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Fake asteroid? NASA expert IDs mystery object as old rocket - Phys.org
The jig may be up for an "asteroid" that's expected to get nabbed by Earth's gravity and become a mini moon next month.
The jig may be up for an "asteroid" that's expected to get nabbed by Earth's gravity and become a mini moon next month. Instead of a cosmic rock, the newly discovered object appears to be an old rocket from a failed moon-landing mission 54 years ago that's finally making its way back home, according to NASA's leading asteroid expert. Observations should help nail its identity. "I'm pretty jazzed about this," Paul Chodas told The Associated Press. "It's been a hobby of mine to find one of these and draw such a link, and I've been doing it for decades now." Chodas speculates that asteroid 2020 SO, as it is formally known, is actually the Centaur upper rocket stage that successfully propelled NASA's Surveyor 2 lander to the moon in 1966 before it was discarded. The lander ended up crashing into the moon after one of its thrusters failed to ignite on the way there. The rocket, meanwhile, swept past the moon and into orbit around the sun as intended junk, never to be seen againuntil perhaps now. A telescope in Hawaii last month discovered the mystery object heading our way while doing a search intended to protect our planet from doomsday rocks. The object promptly was added to the International Astronomical Union's Minor Planet Center's tally of asteroids and comets found in our solar system, just 5,000 shy of the 1 million mark. The object is estimated to be roughly 26 feet (8 meters) based on its brightness. That's in the ballpark of the old Centaur, which would be less than 32 feet (10 meters) long including its engine nozzle and 10 feet (3 meters) in diameter. What caught Chodas' attention is that its near-circular orbit around the sun is quite similar to Earth'sunusual for an asteroid. "Flag number one," said Chodas, who is director of the Center for Near-Earth Object Studies at NASA's Jet Propulsion Laboratory in Southern California. The object is also in the same plane as Earth, not tilted above or below, another red flag. Asteroids usually zip by at odd angles. Lastly, it's approaching Earth at 1,500 mph (2,400 kph), slow by asteroid standards. As the object gets closer, astronomers should be able to better chart its orbit and determine how much it's pushed around by the radiation and thermal effects of sunlight. If it's an old Centauressentially a light empty canit will move differently than a heavy space rock less susceptible to outside forces. That's how astronomers normally differentiate between asteroids and space junk like abandoned rocket parts, since both appear merely as moving dots in the sky. There likely are dozens of fake asteroids out there, but their motions are too imprecise or jumbled to confirm their artificial identity, said Chodas. Sometimes it's the other way around. A mystery object in 1991, for example, was determined by Chodas and others to be a regular asteroid rather than debris, even though its orbit around the sun resembled Earth's. Even more exciting, Chodas in 2002 found what he believes was the leftover Saturn V third stage from 1969s Apollo 12, the second moon landing by NASA astronauts. He acknowledges the evidence was circumstantial, given the object's chaotic one-year orbit around Earth. It never was designated as an asteroid, and left Earth's orbit in 2003. The latest object's route is direct and much more stable, bolstering his theory. "I could be wrong on this. I don't want to appear overly confident," Chodas said. "But it's the first time, in my view, that all the pieces fit together with an actual known launch." And he's happy to note that it's a mission that he followed in 1966, as a teenager in Canada. Asteroid hunter Carrie Nugent of Olin College of Engineering in Needham, Massachusetts, said Chodas' conclusion is "a good one" based on solid evidence. She's the author of the 2017 book "Asteroid Hunters." "Some more data would be useful so we can know for sure," she said in an email. "Asteroid hunters from around the world will continue to watch this object to get that data. I'm excited to see how this develops!" The Harvard-Smithsonian Center for Astrophysics' Jonathan McDowell noted there have been "many, many embarrassing incidents of objects in deep orbit ... getting provisional asteroid designations for a few days before it was realized they were artificial." It's seldom clear-cut. Last year, a British amateur astronomer, Nick Howes, announced that an asteroid in solar orbit was likely the abandoned lunar module from NASA's Apollo 10, a rehearsal for the Apollo 11 moon landing. While this object is likely artificial, Chodas and others are skeptical of the connection. Skepticism is good, Howes wrote in an email. "It hopefully will lead to more observations when it's next in our neck of the woods" in the late 2030s. Chodas' latest target of interest was passed by Earth in their respective laps around the sun in 1984 and 2002. But it was too dim to see from 5 million miles (8 million kilometers) away, he said. He predicts the object will spend about four months circling Earth once it's captured in mid-November, before shooting back out into its own orbit around the sun next March. Chodas doubts the object will slam into Earth"at least not this time around." © 2020 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed without permission. Citation: Fake asteroid? NASA expert IDs mystery object as old rocket (2020, October 11) retrieved 11 October 2020 from https://phys.org/news/2020-10-fake-asteroid-nasa-expert-ids.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
Mind and space bending physics on a convenient chip - Phys.org
Thanks to Einstein, we know that our three-dimensional space is warped and curved. And in curved space, normal ideas of geometry and straight lines break down, creating a chance to explore an unfamiliar landscape governed by new rules. But studying how physic…
Thanks to Einstein, we know that our three-dimensional space is warped and curved. And in curved space, normal ideas of geometry and straight lines break down, creating a chance to explore an unfamiliar landscape governed by new rules. But studying how physics plays out in a curved space is challenging: Just like in real estate, location is everything. "We know from general relativity that the universe itself is curved in various places," says JQI Fellow Alicia Kollár, who is also a professor of physics at the University of Maryland (UMD). "But, any place where there's actually a laboratory is very weakly curved because if you were to go to one of these places where gravity is strong, it would just tear the lab apart." Spaces that have different geometric rules than those we usually take for granted are called non-Euclidean. If you could explore non-Euclidean environments, you would find perplexing landscapes. Space might contract so that straight, parallel lines draw together instead of rigidly maintaining a fixed spacing. Or it could expand so that they forever grow further apart. In such a world, four equal-length roads that are all connected by right turns at right angles might fail to form a square block that returns you to your initial intersection. These environments overturn core assumptions of normal navigation and can be impossible to accurately visualize. Non-Euclidean geometries are so alien that they have been used in videogames and horror stories as unnatural landscapes that challenge or unsettle the audience. But these unfamiliar geometries are much more than just distant, otherworldly abstractions. Physicists are interested in new physics that curved space can reveal, and non-Euclidean geometries might even help improve designs of certain technologies. One type of non-Euclidean geometry that is of interest is hyperbolic spacealso called negatively-curved space. Even a two-dimensional, physical version of a hyperbolic space is impossible to make in our normal, "flat" environment. But scientists can still mimic hyperbolic environments to explore how certain physics plays out in negatively curved space. In a recent paper in Physical Review A, a collaboration between the groups of Kollár and JQI Fellow Alexey Gorshkov, who is also a physicist at the National Institute of Standards and Technology and a Fellow of the Joint Center for Quantum Information and Computer Science, presented new mathematical tools to better understand simulations of hyperbolic spaces. The research builds on Kollár's previous experiments to simulate orderly grids in hyperbolic space by using microwave light contained on chips. Their new toolbox includes what they call a "dictionary between discrete and continuous geometry" to help researchers translate experimental results into a more useful form. With these tools, researchers can better explore the topsy-turvy world of hyperbolic space. The situation isn't precisely like Alice falling down the rabbit hole, but these experiments are an opportunity to explore a new world where surprising discoveries might be hiding behind any corner and the very meaning of turning a corner must be reconsidered. "There are really many applications of these experiments," says JQI postdoctoral researcher Igor Boettcher, who is the first author of the new paper. "At this point, it's unforeseeable what all can be done, but I expect that it will have a lot of rich applications and a lot of cool physics." A Curved New World In flat space, the shortest distance between two points is a straight line, and parallel lines will never intersectno matter how long they are. In a curved space, these basics of geometry no longer hold true. The mathematical definitions of flat and curved are similar to the day to day meaning when applied to two dimensions. You can get a feel for the basics of curved spaces by imaginingor actually playing around withpieces of paper or maps. For instance, the surface of a globe (or any ball) is an example of a two-dimensional positively curved space. And if you try to make a flat map into a globe, you end up with excess paper wrinkling up as you curve it into a sphere. To have a smooth sphere you must lose the excess space, resulting in parallel lines eventually meeting, like the lines of longitude that start parallel at the equator meeting at the two poles. Due to this loss, you can think of a positively curved space as being a less-spacy space than flat space. Hyperbolic space is the opposite of a positively curved spacea more-spacy space. A hyperbolic space curves away from itself at every point. Unfortunately, there isn't a hyperbolic equivalent of a ball that you can force a two-dimensional sheet into; it literally won't fit into the sort of space that we live in. The best you can do is make a saddle (or a Pringle) shape where the surrounding sheet hyperbolically curves away from the center point. Making every point on a sheet similarly hyperbolic is impossible; there isn't a way to keep curving and adding paper to create a second perfect saddle point without it bunching up and distorting the first hyperbolic saddle point. The extra space of a hyperbolic geometry makes it particularly interesting since it means that there is more room for forming connections. The differences in the possible paths between points impacts how particles interact and what sort of uniform gridlike the heptagon grid shown abovecan be made. Taking advantage of the extra connections that are possible in a hyperbolic space can make it harder to completely cut sections of a grid off from each other, which might impact designs of networks like the internet. Navigating Labyrinthine Circuits Since it is impossible to physically make a hyperbolic space on Earth, researchers must settle for creating lab experiments that reproduce some of the features of curved space. Kollár and colleagues previously showed that they can simulate a uniform, two-dimensional curved space. The simulations are performed using circuits (like the one shown above) that serve as a very organized maze for microwaves to travel through. A feature of the circuits is that microwaves are indifferent to the shapes of the resonators that contain them and are just influenced by the total length. It also doesn't matter at what angle the different paths connect. Kollár realized that these facts mean the physical space of the circuit can effectively be stretched or squeezed to create a non-Euclidean spaceat least as far as the microwaves are concerned. In their prior work, Kollár and colleagues were able to create mazes with various zigs-zagging path shapes and to demonstrate that the circuits simulated hyperbolic space. Despite the convenience and orderliness of the circuits they used, the physics playing out in them still represents a strange new world that requires new mathematical tools to efficiently navigate. Hyperbolic spaces offer different mathematical challenges to physicists than the Euclidean spaces in which they normally work. For instance, researchers can't use the standard physicist trick of imagining a lattice getting smaller and smaller to figure out what happens for an infinitely small grid, which should act like a smooth, continuous space. This is because in a hyperbolic space the shape of the lattice changes with its size due to the curving of the space. The new paper establishes mathematical tools, such as a dictionary between discrete and continuous geometry, to circumvent these issues and make sense of the results of simulations. With the new tools, researchers can get exact mathematical descriptions and predictions instead of just making qualitative observations. The dictionary allows them to study continuous hyperbolic spaces even though the simulation is only of a grid. With the dictionary, researchers can take a description of microwaves traveling between the distinct points of the grid and translate them into an equation describing smooth diffusion, or convert mathematical sums over all the sites on the grid to integrals, which is more convenient in certain situations. "If you give me an experiment with a certain number of sites, this dictionary tells you how to translate it to a setting in continuous hyperbolic space," Boettcher says. "With the dictionary, we can infer all the relevant parameters you need to know in the laboratory setup, especially for finite or small systems, which is always experimentally important." With the new tools to help understand simulation results, researchers are better equipped to answer questions and make discoveries with the simulations. Boettcher says he's optimistic about the simulations being useful for investigating the AdS/CFT correspondence, a physics conjecture for combining theories of quantum gravity and quantum field theories using a non-Euclidean description of the universe. And Kollár plans to explore if these experiments can reveal even more physics by incorporating interactions into the simulations. "The hardware opened up a new door," Kollár says. "And now we want to see what physics this will let us go to." More information: "Quantum simulation of hyperbolic space with circuit quantum electrodynamics: From graphs to geometry," Igor Boettcher, Przemyslaw Bienias, Ron Belyansky, Alicia J. Kollar, Alexey V. Gorshkov, Phys. Rev. A, 102, 032208 (2020). dx.doi.org/10.1103/PhysRevA.102.032208 Citation: Mind and space bending physics on a convenient chip (2020, October 8) retrieved 8 October 2020 from https://phys.org/news/2020-10-mind-space-physics-convenient-chip.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
The black hole always chirps twice: Scientists find clues to decipher the shape of black holes - Phys.org
A team of gravitational wave researchers led by the ARC Center of Excellence for Gravitational Wave Discovery (OzGrav) report that when two black holes collide and merge, the remnant black hole "chirps" not once, but multiple times, emitting gravitational wav…
A team of gravitational wave researchers led by the ARC Center of Excellence for Gravitational Wave Discovery (OzGrav) report that when two black holes collide and merge, the remnant black hole "chirps" not once, but multiple times, emitting gravitational wavesintense ripples in the fabric space and timethat reveal information about its shape. Their study has been published in Communications Physics. Black holes are among the most fascinating objects in the universe. At their surface, known as the event horizon, gravity is so strong that not even light can escape. Usually, black holes are silent objects that swallow anything that falls too closely to them; however, when two black holes collide and merge, they produce one of the most catastrophic events in universe: In a fraction of a second, a highly deformed black hole forms and releases tremendous amounts of energy as it settles to its final state. This phenomenon gives astronomers a unique chance to observe rapidly changing black holes and explore gravity in its most extreme form. Although colliding black holes do not produce light, astronomers can observe the detected gravitational waves they createripples in the fabric of space and time. Scientists speculate that, after a collision, the behavior of the remnant black hole is key to understanding gravity and should be encoded in the emitted gravitational waves. In the article published in Communications Physics, the scientists, led by OzGrav alumnus Prof. Juan Calderón Bustillo, reports how gravitational waves encode the shape of merging black holes as they settle into their final form. Fig. 1. a: The stages of a black hole merger. First, both black holes orbit each other, slowly approaching, during the inspiral stage.. Second the two black holes merge, forming a distorted black hole. Finally, the black hole reaches its final form. b: Frequency of the gravitational-wave signals observed from the top of the collision (leftmost) and from various positions on its equator (rest) as a function of time. The first signal shows the typical chirping signal, in which the frequency raises as a function of time. The other three show that, after the collision (at t=0) the frequency drops and rises again, producing a second chirp. Credit: C. Evans, J. Calderón Bustillo Graduate student and co-author Christopher Evans from the Georgia Institute of Technology (U.S.) says, "We performed simulations of black-hole collisions using supercomputers and then compared the rapidly changing shape of the remnant black hole to the gravitational waves it emits. We discovered that these signals are far more rich and complex than commonly thought, allowing us to learn more about the vastly changing shape of the final black hole." The gravitational waves from colliding black holes are simple signals known as "chirps." As the two black holes approach each other, they emit a signal of increasing frequency and amplitude that indicates the speed and radius of the orbit. Prof. Calderón Bustillo says, "The pitch and amplitude of the signal increases as the two black holes approach faster and faster. After the collision, the final remnant black hole emits a signal with a constant pitch and decaying amplitudelike the sound of a bell being struck." This principle is consistent with all gravitational-wave observations so far when studying the collision from the top. However, the study found something completely different happens if the collision is observed from the "equator" of the final black hole. "When we observed black holes from their equator, we found that the final black hole emits a more complex signal, with a pitch that goes up and down a few times before it dies," says Prof. Calderón Bustillo. "In other words, the black hole actually chirps several times." The team discovered that this is related to the shape of the final black hole, which acts like a kind of gravitational-wave lighthouse: "When the two original parent black holes are of different sizes, the final black hole initially looks like a chestnut, with a cusp on one side and a wider, smoother back on the other," says Bustillo. "It turns out that the black hole emits more intense gravitational waves through its most curved regions, which are those surrounding its cusp. This is because the remnant black hole is also spinning and its cusp and backside repeatedly point to all observers, producing multiple chirps." Co-author Prof. Pablo Laguna, former chair of the School of Physics at Georgia Tech and now professor at the University of Texas at Austin, said, "While a relation between the gravitational waves and the behavior of the final black hole has been long conjectured, our study provides the first explicit example of this kind of relation." More information:Communications Physics (2020). 10.1038/s42005-020-00446-7 Citation: The black hole always chirps twice: Scientists find clues to decipher the shape of black holes (2020, October 7) retrieved 7 October 2020 from https://phys.org/news/2020-10-black-hole-chirps-scientists-clues.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
US Nobel winner's 25-year odyssey to black hole at center of galaxy - Phys.org
For US astronomer Andrea Ghez, who won this year's Nobel Physics Prize, what makes black holes so fascinating is how tricky they are to conceptualize.
For US astronomer Andrea Ghez, who won this year's Nobel Physics Prize, what makes black holes so fascinating is how tricky they are to conceptualize. If she's asked to explain them to an average person, her standard answer is: "A black hole is an object whose pull of gravity is so intense that nothing can escape itnot even light." That doesn't always satisfy people's curiosity. "Very few people understand what a black hole isbut I think so many people are fascinated by them," the professor at the University of California, Los Angeles told AFP by phone after she was co-awarded this year's prize, along with Roger Penrose of Great Britain and Reinhard Genzel of Germany. This summer, Ghez's team celebrated the 25th anniversary of the start of their project, using a massive telescope in Hawaii, new optical technologies and innumerable calculations to measure the supermassive black hole at the center of the Milky Way called Sagittarius A*pronounced "Sagittarius A-star." "It's very hard to conceptualize a black hole," she said. "The laws of physics are so different near a black hole than here on Earth, that the things that we're looking for, we don't have an intuition for." "So I can think of it mathematically I can think of it abstractly but it's very hard to form a picture because you get this mixing of space and time," she added. The way to "see" a black hole, which is by definition invisible, is to observe the orbits of the stars around it. Ghez says that after 25 years, she has a detailed map in her mind of some of the brightest in a jumble of stars locked in tight orbits around Sagittarius A*. "I feel like all the stars are like children whose names you know and recognize, but every year they're a little different," said the astronomer. One star, called S2, completes its orbit in less than 16 years, speeding up on its approach to the black hole and slowing down as it moves away. Our Sun takes 200 million years to complete its orbitdinosaurs were roaming the Earth when we started our current lap. 'Torn apart' What does the professor think it would be like to fall through a black hole? "We won't survive," she said. "So if you were to think about falling into a black hole feet first, the first thing that would happen is that the pull of gravity is so much stronger in your feet than your head that you would actually be torn apart. "We wouldn't feel anything because we wouldn't exist, we wouldn't survive it, we would be broken down into our fundamental pieces. I would not want to do this." Ghez earned her PhD at Caltech in 1992 and has been at UCLA since 1994, where she co-directs the Galactic Center Group. She's convinced that more of the mysteries surrounding black holes will be unraveled in her lifetime. "I think this is an area of physics where the rate of discovery is getting faster and faster because technology is evolving so quickly," she said. The last woman to win a Nobel Physics Prize was Canadian Donna Strickland, two years ago. Before her, there were two other womenMaria Goeppert Mayer in 1962 and Marie Curie in 1903. A total of four women, against more than 200 men. "The field has been dominated by men for a long time," said Ghez. "But today, there are a lot of women going into the field. And so I'm delighted to be able to serve as a role model for young women." © 2020 AFP Citation: US Nobel winner's 25-year odyssey to black hole at center of galaxy (2020, October 6) retrieved 6 October 2020 from https://phys.org/news/2020-10-nobel-winner-year-odyssey-black.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
Very Large Telescope spots galaxies trapped in the web of a supermassive black hole - Phys.org
With the help of ESO's Very Large Telescope (VLT), astronomers have found six galaxies lying around a supermassive black hole when the Universe was less than a billion years old. This is the first time such a close grouping has been seen so soon after the Big…
With the help of ESO's Very Large Telescope (VLT), astronomers have found six galaxies lying around a supermassive black hole when the Universe was less than a billion years old. This is the first time such a close grouping has been seen so soon after the Big Bang and the finding helps us better understand how supermassive black holes, one of which exists at the centre of our Milky Way, formed and grew to their enormous sizes so quickly. It supports the theory that black holes can grow rapidly within large, web-like structures which contain plenty of gas to fuel them. "This research was mainly driven by the desire to understand some of the most challenging astronomical objectssupermassive black holes in the early Universe. These are extreme systems and to date we have had no good explanation for their existence," said Marco Mignoli, an astronomer at the National Institute for Astrophysics (INAF) in Bologna, Italy, and lead author of the new research published today in Astronomy & Astrophysics. The new observations with ESO's VLT revealed several galaxies surrounding a supermassive black hole, all lying in a cosmic "spider's web" of gas extending to over 300 times the size of the Milky Way. "The cosmic web filaments are like spider's web threads," explains Mignoli. "The galaxies stand and grow where the filaments cross, and streams of gasavailable to fuel both the galaxies and the central supermassive black holecan flow along the filaments." The light from this large web-like structure, with its black hole of one billion solar masses, has travelled to us from a time when the Universe was only 0.9 billion years old. "Our work has placed an important piece in the largely incomplete puzzle that is the formation and growth of such extreme, yet relatively abundant, objects so quickly after the Big Bang," says co-author Roberto Gilli, also an astronomer at INAF in Bologna, referring to supermassive black holes. The very first black holes, thought to have formed from the collapse of the first stars, must have grown very fast to reach masses of a billion suns within the first 0.9 billion years of the Universe's life. But astronomers have struggled to explain how sufficiently large amounts of "black hole fuel" could have been available to enable these objects to grow to such enormous sizes in such a short time. The new-found structure offers a likely explanation: the "spider's web" and the galaxies within it contain enough gas to provide the fuel that the central black hole needs to quickly become a supermassive giant. But how did such large web-like structures form in the first place? Astronomers think giant halos of mysterious dark matter are key. These large regions of invisible matter are thought to attract huge amounts of gas in the early Universe; together, the gas and the invisible dark matter form the web-like structures where galaxies and black holes can evolve. "Our finding lends support to the idea that the most distant and massive black holes form and grow within massive dark matter halos in large-scale structures, and that the absence of earlier detections of such structures was likely due to observational limitations," says Colin Norman of Johns Hopkins University in Baltimore, US, also a co-author on the study. The galaxies now detected are some of the faintest that current telescopes can observe. This discovery required observations over several hours using the largest optical telescopes available, including ESO's VLT. Using the MUSE and FORS2 instruments on the VLT at ESO's Paranal Observatory in the Chilean Atacama Desert, the team confirmed the link between four of the six galaxies and the black hole. "We believe we have just seen the tip of the iceberg, and that the few galaxies discovered so far around this supermassive black hole are only the brightest ones," said co-author Barbara Balmaverde, an astronomer at INAF in Torino, Italy. These results contribute to our understanding of how supermassive black holes and large cosmic structures formed and evolved. ESO's Extremely Large Telescope, currently under construction in Chile, will be able to build on this research by observing many more fainter galaxies around massive black holes in the early Universe using its powerful instruments. More information: M. Mignoli et al. Web of the giant: Spectroscopic confirmation of a large-scale structure around the z=6.31 quasar SDSS J1030+0524, Astronomy & Astrophysics (2020). DOI: 10.1051/0004-6361/202039045 Citation: Very Large Telescope spots galaxies trapped in the web of a supermassive black hole (2020, October 1) retrieved 1 October 2020 from https://phys.org/news/2020-10-large-telescope-galaxies-web-supermassive.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
Mutations that affect aging: More common than we thought? - Phys.org
The number of mutations that can contribute to aging may be significantly higher than previously believed, according to new research on fruit flies. The study by scientists at Linköping University, Sweden, supports a new theory about the type of mutation that…
The number of mutations that can contribute to aging may be significantly higher than previously believed, according to new research on fruit flies. The study by scientists at Linköping University, Sweden, supports a new theory about the type of mutation that can lie behind aging. The results have been published in BMC Biology. We live, we age and we die. Many functions of our bodies deteriorate slowly but surely as we age, and eventually an organism dies. This thought may not be very encouraging, but most of us have probably accepted that this is the fate of all living creaturesdeath is part of life. However, those who study evolutionary biology find it far from clear why this is the case. "The evolution of aging is, in a manner of speaking, a paradox. Evolution causes continuous adaptation in organisms, but even so it has not resulted in them ceasing to age," says Urban Friberg, senior lecturer in the Department of Physics, Chemistry and Biology at Linköping University and leader of the study. Nearly 70 years ago, evolutionary biologists proposed two theories concerning two different types of mutation that contribute to aging. Both of these mutations have a detrimental effect as the organism becomes olderwhich leads to agingwhile they are either advantageous or neutral early in life. Researchers have, however, not been able to determine which of the two types of mutation contributes most to aging, despite experimental studies. A new theory was proposed a few years ago suggesting that aging is caused by mutations with a detrimental effect early in life, and whose negative effects increase with age. Those who support this hypothesis believe that many of the mutations that arise have negative effects right from the start, compared with the normal variant of a gene. The study now published describes experiments to test the theory of mutations that have a detrimental effect throughout life and contribute to aging. The authors used one of the most well-studied animals in the world, namely the fruit fly, or Drosophila melanogaster. They tested 20 different mutations that they had placed into the genetic material of the flies. For each individual mutation, they studied a group of flies with the mutation and a control group without it. Each mutation had a specific, visible effect, which made it easy to follow, such as a somewhat different appearance of the wings or a different shape of the eyes. As an organism ages, the probability that an individual dies increases, and its ability to reproduce falls. The researchers determined the fertility of the fruit flies and used it as a measure of aging. They counted the number of eggs laid by each female early in life, after two weeks, and finally after a further two weeks (which is a ripe old age for a fruit fly!). The researchers wanted to see whether the difference between flies with the mutations and the control group changed as they aged. The results support the theory they were testing. Most of the mutations had a negative effect on the fertility of the fruit flies early in life, and most of them also caused reproductive aging to occur more rapidly. "The results suggest that mutations that are detrimental early in life can also contribute to aging. Thus it may be that mutations that bring on aging are significantly more common than we previously believed," says Martin Iinatti Brengdahl, doctoral student in the Department of Physics, Chemistry and Biology and principal author of the study. More information: "Deleterious mutations show increasing negative effects with age in Drosophila melanogaster", Martin I. Brengdahl, Christopher M. Kimber, Phoebe Elias, Josephine Thompson and Urban Friberg, (2020), BMC Biology, published online 30 September, DOI: 10.1186/s12915-020-00858-5 Citation: Mutations that affect aging: More common than we thought? (2020, September 29) retrieved 29 September 2020 from https://phys.org/news/2020-09-mutations-affect-aging-common-thought.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
Evolution of radio-resistance is more complicated than previously thought - Phys.org
The toughest organisms on Earth, called extremophiles, can survive extreme conditions like extreme dryness (desiccation), extreme cold, space vacuum, acid, or even high-level radiation. So far, the toughest of all seems to be the bacterium Deinococcus radiodu…
The toughest organisms on Earth, called extremophiles, can survive extreme conditions like extreme dryness (desiccation), extreme cold, space vacuum, acid, or even high-level radiation. So far, the toughest of all seems to be the bacterium Deinococcus radioduransable to survive doses of radiation a thousand times greater than those fatal to humans. But to this date, scientists remained puzzled by how radio-resistance could have evolved in several organisms on our planet, naturally protected from solar radiation by its magnetic field. While some scientists suggest that radio-resistance in extremophile organisms could have evolved along with other kinds of resistance, such as resistance to desiccation, a question remained: which genes are specifically involved in radio-resistance? To address this question, the team of Dr. Cox, at the University of Wisconsin-Madison, decided to "let the cells tell them". The researchers started with the naturally non-resistant bacteria, E. coli, and exposed it to iterative cycles of high-level irradiation. After many rounds of radiation exposure and outgrowth, a few radio-resistant populations emerged. Using whole-genome sequencing, the researchers studied the genetic alterations present in each radio-resistant population and determined which mutation provided radio-resistance to the bacteria. In their first study, the team of Dr. Cox started by exposing E. coli to 50 rounds of ionization (Bruckbauer et al 2019b). After about 10 rounds, some radio-resistant populations emerged, and after 50, the study of their genetic profile highlighted three mutations responsible for radio-resistanceall in genes linked to DNA repair mechanisms. Here, in their new study, the team exposed the bacteria to 50 more rounds of radiation exposure and selection. The results published in Frontiers in Microbiology show that the populations of radioresistant E. coli, continued to evolve and sub-populations emerged. Surprisingly, while radio-resistance induced by the first series of ionization could mainly be associated with three mutations, the second induced hundreds of mutations including large deletions and duplications of several genes. "The four populations we are evolving in this new trial have now achieved levels of radio-resistance that are approaching the levels seen with Deinococcus radiodurans. As the current trial has progressed, the genomic alterations have proven to be much more complex than anticipated." Dr. Cox says. Although it is harder to pinpoint all the mutations contributing to the increase of radio-resistance this time around, the researchers show that more cellular metabolisms are affected (ATP synthesis, iron-sulfur cluster biogenesis, cadaverine synthesis, and reactive oxygen species response). Furthermore, this study proves that radio-resistance can develop to the level of Deinococcus radiodurans, independently to desiccation-resistance. As the exposition to radiation and experimental evolution continues, more data are gathered on how to induce radio-resistance in bacteria. This could one day constitute a precious toolbox of mutations to engineer radioresistant probiotics helping for example patients treated with radiotherapy, or astronauts exposed to space radiation. Citation: Evolution of radio-resistance is more complicated than previously thought (2020, September 22) retrieved 22 September 2020 from https://phys.org/news/2020-09-evolution-radio-resistance-complicated-previously-thought.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
Rosetta spacecraft detects unexpected ultraviolet aurora at a comet - Phys.org
Data from Southwest Research Institute-led instruments aboard ESA's Rosetta spacecraft have helped reveal auroral emissions in the far ultraviolet around a comet for the first time.
Data from Southwest Research Institute-led instruments aboard ESA's Rosetta spacecraft have helped reveal auroral emissions in the far ultraviolet around a comet for the first time. At Earth, auroras are formed when charged particles from the Sun follow our planet's magnetic field lines to the north and south poles. There, solar particles strike atoms and molecules in Earth's atmosphere, creating shimmering curtains of colorful light in high-latitude skies. Similar phenomena have been seen at various planets and moons in our solar system and even around a distant star. SwRI's instruments, the Alice far-ultraviolet (FUV) spectrograph and the Ion and Electron Sensor (IES), aided in detecting these novel phenomena at comet 67P/Churyumov-Gerasimenko (67P/C-G). "Charged particles from the Sun streaming towards the comet in the solar wind interact with the gas surrounding the comet's icy, dusty nucleus and create the auroras," said SwRI Vice President Dr. Jim Burch who leads IES. "The IES instrument detected the electrons that caused the aurora." The envelope of gas around 67P/C-G, called the "coma," becomes excited by the solar particles and glows in ultraviolet light, an interaction detected by the Alice FUV instrument. "Initially, we thought the ultraviolet emissions at comet 67P were phenomena known as 'dayglow,' a process caused by solar photons interacting with cometary gas," said SwRI's Dr. Joel Parker who leads the Alice spectrograph. "We were amazed to discover that the UV emissions are aurora, driven not by photons, but by electrons in the solar wind that break apart water and other molecules in the coma and have been accelerated in the comet's nearby environment. The resulting excited atoms make this distinctive light." Animation of ultraviolet aurora being produced at Chury. Credit: ESA (spacecraft: ESA/ATG medialab) Dr. Marina Galand of Imperial College London led a team that used a physics-based model to integrate measurements made by various instruments aboard Rosetta. "By doing this, we didn't have to rely upon just a single dataset from one instrument," said Galand, who is the lead author of a Nature Astronomy paper outlining this discovery. "Instead, we could draw together a large, multi-instrument dataset to get a better picture of what was going on. This enabled us to unambiguously identify how 67P/C-G's ultraviolet atomic emissions form, and to reveal their auroral nature." "I've been studying the Earth's auroras for five decades," Burch said. "Finding auroras around 67P, which lacks a magnetic field, is surprising and fascinating." Following its rendezvous with 67P/C-G in 2014 through 2016, Rosetta has provided a wealth of data revealing how the Sun and solar wind interact with comets. In addition to discovering these cometary auroras, the spacecraft was the first to orbit a comet's nucleus, the first to fly alongside a comet as it travelled into the inner Solar System and the first to send a lander to a comet's surface. More information: Far-ultraviolet aurora identified at comet 67P/Churyumov-Gerasimenko, Nature Astronomy, DOI: 10.1038/s41550-020-1171-7 , www.nature.com/articles/s41550-020-1171-7 Citation: Rosetta spacecraft detects unexpected ultraviolet aurora at a comet (2020, September 21) retrieved 21 September 2020 from https://phys.org/news/2020-09-rosetta-spacecraft-unexpected-ultraviolet-aurora.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
Finding in 100-million-year-old amber reveals sexual intercourse of ostracods - Phys.org
Small bivalved crustacean ostracods are the most abundant fossil arthropods since the Ordovician and play an important role in paleoenvironmental reconstruction and evolutionary biology.
Small bivalved crustacean ostracods are the most abundant fossil arthropods since the Ordovician and play an important role in paleoenvironmental reconstruction and evolutionary biology. The vast majority of fossil ostracods are represented by calcified shells, and their soft parts, which can provide invaluable information about ancient ostracod autoecology, are extremely rare. Recently, Dr. Wang He and Prof. Wang Bo, from the Nanjing Institute of Geology and Palaeontology of the Chinese Academy of Sciences (NIGPAS), and their collaborators presented exceptionally well-preserved ostracods with soft parts (appendages and reproductive organs) from mid-Cretaceous Myanmar amber (~100 million years old), which revealed sexual intercourse of ostracods. The study was published in Proceedings of the Royal Society B on Sept. 15. The ostracod assemblage in the amber is composed of 39 individuals in one amber piece and includes males, females and juveniles. X-ray micro-computed tomography was used to obtain high-resolution three-dimensional images of their soft parts. The micro-CT reconstruction provided direct evidence of the male clasper, sperm pumps (Zenker organs), hemipenes, eggs and female seminal receptacles containing giant sperm. This is the first time that giant ostracod sperm was found in Cretaceous ostracod fossils; its length was at least one-third of the body length of the ostracod. This discovery is also the earliest known animal sperm record, and approximately 50-million years older than the previous oldest fossil records of animal sperm. Analyses of the fossil and extant ostracods show that during sexual reproduction, the male used its sexually dimorphic fifth limb, which has hook-like endopods, to grasp a female while introducing its hemipenes into the female's paired vaginas. The male's pair of Zenker organs then transferred the exceptionally long but immotile sperm via the male hemipenes into the female. The Zenker organ is readily identified in extant cypridoidean ostracods as a large, spiny, sclerotized part of the deferent sperm duct. Muscle fibers alongside the organ connect the numerous spines, which are often arranged in a number of whorls that are taxonomically characteristic at the family level. Once in the female, the sperm are pushed up the two long sperm canals, each ending in a sac-like seminal receptacle for sperm storage; there, they finally become motile, arrange themselves into a more organized assemblage and fertilize eggs during the process of oviposition. Research reveals that the repertoire of reproduction behavior in ostracods, which is associated with considerable morphological adaptations, has remained unchanged over at least 100 million yearsa paramount example of evolutionary stasis. The appearance of a complex reproductive mechanism involving giant sperm improved mating success and may have been an important contributor to the late Mesozoic explosive radiation of the superfamily Cypridoidea, which today includes the vast majority of nonmarine ostracod species. More information: Exceptional preservation of reproductive organs and giant sperm in Cretaceous ostracods, Proceedings of the Royal Society B (2020). rspb.royalsocietypublishing.or … .1098/rspb.2020.1661 Citation: Finding in 100-million-year-old amber reveals sexual intercourse of ostracods (2020, September 15) retrieved 15 September 2020 from https://phys.org/news/2020-09-million-year-old-amber-reveals-sexual-intercourse.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
New Hubble data suggests there is an ingredient missing from current dark matter theories - Phys.org
Observations by the NASA/ESA Hubble Space Telescope and the European Southern Observatory's Very Large Telescope (VLT) in Chile have found that something may be missing from the theories of how dark matter behaves. This missing ingredient may explain why rese…
This NASA/ESA Hubble Space Telescope image shows the massive galaxy cluster MACSJ 1206. Embedded within the cluster are the distorted images of distant background galaxies, seen as arcs and smeared features. These distortions are caused by the dark matter in the cluster, whose gravity bends and magnifies the light from faraway galaxies, an effect called gravitational lensing. This phenomenon allows astronomers to study remote galaxies that would otherwise be too faint to see. Credit: NASA, ESA, G. Caminha (University of Groningen), M. Meneghetti (Observatory of Astrophysics and Space Science of Bologna), P. Natarajan (Yale University), the CLASH team, and M. Kornmesser (ESA/Hubble) Observations by the NASA/ESA Hubble Space Telescope and the European Southern Observatory's Very Large Telescope (VLT) in Chile have found that something may be missing from the theories of how dark matter behaves. This missing ingredient may explain why researchers have uncovered an unexpected discrepancy between observations of the dark matter concentrations in a sample of massive galaxy clusters and theoretical computer simulations of how dark matter should be distributed in clusters. The new findings indicate that some small-scale concentrations of dark matter produce lensing effects that are 10 times stronger than expected. Dark matter is the invisible glue that keeps stars, dust, and gas together in a galaxy. This mysterious substance makes up the bulk of a galaxy's mass and forms the foundation of our Universe's large-scale structure. Because dark matter does not emit, absorb, or reflect light, its presence is only known through its gravitational pull on visible matter in space. Astronomers and physicists are still trying to pin down what it is. Galaxy clusters, the most massive and recently assembled structures in the Universe, are also the largest repositories of dark matter. Clusters are composed of individual member galaxies that are held together largely by the gravity of dark matter. "Galaxy clusters are ideal laboratories in which to study whether the numerical simulations of the Universe that are currently available reproduce well what we can infer from gravitational lensing," said Massimo Meneghetti of the INAF-Observatory of Astrophysics and Space Science of Bologna in Italy, the study's lead author. "We have done a lot of testing of the data in this study, and we are sure that this mismatch indicates that some physical ingredient is missing either from the simulations or from our understanding of the nature of dark matter," added Meneghetti. This video begins with an image from the NASA/ESA Hubble Space Telescope of the massive galaxy cluster MACSJ 1206. Embedded within the cluster are the distorted images of distant background galaxies, seen as arcs and smeared features. These distortions are caused by the dark matter in the cluster, whose gravity bends and magnifies the light from faraway galaxies, an effect called gravitational lensing. This phenomenon allows astronomers to study remote galaxies that would otherwise be too faint to see. The video then shows an artists impression of small-scale concentrations of dark matter (represented in this video in blue). Dark matter is the invisible glue that keeps stars bound together inside a galaxy and makes up the bulk of the matter in the Universe. These blue halos reflect how the galaxy clusters dark matter is distributed, revealed by new results from the Hubble Space Telescope. This was accomplished by a team of astronomers by measuring the amount of gravitational lensing. Credit: NASA, ESA, G. Caminha (University of Groningen), M. Meneghetti (Observatory of Astrophysics and Space Science of Bologna), P. Natarajan (Yale University), the CLASH team, and M. Kornmesser (ESA/Hubble) "There's a feature of the real Universe that we are simply not capturing in our current theoretical models," added Priyamvada Natarajan of Yale University in Connecticut, U.S., one of the senior theorists on the team. "This could signal a gap in our current understanding of the nature of dark matter and its properties, as these exquisite data have permitted us to probe the detailed distribution of dark matter on the smallest scales." The distribution of dark matter in clusters is mapped by measuring the bending of lightthe gravitational lensing effectthat they produce. The gravity of dark matter concentrated in clusters magnifies and warps light from distant background objects. This effect produces distortions in the shapes of background galaxies which appear in images of the clusters. Gravitational lensing can often also produce multiple images of the same distant galaxy. The higher the concentration of dark matter in a cluster, the more dramatic its light-bending effect. The presence of smaller-scale clumps of dark matter associated with individual cluster galaxies enhances the level of distortions. In some sense, the galaxy cluster acts as a large-scale lens that has many smaller lenses embedded within it. Hubble's crisp images were taken by the telescope's Wide Field Camera 3 and Advanced Camera for Surveys. Coupled with spectra from the European Southern Observatory's Very Large Telescope (VLT), the team produced an accurate, high-fidelity, dark-matter map. By measuring the lensing distortions astronomers could trace out the amount and distribution of dark matter. The three key galaxy clusters, MACS J1206.2-0847, MACS J0416.1-2403, and Abell S1063, were part of two Hubble surveys: The Frontier Fields and the Cluster Lensing And Supernova survey with Hubble (CLASH) programs. To the team's surprise, in addition to the dramatic arcs and elongated features of distant galaxies produced by each cluster's gravitational lensing, the Hubble images also revealed an unexpected number of smaller-scale arcs and distorted images nested near each cluster's core, where the most massive galaxies reside. The researchers believe the nested lenses are produced by the gravity of dense concentrations of matter inside the individual cluster galaxies. Follow-up spectroscopic observations measured the velocity of the stars orbiting inside several of the cluster galaxies to therby pin down their masses. "The data from Hubble and the VLT provided excellent synergy," shared team member Piero Rosati of the Università degli Studi di Ferrara in Italy, who led the spectroscopic campaign. "We were able to associate the galaxies with each cluster and estimate their distances." "The speed of the stars gave us an estimate of each individual galaxy's mass, including the amount of dark matter," added team member Pietro Bergamini of the INAF-Observatory of Astrophysics and Space Science in Bologna, Italy. By combining Hubble imaging and VLT spectroscopy, the astronomers were able to identify dozens of multiply imaged, lensed, background galaxies. This allowed them to assemble a well-calibrated, high-resolution map of the mass distribution of dark matter in each cluster. Movie illustrating the three-dimensional model of the mass distribution in the galaxy cluster MACSJ1206. Most of the mass is in the form of diffused dark matter and hot gas. In the movies, this mass appears as a smooth and extended chain of mountains. In addition, other dark matter and stars are concentrated in cluster galaxies. These correspond to the sharp peaks adding up in the second part of the movie. This detailed model was obtained by combining observations of the gravitational lensing effects produced by the cluster gravity with measurements of the velocity of the stars orbiting inside the cluster galaxies. The latest were made with the MUSE spectrograph of the European Southern Observatorys Very Large Telescope (VLT) in Chile. Credit: P. Bergamini (INAF-Observatory of Astrophysics and Space Science of Bologna) The team compared the dark-matter maps with samples of simulated galaxy clusters with similar masses, located at roughly the same distances. The clusters in the computer model did not show any of the same level of dark-matter concentration on the smallest scalesthe scales associated with individual clustergalaxies. "The results of these analyses further demonstrate how observations and numerical simulations go hand in hand", said team member Elena Rasia of the INAF-Astronomical Observatory of Trieste, Italy. "With high-resolution simulations, we can match the quality of observations analyzed in our paper, permitting detailed comparisons like never before," added Stefano Borgani of the Università degli Studi di Trieste, Italy. Astronomers, including those of this team, look forward to continuing to probe dark matter and its mysteries in order to finally pin down its nature. More information: Massimo Meneghetti et al, "An excess of small-scale gravitational lenses observed in galaxy clusters" Science 11 Sep 2020: Vol. 369, Issue 6509, pp. 1347-1351, science.sciencemag.org/cgi/doi … 1126/science.aax5164 Citation: New Hubble data suggests there is an ingredient missing from current dark matter theories (2020, September 10) retrieved 10 September 2020 from https://phys.org/news/2020-09-hubble-ingredient-current-dark-theories.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.