 190 million-year-old fern cells described in 2014 in the journal Science were buried in volcanic ash and fossilized so quickly that some were frozen in the process of cell division. Unmistakable chromosomes are visible in some of these cells.

In 2020, Bailleul and her colleagues reported the possible preservation of DNA in the skull of an infant Hypacrosaurus, a kind of duck-billed dinosaur that lived 75 million years ago, found in Montana. The possible DNA was found in cartilage, the connective tissue that makes up the joints.

For the new study, the researchers turned to a well-preserved specimen of Caudipteryx held by the Shandong Tianyu Museum of Nature in China. Originally discovered in the northeastern province of Liaoning, the fossil has ample preserved cartilage, which the researchers stained with the same dyes used to image DNA in modern tissue. These dyes bind to DNA and turn it a specific color, depending on the dye, allowing the DNA to stand out against the rest of the nucleus. By examining the stained, fossilized cartilage with several microscopy methods, Bailleul and her team showed that the cartilage cells contain structures that look just like nuclei with a scramble of chromatin inside.

The stained dinosaur nuclei’s resemblance to modern cells doesn’t prove there is DNA inside them, though, Bailleul cautioned. "What it means is that there are definitely parts of original organic molecules, perhaps some original DNA in there, but we don’t know that yet for sure," she said. "We just need to go figure out exactly what these organic molecules are."

The imaging definitely seems to show nuclei, Carlisle said, but it’s harder to identify fossilized chromosomes, because no one really knows what happens to chromosomes as they decay. It’s possible that the contents of the nucleus might just collapse into structures that look like chromosomes but are really just a jumble of meaningless mineralized junk; it’s also possible that the fossilization process preserves some of the original molecular structure. (One 2012 study suggests that DNA in bone will completely break down in about 7 million years, but the timing may depend heavily on environmental factors.)

"It would be really interesting to do more experiments into that, looking at what happens inside the nuclei instead of just what happens to it from the surface," Carlisle said.

Bailleul and her colleagues hope to collect more chemical data to nail down the identity of the mysterious structures.

"I hope we can reconstruct a sequence, someday, somehow," she said. "Let’s see: I could be wrong, but I could also be right."

Source: https://www.livescience.com/dinosaur-dna-fossils.html?utm_source=SmartBrief&utm_medium=email&utm_campaign=368B3745-DDE0-4A69-A2E8-62503D85375D&utm_content=FDA2F203-A8D8-4A6F-8372-A21AA22D887C&utm_term=23709803-d360-4259-9c73-be4ff46b5c71

Hints of a previously unknown, primordial form of the substance could explain why the cosmos now seems to be expanding faster than theory predicts.

Data from the Atacama Cosmology Telescope suggest the existence of two types of dark energy at the very start of the Universe.

Cosmologists have found signs that a second type of dark energy — the ubiquitous but enigmatic substance that is pushing the current Universe’s expansion to accelerate — might have existed in the first 300,000 years after the Big Bang.

Two separate studies — both posted on the arXiv preprint server in the past week 1,2 — have detected a tentative first trace of this ‘early dark energy’ in data collected between 2013 and 2016 by the Atacama Cosmology Telescope (ACT) in Chile. If the findings are confirmed, they could help to solve a long-standing conundrum surrounding data about the early Universe, which seem to be incompatible with the rate of cosmic expansion measured today. But the data are preliminary and don’t show definitively whether this form of dark energy really existed.

“There are a number of reasons to be careful to take this as a discovery of new physics,” says Silvia Galli, a cosmologist at the Paris Institute of Astrophysics.

The authors of both preprints — one posted by the ACT team, and the other by an independent group — admit that the data are not yet strong enough to detect early dark energy with high confidence. But they say that further observations from the ACT and another observatory, the South Pole Telescope in Antarctica, could provide a more stringent test soon. “If this really is true — if the early Universe really did feature early dark energy — then we should see a strong signal,” says Colin Hill, a co-author of the ACT team’s paper1 who is a cosmologist at Columbia University in New York City.

Mapping the CMB

Both the ACT and the South Pole Telescope are designed to map the cosmic microwave background (CMB), primordial radiation sometimes described as the afterglow of the Big Bang. The CMB is one of the pillars of cosmologists’ understanding of the Universe. By mapping subtle variations in the CMB across the sky, researchers have found compelling evidence for the ‘standard model of cosmology’. This model describes the evolution of a Universe containing three primary ingredients: dark energy; the equally mysterious dark matter, which is the primary cause of the formation of galaxies; and ordinary matter, which accounts for less than 5% of the Universe’s total mass and energy.

Current state-of-the-art CMB maps were provided by the European Space Agency’s Planck mission, which was active between 2009 and 2013. Calculations based on Planck data predict — assuming that the standard model of cosmology is correct — exactly how fast the Universe should be expanding now. But for the past decade or so, increasingly accurate measurements of that expansion, based on observations of supernova explosions and other techniques, have found it to be 5–10% faster3.

How fast is the Universe expanding? Cosmologists just got more confused

Theorists have suggested a plethora of modifications to the standard model that could explain this difference. Two years ago, cosmologist Marc Kamionkowski at Johns Hopkins University in Baltimore, Maryland, and his collaborators suggested an extra ingredient for the standard model4. Their ‘early dark energy’ — which made more precise an idea that they and other teams had been working on for several years — would be a sort of fluid that permeated the Universe before withering away within a few hundred thousand years of the Big Bang. “It’s not a compelling argument, but it’s the only model we can get to work,” says Kamionkowski.

Early dark energy would not have been strong enough to cause an accelerated expansion, as ‘ordinary’ dark energy is currently doing. But it would have caused the plasma that emerged from the Big Bang to cool down faster than it would have otherwise. This would affect how CMB data should be interpreted — especially when it comes to measurements of the age of the Universe and its rate of expansion that are based on how far sound waves were able to travel in the plasma before it cooled into gas. Planck and similar observatories use features that were left in the sky after this transition to make such calculations.

The two latest studies find that the ACT’s map of the CMB’s polarization fits better with a model including early dark energy than with the standard one. Interpreting the CMB on the basis of the early dark energy model and ACT data would mean that the Universe is now 12.4 billion years old, about 11% younger than the 13.8 billion years calculated using the standard model, says Hill. Correspondingly, the current expansion would be about 5% faster than the standard model predicts — closer to what astronomers calculate today.

Inconsistencies remain

Hill says that he was previously sceptical about early dark energy, and that his team’s findings surprised him. Vivian Poulin, an astrophysicist at the University of Montpellier in France and a co-author of the second study2 based on ACT data, says it was reassuring that his team’s analysis agreed with the ACT team’s own. “The lead authors are very, very hard-nosed, conservative people, who really understand the data and the measurements,” Kamionkowski says.

But Galli warns that the ACT data seem to be inconsistent with calculations by the Planck team, which she was part of. And although the ACT’s polarization data might favour early dark energy, it is unclear whether its other major set of data — its map of CMB temperatures — shows such a preference. For these reasons, she adds, it will be crucial to cross-check the results using the South Pole Telescope, an experiment she is part of.

Wendy Freedman, an astronomer at the University of Chicago in Illinois who has contributed to some of the most precise measurements of cosmic expansion, says that the ACT-based results are interesting, if preliminary. “It is important to pursue different models” and compare them with the standard one, she says.

doi: https://doi.org/10.1038/d41586-021-02531-5

Source: https://www.nature.com/articles/d41586-021-02531-5?utm_source=Nature+Briefing&utm_campaign=51bb877e21-briefing-dy-20210917&utm_medium=email&utm_term=0_c9dfd39373-51bb877e21-46019854

The surprising discovery doesn’t make it any less likely that scientists will find life on the Red Planet.

Evidence of ancient life may have been scrubbed from parts of Mars, a new NASA study has found.

The space agency’s Curiosity rover made the surprising discovery while investigating clay-rich sedimentary rocks around its landing site in Gale Crater, a former lake that was made when an asteroid struck the Red Planet roughly 3.6 billion years ago.

Clay is a good signpost towards evidence of life because it’s usually created when rocky minerals weather away and rot after contact with water — a key ingredient for life. It is also an excellent material for storing microbial fossils.

But when Curiosity took two samples of ancient mudstone, a sedimentary rock containing clay, from patches of the dried-out lake bed, dated to the same time and place (3.5 billion years ago and just 400m apart), researchers found that one patch contained only half the expected amount of clay minerals. Instead, that patch held a greater quantity of iron oxides, the compounds that give Mars its rusty hue.

The team believes the culprit behind this geological disappearing act is brine: supersalty water that leaked into the mineral-rich clay layers and destabilized them, flushing them away and wiping patches of both the geological — and possibly even the biological — record clean.

"We used to think that once these layers of clay minerals formed at the bottom of the lake in Gale Crater, they stayed that way, preserving the moment in time they formed for billions of years," study lead author Tom Bristow, a researcher at NASA’s Ames Research Center in Mountain View, California, said in a statement. "But later brines broke down these clay minerals in some places — essentially resetting the rock record."

The rover completed its analysis by drilling into the layers of the Martian rock before using its chemistry and mineralogy instrument, known as CheMin, to investigate the samples.

The process of chemical transformation in sediments is called diagenesis, and it could have created new life beneath Mars even as it erased some of the evidence of the old life on its surface, according to the study authors. So even though old records of life may have been erased in the brine patches, the chemical conditions brought about by the influx of salty water may have enabled more life to spring up in its place, the scientists said.

"These are excellent places to look for evidence of ancient life and gauge habitability," study co-author John Grotzinger, a geology professor at the California Institute of Technology, said in the statement. "Even though diagenesis may erase the signs of life in the original lake, it creates the chemical gradients necessary to support subsurface life, so we are really excited to have discovered this."

Curiosity’s mission to Mars began nine years ago, but the rover has continued to study the Red Planet well past its initial two-year mission timeline, to establish the historic habitability of Mars for life. It is now working in collaboration with the new Perseverance Mars rover, which landed in February 2021 and has been tasked with collecting rock and soil samples for a possible return to Earth.

The research done by Curiosity has not only revealed how the Martian climate changed but also helped Perseverance determine which soil samples to collect to increase the odds of finding life.

"We’ve learned something very important: There are some parts of the Martian rock record that aren’t so good at preserving evidence of the planet’s past and possible life," co-author Ashwin Vasavada, a Curiosity project scientist at NASA’s Jet Propulsion Laboratory in California, said in the statement. "The fortunate thing is, we find both close together in Gale Crater and can use mineralogy to tell which is which."

The search for life on Mars has been given fresh impetus by a new study that could have triangulated the possible location of the six methane emissions detected by the Curiosity rover during its time in Gale crater, Live Science reported. Since all of the methane in Earth’s atmosphere comes from biological sources, scientists are thrilled to find the gas on Mars.

The researchers published their findings July 9 in the journal Science.

Source: https://www.livescience.com/mars-life-evidence-erased.html

[This is a fascinating little excerpt I came across. This is clearly not a common thing, but even so, this is definitely strange. Jan]

In a story about Sharks, it had this interesting piece:

Some captive female sharks have been known to reproduce without the aid of a male, essentially cloning themselves, Shiffman said. In 2001, a female hammerhead shark gave birth in the Henry Doorly Zoo in Nebraska without mating with a male, taking researchers by surprise. It’s an example of parthenogenesis, wherein embryos can be created with external fertilization, and has been seen in all types of animals except for mammals.

Source: https://www.livescience.com/38701-8-weird-facts-about-sharks.html

[This is fascinating. Some of this stuff is taking us well into the incredible unknown…. science fiction stuff. Jan]

Physicists have created the first ever two-dimensional supersolid — a bizarre phase of matter that behaves like both a solid and a frictionless liquid at the same time.

Supersolids are materials whose atoms are arranged into a regular, repeating, crystal structure, yet are also able to flow forever without ever losing any kinetic energy. Despite their freakish properties, which appear to violate many of the known laws of physics, physicists have long predicted them theoretically — they first appeared as a suggestion in the work of the physicist Eugene Gross as early as 1957.

Now, using lasers and super-chilled gases, physicists have finally coaxed a supersolid into a 2D structure, an advancement that could enable scientists to crack the deeper physics behind the mysterious properties of the weird matter phase.

Related: 12 stunning quantum physics experiments

Of particular interest to the researchers is how their 2D supersolids will behave when they’re spun in a circle, alongside as the tiny little whirlpools, or vortices, that will pop up inside them.

"We expect that there will be much to learn from studying rotational oscillations, for example, as well as vortices that can exist within a 2D system much more readily than in 1D," lead author Matthew Norcia, a physicist at Innsbruck University’s Institute for Quantum Optics and Quantum Information (IQOQI) in Austria, told Live Science in an email.

To create their supersolid, the team suspended a cloud of dysprosium-164 atoms inside optical tweezers before cooling the atoms down to just above zero Kelvin (minus 459.67 degrees Fahrenheit, or minus 273.15 degrees Celsius) using a technique called laser-cooling.

Firing a laser at a gas typically heats it up, but if the photons (light particles) in the laser beam are traveling in the opposite direction of the moving gas particles, they can actually cause slow and cool the gas particles. After cooling the dysprosium atoms as far as they could with the laser, the researchers loosened the "grip" of their optical tweezers, creating just enough space for the most energetic atoms to escape.

Since "warmer" particles jiggle faster than cooler ones, this technique, called evaporative cooling, left the researchers with just their super-cooled atoms; and these atoms had been transformed into a new phase of matter — a Bose-Einstein condensate: a collection of atoms that have been super-cooled to within a hair’s breadth of absolute zero.

When a gas is cooled to near zero temperature, all its atoms lose their energy, entering into the same energy states. As we can only distinguish between the otherwise identical atoms in a gas cloud by looking at their energy levels, this equalizing has a profound effect: The once disparate cloud of vibrating, jiggling, colliding atoms that make up a warmer gas then become, from a quantum mechanical point of view, perfectly identical.

This opens the door to some truly weird quantum effects. One key rule of quantum behavior, Heisenberg’s uncertainty principle, says you cannot know both a particle’s position and its momentum with absolute accuracy. Yet, now that the Bose-Einstein condensate atoms are no longer moving, all of their momentum is known. This leads to the atoms’ positions becoming so uncertain that the places they could possibly occupy grow to be larger in area than the spaces between the atoms themselves.

Instead of discrete atoms, then, the overlapping atoms in the fuzzy Bose-Einstein condensate ball act as if they are just one giant particle. This gives some Bose-Einstein condensates the property of superfluidity — allowing their particles to flow without any friction. In fact, if you were to stir a mug of a superfluid Bose-Einstein condensate, it would never stop swirling.

The researchers used dysprosium-164 (an isotope of dysprosium) because it (alongside its neighbor on the periodic table Holmium) is the most magnetic of any discovered element. This means that when the dysprosium-164 atoms were supercooled, in addition to becoming a superfluid, they also clumped together into droplets, sticking to each other like little bar magnets.

By "carefully tuning the balance between long-range magnetic interactions and short-range contact interactions between atoms," Norcia said, the team was able to make a long, one dimensional tube of droplets that also contained free-flowing atoms — a 1D supersolid. That was their previous work.

To make the leap from a 1D to a 2D supersolid, the team used a larger trap and dropped the intensity of their optical tweezer beams across two directions. This, alongside keeping enough atoms in the trap to maintain a high enough density, finally allowed them to create a zig-zag structure of droplets, similar to two offset 1D tubes sitting next to each other, a 2D supersolid.

With the task of its creation behind them, the physicists now want to use their 2D supersolid to study all of the properties that emerge from having this extra dimension. For instance, they plan to study vortices that emerge and are trapped between the droplets of the array, especially as these eddies of swirling atoms, at least in theory, can spiral forever.

This also brings researchers one step closer to the bulk, 3D, supersolids envisioned by early proposals like Gross’, and the even more alien properties they may have.

The researchers published their findings Aug. 18 in the journal Nature.

Source: https://www.livescience.com/first-2d-supersolid.html?utm_source=SmartBrief&utm_medium=email&utm_campaign=368B3745-DDE0-4A69-A2E8-62503D85375D&utm_content=C9CD1E7B-5808-4D61-9CFD-A048B7CD63FB&utm_term=23709803-d360-4259-9c73-be4ff46b5c71

[This is astounding. Jan]

Scientists used an unconventional method of creating nuclear fusion to yield a record-breaking burst of energy of more than 10 quadrillion watts, by firing intense beams of light from the world’s largest lasers at a tiny pellet of hydrogen.

Researchers at the Lawrence Livermore National Laboratory in Northern California said they had focused 192 giant lasers at the National Ignition Facility (NIF) onto a pea-size pellet, resulting in the release of 1.3 megajoules of energy in 100 trillionths of a second — roughly 10% of the energy of the sunlight that hits Earth every moment, and about 70% of the energy that the pellet had absorbed from the lasers. The scientists hope one day to reach the break-even or "ignition" point of the pellet, where it gives off 100% or more energy than it absorbs.

The energy yield is significantly larger than the scientists expected and much greater than the previous record of 170 kilojoules they set in February.

The researchers hope the result will expand their ability to research nuclear fusion weapons, the NIF’s core mission, and that it could lead to new ways to harness energy from nuclear fusion — the process that powers the sun and other stars. Some scientists hope that nuclear fusion could one day be a relatively safe and sustainable method for generating energy on Earth.

"This result is a historic step forward for inertial confinement fusion research, opening a fundamentally new regime for exploration and the advancement of our critical national security missions," Kim Budil, the director of Lawrence Livermore National Laboratory, said in a statement.

CLOSE
Giant lasers
Modern nuclear power plants use nuclear fission, which generates energy by splitting the heavy nuclei of elements like uranium and plutonium into lighter nuclei. But stars can generate even more energy from nuclear fusion, a process of smashing together lighter nuclei to make heavier elements.

Stars can fuse many different elements, including carbon and oxygen, but their main energy source comes from the fusion of hydrogen into helium. Because stars are so large and have such strong gravity, the fusion process takes place at very high pressures within the star.

Most Earthbound efforts to generate energy from fusion, such as the giant ITER project being built in France, instead use a doughnut-shaped chamber called a tokamak to confine a thin plasma of hot, neutron-heavy hydrogen inside strong magnetic fields.

Scientists and engineers have worked for more than 60 years to achieve sustainable nuclear fusion within tokamaks, with only limited success. But some researchers think they will be able to sustain fusion in tokamaks within a few years, Live Science previously reported. (ITER is not projected to do this until after 2035.)

The method developed at Lawrence Livermore National Laboratory is one of a few ways of achieving nuclear fusion without using a tokamak.

Instead, the NFI uses an array of laser-light amplifiers the size of three football fields to focus laser beams on hydrogen fuel pellets in a 33-foot-wide (10 meters) spherical metal "target chamber." These lasers are the world’s most powerful, capable of generating up to 4 megajoules of energy.

The method was originally designed so that scientists could study the behavior of hydrogen in thermonuclear weapons — so-called hydrogen bombs — but scientists think it could also have applications for generating energy from nuclear fusion.

Though stars can fuse many different elements, their main energy source comes from the fusion of hydrogen into helium.

Fusion power
Although the NIF setup couldn’t be used in a fusion power plant — its lasers can only fire about once a day, while a power plant would need to vaporize several fuel pellets every second — there are efforts to modify the process so that it can be used commercially.

Plasma physicist Siegfried Glenzer of the SLAC National Accelerator Laboratory at Stanford University, who previously worked at the Livermore facility but was not involved in the new research, told The New York Times that scientists at SLAC are working on a lower-powered laser system that could fire much more rapidly.

Glenzer hopes energy from nuclear fusion will become prominent in the efforts to replace fossil fuels, which have been dominated by solar energy and other technologies in recent years. "This is very promising for us, to achieve an energy source on the planet that won’t emit CO2," he said in the Times article, referring to the greenhouse gas carbon dioxide.

Physicist Stephen Bodner, who formerly headed laser plasma research at the Naval Research Laboratory in Washington, D.C., but is now retired, is critical of some details of the NIF’s design. But he admits he is surprised by the results, which approached the "ignition" of the pellet — the point where it emits as much or more energy than it absorbed. "They have come close enough to their goal of ignition and break-even to call it a success," Bodner told the Times.

Although Bodner favors a different design, "it demonstrates to the skeptic that there is nothing fundamentally wrong with the laser fusion concept," he said. "It is time for the U.S. to move ahead with a major laser fusion energy program."

Source: https://www.livescience.com/fusion-experiment-record-breaking-energy.html?utm_source=SmartBrief&utm_medium=email&utm_campaign=368B3745-DDE0-4A69-A2E8-62503D85375D&utm_content=C9CD1E7B-5808-4D61-9CFD-A048B7CD63FB&utm_term=23709803-d360-4259-9c73-be4ff46b5c71

Dan Caselden was up late on November 3, 2018, playing the video game Counter-Strike, when he made astronomy history. Every time he died, he would jump on his laptop to check in on an automated search he was running of NASA space telescope images.

Suddenly, in the early hours of the morning, something bizarre popped into view. “It was very confusing,” said Caselden. “It was moving faster than anything I’ve discovered. It was faint and fast, which made it very weird.”

Caselden emailed the astronomers he was working with as part of the Backyard Worlds: Planet 9 project. Once they ruled out the possibility that it was an image artifact, they realized they were looking at something wholly unusual, an exceedingly faint object 50 light-years away blazing through the galaxy at 200 kilometers per second. It was given the name WISE 1534-1043, but by virtue of its singular characteristics and chance discovery, it soon earned the nickname “The Accident.”

Astronomers now think Caselden found a brown dwarf — a failed star that lacks the necessary bulk to begin nuclear fusion in its core. “It forms like a star,” said Sarah Casewell, an astronomer at the University of Leicester in the U.K. “However, it never gains enough mass to fuse hydrogen into helium and start burning anything.”

The discovery of the Accident highlighted how we still have much to learn about brown dwarfs. These objects range in mass from an estimated 13 times the mass of Jupiter to 75 times or more, but exactly where those two boundaries lie is an ongoing dilemma. “People argue about that in conferences all the time,” said Beth Biller, an astronomer at the University of Edinburgh in the U.K., particularly the lower limit. While 13 Jupiter masses is roughly the mass at which deuterium fusion can take place — the characteristic that differentiates brown dwarfs from gas giant planets — the boundary can vary. “There’s nothing special about 13 Jupiter masses,” said Biller. “It’s completely ad hoc.”

Brown dwarfs also vary greatly in temperature. The hottest ones have surface temperatures of around 2,000 degrees Celsius — “about that of a candle flame,” said Biller. The coldest are below 200 degrees. As they do not have their own source of heat, brown dwarfs will gradually cool over billions of years to these lower temperatures. (Subdwarfs, which blur the boundary further between planets and brown dwarfs, can be cooler still. An object called WISE 0855-0714 is below freezing. “It’s the coldest object we know of outside of our solar system,” said Biller.)

What a brown dwarf might look like up close is also unclear. Despite their name — proposed by astronomer Jill Tarter in 1975 — they are likely not brown. They’re more orange or red. “For better or worse it’s stuck as a name,” said Davy Kirkpatrick, an astronomer at the California Institute of Technology.

They also have atmospheres, and those atmospheres may show some kind of banding and spotlike storms, like on Jupiter. Last year, Biller and her colleagues used these storms to measure the wind speed on a brown dwarf about 34 light-years away. They first watched features in its atmosphere come into and out of view as they rotated, and then compared this speed to a measurement of the object’s interior rotation speed gleaned from its magnetic field. Comparing the two values, the researchers calculated a wind speed of over 2,300 kilometers per hour — more than five times that of Jupiter’s winds.

Because brown dwarfs bridge the gap between stars and planets, they can help us understand both. At the upper end of the mass scale, the boundary between the largest brown dwarfs and the smallest stars can give us insights into how nuclear fusion begins. An object needs to reach temperatures of around 3 million degrees Celsius in its core to kick-start nuclear fusion, said Nolan Grieves of the University of Geneva in Switzerland; this ignites a chain reaction that turns hydrogen into helium. But no one is exactly sure how much mass is needed for that to happen, and at what point a brown dwarf becomes a star. “There’s a lot of aspects of stellar evolution that our knowledge is still pretty uncertain on,” said Biller. “Where that fusion limit is exactly is one of those questions.”

Recent work led by Grieves identified five high-mass brown dwarfs with masses between 77 and 98 times that of Jupiter. “They’re right on the border where hydrogen fusion starts to take place,” said Grieves. It’s unclear at the moment, however, which side of the boundary these five objects actually sit on. “We don’t know the true nature of these objects,” said Grieves, “because they’re so close to this limit.”

Some brown dwarfs may even be so starlike that they could host their own planets. “We know of some brown dwarf systems that look like they have protoplanetary disks around them,” said Kirkpatrick. “And there’s every indication that there are probably brown dwarfs that have their own exoplanets in orbit around them as well. A holy grail is to find a brown dwarf with a transiting exoplanet.”

On the opposite end of the brown dwarf mass scale lies the Accident. It’s an extremely small, cold and faint object — “just barely at the level where we could detect it,” said Kirkpatrick. Astronomers are eager to work out what the difference is between a low-mass brown dwarf and a high-mass gas giant planet. This makes small and faint brown dwarfs like the Accident useful targets.

The Accident also appears to be made of some strange stuff. As the universe ages, supernovas spit out lots of heavier elements such as carbon and oxygen — what astronomers call “metals.” Because of this, old objects that formed early in the universe’s history tend to have few metals, while new objects have more. Yet despite being found in our local solar neighborhood — home mostly to young, metal-rich stars — the Accident appears to be metal-poor. “We think this is probably an older brown dwarf, probably one that was created before the Milky Way had all the metal enrichment it does now,” said Kirkpatrick. Casewell added it was likely “one of the first brown dwarfs formed” in our galaxy, originating in the outer galactic halo surrounding the Milky Way and then migrating inward.

As with so many other phenomena in our universe, the finding highlights that these puzzling yet mysterious objects come in all manner of flavors, and fitting them into rigidly defined categories is no simple task. Caselden, meanwhile, hopes he can contribute more to the field in future, perhaps homing in on similar objects now he knows what to look for. “I want to find another Accident,” he said. “And I want to have it not be an accident.”

Correction: August 5, 2021
An earlier version of this article stated that stellar cores need to reach temperatures of 100 million degrees Celsius to sustain nuclear fusion. While this is true for Sun-like stars, extremely low-mass stars can burn hydrogen at temperatures as low as 3 million degrees Celsius.

Source: https://www.quantamagazine.org/neither-star-nor-planet-a-strange-brown-dwarf-puzzles-astronomers-20210804/

[I didn't even know the females in animal species were contesting for mates. Hmmmm. Well, as they say, "All is fair, in love and war".  Jan]

s the midday sun hangs over the Scandinavian spruce forest, a swarm of hopeful suitors takes to the air. They are dance flies, and it is time to attract a mate. Zigzagging and twirling, the flies show off their wide, darkened wings and feathery leg scales. They inflate their abdomens like balloons, making themselves look bigger and more appealing to a potential partner.

Suddenly, the swarm electrifies with excitement at the arrival of a new fly, the one they have all been waiting for: a male. It’s time for the preening flock of females to shine.

The flies are flipping the classic drama reenacted across the animal kingdom, in which eager males with dazzling plumage, snarls of antlers or other extraordinary traits compete for a chance to woo a reluctant female. Such competitions between males for the favor of choosy females are enshrined in evolutionary theory as “sexual selection,” with the females’ choices molding the evolution of the males’ instruments of seduction over generations.

Yet it’s becoming clear that this traditional picture of sexual selection is woefully incomplete. Dramatic and obvious reversals of the selection scenario, like that of the dance flies, aren’t often observed in nature, but recent research suggests that throughout the tree of animal life, females jockey for the attention of males far more than was believed. A new study hosted on the preprint server biorxiv.org has found that in animals as diverse as sea urchins and salamanders, females are subject to sexual selection — not as harshly as males are, but enough to make biologists rethink the balance of evolutionary forces shaping species in their accounts of the history of life.

The new work turns a spotlight on a lopsidedness in sexual selection research that may have robbed evolutionary studies on about half of all animal species of important context. Scientists have reported scattered evidence of female sexual selection in the past, but more often they haven’t had reason to look for it. That could now be changing.

“We really don’t know very much compared to how much we’ve worked on the male side of things,” said Tommaso Pizzari, an evolutionary biologist at the University of Oxford who was not involved with the new paper. “Sexual selection in females is still relatively unknown. It’s still barely charted territory.”

Michele Aldeghi
The concept of sexual selection dates back to Charles Darwin’s first writings on natural selection — briefly mentioned in The Origin of Species, and then covered more extensively in The Descent of Man — where he detailed reproductive preferences between the sexes as potentially driving evolutionary change. Within the framework of conventional natural selection, it makes sense that individuals prefer fit mates. But a key point of sexual selection is that attractiveness to potential mates can be a criterion for selection in itself, independently of how it affects fitness otherwise. Members of one sex can develop traits and behaviors appealing to the other that directly conflict with survival-driven natural selection. Taken to extremes, this can result in the unwieldy, exceptionally elongated display feathers of some male birds, for example, which are only useful in the mating contests that the males stage.

The Victorian View of Females
Yet from its very beginning, the science focused on males as the objects of sexual selection. Darwin saw females as reluctantly picking mates from gaggles of desperate male suitors. He was open to the idea of sexual selection in either direction, but the intensity of the obvious competitions for mates among males fed the idea that sexual selection happened primarily to males; the females were prizes to be won. Females might be setting the terms of the mating competitions, but it was the males who were truly being reshaped through evolution by those choices.

Darwin’s perspective was typical of his time. Theories about sexual selection were born “in the Victorian era, when you had these certain sexual stereotypes about how women should behave,” said Rebecca Boulton, an evolutionary biologist at the University of Exeter in the U.K. “And so, because the field essentially sprung up at that time, it was like, ‘Of course females aren’t mating with multiple males. Of course they’re coy or choosy.”

This viewpoint has contributed to a ubiquitous bias in how sexual selection has been investigated in the last century and a half, the researchers behind the new study argue. They estimate that studies of male-male competition and the phenomenon of female choice are 10 times more common than studies targeting the reverse.

Photo of two female wattled jacanas fighting.
Two female wattled jacanas (Jacana jacana) fight for control over territory and the potential male mates it holds.

NJDemong
“A lot of people are influenced by the culture that they live in and the things that [they] see,” said Salomé Fromonteil, a graduate student in evolutionary biology now at Uppsala University in Sweden and Ludwig Maximilian University in Munich, and lead author on the study. “It’s influenced by what we read, and what they read is that sexual selection works on males primarily.”

There are undeniable exceptions. Some that have caught researchers’ attention are in species with “sex roles” that are flipped from the conventional arrangement, as in the dance flies. Females of the American tropical wading birds called wattled jacanas (Jacana jacana) keep and defend territories rich in male mates. Among the seahorses and other pipefish, males even take on the job of “pregnancy” by internally incubating their young in a specialized pouch.

Still, scientists studying sexual selection have mostly continued to defer to Darwin’s initial observations in the 19th century. It was generally accepted that males — with their propensity for ornaments and courtship displays — experienced greater sexual selection pressures.

“Of course, that’s not how research should be,” said Tim Janicke, an evolutionary biologist at the Center for Functional and Evolutionary Ecology at the University of Montpellier in France, and senior author of the new study. “If the aim is to describe general patterns in nature, we need data-driven syntheses behind this.”

In 2016, Janicke and his team dove into the published literature measuring the strength of sexual selection acting on a variety of animal species and compared those values between the sexes. That study, published in Science Advances, confirmed that males experience a higher degree of sexual selection than females did.

Photo of a pair of seahorses.
A pair of mated seahorses. The reproductive roles in seahorses are flipped from the usual pattern in nature, with the male carrying fertilized eggs in its pouch until the young hatch.

Bae Jiwon
But as further examples of species likely to be undergoing female sexual selection accumulated, Janicke and his team were struck by a question that their study had not addressed: Just how common is sexual selection among females? They began to wonder whether it was “something rare, or whether it’s actually a general pattern,” Janicke said.

In early 2020, Janicke and Fromonteil were planning to start an empirical study on sexual selection in beetles to probe that question. Then the COVID-19 pandemic and the institutional shutdowns it triggered made laboratory experiments suddenly infeasible. But a meta-analysis of the data from the 2016 study could be done even in “confinement,” as Janicke puts it.

To compare the relative strength of sexual selection in a wide range of species, the scientists needed some way of quantifying that selection intensity. They settled on a method using the Bateman gradient, a measurement named after the 20th-century British geneticist Angus John Bateman.

More Mates, More Sexual Selection
Bateman recognized that while males can produce many sperm at low metabolic cost, females have to make relatively high investments in far fewer eggs. In the 1940s, his research on fruit flies led Bateman to propose that this fundamental divergence in gamete investment drives apart the mating strategies of males and females: To maximize their reproductive capacity, males might routinely seek out and compete for many mating partners, while females might instead evolve to be choosy.

Other researchers built on this idea, developing the Bateman gradient to describe the fitness benefits of having multiple mating partners. The measurement is the slope of the line comparing reproductive output to the number of mating events — in effect, it shows how sharply an organism’s number of offspring increases with more mating. The steeper the positive slope, the greater the fitness benefit of more mating events, which in most species means having more mates. (By mating with multiple males rather than just one, a female can sometimes hedge her bets about which mate will produce the fittest offspring.)

“If there’s positive selection on having more mating partners, this should translate into competition for mating partners,” said Janicke. “And this competition is basically the essence of Darwinian sexual selection.” For this reason, Bateman gradients are a common way of indirectly quantifying sexual selection.

From a sweep of the scientific literature, the team compiled 111 Bateman gradients calculated for females in 72 animal species, ranging from beetles to mollusks to mammals. The gradients varied widely, but they clustered in the positive range. The team also found, as expected, that species with “polyandrous” females who had access to many partners simultaneously had Bateman gradient values considerably greater than those of species with “monandrous” females who mostly mated with one male at a time.

Udo Schmidt
The findings suggest that — as has long been presumed for males — females get a fitness boost from multiple matings, and that opens the door to widespread sexual selection. The positive female Bateman gradients don’t appear to be as large as those for males, Janicke said, but their pervasiveness hints at the importance of sexual selection in the evolution of females, even in species seen as having “typical” sex roles.

While acknowledging that the Bateman gradient is a “powerful measurement to quantify sexual selection,” Janicke noted that it only reflects selection directly related to the act of mating. In species that spawn profusions of eggs, such as many fish as well as corals and other marine invertebrates, there are opportunities for selection after mating, too, with eggs competing for access to sperm, or sperm having choice capabilities that affect fertilization. Janicke’s study did not extend to this kind of post-mating sexual selection. It’s therefore possible that even more female sexual selection occurs than the new study suggests, but future work will need to test that possibility.

For Pizzari, the study “confirms something that I think we have been, as a community, beginning to realize for quite some time now: that sexual selection is potentially quite important in females across a number of species, as well as for males.”

Sexual selection in females is still relatively unknown. It’s still barely charted territory.

Tommaso Pizzari, University of Oxford

Alternative explanations, however, do still need to be tested. Some of the gradients that Janicke’s team identified may be rooted in certain females’ inherent attractiveness to males due to their reproductive output. “It may well be that the females that have more eggs to produce … happen to attract a lot more males simply because they have a higher reproductive value,” Pizzari said. If so, it wouldn’t be that more matings were more beneficial to females, “it’s that males are more interested in mating with fecund females.”

If that is the case, however, then Jonathan Henshaw, an evolutionary biologist at the University of Freiburg in Germany who was also not involved with the study, thinks that empirical tests could help isolate this effect. “If you really wanted to know what the causal effect of mating on reproductive success is, the best thing would be to do as others have done and actually manipulate the number of mates that are available to individual females,” he said.

Experiments could also help reveal whether sexual selection is playing out in these females in the wild, and how selection might be influencing the traits that females use to compete with one another. “The potential for … different mechanisms of sexual selection is there,” Boulton said. “Whether that’s what’s actually happening is something that is a little bit harder to tease apart.”

Confrontations and Decorations
Now that scientists are becoming more aware that they should look for evidence of female sexual selection, the traits and behaviors it cultivates in females may become more obvious. Black grouse (Tetrao tetrix) were considered a classic example of male sexual selection: The males have distinct, vivid coloration, and they compete for females in elaborate courtship display arenas called leks. But recent evidence suggests that while the males are putting on their show, the females are also aggressively jockeying for their choices. Female Mediterranean fruit flies (Ceratitis capitata) take a very similar approach. Certain dung beetle females have even evolved horns that may be used for battling with other females in contests over access to males.

But such intrasexual combat isn’t likely to develop in most females, Boulton argues. Fighting has an inherent risk of bodily harm — something that males can more easily afford since they just need to survive until copulation. Female reproductive success takes time: They have to live long enough to lay all their eggs, and sometimes to care for the newborns. “Whereas the males, they’ve kind of got less to lose,” she said.

The ornaments and competitions that females use to gain mates may sometimes have been overlooked because they are more subtle and look like pared-down versions of what males sport. For instance, female Malurus fairy wrens are undergoing sexual selection on their bill and plumage coloration independently of similar pressures on the males. Both male and female chickens (Gallus gallus) have fleshy ornamental combs. Hens prefer roosters with bigger combs as mates, but the roosters give more sperm to hens with bigger combs, too.

Photo of a female fairy wren.
A female emperor fairy wren (Malurus cyanocephalus). Studies suggest that the females in this genus experience sexual selection that acts on their bill and plumage.

Nigel Voaden
Such ornamentation traits in females are sometimes viewed as byproducts of sexual selection on a female’s male ancestors — “leaky sexual dimorphism,” Pizzari said. But he argues that males may pay attention to these ornaments, which could give them evolutionary significance in the females. “They might have been the target of adaptive selection in their own right.”

Another trait that males commonly seem to key in on is female body size, Boulton said. Males tend to prefer bigger and heavier females. This preference might be rooted in the value of size as a signal of the females’ overall health and reproductive potential, but it could also be a platform for female competitiveness.

No matter how female animals respond to sexual selection in nature, the new findings help reiterate how much of it went largely undetected by science for many decades. Part of the rigid stereotyping around research into sexual selection was likely informed by culture and patriarchal attitudes.

The stereotype of male-centered sexual selection may also have persisted so stubbornly “because there’s a kernel of truth in it — that in the vast majority of species, males do gain more from additional matings than females do,” Henshaw said. The pitfall is that “it’s sort of easy to go from that truth to an opposite stereotype which says that ‘generally speaking, females don’t gain anything from extra matings.’ But then you’ve kind of gone too far.”

Extreme physical differences between the sexes in some species may also have blunted the search for the more hidden but widespread sexual selection among females. “If you have a species that shows this striking sexual dimorphism, you might not start to study intrasexual selection among females,” Janicke said, because male selection would seem like the default explanation.

And yet, despite the weight of human assumptions and sensory biases, a pattern is beginning to rise to the surface: Female sexual selection is the norm. “Generally speaking, sexual selection operates on females,” Fromonteil said.

Janicke plans to continuously update the database with Bateman gradients as they are published. “This database will grow and grow, and we’ll see what other kinds of questions we can still address with this. But I am very confident that this pattern on sexual selection for females will not change,” he said.

Source: https://www.quantamagazine.org/mating-contests-among-females-may-shape-their-evolution-20210802/