ERIK MARTIN WILLÈN: September 2022

Friday, September 30, 2022

Webb, Hubble Capture Detailed Views of DART Impact - UNIVERSE

Two of NASA’s Great Observatories, the James Webb Space Telescope and the Hubble Space Telescope, have captured views of a unique NASA experiment designed to intentionally smash a spacecraft into a small asteroid in the world’s first-ever in-space test for planetary defense. These observations of NASA’s Double Asteroid Redirection Test (DART) impact mark the first time that Webb and Hubble simultaneously observed the same celestial target.

On Sept. 26, 2022, at 7:14 pm EDT, DART intentionally crashed into Dimorphos, the asteroid moonlet in the double-asteroid system of Didymos. It was the world’s first test of the kinetic impact mitigation technique, using a spacecraft to deflect an asteroid that poses no threat to Earth, and modifying the object’s orbit. DART is a test for defending Earth against potential asteroid or comet hazards.

The coordinated Hubble and Webb observations are more than just an operational milestone for each telescope – there are also key science questions relating to the makeup and history of our solar system that researchers can explore when combining the capabilities of these observatories.

“Webb and Hubble show what we’ve always known to be true at NASA: We learn more when we work together,” said NASA Administrator Bill Nelson. “For the first time, Webb and Hubble have simultaneously captured imagery from the same target in the cosmos: an asteroid that was impacted by a spacecraft after a seven-million-mile journey. All of humanity eagerly awaits the discoveries to come from Webb, Hubble, and our ground-based telescopes – about the DART mission and beyond.”

Observations from Webb and Hubble together will allow scientists to gain knowledge about the nature of the surface of Dimorphos, how much material was ejected by the collision, and how fast it was ejected. Additionally, Webb and Hubble captured the impact in different wavelengths of light – Webb in infrared and Hubble in visible. Observing the impact across a wide array of wavelengths will reveal the distribution of particle sizes in the expanding dust cloud, helping to determine whether it threw off lots of big chunks or mostly fine dust. Combining this information, along with ground-based telescope observations, will help scientists to understand how effectively a kinetic impact can modify an asteroid’s orbit.

This animated GIF combines three of the images NASA’s Hubble Space Telescope captured after NASA’s Double Asteroid Redirection Test (DART) intentionally impacted Dimorphos, a moonlet asteroid in the double asteroid system of Didymos. The animation spans from 22 minutes after impact to 8.2 hours after the collision took place. As a result of the impact, the brightness of the Didymos-Dimorphos system increased by 3 times. The brightness also appears to hold fairly steady, even eight hours after impact. Credits: Science: NASA, ESA, Jian-Yang Li (PSI); animation: Alyssa Pagan (STScI) Download full-resolution, uncompressed versions and supporting visuals from the Space Telescope Science Institute

Webb Captures Impact Site Before and After Collision

Webb took one observation of the impact location before the collision took place, then several observations over the next few hours. Images from Webb’s Near-Infrared Camera (NIRCam) show a tight, compact core, with plumes of material appearing as wisps streaming away from the center of where the impact took place.

Observing the impact with Webb presented the flight operations, planning, and science teams with unique challenges, because of the asteroid’s speed of travel across the sky. As DART approached its target, the teams performed additional work in the weeks leading up to the impact to enable and test a method of tracking asteroids moving over three times faster than the original speed limit set for Webb.

“I have nothing but tremendous admiration for the Webb Mission Operations folks that made this a reality,” said principal investigator Cristina Thomas of Northern Arizona University in Flagstaff, Arizona. “We have been planning these observations for years, then in detail for weeks, and I’m tremendously happy this has come to fruition.”

Scientists also plan to observe the asteroid system in the coming months using Webb’s Mid-Infrared Instrument (MIRI) and Webb’s Near-Infrared Spectrograph (NIRSpec). Spectroscopic data will provide researchers with insight into the asteroid’s chemical composition.

Webb observed the impact over five hours total and captured 10 images. The data was collected as part of Webb’s Cycle 1 Guaranteed Time Observation Program 1245 led by Heidi Hammel of the Association of Universities for Research in Astronomy (AURA).

This animation, a timelapse of images from NASA’s James Webb Space Telescope, covers the time spanning just before impact at 7:14 p.m. EDT, Sept. 26, through 5 hours post-impact. Plumes of material from a compact core appear as wisps streaming away from where the impact took place. An area of rapid, extreme brightening is also visible in the animation. Credits: Science: NASA, ESA, CSA, Cristina Thomas (Northern Arizona University), Ian Wong (NASA-GSFC); Joseph DePasquale (STScI) Download full-resolution, uncompressed versions and supporting visuals from the Space Telescope Science Institute

Hubble Images Show Movement of Ejecta After Impact

Hubble also captured observations of the binary system ahead of the impact, then again 15 minutes after DART hit the surface of Dimorphos. Images from Hubble’s Wide Field Camera 3 show the impact in visible light. Ejecta from the impact appear as rays stretching out from the body of the asteroid. The bolder, fanned-out spike of ejecta to the left of the asteroid is in the general direction from which DART approached.

Some of the rays appear to be curved slightly, but astronomers need to take a closer look to determine what this could mean. In the Hubble images, astronomers estimate that the brightness of the system increased by three times after impact, and saw that brightness hold steady, even eight hours after impact.

These images from NASA’s Hubble Space Telescope, taken (left to right) 22 minutes, 5 hours, and 8.2 hours after NASA’s Double Asteroid Redirection Test (DART) intentionally impacted Dimorphos, show expanding plumes of ejecta from the asteroid’s body. The Hubble images show ejecta from the impact that appear as rays stretching out from the body of the asteroid. The bolder, fanned-out spike of ejecta to the left of the asteroid is in the general direction from which DART approached. These observations, when combined with data from NASA’s James Webb Space Telescope, will allow scientists to gain knowledge about the nature of the surface of Dimorphos, how much material was ejected by the collision, how fast it was ejected, and the distribution of particle sizes in the expanding dust cloud. Credits: Science: NASA, ESA, Jian-Yang Li (PSI); image processing: Alyssa Pagan (STScI) Download full-resolution, uncompressed versions and supporting visuals from the Space Telescope Science Institute

Hubble plans to monitor the Didymos-Dimorphos system 10 more times over the next three weeks. These regular, relatively long-term observations as the ejecta cloud expands and fades over time will paint a more complete picture of the cloud’s expansion from the ejection to its disappearance.

“When I saw the data, I was literally speechless, stunned by the amazing detail of the ejecta that Hubble captured,” said Jian-Yang Li of the Planetary Science Institute in Tucson, Arizona, who led the Hubble observations. “I feel lucky to witness this moment and be part of the team that made this happen.”

Hubble captured 45 images in the time immediately before and following DART’s impact with Dimorphos. The Hubble data was collected as part of Cycle 29 General Observers Program 16674.

“This is an unprecedented view of an unprecedented event,” summarized Andy Rivkin, DART investigation team lead of the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland.

The James Webb Space Telescope is the world's premier space science observatory. Webb will solve mysteries in our solar system, look beyond to distant worlds around other stars, and probe the mysterious structures and origins of our universe and our place in it. Webb is an international program led by NASA with its partners, ESA (European Space Agency) and CSA (Canadian Space Agency).

The Hubble Space Telescope is a project of international cooperation between NASA and ESA. NASA's Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore, Maryland, conducts Hubble and Webb science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy, in Washington, D.C.

Banner image: These images, Hubble on the left and Webb on the right, show observations of the Didymos-Dimorphos system several hours after NASA’s Double Asteroid Redirection Test (DART) intentionally impacted the moonlet asteroid. Credits: Science: NASA, ESA, CSA, Jian-Yang Li (PSI), Cristina Thomas (Northern Arizona University), Ian Wong (NASA-GSFC); image processing: Joseph DePasquale (STScI), Alyssa Pagan (STScI) Download full-resolution, uncompressed versions and supporting visuals from the Space Telescope Science Institute

Source: Webb, Hubble Capture Detailed Views of DART Impact | NASA

Artificial Intelligence Reduces a 100,000-Equation Quantum Physics Problem to Only Four Equations

Using artificial intelligence, physicists have compressed a daunting quantum problem that until now required 100,000 equations into a bite-size task of as few as four equations — all without sacrificing accuracy. The work, published in the September 23 issue of Physical Review Letters, could revolutionize how scientists investigate systems containing many interacting electrons. Moreover, if scalable to other problems, the approach could potentially aid in the design of materials with sought-after properties such as superconductivity or utility for clean energy generation.

“We start with this huge object of all these coupled-together differential equations; then we’re using machine learning to turn it into something so small you can count it on your fingers,” says study lead author Domenico Di Sante, a visiting research fellow at the Flatiron Institute’s Center for Computational Quantum Physics (CCQ) in New York City and an assistant professor at the University of Bologna in Italy.

The formidable problem concerns how electrons behave as they move on a gridlike lattice. When two electrons occupy the same lattice site, they interact. This setup, known as the Hubbard model, is an idealization of several important classes of materials and enables scientists to learn how electron behavior gives rise to sought-after phases of matter, such as superconductivity, in which electrons flow through a material without resistance. The model also serves as a testing ground for new methods before they’re unleashed on more complex quantum systems.

The Hubbard model is deceptively simple, however. For even a modest number of electrons and cutting-edge computational approaches, the problem requires serious computing power. That’s because when electrons interact, their fates can become quantum mechanically entangled: Even once they’re far apart on different lattice sites, the two electrons can’t be treated individually, so physicists must deal with all the electrons at once rather than one at a time. With more electrons, more entanglements crop up, making the computational challenge exponentially harder.

One way of studying a quantum system is by using what’s called a renormalization group. That’s a mathematical apparatus physicists use to look at how the behavior of a system — such as the Hubbard model — changes when scientists modify properties such as temperature or look at the properties on different scales. Unfortunately, a renormalization group that keeps track of all possible couplings between electrons and doesn’t sacrifice anything can contain tens of thousands, hundreds of thousands or even millions of individual equations that need to be solved. On top of that, the equations are tricky: Each represents a pair of electrons interacting.

Di Sante and his colleagues wondered if they could use a machine learning tool known as a neural network to make the renormalization group more manageable. The neural network is like a cross between a frantic switchboard operator and survival-of-the-fittest evolution. First, the machine learning program creates connections within the full-size renormalization group. The neural network then tweaks the strengths of those connections until it finds a small set of equations that generates the same solution as the original, jumbo-size renormalization group. The program’s output captured the Hubbard model’s physics even with just four equations.

“It’s essentially a machine that has the power to discover hidden patterns,” Di Sante says. “When we saw the result, we said, ‘Wow, this is more than what we expected.’ We were really able to capture the relevant physics.”

Training the machine learning program required a lot of computational muscle, and the program ran for entire weeks. The good news, Di Sante says, is that now that they have their program coached, they can adapt it to work on other problems without having to start from scratch. He and his collaborators are also investigating just what the machine learning is actually “learning” about the system, which could provide additional insights that might otherwise be hard for physicists to decipher.

Ultimately, the biggest open question is how well the new approach works on more complex quantum systems such as materials in which electrons interact at long distances. In addition, there are exciting possibilities for using the technique in other fields that deal with renormalization groups, Di Sante says, such as cosmology and neuroscience.

Source: https://www.simonsfoundation.org/2022/09/26/artificial-intelligence-reduces-a-100000-equation-quantum-physics-problem-to-only-four-equations/

Image: A visualization of a mathematical apparatus used to capture the physics and behavior of electrons moving on a lattice. Each pixel represents a single interaction between two electrons. Until now, accurately capturing the system required around 100,000 equations—one for each pixel. Using machine learning, scientists reduced the problem to just four equations. That means a similar visualization for the compressed version would need just four pixels. Credit: Domenico Di Sante/Flatiron Institute

Source: Artificial Intelligence Reduces a 100,000-Equation Quantum Physics Problem to Only Four Equations – Scents of Science (myfusimotors.com)

Ending a 50-year mystery, scientists reveal how bacteria can move

School of Medicine researchers and their collaborators have solved a decades-old mystery about how E. coli and other bacteria are able to move.

Bacteria push themselves forward by coiling long, threadlike appendages into corkscrew shapes that act as makeshift propellers. But how exactly they do this has baffled scientists, because the “propellers” are made of a single protein.

An international team led by UVA’s Edward H. Egelman, PhD, a leader in the field of high-tech cryo-electron microscopy (cryo-EM), has cracked the case. The researchers used cryo-EM and advanced computer modeling to reveal what no traditional light microscope could see: the strange structure of these propellers at the level of individual atoms.

“While models have existed for 50 years for how these filaments might form such regular coiled shapes, we have now determined the structure of these filaments in atomic detail,” said Egelman, of UVA’s Department of Biochemistry and Molecular Genetics. “We can show that these models were wrong, and our new understanding will help pave the way for technologies that could be based upon such miniature propellers.”

BLUEPRINTS FOR BACTERIA’S ‘SUPERCOILS’

Different bacteria have one or many appendages known as a flagellum, or, in the plural, flagella. A flagellum is made of thousands of subunits, but all these subunits are exactly the same. You might think that such a tail would be straight, or at best a bit flexible, but that would leave the bacteria unable to move. That’s because such shapes can’t generate thrust. It takes a rotating, corkscrew-like propeller to push a bacterium forward. Scientists call the formation of this shape “supercoiling,” and now, after more than 50 years, they understand how bacteria do it.

Using cryo-EM, Egelman and his team found that the protein that makes up the flagellum can exist in 11 different states. It is the precise mixture of these states that causes the corkscrew shape to form.

It has been known that the propeller in bacteria is quite different than similar propellers used by hearty one-celled organisms called archaea. Archaea are found in some of the most extreme environments on Earth, such as in nearly boiling pools of acid, the very bottom of the ocean and in petroleum deposits deep in the ground.

Egelman and colleagues used cryo-EM to examine the flagella of one form of archaea, Saccharolobus islandicus, and found that the protein forming its flagellum exists in 10 different states. While the details were quite different than what the researchers saw in bacteria, the result was the same, with the filaments forming regular corkscrews. They conclude that this is an example of “convergent evolution” – when nature arrives at similar solutions via very different means. This shows that even though bacteria and archaea’s propellers are similar in form and function, the organisms evolved those traits independently.

“As with birds, bats and bees, which have all independently evolved wings for flying, the evolution of bacteria and archaea has converged on a similar solution for swimming in both,” said Egelman, whose prior imaging work saw him inducted into the National Academy of Sciences, one of the highest honors a scientist can receive. “Since these biological structures emerged on Earth billions of years ago, the 50 years that it has taken to understand them may not seem that long.”

Source: https://newsroom.uvahealth.com/2022/09/26/ending-a-50-year-mystery-uva-reveals-how-bacteria-can-move/

Journal article: https://www.cell.com/cell/fulltext/S0092-8674(22)00996-5?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS0092867422009965%3Fshowall%3Dtrue

Source: Ending a 50-year mystery, scientists reveal how bacteria can move – Scents of Science (myfusimotors.com)

Mila Kunis Reveals How Ashton Kutcher Saved Her While Filming LUCKIEST GIRL ALIVE | Interview - Jake's Takes

THE BOYS Season 3 Bloopers & Gag Reel (2022) with Karl Urban and Antony Starr

Funny and Weird Clips (2771)

Thursday, September 29, 2022

First Images from Italian Space Agency’s LICIACube Satellite - UNIVERSE

Image captured by the Italian Space Agency’s LICIACube a few minutes after the intentional collision of NASA’s Double Asteroid Redirection Test (DART) mission with its target asteroid, Dimorphos, captured on Sept. 26, 2022. Credits: ASI/NASA

Source: First Images from Italian Space Agency’s LICIACube Satellite | NASA

NASA’s Juno Will Perform Close Flyby of Jupiter’s Icy Moon Europa - UNIVERSE

This image of Jupiter’s moon Europa was taken by the JunoCam imager aboard NASA’s Juno spacecraft on Oct. 16, 2021, from a distance of about 51,000 miles (82,000 kilometers). Image data: NASA/JPL-Caltech/SwRI/MSSS. Image processing: Andrea Luck CC BY

As the spacecraft makes a close approach of the moon, it is expected to provide valuable science – and remarkable imagery – for NASA’s upcoming Europa Clipper mission.

On Thursday, Sept. 29, at 2:36 a.m. PDT (5:36 a.m. EDT), NASA’s Juno spacecraft will come within 222 miles (358 kilometers) of the surface of Jupiter’s ice-covered moon, Europa. The solar-powered spacecraft is expected to obtain some of the highest-resolution images ever taken of portions of Europa’s surface, as well as collect valuable data on the moon’s interior, surface composition, and ionosphere, along with its interaction with Jupiter’s magnetosphere.

Such information could benefit future missions, including the agency’s Europa Clipper, which is set to launch in 2024 to study the icy moon. “Europa is such an intriguing Jovian moon, it is the focus of its own future NASA mission,” said Juno Principal Investigator Scott Bolton of the Southwest Research Institute in San Antonio. “We’re happy to provide data that may help the Europa Clipper team with mission planning, as well as provide new scientific insights into this icy world.”

Juno’s extended mission includes flybys of the moons Ganymede, Europa, and Io. This graphic depicts the spacecraft’s orbits of Jupiter – labeled “PJ” for perijove, or point of closest approach to the planet – from its prime mission in gray to the 42 orbits of its extended mission in shades of blue and purple. Credits: NASA/JPL-Caltech/SwRI

With an equatorial diameter of 1,940 miles (3,100 kilometers), Europa is about 90% the size of Earth’s Moon. Scientists think a salty ocean lies below a miles-thick ice shell, sparking questions about potential conditions capable of supporting life underneath Europa’s surface.

The close flyby will modify Juno’s trajectory, reducing the time it takes to orbit Jupiter from 43 to 38 days. It will be the closest a NASA spacecraft has approached Europa since Galileo came within 218 miles (351 kilometers) on Jan. 3, 2000. In addition, this flyby marks the second encounter with a Galilean moon during Juno’s extended mission. The mission explored Ganymede in June 2021 and plans to make close approaches of Io in 2023 and 2024.

Data collection will begin an hour prior to closest approach, when the spacecraft is 51,820 miles (83,397 kilometers) from Europa.

“The relative velocity between spacecraft and moon will be 14.7 miles per second (23.6 kilometers per second), so we are screaming by pretty fast,” said John Bordi, Juno deputy mission manager at JPL. “All steps have to go like clockwork to successfully acquire our planned data, because soon after the flyby is complete, the spacecraft needs to be reoriented for our upcoming close approach of Jupiter, which happens only 7 ½ hours later.”

The spacecraft’s full suite of instruments and sensors will be activated for the Europa encounter. Juno’s Jupiter Energetic-Particle Detector Instrument (JEDI) and its medium-gain (X-band) radio antenna will collect data on Europa’s ionosphere. Its Waves, Jovian Auroral Distributions Experiment (JADE), and Magnetometer (MAG) experiments will measure plasma in the moon’s wake as Juno explores Europa’s interaction with Jupiter’s magnetosphere.

MAG and Waves will also search for possible water plumes above Europa’s surface. “We have the right equipment to do the job, but to capture a plume will require a lot of luck,” said Bolton. “We have to be at the right place at just the right time, but if we are so fortunate, it’s a home run for sure.”

Inside and Out

Juno’s Microwave Radiometer (MWR) will peer into Europa’s water-ice crust, obtaining data on its composition and temperature. This is the first time such data will have been collected to study the moon’s icy shell.

In addition, the mission expects to take four visible-light images of the moon with JunoCam (a public-engagement camera) during the flyby. The Juno science team will compare them to images from previous missions, looking for changes in Europa’s surface features that might have occurred over the past two decades. These visible-light images will have an expected resolution better than 0.6 miles (1 kilometer) per pixel.

Although Juno will be in Europa’s shadow when closest to the moon, Jupiter’s atmosphere will reflect enough sunlight for Juno’s visible-light imagers to collect data. Designed to take images of star fields and search for bright stars with known positions to help Juno get its bearings, the mission’s star camera (called the Stellar Reference Unit) will take a high-resolution black-and-white image of Europa’s surface. Meanwhile, the Jovian Infrared Auroral Mapper (JIRAM) will attempt to collect infrared images of its surface.

Juno’s closeup views and data from its MWR instrument will inform the Europa Clipper mission, which will perform nearly 50 flybys after it arrives at Europa in 2030. Europa Clipper will gather data on the moon’s atmosphere, surface, and interior – information that scientists will use to better understand Europa’s global subsurface ocean, the thickness of its ice crust, and possible plumes that may be venting subsurface water into space.

More About the Mission

NASA’s Jet Propulsion Laboratory, a division of Caltech in Pasadena, California, manages the Juno mission for the principal investigator, Scott J. Bolton, of the Southwest Research Institute in San Antonio. Juno is part of NASA’s New Frontiers Program, which is managed at NASA’s Marshall Space Flight Center in Huntsville, Alabama, for the agency’s Science Mission Directorate in Washington. Lockheed Martin Space in Denver built and operates the spacecraft.

More information about Juno is available at: https://www.nasa.gov/juno and https://www.missionjuno.swri.edu

Source: NASA’s Juno Will Perform Close Flyby of Jupiter’s Icy Moon Europa | NASA

ESA astronaut Samantha Cristoforetti becomes first European female ISS commander

Since beginning her Minerva mission in April 2022, Samantha has served as lead of the United States Orbital Segment (USOS), overseeing activities in the US, European, Japanese and Canadian modules and components of the Station.

Upon taking her new role, she will become the fifth European commander of the Space Station, following in the footsteps of previous ESA astronauts Frank De Winne, Alexander Gerst, Luca Parmitano and Thomas Pesquet. She will also become the first European female to occupy the position.

“I am humbled by my appointment to the position of commander,” says Samantha “and look forward to drawing on the experience I’ve gained in space and on Earth to lead a very capable team in orbit.”

ESA’s Director General Josef Aschbacher shares Samantha’s outlook. “Samantha’s selection for commandership clearly demonstrates the faith and value our international partners place in ESA astronauts. Throughout her Minerva mission she has contributed greatly to the scientific and operational successes of the Station, and I anticipate that it will continue to thrive under her command.”

Samantha will officially become commander following a traditional handover ceremony which centres around the symbolic passing of a key from the previous commander. The ceremony itself will take place on Wednesday 28 September 2022 at 15:35 CEST (14:35 BST), and will be broadcast live from the International Space Station on ESA Web TV.

David Parker, ESA’s Director of Human and Robotic Exploration, shared his view that “Samantha’s wealth of knowledge and experience makes her an excellent candidate for this role. As the first European woman to fulfil the position of commander, she once again pushes forward boundaries for female representation in the space sector.”

The full title of this role is International Space Station crew commander. Commanderships are awarded based on joint decisions taken by NASA (United States), Roscosmos (Russia), JAXA (Japan), ESA (Europe), and CSA (Canada). ESA is represented in this selection process by Head of the European Astronaut Centre and ISS Programme Manager, Frank De Winne.

“I’m pleased that scheduling has changed in such a way that Samantha is once again due to occupy to position of commander,” says Frank. “She retains our full endorsement to fulfil this important leadership role. There is no doubt that her leadership will ensure continued mission success.”

Source: ESA

Source: ESA astronaut Samantha Cristoforetti becomes first European female ISS commander – Scents of Science (myfusimotors.com)