It’s possible that I shall make an ass of myself. But in that case one can always get out of it with a little dialectic. I have, of course, so worded my proposition as to be right either way (K.Marx, Letter to F.Engels on the Indian Mutiny)
Wednesday, December 29, 2021
Kenney asks Albertans to reconsider New Year's plans and to not 'look for loopholes'
LEAVE THAT TO UCP
Tue., December 28, 2021
CALGARY — Alberta Premier Jason Kenney asked people to reconsider their New Year's plans and not "look for loopholes" as the province recorded more than 8,000 COVID-19 cases over a five-day period.
Kenney asked people to keep gatherings small and not congregate with more than nine other adults, and get vaccinated.
Chief medical officer of health, Dr. Deena Hinshaw, says the province's new COVID-19 cases ranged between 2,500 on Christmas Day and 750 on Boxing Day.
She says province recorded 8,250 cases between Dec. 23 and 28, but adds that the numbers are preliminary and the number of completed tests varied considerably from day-to-day.
She says hospitalizations remain "relatively stable" but notes it's still too soon to know if Omicron will stress the health system.
Hinshaw says the number of new deaths wouldn't be available until Wednesday.
This report by The Canadian Press was first published Dec. 28, 2021.
The Canadian Press
How Real Is the Planetary Defense Coordination Office From ‘Don’t Look Up'? SOURCE: NETFLIX | NSF.GOV
There's been a lot of discussion around "anti-science" rhetoric and beliefs in recent years, especially in the wake of the COVID-19 pandemic and all of the socio-political discussions around the virus. Adam McKay's newest Netflix film, Don't Look Up, feels like one big allegorical diatribe against science "naysayers" who would rather eschew factual evidence and data in lieu of personal beliefs/agendas. But since it does so with a heavy dose of comedy, fans are wondering how much of the content in the film is real, like the Planetary Defense Coordination Office. Is NASA's Planetary Defense Coordination Office real?
Abso-freaking-lutely. The patch that is highlighted in the popular Netflix film belongs to an actual agency, and in case you were wondering if it it's legit, yes — the film even provides a meta moment to inform the audience that it totally exists.
In one scene, Leonardo DiCaprio's character, Randall Mindy says, "I'm on hold. She is calling Dr. Oglethorpe, who is that?" Jennifer Lawrence's character, Kate Dibiasky says, "Dr. Oglethorpe, head of the Planetary Defense Coordination Office." Which prompts the response from Leo: "Is that a real place?"
SOURCE: NETFLIX
Then, on-screen text pops up to inform the audience that yes, the Planetary Defense Coordination Office is a real division of NASA, and that the patch in the movie is actually the one utilized by the agency.
Geeky reported that an actually astronomer and climate change scientist Amy Mainzer worked as a consultant for the film.
In an interview with collectSPACE, Amy said, "Obviously this is a sci-fi movie, right? We are getting into sci-fi territory very quickly, because obviously we don’t know of a gigantic comet that is about to hit Earth. That is not real. So fortunately, that’s the big news, right?"
SOURCE: TWITTER | @CINEPHILEJEN
She continued, "But the Planetary Defense Coordination Office is very real, and it didn’t really exist until relatively recently." This particular office didn't come into existence until January of 2016.
NASA created the division to work with its international allies in order to create Earth defense strategies, and it also serves to manage NASA's Near-Earth Object Observation initiative, which was founded in 1998.
"You’d think it would be a no-brainer to have a full program to search for asteroids and comets, but even that has been a long time coming. People have been working on it for a long time, but I would say with very modest resources, considering what it takes to go out there and solve this particular problem. So we are finally getting to the point where we are conducting a much more comprehensive study of these objects," Amy said.
SOURCE: TWITTER | @LEODICAPRIO
The events of 'Don't Look Up' are loosely based on a true story.
Mainzer's team actually discovered the massive NEOWISE comet in 1997. It's the basis of that staggering find that helped inform Don't Look Up.
"I did a lot of work on the design of an orbit and I actually modeled some aspects of the comet in the movie after Comet NEOWISE to be realistic. I tried to choose something that would fit the needs of the movie, but also not stray too far from reality," she said.
Mainzer said that she was very happy to work on the film and it's pro-empirical evidence stance: "We need to make science-based decisions. It’s important because, if we don’t, we’re not going to end up with the best possible outcomes for a host of different problems, be it the threat of asteroids and comets or climate change or extreme weather. Or the pandemic. We have scientific decisions to make and it couldn’t be more important than doing it now."
SOURCE: TWITTER | @AMYMAINZER
Don't Look Up is currently streaming on Netflix.
NASA Shares Best Space Station Science Pictures from 2021
Matthew Hart Tue, December 28, 2021
The International Space Station (ISS) has been hopping with science experiments this year. Thanks to companies like SpaceX and Northrop Grumman, NASA’s been able to send everything from problem-solving slime molds to tardigrades and squid to the space station for study. Now, in a new compilation, NASA offers up images from some of the most memorable scientific endeavors aboard the ISS from 2021. And they’re getting us hyped for 2022.
NASA’s Johnson Space Center recently posted the above compilation to its YouTube channel. “It has been a busy year of research aboard the International Space Station,” the agency notes in the video’s description. The space center notes that astronauts have performed 13 spacewalks, installed new solar panels, and upgraded the station’s power supply. As well as performed literally hundreds of scientific experiments.
NASA Johnson
The images in the compilation show just a handful of the most exciting science experiments conducted aboard the ISS this year. Toward the beginning of the compilation is a close-up look at how astronauts have been culturing living heart cells, for example. We also get a glimpse of NASA astronaut Victor Glover conducting experiments for Rodent Research-10; an investigation into how spaceflight in microgravity affects the cellular and molecular mechanisms of normal bone tissue regeneration in space.
NASA Johnson
All of the experiments in the compilation are exciting, but the ones centering around the upcoming Artemis missions to the Moon really help to loose the imagination. Astronauts are working to see how well they can harvest plants such as chiles and lettuce, for example. Which is cool because the only time we’d actually order a salad would be on the Moon. The astronauts even managed to pull off the first-ever “plant transplant” in space. DLR_next
For anybody who needs to catch up on other ISS news before the year closes out, there’s been a ton. From surreal spacewalks to the “Space Olympics,” astronauts aboard the ISS have been showing us what life away from Earth feels like. Now, all we can say is we want to go into space more than ever. Although waiting for some kind of space-pizza delivery service first may be in order. (We promise to do very serious science experiments with the cheese.)
Mars mission, moon rocket, astronauts’ choice: ESA has big plans for 2022. Director General Joseph Asbacher explains the plans in an interview with tagesschau.de It calls for new rules of space.
tagesschau.de: What are your ESA highlights for the coming year?
Josef Aschbacher: We have a very important mission starting between the end of September and the beginning of October. Her name is “ExoMars” and she has a rover on board called “Rosalind Franklin”. The rover is the largest ever on Mars. He has a wide range of scientific instruments on board for the exploration of Mars. We are carrying out the mission in a very close partnership with our Russian partners from Roscosmos.
Josef Asbacher has been Director General of the European Space Agency (ESA) since March 2021. Prior to this, the original Austrian worked for many years in various positions at the European Space Agency, including Director of Earth Observation Programs.
tagesschau.de: How far does this mission go beyond NASA’s mission with “Perseverance” – Rover Which landed on Mars in February?
Ashbacher: There are more scientific instruments on board our mission. For the first time we will drill up to 1.70 meters into the surface of Mars with an drill, take samples and analyze them in the lab. It will be very exciting and very complex.
tagesschau.de: In 2022, NASA wants to put “Artemis I”, the first mission of the space shuttle Orion, into orbit around the moon. Here, too, the European Space Agency is very involved.
Ashbacher: This is correct. NASA’s SLS — the lunar rocket that will return to the moon decades after Apollo — has a small ESA logo. We supply very basic components, eg “European Service Unit” with electrical supply and drive systems. Without the module being built in Bremen, NASA’s Moon mission could not be performed. We are an essential partner that NASA depends on. The start time window is mid-February. There is no set date yet. See also Deep Reprogramming of the Innate Immune System - The Practice of Healing “We must use space sustainably”
tagesschau.de: Space has long gone from a scientific space to an economic one. They have recently expressed concern about the dominance of Elon Musk and his “Starlink” satellite. What is the problem?
Ashbacher: Elon Musk has launched nearly 2,000 “Starlink” generation satellites so far. On the other hand, this is very good because there is a lot of activity in the space. On the other hand, these satellites make up about half of all the satellites currently active in space. This is a good thing for Elon Musk, I personally admire his huge vision and energy to achieve very complex projects. However, its activity also has consequences, namely that space is occupied and occupied by its satellites – not only physically by the satellites themselves, but also by the frequencies used.
Here is the problem: we must use space sustainably. We all depend on satellites on a daily basis – for example for navigation devices, weather forecasting, or information on agriculture and forestry, disaster control and climate research in the broadest sense. Telecommunication is also very limited by space. Space has limited resources. We must think globally together about how resources are used and who has the right to use satellites and their associated frequencies. This requires new binding rules.
tagesschau.de: Elon Musk is behaving like this because no global regulatory “space agency” is slowing it down. Bringing space agencies and companies—that is, states and the private sector—to one table seems utopian, right?
Ashbacher: It is a challenge and a very complex process. You have a mix of public and private individuals like Elon Musk or Jeff Bezos. But we must not forget that the national authorities of states issue licenses to launch and operate satellites. This is regulated at the national level, but also at the international level through the International Telecommunication Union, which is the international telecommunications body based in Geneva. So you can actually step in for regulation.
tagesschau.de: You have held the position of Director General of the European Space Agency since March and have made it your mission to make Europe more confident in space. In the United States, enthusiasm for space activities is greater than in Europe. Have you noticed a rethink among politicians in ESA member states who release money?
Ashbacher: The United States is placing more emphasis on expansion and exploration. NASA’s program focuses on the space station, the moon, and Mars. The European program focuses more on our planet, ie climate protection and sustainability as well as practical applications for people such as reliable telecommunications and navigation. This is reflected in politics as well, and this is exactly what Europe’s priorities in space correspond to. Of course, Europe also has astronaut and exploration programs, but it is less funded than NASA.
tagesschau.de: When it comes to astronauts, the European Space Agency currently has a permanent subscription to the International Space Station. Following French ESA astronaut Thomas Pesquet, German astronaut Matthias Maurer followed in November.
Ashbacher: I agree. Now we have Matthias Maurer On the International Space Station. He has conducted more than 35 experiments on the International Space Station with German participation and many other international experiments. After Matthias Maurer, the Italian will be in the spring ESA astronaut Samantha Cristoforetti Fly to the International Space Station. She should also meet Matthias Maurer there. Then, as ESA, we will have three astronauts in direct order in space for the first time. The last four to six candidates for the ESA application process will then be selected by the end of next year. We had with 22,589 applicants set a record for interested parties.
tagesschau.de: Will the European Space Agency’s new Ariane 6 launch pad also launch from the Kourou spaceport for the first time next year?
Ashbacher: The question is currently under discussion. We currently have two great gurus to really answer this question. One is the so-called “hot launch test” at the facilities of the German Aerospace Center in Lampoldshausen. This test will be done early next year. If there are no technical changes after that, the Ariane 6 could start in the second half, towards the end of the year.
The interview was conducted by Ute Spangenberger, SWR, for tagesschau.de.
Here’s DART’s First Picture From Space. We Are Already Looking Forward to its Last Image
It might not look like much, but here is the first monumental image from the Double Asteroid Redirection Test (DART). Earlier this month, a circular door covering the aperture of its DRACO telescopic camera was opened, allowing the camera to take its first image.
Now, imagine what the camera’s last image will be like: a REALLY closeup view of a binary asteroid system, Didymos and especially, its moonlet Dimorphos. The goal of DART is to intentionally collide with Dimorphos. If everything goes according to plan, this will alter the asteroid’s motion so that ground-based telescopes can accurately measure any changes.
DART is the world’s first planetary defense test mission. It will demonstrate that a spacecraft can autonomously navigate to and perform a kinetic impact on a relatively small target asteroid. This will test if this is a viable technique to deflect a genuinely dangerous asteroid.
DART will reach its target on Sept. 26, 2022. FYI, the Didymos asteroid system does not pose a threat to Earth.
DART launched on November 24. As in any mission that launches to space, there’s always concern about how the instruments will react to the violent vibrations of launch and the extreme temperature shift. NASA said that because components of DART’s telescopic instrument are sensitive to movements as small as 5 millionths of a meter, even a tiny shift of something in the instrument could be very serious.
But all seems to be well with the DRACO camera. Below is another image taken on December 10.
On Dec. 10, DART’s DRACO camera captured and returned this image of the stars in Messier 38, or the Starfish Cluster, which lies some 4,200 light years away. Credits: NASA/Johns Hopkins APL
DRACO (short for Didymos Reconnaissance and Asteroid Camera for Optical navigation) is a high-resolution camera, inspired by the imager on the New Horizons spacecraft. Recall the excitement of the first close-up images of the Pluto system, and later when New Horizons flew past the Kuiper Belt object, Arrokoth.
As DART’s only instrument, DRACO will capture images of the asteroid Didymos and its moonlet asteroid Dimorphos, as well as support the spacecraft’s autonomous guidance system to direct DART to its final kinetic impact.
DRACO’s first image, taken on Tuesday, Dec. 7, 2021 was taken about 2 million miles (11 light seconds) from Earth — very close, astronomically speaking. The image shows about a dozen stars, crystal-clear and sharp against the black backdrop of space, near where the constellations Perseus, Aries and Taurus intersect.
Artist’s impression of NASA’s Double Asteroid Redirection Test (DART) spacecraft speeding toward the smaller of the two bodies in the Didymos asteroid system. Credit: NASA/Johns Hopkins University Applied Physics Laboratory
NASA said the DART navigation team at the Jet Propulsion Laboratory used the stars in the image to determine precisely how DRACO was oriented, providing the first measurements of how the camera is pointed relative to the spacecraft. With those measurements in hand, the DART team could accurately move the spacecraft to point DRACO at objects of interest, such as Messier 38 (M38), also known as the Starfish Cluster, that DART captured in the second image, taken on Dec. 10.
Located in the constellation Auriga, the cluster of stars lies some 4,200 light years from Earth. Intentionally capturing images with many stars like M38 helps the team characterize optical imperfections in the images as well as calibrate how absolutely bright an object is — all important details for accurate measurements when the spacecraft gets closer to Didymos and DRACO starts imaging the spacecraft’s final destination.
Lead image caption: On Dec. 7, after opening the circular door to its telescopic imager, NASA’s DART captured this image of about a dozen stars near where the constellations Perseus, Aries and Taurus intersect.Credits: NASA/Johns Hopkins APL
HOLD ON
The Earth Is Spinning Faster Than Average By Adesola Mojo On Dec 28, 2021
TORONTO —
Let’s start with some well-known facts about the Earth – it’s the fifth-largest planet in the solar system, 70 per cent of its surface is covered in water, and it’s the only planet known to have life on it.
One lesser-known fact is that a day on Earth isn’t exactly 24 hours long.
Sure, the Earth takes about 86,400 seconds – 1,440 minutes – on average, to make a full rotation around the sun. But there are a number of factors that affect the Earth’s rotation, causing it to speed up or slow down.
“We’re all used to the idea that Earth rotates every 24 hours, but of course, nothing’s ever really that simple,” Elaina Hyde, director of the Allan I. Carswell observatory and assistant professor at York University, told CTVNews.ca in a video call.
“We’re a rocky planet with a molten core, we have an atmosphere, we have oceans – all of these things can combine with different kinds of complex motions to create effects…like what we have been seeing.”
Hyde is referring to changes in the speed of the Earth’s rotation in recent years. In 2020, scientists say the Earth sped up so much that it broke a previous record for the shortest day on Earth 28 times. The shortest of these days was recorded on July 19, when Earth rotated around the sun 1.4602 milliseconds faster than the average time of 86,400 seconds.
WHAT CAUSES THE EARTH TO SPEED UP?
When it comes to explaining why these shifts happen, Hyde says there’s no single answer. She points to natural events such as earthquakes, as well as the movement of jet streams, and rising ocean levels as a result of climate change as just a few factors that come into play. Hyde also highlights the slowing down of major ocean currents, particularly in the northern Atlantic Ocean, as having an impact as well.
Each of these activities affects the Earth’s angular momentum, she explains, or the rate at which it rotates, taking into account its massive size.
“Saying that this was due to any one cause is not statistically significant,” Hyde said. “It is a combination of effects.”
While the Earth’s rotation has since slowed down, 2021 is still predicted to be the shortest year in a decade by milliseconds, says Hyde. This may create a need for a negative leap second.
Negative leap seconds, the opposite of regular leap seconds, involve subtracting time from the Earth’s timekeeping system so that it aligns with astronomical time, or the time it actually takes the Earth to complete a rotation around the sun.
Co-ordinated universal time, or UTC, is the time standard used to adjust clocks on Earth. It’s determined using an atomic clock. These clocks calculate time based on the movement of atoms. Placing an atom under specific frequencies of radiation will cause its electrons to move between different states of energy. The amount of cycles of radiation necessary for atoms to move between both energy states amounts to a second. Since 1967, one second has been defined as “9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the cesium-133 atom.”
“This clock does not depend on any external force to give you that count of time, it’s a completely independent measurement,” said Hyde. “Atomic clocks are incredibly accurate at keeping time.”
Since many factors can affect the speed at which the Earth rotates, the time it takes to complete a rotation doesn’t always align with UTC on Earth. This creates the need for an adjustment. According to the National Institute of Standards and Technology (NIST), leap seconds are added, or subtracted, when there is a difference of 0.4 seconds or more between UTC and astronomical time.
“To keep our very precise atomic clocks lined up so that we can still keep using the months and the days and the years in the calendar system we have, we have to make adjustments,” explained Hyde. “[A leap second] is basically an artificial adjustment that we make in our calendar system to bring ourselves up to date.”
According to the NIST, leap seconds have been added once every 18 months or so since 1972, making them quite common. Negative leap seconds, on the other hand, have never been implemented. THE POSSIBILITY OF A NEGATIVE LEAP SECOND
While the Earth’s spin has slowed down since last year, it’s still spinning slightly faster than average. Research shows the average length of a day in the first half of 2021 was 0.39 milliseconds less than it was the year before. From July to September though, days were actually 0.05 milliseconds longer than the 2020 average.
“It is more usual to have the leap second going in the direction of making the day longer because that is the overall pattern that we’re expecting,” said Hyde. “But like I said, all kinds of events can cause it to go the other way, it’s just not as common though.”
Looking at the speed at which the planet is rotating now, it’s possible a negative leap second may need to be implemented within the decade. The International Earth Rotation and Reference Systems Service is responsible for that decision. But when looking at the impact this change might have on day-to-day life, Hyde insists it isn’t something to worry about, unless stock market trading is involved.
“It’s not going to be a big effect for anyone,” she said. “But if you are interested in high-frequency trading or any kind of computational activities that take place multiple times a second, please make sure to keep up with these atomic clocks when they make the adjustment.”
This is as simple as going online and staying up to date with atomic clocks such as this one.
Still, there’s no guarantee that a negative leap second will need to be applied just yet. While it may be easy to plot out the Earth’s rotation over the long term, these kinds of measurements are tougher to predict in the short-term, says Hyde.
“It’s much more difficult because we don’t know exactly when earthquakes are going to appear all over Earth, we don’t know exactly how much water is going into the oceans due to climate change there’s a lot of unknowns,” she said. “Earth is an unpredictable system by nature. So making very, very precise predictions…is hard.”
Scientists at the U.S. Naval Research Laboratory evaluate early data the ESA/NASA Solar Orbiter spacecraft sent back to Earth as it observes comet Leonard, a mass of space dust, rock and ice just over half a mile across (1 kilometer) as it heads inbound to the sun.
Imagery captured between Dec. 17 and 19 by the NRL's Solar Orbiter Heliospheric Imager (SoloHI) aboard the ESA/NASA Solar Orbiter spacecraft, shows comet Leonard streaking diagonally across the field of view. Planets Venus and Mercury are also visible in the top right, Venus appearing brighter and moving from left to right.
"When SoloHI recorded these images, the comet was approximately between the Sun and the spacecraft, with its gas (ion) and dust tails pointing towards the spacecraft," Karl Battams, Ph.D., a computational scientist in NRL's Heliospheric Physics section said. "Toward the end of the image sequence, our view of both of the tails improves as the viewing angle at which we see the comet increases, and SoloHI gets a side-on view of the comet."
Two other observation platforms, the Parker Solar Probe and the Solar Terrestrial Relations Observatory, are looking at the comet from very different locations in space, which could give us a lot of valuable information about the 3D structure of the tail and of the solar outflows.
"We hope to use the two views from Solar Orbiter and STEREO to get a 3D structure and velocity," said Robin Colaninno, Ph.D., an astrophysicist and SoloHI PI at NRL. "The changes in the comet's tail give us great insight into the solar winds."
Comet Leonard as captured by NASA's Solar Terrestrial Relations Observatory-A (STEREO) spacecraft, HI-2 telescope, which has watched the comet since early November. This animated “difference image” was created by subtracting the current frame from the previous frame to highlight differences between them. Difference images are useful for seeing subtle changes in Leonard's ion tail (the trail of ionized gases streaming from the comet's body, or nucleus), which becomes longer and brighter toward the end of the clip. Credit: NASA/NRL/Karl Battams
Comets are remnants of the swarm of planetesimals that formed the solar system and retain records from before and during planet formation.
Comet Leonard, formally known as C/2021 A1, was discovered Jan. 3, 2021 by Gregory Leonard, a senior research specialist at the University of Arizona's Lunar and Planetary Laboratory in Arizona. Leonard spotted the comet in images taken from the Mt. Lemmon Skycenter in Arizona.
Battams said there has been much discussion among astronomers in the past week about this comet.
"Many folks reported a significant brightening around the 14th (before the SoloHI images), and then a subsequent so-called "outburst" in the past 24 hours, with indeterminate behavior in the meantime," Battams said. "My suspicion is that the comet is increasingly unhappy, and these outbursts could be the beginning of a slow and fatal disruption. But it's too early to say for sure—it could just be letting off steam, so to speak."
SoloHI will continue observing the comet until it leaves its field of view until Dec. 22. Comet Leonard's closest pass on Jan. 3, 2021 will take it within 56 million miles (90 million kilometers) of the Sun, slightly more than half Earth's distance. If it does not disintegrate, current orbit calculations show that its path will send it out into interstellar space, never to return to our solar system.
The three-body problem is one of the oldest problems in physics: It concerns the motions of systems of three bodies—like the sun, Earth, and the moon—and how their orbits change and evolve due to their mutual gravity. The three-body problem has been a focus of scientific inquiry ever since Newton.
When one massive object comes close to another, their relative motion follows a trajectory dictated by their mutual gravitational attraction, but as they move along and change their positions along their trajectories, the forces between them, which depend on their mutual positions, also change, which, in turn, affects their trajectory. For two bodies (e.g., the Earth moving around the sun without the influence of other bodies), the orbit of the Earth would continue to follow a specific curve (an ellipse), which can be accurately described mathematically. However, under the influence of a third object, the complex interactions lead to the three-body problem—the system becomes chaotic and unpredictable, and the system's evolution over long time scales cannot be predicted. Indeed, while this phenomenon has been known for over 400 years, ever since Newton and Kepler, a neat mathematical description for the three-body problem is still lacking.
The absence of a solution to the three-body problem means that scientists cannot predict what happens during a close interaction between a binary system (formed of two stars that orbit each other like Earth and the sun) and a third star, except by simulating it on a computer and following the evolution step-by-step. These simulations show that when such an interaction occurs, it proceeds in two phases: First, a chaotic phase during which all three bodies pull on each other violently until one star is ejected far from the other two, which then settle down to an ellipse. If the third star is on a bound orbit, it eventually comes back down toward the binary, whereupon the first phase ensues once again. This triple dance ends when, in the second phase, one of the stars escapes on an un-bound orbit, never to return.
In a paper accepted for publication in Physical Review X this month, Ph.D. student Yonadav Barry Ginat and Professor Hagai Perets of the Technion-Israel Institute of Technology used this randomness to provide a statistical solution to the entire two-phase process. Instead of predicting the actual outcome, they calculated the probability of any given outcome of each phase-1 interaction. While chaos implies that a complete solution is impossible, its random nature allows calculation of the probability that a triple interaction ends in one particular way rather than another. Then, the entire series of close approaches could be modeled by using a the theory of random walks, sometimes called "drunkard's walk." The term got its name from mathematicians thinking about how a drunk would walk, regarding it as a random process—with each step, the drunk doesn't realize where they are and takes the next step in some random direction.
The triple system behaves, essentially, in the same way. After each close encounter, one of the stars is ejected randomly (but with the three stars collectively still conserving the overall energy and momentum of the system). This series of close encounters could be regarded as a drunkard's walk. Like a drunk's step, a star is ejected randomly, comes back, and another (or the same star) is ejected to a likely different random direction (similar to another step taken by the drunk) and comes back, and so forth, until a star is completely ejected and never returns (akin to a drunk falling into a ditch).
What Ginat and Perets showed in their research was how this could be done for the three-body problem: They computed the probability of each phase-2 binary-single configuration (the probability of finding different energies, for example), and then composed all of the individual phases using the theory of random walks to find the final probability of any possible outcome, much like calculating long-term weather forecasts.
"We came up with the random walk model in 2017, when I was an undergraduate student," said Mr. Ginat, "I took a course that Prof. Perets taught, and there I had to write an essay on the three-body problem. We didn't publish it at the time, but when I started a Ph.D., we decided to expand the essay and publish it."
The three-body problem was studied independently by research groups in recent years, including Nicholas Stone of the Hebrew University in Jerusalem, collaborating with Nathan Leigh, then at the American Museum of Natural History, and Barak Kol, also of the Hebrew University. Now, with the current study by Ginat and Perets, the entire, multi-stage, three-body interaction is fully solved statistically.
"This has important implications for our understanding of gravitational systems, and in particular, cases where many encounters between three stars occur, like in dense clusters of stars," said Prof. Perets. "In such regions, many exotic systems form through three-body encounters, leading to collisions between stars and compact objects like black holes, neutron stars and white dwarves, which also produce gravitational waves that have been directly detected only in the last few years. The statistical solution could serve as an important step in modeling and predicting the formation of such systems."
The random walk model can also do more: So far, studies of the three-body problem treat the individual stars as idealized point particles. In reality, of course, they are not, and their internal structure might affect their motion, for example, in tides. Tides on Earth are caused by the moon and change the planet's shape slightly. Friction between the water and the rest of the planet dissipates some of the tidal energy as heat. Energy is conserved, however, so this heat must come from the moon's energy in its motion about the Earth. Similarly for the three-body problem, tides can draw orbital energy out of the three-bodies' motion.
"The random walk model accounts for such phenomena naturally," said Mr. Ginat. "All you have to do is to remove the tidal heat from the total energy in each step, and then compose all the steps. We found that we were able to compute the outcome probabilities in this case, too." As it turns out, a drunkard's walk can sometime shed light on some of the most fundamental questions in physics.
More information:Yonadav Barry Ginat et al, Analytical, Statistical Approximate Solution of Dissipative and Nondissipative Binary-Single Stellar Encounters,Physical Review X(2021).DOI: 10.1103/PhysRevX.11.031020
Like a sprinkle of powdered sugar on a rich red velvet cake, this scene from the ESA/Roscosmos ExoMars Trace Gas Orbiter captures the contrasting colors of bright white water-ice against the rusty red martian soil.
This delightful image was taken 5 July 2021 and soaks in the view of a 4 km-wide crater in Mars' north polar region of Vastitas Borealis, centered at 70.6 °N/230.3°E.
The crater is partially filled with water ice, which is also particularly predominant on its north-facing slopes that receive fewer hours of sunlight on average throughout the year.
The dark material clearly visible on the crater rim—giving it a somewhat scorched appearance—likely consists of volcanic materials such as basalt.
Most of the surrounding terrain is ice free, but has been shaped by ongoing aeolian processes. The streaks at the bottom right of the image are formed by winds that have removed the brighter iron oxide dust from the surface, exposing a slightly darker underlying substrate.
TGO arrived at Mars in 2016 and began its full science mission in 2018. The spacecraft is not only returning spectacular images, but also providing the best ever inventory of the planet's atmospheric gasses, and mapping the planet's surface for water-rich locations. It will also provide data relay services for the second ExoMars mission comprising the Rosalind Franklin rover and Kazachok platform, when it arrives on Mars in 2023.
Two galaxies hidden by cosmic dust discovered, more to be found with Canada's help
Canada is one of NASA's partners in the just-launched James Webb Space Telescope
Author of the article: Spiro Papuckoski Publishing date: Dec 26, 2021
Two distant galaxies previously hidden by cosmic dust were recently discovered.
PHOTO BY MIK38 /iStock / Getty Images
The size of the universe may be unknown, but astronomers keep discovering galaxies farther and farther away.
Two previously invisible galaxies 29 billion light-years away were located by researchers at the University of Copenhagen’s Niels Bohr Institute, according to a recent study published in Nature
That’s far away — to put it mildly — as one light-year is the equivalent to 9.46 trillion kilometres. Multiply that by 29 billion and see if you can bust your calculator.
The researchers explain that the two galaxies hidden behind a thick layer of cosmic dust that surrounds them were invisible to the optical lens of the Hubble Space Telescope.
But by using the Atacama Large Millimeter Array telescopes in Chile’s Atacama Desert, astronomers were able to capture radio waves from the distant galaxies.
“We were looking at a sample of very distant galaxies, which we already knew existed from the Hubble Space Telescope,” Pascal Oesch, the Cosmic Dawn Center associate professor at the Niels Bohr Institute, told the university’s website .
“And then we noticed that two of them had a neighbour that we didn’t expect to be there at all. As both galaxies are surrounded by dust, some of their light is blocked, making them invisible to Hubble.”
What this new discovery suggests is that more galaxies formed in the early universe than what was previously estimated.
“Our discovery demonstrates that up to one in five of the earliest galaxies may have been missing from our map of the heavens. Before we can start to understand when and how galaxies formed in the universe, we first need a proper accounting,” said Oesch.
To help locate the missing galaxies, the Canadian Space Agency, NASA and European Space Agency launched a newly-built super telescope — the James Webb Space Telescope — i nto orbit on Christmas Day.
Once in place, the new telescope will help astronomers further map out the universe’s origins.
“The next step is to identify the galaxies we overlooked, because there are far more than we thought,” said Oesch.
“That’s where the James Webb Telescope will be a huge step forward. It will be much more sensitive than Hubble and able to investigate longer wavelengths, which ought to allow us to see these hidden galaxies with ease.”
