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Supernova Explosions Reveal Precise Details of Dark Energy and Dark Matter – SciTechDaily

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Artist’s impression of two white dwarf stars merging and creating a Type Ia supernova. Credit: ESO/L. Calçada

An analysis of more than two decades’ worth of supernova explosions convincingly boosts modern cosmological theories and reinvigorates efforts to answer fundamental questions.

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A powerful new analysis has been performed by astrophysicists that places the most precise limits ever on the composition and evolution of the universe. With this analysis, dubbed Pantheon+, cosmologists find themselves at a crossroads.

Pantheon+ convincingly finds that the cosmos is made up of about two-thirds dark energy and one-third matter — predominantly in the form of dark matter — and is expanding at an accelerating pace over the last several billion years. However, Pantheon+ also cements a major disagreement over the pace of that expansion that has yet to be solved.

By putting prevailing modern cosmological theories, known as the Standard Model of Cosmology, on even firmer evidentiary and statistical footing, Pantheon+ further closes the door on alternative frameworks accounting for dark energy and dark matter. Both are bedrocks of the Standard Model of Cosmology but have yet to be directly detected. They rank among the model’s biggest mysteries. Following through on the results of Pantheon+, researchers can now pursue more precise observational tests and hone explanations for the ostensible cosmos.

G299 Type Ia Supernova

G299 was left over by a particular class of supernovas called Type Ia. Credit: NASA/CXC/U.Texas

“With these Pantheon+ results, we are able to put the most precise constraints on the dynamics and history of the universe to date,” says Dillon Brout, an Einstein Fellow at the Center for Astrophysics | Harvard & Smithsonian. “We’ve combed over the data and can now say with more confidence than ever before how the universe has evolved over the eons and that the current best theories for dark energy and dark matter hold strong.”

Brout is the lead author of a series of papers describing the new Pantheon+ analysis, published jointly on October 19 in a special issue of The Astrophysical Journal.

Pantheon+ is based on the largest dataset of its kind, comprising more than 1,500 stellar explosions called Type Ia supernovae. These bright blasts occur when <span class="glossaryLink" aria-describedby="tt" data-cmtooltip="

white dwarf
A white dwarf star is the remnant of star that has exhausted its nuclear fuel, but it lacks the mass to become a neutron star. A typical white dwarf is only slightly bigger than Earth, yet it is 200,000 times as dense.

” data-gt-translate-attributes=”["attribute":"data-cmtooltip", "format":"html"]”>white dwarf stars — remnants of stars like our Sun — accumulate too much mass and undergo a runaway thermonuclear reaction. Because Type Ia supernovae outshine entire galaxies, the stellar detonations can be glimpsed at distances exceeding 10 billion light years, or back through about three-quarters of the universe’s total age. Given that the supernovae blaze with nearly uniform intrinsic brightnesses, scientists can use the explosions’ apparent brightness, which diminishes with distance, along with redshift measurements as markers of time and space. That information, in turn, reveals how fast the universe expands during different epochs, which is then used to test theories of the fundamental components of the universe.

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The breakthrough discovery in 1998 of the universe’s accelerating growth was thanks to a study of Type Ia supernovae in this manner. Scientists attribute the expansion to an invisible energy, therefore monikered dark energy, inherent to the fabric of the universe itself. Subsequent decades of work have continued to compile ever-larger datasets, revealing supernovae across an even wider range of space and time, and Pantheon+ has now brought them together into the most statistically robust analysis to date.

“In many ways, this latest Pantheon+ analysis is a culmination of more than two decades’ worth of diligent efforts by observers and theorists worldwide in deciphering the essence of the cosmos,” says Adam Riess, one of the winners of the 2011 Nobel Prize in Physics for the discovery of the accelerating expansion of the universe and the Bloomberg Distinguished Professor at Johns Hopkins University (JHU) and the Space Telescope Science Institute in Baltimore, Maryland. Riess is also an alum of Harvard University, holding a PhD in astrophysics.

“With this combined Pantheon+ dataset, we get a precise view of the universe from the time when it was dominated by dark matter to when the universe became dominated by dark energy.” — Dillon Brout

Brout’s own career in cosmology traces back to his undergraduate years at JHU, where he was taught and advised by Riess. There Brout worked with then-PhD-student and Riess-advisee Dan Scolnic, who is now an assistant professor of physics at Duke University and another co-author on the new series of papers.

Several years ago, Scolnic developed the original Pantheon analysis of approximately 1,000 supernovae.

Now, Brout and Scolnic and their new Pantheon+ team have added some 50 percent more supernovae data points in Pantheon+, coupled with improvements in analysis techniques and addressing potential sources of error, which ultimately has yielded twice the precision of the original Pantheon.

“This leap in both the dataset quality and in our understanding of the physics that underpin it would not have been possible without a stellar team of students and collaborators working diligently to improve every facet of the analysis,” says Brout.

Taking the data as a whole, the new analysis holds that 66.2 percent of the universe manifests as dark energy, with the remaining 33.8 percent being a combination of dark matter and matter. To arrive at even more comprehensive understanding of the constituent components of the universe at different epochs, Brout and colleagues combined Pantheon+ with other strongly evidenced, independent, and complementary measures of the large-scale structure of the universe and with measurements from the earliest light in the universe, the cosmic microwave background.

“With these Pantheon+ results, we are able to put the most precise constraints on the dynamics and history of the universe to date.” — Dillon Brout

Another key Pantheon+ result relates to one of the paramount goals of modern cosmology: nailing down the current expansion rate of the universe, known as the Hubble constant. Pooling the Pantheon+ sample with data from the SH0ES (Supernova H0 for the Equation of State) collaboration, led by Riess, results in the most stringent local measurement of the current expansion rate of the universe.

Pantheon+ and SH0ES together find a Hubble constant of 73.4 kilometers per second per megaparsec with only 1.3% uncertainty. Stated another way, for every megaparsec, or 3.26 million light years, the analysis estimates that in the nearby universe, space itself is expanding at more than 160,000 miles per hour.

However, observations from an entirely different epoch of the universe’s history predict a different story. Measurements of the universe’s earliest light, the cosmic microwave background, when combined with the current Standard Model of Cosmology, consistently peg the Hubble constant at a rate that is significantly less than observations taken via Type Ia supernovae and other astrophysical markers. This sizable discrepancy between the two methodologies has been termed the Hubble tension.

The new Pantheon+ and SH0ES datasets heighten this Hubble tension. In fact, the tension has now passed the important 5-sigma threshold (about one-in-a-million odds of arising due to random chance) that physicists use to distinguish between possible statistical flukes and something that must accordingly be understood. Reaching this new statistical level highlights the challenge for both theorists and astrophysicists to try and explain the Hubble constant discrepancy.

“We thought it would be possible to find clues to a novel solution to these problems in our dataset, but instead we’re finding that our data rules out many of these options and that the profound discrepancies remain as stubborn as ever,” says Brout.

The Pantheon+ results could help point to where the solution to the Hubble tension lies. “Many recent theories have begun pointing to exotic new physics in the very early universe, however, such unverified theories must withstand the scientific process and the Hubble tension continues to be a major challenge,” says Brout.

Overall, Pantheon+ offers scientists a comprehensive look back through much of cosmic history. The earliest, most distant supernovae in the dataset gleam forth from 10.7 billion light years away, meaning from when the universe was roughly a quarter of its current age. In that earlier era, dark matter and its associated gravity held the universe’s expansion rate in check. Such a state of affairs changed dramatically over the next several billion years as the influence of dark energy overwhelmed that of dark matter. Dark energy has since flung the contents of the cosmos ever farther apart and at an ever-increasing rate.

“With this combined Pantheon+ dataset, we get a precise view of the universe from the time when it was dominated by dark matter to when the universe became dominated by dark energy,” says Brout. “This dataset is a unique opportunity to see dark energy turn on and drive the evolution of the cosmos on the grandest scales up through present time.”

Studying this changeover now with even stronger statistical evidence will hopefully lead to new insights into dark energy’s enigmatic nature.

“Pantheon+ is giving us our best chance to date of constraining dark energy, its origins, and its evolution,” says Brout.

Reference: “The Pantheon+ Analysis: Cosmological Constraints” by Dillon Brout, Dan Scolnic, Brodie Popovic, Adam G. Riess, Anthony Carr, Joe Zuntz, Rick Kessler, Tamara M. Davis, Samuel Hinton, David Jones, W. D’Arcy Kenworthy, Erik R. Peterson, Khaled Said, Georgie Taylor, Noor Ali, Patrick Armstrong, Pranav Charvu, Arianna Dwomoh, Cole Meldorf, Antonella Palmese, Helen Qu, Benjamin M. Rose, Bruno Sanchez, Christopher W. Stubbs, Maria Vincenzi, Charlotte M. Wood, Peter J. Brown, Rebecca Chen, Ken Chambers, David A. Coulter, Mi Dai, Georgios Dimitriadis, Alexei V. Filippenko, Ryan J. Foley, Saurabh W. Jha, Lisa Kelsey, Robert P. Kirshner, Anais Möller, Jessie Muir, Seshadri Nadathur, Yen-Chen Pan, Armin Rest, Cesar Rojas-Bravo, Masao Sako, Matthew R. Siebert, Mat Smith, Benjamin E. Stahl and Phil Wiseman, 19 October 2022, The Astrophysical Journal.
DOI: 10.3847/1538-4357/ac8e04

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YouTuber Mark Rober drops eggs from space to land in Victor Valley – VVdailypress.com

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Former NASA engineer Mark Rober, the YouTuber best known for his Backyard Squirrel Maze and Exploding Glitter Bomb videos, recently dropped a couple of eggs from space that fell in the Victor Valley.

The 42-year-old Rober and his team of scientists dropped both eggs, with the intention of them not breaking, from a height of nearly 19 miles and with the help of a high-altitude balloon provided by Night Crew Labs.

The launch occurred earlier this year, but the “Egg Drop From Space” video was uploaded to YouTube on Black Friday.

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It includes shots of the team driving on Bear Valley Road toward Deadman’s Point in Apple Valley. Also shown are Bell Mountain, Interstate 15 and an area west of I-15 and near the Dale Evans Parkway offramp. 

A shot from the weather balloon in space showed the Victor Valley, including landmarks such as Spring Valley Lake and the Mojave River. 

The egg-drop project

When Rober started conceptualizing his egg drop project nearly three years ago, he knew that a successful record drop would come from his experience of landing scientific gear on other planets when he worked for NASA.

A graduate of USC, Rober worked at NASA for nine years, seven of them on the Mars Curiosity project. He also spent five years at Apple working on advanced virtual reality technology for autonomous vehicles before quitting to become a full-time YouTuber.

Rober confessed that before he embarked on the egg drop project, he didn’t know that it would be the most “physically, financially and mentally draining video” he would ever attempt. 

The plan

Rober’s team included rocket and propulsion specialist Joe Barnard, of BPS Systems, which helped with the rocket’s guidance system and design.

Rober’s original plan was to affix an egg onto a rocket, which would be lifted by a large weather balloon. Once in space, the rocket would be released and would guide the rocket to an area over the drop target. 

At 300 feet above the ground, the egg would be released and free-fall toward a specially designed mattress. 

After determining the terminal velocity of the egg to be 74 mph, he successfully tested the speed inside his Crunch Lab located near San Francisco

Rober and his team then headed to the Northern California town of Gridley for three low-altitude tests, which all failed. 

‘A fatal flaw’

Rober sought the guidance of NASA engineer Adam Steltzner, who works for the Jet Propulsion Laboratory and on several flight projects including Galileo, Cassini, Mars Pathfinder and the Mars Exploration Rovers.

After listening to Rober and details about his project, Steltzner found a “fatal flaw” in the project and asked him, “How did you not get busted by the FAA?”

Rober realized that his project was akin to creating a precision-guided missile, which is frowned upon by the federal government. 

Heading to the High Desert

After going back to the drawing board, Rober’s team decided to conduct a rocket launch with a general egg drop target area in the High Desert. 

The launch would use a weather balloon, which would lift a larger and heavier rocket to guarantee the egg would reach supersonic speed on its way down. 

The helium-filled balloon would release the rocket, which would begin separating. 

A portion of the rocket, carrying the egg, would slow before losing its nose cone and deploying a parachute and cushioned airbags, which were borrowed from the Spirit and Opportunity landing projects.

Just before liftoff, Rober discovered that the newly designed, the two-piece rocket might unexpectedly separate at Mach 2. 

Rober and his team fixed the rocket’s connection point and ran vacuum and heat tests on the egg chamber.

They also built redundancy into the system, which included creating a custom beach ball, filled with packing materials to protect a second egg.

The entire payload, suspended from the balloon, would detach and simply fall to earth over the target. 

The launch

Rober’s friend, JPL systems engineer Allen Chen, traveled to the Victor Valley for Rober’s second launch. 

In 2012, Chen uttered the famous words, “Touchdown confirmed, we’re safe on Mars,” after the Curiosity Rover had survived the harrowing plunge and landed on the red planet.

Somewhere near Apple Valley, the lift-off of Rober’s balloon, rocket, beach ball and eggs was successful. 

As the team drove and arrived at the projected landing site, they discovered that the balloon had surpassed the 100,000-foot mark. 

As the group celebrated, moments later, they discovered that the balloon had suddenly lost altitude and came crashing down to earth. 

As the balloon ascended, the cord that held the rocket, beach ball and eggs had wound so tight that it pulled down on the balloon, causing it to come hurtling down at 150 mph, “Which is way faster than the eggs could survive,” Rober explained. 

As the team looked for the wreckage, they spotted the parachute, the rocket and the beach ball. 

Rober was excited that at 20,000 feet, the payload had autonomously detached itself from the balloon. 

Rober held back his excitement as he opened the rocket to inspect the egg. 

As a smiling Rober pulled an uncracked egg from the rocket and held it high, Chen joyously said, “Touchdown confirmed, we’re safe on earth.”

That was repeated when Rober ripped open the beach ball and pulled out a second uncracked egg that he kissed. 

“Two for two, baby!” shouted Rober as he high-fived Chen. “Two for two!”

Rober ended the video by saying that the egg drop from space project reminded him that in life things rarely unfold how we think they will. 

“But by learning from your failures, coupled with a bit of tenacity, us humans can accomplish a feat as incredible as the world’s smartest Martian robot or as ridiculous as the world’s tallest egg drop,” Rober said. 

Daily Press reporter Rene Ray De La Cruz may be reached at 760-951-6227 or RDeLaCruz@VVDailyPress.com. Follow him on Twitter @DP_ReneDeLaCruz

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In a B.C. first, UVic mini-satellite launched into space after four years of work

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A University of Victoria satellite the size of a two-litre milk carton, designed to calibrate light, was fired into space Saturday, after four years of work by dozens of students, faculty and researchers.

ORCASat started its journey to space at 11:20 a.m. Saturday as part of NASA’s SpaceX Falcon 9 rocket launch at Kennedy Space Center in Florida.

Early this morning, about 4 a.m., the satellite is scheduled to be taken on board the International Space Station where it will wait for a few weeks before being fired into space to orbit the Earth for as long as it can survive.

Saturday’s successful launch was extra-sweet because a planned Tuesday launch was postponed due to poor weather. Watchers from UVic returned home after the delayed launch.

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A nervous Alex Doknjas, ORCASat project manager, went into his family’s living room at 10:30 a.m. Saturday where he waited with loved ones and about 20 others on a video chat, including a UVic group, to watch the event together. Cheers and claps erupted when the rocket launched on time. “It’s great. It’s fantastic,” he said.

There was a little wind picking up on the launch site shortly before liftoff was scheduled and Doknjas said he was worried it was about to get scrubbed again, but that didn’t happen.

The excitement has been years in the making thanks to about 140 people who have been part of a team at the University of Victoria Centre for Aerospace Research.

Full-time researchers, co-op and volunteer students from UVic Satellite Design, UBC Orbit, and Simon Fraser University Satellite Design have all contributed.

The ORCASat (for Optical Reference Calibration Satellite) measures 10 centimetres by 10 centimetres by 23 centimetres and weighs 2.5 kilograms.

Doknjas said as far as he knows this is the first “Cubesat” designed and built in this province. “That’s a pretty big milestone.”

The estimated date to launch ORCASat is between Dec. 29 and the first week in January.

ORCASat will be doing a 400-kilometre orbit around Earth and travelling at 7.5 kilometres a second. “It’s pretty fast.”

It is not known exactly how long it will last but it could be six to eight months, up to 18 months, Doknjas said. Factors such as sun flares, solar radiation, pressure and more can all impact the life of the satellite.

ORCASat is basically an artificial star, a reference light source in orbit that can be viewed by telescopes on Earth.

Astronomers can measure how bright ORCASat appears, just as they would an astronomical object.

At the same time, the satellite, using two laser light sources, will measure the amount of light that an astronomical object is emitting.

This will allow ground-based telescopes to be calibrated to measure the absolute brightness of an astronomical object, not how they appear after passing through the atmosphere and the optics of a telescope.

This is the first satellite ever to carry a light source capable of performing this experiment to this level of accuracy.

It is a proof-of-concept technology which in the future could be developed to be applicable in such areas as climate change, Earth observation and methane gas research, Doknjas said.

parrais@timescolonist.com

cjwilson@timescolonist.com

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NASA’s Orion spacecraft breaks Apollo 13 flight record

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The Artemis 1 Orion crew vehicle has set a new record for a NASA flight. At approximately 8:40AM ET on Saturday, Orion flew farther than any spacecraft designed to carry human astronauts had ever before, surpassing the previous record set by Apollo 13 back in 1970. As of 10:17AM ET, Orion was approximately 249,666 miles ( from 401,798 kilometers) from Earth.

“Artemis I was designed to stress the systems of Orion and we settled on the distant retrograde orbit as a really good way to do that,” said Jim Geffre, Orion spacecraft integration manager. “It just so happened that with that really large orbit, high altitude above the moon, we were able to pass the Apollo 13 record. But what was more important though, was pushing the boundaries of exploration and sending spacecraft farther than we had ever done before.”

Of all the missions that could have broken the record, it’s fitting that Artemis 1 was the one to do it. As Space.com points out, Apollo 13’s original flight plan didn’t call for a record-setting flight. It was only after a mid-mission explosion forced NASA to plot a new return course that Apollo 13’s Odyssey command module set the previous record at 248,655 miles (400,171 kilometers) from Earth.

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With a limited oxygen supply on the Aquarius Lunar Module, NASA needed to get Apollo 13 back to Earth as quickly as possible. The agency eventually settled on a flight path that used the Moon’s gravity to slingshot Apollo 13 back to Earth. One of the NASA personnel who was critical to the safe return of astronauts Jim Lovell, Jack Swigert and Fred Haise was Arturo Campos. He wrote the emergency plan that gave the Command and Service Module enough power to make it back to Earth. Artemis 1 is carrying a “Moonikin” test dummy named after the late Arturo.

Earlier this week, Orion completed a flyby of the Moon. After the spacecraft completes half an orbit around the satellite, it will slingshot itself toward the Earth. NASA expects Orion to splash down off the coast of San Diego on December 11th.

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