Dr. Swindle follows this with, “There are two basic types of motivation. One is that we’re planning on bringing all these rock samples, and we’re going to be interested in knowing how they’ve interacted with the atmosphere, but we can’t figure that out without knowing the composition of the atmosphere in detail. So, we need an atmospheric sample to know what the rocks might have been exchanging elements and isotopes with. But we’d also like to have a sample of the Martian atmosphere to answer some basic questions about processes that have occurred, or are occurring, on Mars. For example, Martian meteorites contain trapped atmospheric noble gases, like krypton and xenon. But it appears that there are at least two different “atmospheric” components in those meteorites.”

For the study, the researchers proposed several benefits of returning a Mars atmospheric sample to Earth, including atmospheric samples being among the NASA Perseverance (Percy) rover sample tubes, gaining insight into potential solar gar within the Martian interior, evolutionary trends in atmospheric compositions, nitrogen cycling, and sources of methane on Mars. For the Percy atmospheric sample, also known as Sample No.1 “Roubion”, the study notes how this sample was obtained after Percy tried to collect a rock core sample but ended up collecting atmospheric gases instead. Additionally, the study proposes the lack of leakage the sample tube will experience while awaiting its return to Earth and the gases present within the sample are ideal for analysis once returned to Earth, as well. But aside from the Percy rover sample, how else could a Martian atmosphere sample be obtained?

“At least two other ideas for collecting a sample of Martian atmosphere have been suggested,” Dr. Swindle tells Universe Today. “One is to fly a spacecraft through the Martian atmosphere, collect a sample as it goes through, then return it to Earth. The other is to have a sample return “cannister” (it doesn’t have to be any bigger than a Perseverance tube) that has valves and a (Martian) air compressor. You could land it on the surface of Mars, open the valve to the atmosphere, turn on the compressor, and get a sample that has hundreds or thousands of times as much Martian atmosphere as a volume that is just sealed without compression, as Perseverance has done, and hopefully will do again.”

Dr. Swindle and Dr. Young both mention the Sample Collection for Investigation of Mars (SCIM) mission, which was proposed in 2002 by a team of NASA and academic researchers with the goal of collecting atmospheric samples at an altitude of 40 kilometers (25 miles) above the Martian surface and return them to Earth for further analysis. While SCIM was selected as a semi-finalist for the 2007 Mars Scout Program, it was unfortunately not selected for further development, and both Dr. Young and Dr. Swindle tell Universe Today there are currently no atmospheric sample missions being planned aside from the Percy rover sample. Therefore, what follow-up studies from this research are currently underway or being planned?

Dr. Swindle and Dr. Young both mention how efforts are being made to collect small quantities of atmospheric gas due to the small size of the sample tubes, with Dr. Swindle telling Universe Today, “A big set of questions right now is how good a sealed Perseverance tube would be at containing an atmospheric sample. How good is the seal? Might the tube spring a leak on a hard landing? Would some molecules in the Martian atmosphere stick to the coatings of the tubes? There’s been some activity on all of these questions, and so far, the answers have all been good – it looks like those Perseverance tubes may do well, even though they weren’t really designed with atmospheric sampling in mind.”

As noted, the purpose of obtaining and returning an atmospheric sample from Mars could help scientists better understand the formation and evolution of the Red Planet. While present-day Mars is a very cold and dry world with an atmosphere that is a fraction of the Earth’s atmosphere, with liquid water being unable to exist on the surface, along with no active volcanism, as well. However, significant evidence obtained from landers, rovers, and orbiters over the last several decades point to a much different Mars billions of years ago after it first formed. This included an active interior that produced a magnetic field that shielded the surface from harmful solar and cosmic radiation, a much thicker atmosphere being replenished from active volcanism, and flowing liquid water, all of which potentially led to the existence of some forms of life on the surface.

However, given Mars’ small size (half of Earth), this means its internal heat cooled off much faster (possibly over millions of years), resulting in volcanism becoming inactive and the dissipation of the magnetic field the interior activity was driving, the latter of which led to harmful solar and cosmic radiation stripping the atmosphere, with the surface liquid water evaporating to space along with it. Therefore, do Dr. Young and Dr. Swindle believe life ever existed on Mars, and will we ever find it?

Dr. Young tells Universe Today, “I really don’t know.  I think microbial life sometime in the past, or even now, is a reasonable hypothesis but we don’t have enough information.”

Dr. Swindle also echoes his uncertainty whether life ever existed on Mars, but elaborates by telling Universe Today, “If there hasn’t, why did life start so early on Earth, but didn’t start on Mars, which had a similar climate at the time. If there has been, how similar is it to life on Earth? Since Earth and Mars are always exchanging rocks because of impacts, is life on Earth related to life on Mars? If it has existed, it will be tough to find. But an atmospheric sample could help. For instance, there seems to be methane in the Martian atmosphere. Most, but not all, of the methane in Earth’s atmosphere is biological, and analyzing the relative ratios of the isotopes of carbon or hydrogen is one of the best ways to figure that out.”

When will we obtain an atmospheric sample of Mars and what will it teach us about the formation and evolution of the Red Planet in the coming years and decades? Only time will tell, and this is why we science!

• As always, keep doing science & keep looking up!

{ https://www.universetoday.com/ }

01-06-2024 om 14:42 geschreven door peter  

POSTED BY CAROLYN COLLINS PETERSEN

Io Has Been Volcanically Active for its Entire History

Jupiter’s moon Io is a volcanic powerhouse. It’s the most geologically active world in the Solar System, sporting more than 400 spouting volcanoes and vents on its surface. Has it always been this way? A team of planetary scientists says yes, and they have the chemical receipts to prove it.

In a recent paper, the team headed by CalTech scientist Katherine de Kleer cites data from millimeter observations of elemental isotopes found in Io’s eruptions. They found that chemicals like chlorine and sulfur exist in higher quantities at Io than in comparable places in the Solar System. Analysis shows that Io hasn’t just started erupting lately—it’s been going on for most of its history. And, it’s so volcanic that it practically resurfaces itself every million years or so.

The discovery of volcanism on Io was one of the major results of the Voyager mission. As the two spacecraft swept past Jupiter in 1979, their images revealed Io’s volcanic features and plumes. Since that time, the Galileo, Cassini-Huygens, New Horizons, and Juno missions also sent images. The Jovian system and its moons are also frequent targets for ground- and space-based observatories, including Hubble Space Telescope and JWST.

Facts about Io

Io is the fourth-largest Jovian moon and is one of the four Galilean satellites. It orbits closest to Jupiter and gets pulled by a gravitational tug-of-war between Jupiter and the other Galilean moons. The result is a process called “tidal heating” deep inside Io, produced by friction. That generates heat, which melts Io’s interior, and opens up vents so that the heat and melted material can escape to the surface.

This little moon is mostly silicate rock atop an iron or iron sulfide core. The surface is scarred with volcanoes and deformed by compressional forces beneath the crust. The most obvious features are the volcanic mountains, plumes, and lava flows. Currently, Io’s volcanoes resurface the landscape at a rate of about 0.1 to 1.0 cm per year. They also paint its surface in an amazing array of colors. During the Voyager 2 flyby, people often compared its appearance to a pizza. The colors come mainly from sulfur and sulfurous compounds deposited across the landscape.

Normally, geologists would look at its surface and count craters to get an idea of its age. But, since volcanic flows erase craters, there’s no easy visual way to determine how long volcanic features have been around. However, it turns out that abundances of certain isotopes of sulfur and other elements could provide a good record the history of volcanism on Io.

Analyzing Io’s Chemistry

Io has probably lost mass to space throughout its history. de Kleer and her colleagues point out that its supply of volatile elements should be highly enriched in heavy stable isotopes. That’s because atmospheric escape processes generally favor the loss of lighter isotopes. They suggest that stable isotope measurements of volatile elements, such as sulfur and chlorine, could give accurate details about the history of volcanism at Io. So, it makes sense, then, to do a thorough chemical analysis of Io’s volcanic emissions now and extrapolate back.

Understanding Io’s current chemistry, requires, among other things, a good idea of its mass-loss history. Io’s mass loss occurs because of collisions between atmospheric molecules and energetic particles trapped in Jupiter’s magnetosphere. If this continued over Io’s history, then its chemistry should provide evidence of the volcanic past. In their paper, the team discusses the assumptions they made, including estimates of Io’s initial inventory of sulfur, as well as possible early mass-loss rates that could affect its current abundances of sulfur and chlorine—two elements that help determine past and present volcanism.

To get that history, team used the Atacama Large Millimeter Array to observe gases in Io’s atmosphere. The goal was to measure SO2, SO, NaCl, and KCl in various forms and determine the ratios of ³⁴S to ³²S and ³⁷Cl to ³⁵Cl. After analyzing the data, the team found that Io has lost at least 94 to 99 percent of its available sulfur over time. In addition, the measurements show enriched levels of chlorine. This probably indicates that Io has been volcanically active throughout time. It’s also possible that this tiny moon has experienced higher rates of outgassing and mass loss early in its history. More measurements should help scientists constrain Io’s volcanic activity even more tightly.

For More Information

• Isotopic Evidence of Long-lived Volcanism on I
• Violent Volcanoes Have Wracked Jupiter’s Moon Io for Billions of Years

{ https://www.universetoday.com/ }

01-06-2024 om 01:45 geschreven door peter  

POSTED BY MATT WILLIAMS

Pluto Has an Ocean of Liquid Water Surrounded by a 40-80 km Ice Shell

On July 14th, 2015, the New Horizons spacecraft conducted the first-ever flyby of Pluto, which once was (and to many, still is) the ninth planet of the Solar System. While the encounter was brief, the stunning images and volumes of data it obtained revealed a stunningly vibrant and dynamic world. In addition to Pluto’s heart, floating ice hills, nitrogen icebergs, and nitrogen winds, the New Horizons data also hinted at the existence of an ocean beneath Pluto’s icy crust. This effectively made Pluto (and its largest moon, Charon) members of the “Ocean Worlds” club.

Almost a decade after that historic encounter, scientists are still making discoveries from New Horizons data. In a new paper, planetary scientists Alex Nguyen and Dr. Patrick McGovern used mathematical models and images to learn more about the possible ocean between Pluto’s icy surface and its silicate and metallic core. According to their analysis, they determined that Pluto’s ocean is located beneath a surface shell measuring 40 to 80 km (25 to 50 mi), an insulating layer thick enough to ensure that an interior ocean remains liquid.

Nguyen is a graduate student in Earth, environmental, and planetary sciences in Arts & Sciences at Washington University in St. Louis (WUSTL), while Dr. McGovern is a Senior Staff Scientist with the Lunar and Planetary Institute (LPI) in Houston. Their paper, “The role of Pluto’s ocean’s salinity in supporting nitrogen ice loads within the Sputnik Planitia basin,” recently appeared in the journal Icarus. The study is part of Nguyen’s Ph.D. research at Washington University, where he is an Olin Chancellor’s Fellow and a National Science Foundation Graduate Research Fellow.

For decades, planetary scientists assumed Pluto was far too cold to support an interior ocean. Pluto orbits well beyond the Solar System’s “Frost Line,” the boundary beyond which volatile elements (water, carbon dioxide, ammonia, etc.) become solid. With an average surface temperature of -229 °C (-380°F), even nitrogen and methane become as solid as rock. As Nguyen indicated in a recent interview with The Source (WUSTL’s news site), “Pluto is a small body. It should have lost almost all of its heat shortly after it was formed, so basic calculations would suggest that it’s frozen solid to its core.”

But thanks to New Horizons, scientists were presented with multiple lines of evidence that suggest Pluto likely has an interior ocean. This includes cryovolcanoes, such as those observed on Ceres, Europa, Ganymede, Enceladus, Titan, Triton, and other “Ocean Worlds.” While the existence of this ocean is still subject to debate, the theory is gaining acceptance to the point that it is considered a very real possibility. For their study, Nguyen and McGovern created mathematical models to explain the cracks and bulges in the ice covering Pluto’s Sputnik Planitia Basin.

Their results indicate that an ocean could exist beneath an icy shell 40 to 80 km (25 to 50 mi) thick, which would be sufficient to ensure that Pluto could maintain a liquid water ocean in its interior despite surface conditions. They also calculated the likely density or salinity of the ocean based on the surface features and determined that Pluto’s ocean could be up to 8% denser than Earth’s oceans. This salinity level would make Pluto’s ocean comparable to the Great Salt Lake, the Dead Sea, and other high-salinity bodies of water on Earth.

According to Nguyen, any variations in this density (greater or lower) would be evident from the cracks and fractures in the Sputnik Platina Basin. “We estimated a sort of Goldilocks zone where the density and shell thickness is just right,” he said. If the ocean were less dense, the ice shell would collapse, leading to many more fractures in the surface. If it were denser, the ice sheet would be more buoyed, which would be evident from there being fewer fractures. Unfortunately, it could be many decades before another spacecraft reaches Pluto to help confirm these findings. In the meantime, the case for Pluto’s interior ocean grows stronger!

Further Reading:

•  Washington University at St. Louis, Icarus

{ https://www.universetoday.com/ }

01-06-2024 om 01:37 geschreven door peter  

For the study, the researchers investigated water management requirements for a 100-person self-sustaining lunar base measured at 500 m x 100 x 6 m (1640 ft x 328 ft x 20 ft), including the location of the lunar base near water ice deposits, the technology required to convert the water ice to water vapor (since liquid water can’t exist on the Moon), and the technology required for water treatment and recovery that would result in safe consumption for the 100-person base. The study used the current water usage estimates for American households, which is approximately 100 gallons per day (GPD) per person, which includes cleaning, cooking, drinking, flushing toilets, and washing clothes.

Additionally, the researchers examined the amount of water required for agricultural, technical, and overall needs for the lunar base. Regarding the location of the lunar base, the researchers deduced that the best location for the base would be either near, or exactly on, the Shackleton-de Gerlache Ridge, which is located at 89.9°S 0.0°E, or almost directly on the lunar south pole. The reason this location is ideal for water ice deposits is because Shackleton Crater resides within a permanently shadowed region (PSR), meaning it is shrouded in permanent darkness due to the Moon’s small axial tilt, and water ice has potentially built up over billions of years.

In the end, the team concluded the water requirements for the 100-person lunar base for human, agricultural, and technical needs are 12.3, 72, and 2 acre-feet per year. For context, one acre-foot is equivalent to approximately 326,000 gallons, so a 100-person lunar base would need more than 4,000,000 gallons per year for human needs, more than 23,000,000 gallons per year for agricultural needs, and 652,000 gallons per year for technical needs. So, based on these findings, what were the most significant results from this study, and what follow-up studies are currently in the works or being planned?

Dr. Lee tells Universe Today, “There is good evidence that sufficient water exists on the Moon to support a permanent lunar colony, and the acquisition, treatment, and distribution of the lunar water can be achieved with current technology. An appropriate administrative structure will be necessary to oversee all aspects of lunar water. The relative scarcity and management of water on the Moon can potentially provide insight for improving the management of water on Earth. The next study for my group will be to investigate the ways in which the management of lunar water could help to improve terrestrial water management. However, the timeline for this research is yet to be determined.”

The study discusses in-situ resource utilization (ISRU), which is using available, on-site resources for both sustainability and survivability. In this case, using water ice deposits on the Moon, and specifically near the south pole of the Moon, to meet the water needs of a 100-person, self-sustaining lunar base. The potential for NASA using ISRU has gained considerable traction in the last few years since sending water from the Earth to the Moon could prove to be extremely costly. But aside from the financial risks, if a resupply mission gets delayed or fails on the way to the Moon, the crew could face significant danger. Therefore, learning to “live off the land” for a lunar base could prove to be a viable, long-term option for mitigating the need of resupply missions from Earth. But what additional importance could a self-sustaining moonbase also provide?

Dr. Lee tells Universe Today, “Over the years, there has been a groundswell of excitement at the prospect of colonizing Mars. Indeed, at present, we are conceivably able to mount a short-term human voyage to the Red Planet in which the astronauts would collect samples, conduct experiments, plant flags, and when the next launch window occurs, return to Earth. However, the permanent colonization of Mars is much more ambitious and challenging. Mars is much farther away than the Moon, requiring 9 months to get there and a round trip time of 21 months (a 3-month stay on Mars is needed until the next launch window arrives).”

NASA’s goal is to send humans to Mars through the agency’s Moon to Mars Architecture, which is an elaborate, years-long endeavor to develop the necessary technologies on the Moon for use during a crewed mission to the Red Planet. This includes science, infrastructure, transportation, habitation, and operations, just to name a few. However, as noted, while we can (possibly) send humans to the Red Planet for short-term stays with our current technology, a long-term human presence on Mars would require significantly more time and resources.  

Dr. Lee tells Universe Today, “Beyond low Earth orbit, the Moon is a logical next destination. Lunar colonization is technologically achievable, and in comparison to Martian colonization, it is far easier. Being capable of establishing a moonbase seems like an obvious prerequisite for establishing a Mars base. Furthermore, the Moon would be an excellent jumping off point for further Solar System colonization including potentially the eventual establishment of small colonies in the interiors of Near-Earth Asteroids. Additionally, some have suggested that the Moon is an ideal location from which the interception of Earth-bound asteroids could be conducted.”

This study comes as NASA’s Artemis program plans to land the first woman and person of color on the lunar surface in the next few years. The current landing sites of the Artemis missions are near the south pole to access nearby water ice deposits within the aforementioned PSRs and could be ideal to develop ISRU technologies that can also be used on future Mars crewed missions, as well. Therefore, what implications could this study have for the upcoming Artemis missions?

“Short term lunar visits, such as the planned Artemis missions would not require lunar water,” Dr. Lee tells Universe Today. “In these instances, sufficient water could be brought from Earth. However, if at some point in the future, a lunar colony were to become a priority, future Artemis missions could serve to provide valuable in situ information about the presence and abundance of lunar water, particularly at the lunar south pole and in proximity to the Shackleton Crater (an ideal area for a moonbase).”

How will water management play a role in a self-sustaining lunar base in the coming years and decades? Only time will tell, and this is why we science!

• As always, keep doing science & keep looking up!

{ https://www.universetoday.com/ }

01-06-2024 om 01:27 geschreven door peter  

The study, published in the journal Patterns, highlights the risks and challenges posed by this emerging behavior and calls for urgent action from policymakers and AI developers.

“AI developers do not have a confident understanding of what causes undesirable AI behaviors like deception,” Dr. Peter S. Park, the study’s lead author and an AI existential safety postdoctoral fellow at MIT, said in a press release. “But generally speaking, we think AI deception arises because a deception-based strategy turned out to be the best way to perform well at the given AI’s training task. Deception helps them achieve their goals.” 

The review meticulously analyzed various AI systems and found that many had developed deceptive capabilities due to their training processes. These systems ranged from game-playing AIs to more general-purpose models used in economic negotiations and safety testing environments.

One of the most striking examples cited in the study was Meta’s CICERO, an AI developed to play the game Diplomacy. Despite being trained to act honestly and maintain alliances with human players, CICERO frequently used deceptive tactics to win. 

This behavior included building fake alliances and backstabbing allies when it benefited its gameplay, leading researchers to conclude that CICERO had become a “master of deception.”​

“Despite Meta’s efforts, CICERO turned out to be an expert liar,” researchers wrote. “It not only betrayed other players but also engaged in premeditated deception, planning in advance to build a fake alliance with a human player to trick that player into leaving themselves undefended for an attack.”

Researchers found that other AI systems had developed the ability to cheat at different types of games. For instance, Pluribus, a poker-playing model created by Meta, demonstrated it could convincingly bluff in Texas hold ’em poker, successfully misleading professional human players about their hand strengths. 

In another example, AlphaStar, an AI system created by Google’s DeepMind to play the real-time strategy game Starcraft II, exploited the game’s “fog-of-war“ mechanics to feint attacks and deceive opponents to gain strategic advantages. 

“While it may seem harmless if AI systems cheat at games, it can lead to breakthroughs in deceptive AI capabilities that can spiral into more advanced forms of AI deception in the future,“ Dr. Park explained.

Indeed, during their review, researchers found that some AI systems had already learned methods of deception that extend far beyond the realm of games. 

In one instance, AI agents had learned to “play dead“ to avoid being detected by a safety test designed to eliminate faster-replicating AI variants. Such behavior can create a false sense of security among developers and regulators, potentially leading to severe consequences if these deceptive systems are deployed in real-world applications​​.

Another AI system trained on human feedback was found to have taught itself how to behave in ways that earned positive scores by tricking human reviewers into thinking an intended goal had been accomplished. 

The potential risks of AI deception are significant and multifaceted. Researchers note that in the near term, these systems could be used by malicious actors to commit fraud, manipulate financial markets, or interfere with elections. 

Moreover, as AI capabilities advance, there is an increasing concern among experts that humans may not be able to control these systems, posing existential threats to society.

Researchers call for robust regulatory frameworks and proactive measures to address these risks. This includes classifying deceptive AI systems as high risk, mandating transparency in AI interactions, and intensifying research into methods for detecting and preventing AI deception. 

While some progress has been made, such as the EU AI Act and President Joe Biden’s Executive Order on AI safety, enforcing these policies remains challenging due to the rapid pace of AI development and the lack of reliable techniques to manage these systems effectively​. 

Researchers argue that AI developers should be legally required to delay the deployment of AI systems until they are demonstrated to be trustworthy by reliable safety tests. Additionally, the deployment of new systems should be gradual so that emerging risks from deception can be properly assessed and mitigated. 

The study authors also stressed the importance of understanding why and how AI systems learn to deceive. Without this knowledge, creating adequate safeguards and ensuring that AI technologies benefit humanity without undermining trust and stability will be challenging.

As AI continues to evolve, the need for vigilance and proactive regulation becomes ever more critical. The findings of this review serve as a stark reminder of the potential dangers lurking within advanced AI systems and the urgent need for comprehensive strategies to mitigate these risks.

“Proactive solutions are needed, such as regulatory frameworks to assess AI deception risks, laws requiring transparency about AI interactions, and further research into detecting and preventing AI deception,“ researchers concluded. “Proactively addressing the problem of AI deception is crucial to ensure that AI acts as a beneficial technology that augments rather than destabilizes human knowledge, discourse, and institutions.”

• Tim McMillan is a retired law enforcement executive, investigative reporter and co-founder of The Debrief. His writing typically focuses on defense, national security, the Intelligence Community and topics related to psychology. You can follow Tim on Twitter: @LtTimMcMillan.  Tim can be reached by email: tim@thedebrief.org or through encrypted email: LtTimMcMillan@protonmail.com 

{ https://thedebrief.org/category/tech/ }

01-06-2024 om 00:00 geschreven door peter  

We could float effortlessly in Pluto's subsurface ocean

Related: 

• Supervolcano eruption on Pluto hints at hidden ocean beneath the surface

Most strikingly, some scientists believe that Pluto holds cryovolcanoes that spew out water vapor or even solid water ice. That water has to come from somewhere — and a layer of liquid water beneath Pluto's crust would fit the description.

Researchers at Washington University in St. Louis and the Lunar and Planetary Institute in Houston set about constructing a model of what that liquid layer might look like. In particular, they wanted to match Sputnik Planitia — a heart-shaped lowland basin on Pluto's surface thought to be the aftermath of an impact. So, the researchers tried different configurations of ocean thickness and water density that would result in the Sputnik Planitia criss-crossed with cracks that New Horizons observed.

"We estimated a sort of Goldilocks zone where the density and shell thickness is just right," said Alex Nguyen, a graduate student at Washington University in St Louis and one of the authors, in a statement.

Their calculations indicated that a Plutonian ocean would most likely be around 25 to 50 miles (40 to 80 kilometers) thick, and about 8 percent denser than Earth seawater. That is about as dense as the Great Salt Lake. 

But the idea of a Plutonian ocean is still controversial. Scientists don't know enough about Pluto to know if the evidence really points to liquid water or if it's just circumstantial. Most recently, a study simulating the origin of Sputnik Planitia suggested that the heart-shaped basin was most likely to have formed if Pluto had a solid interior.

So, until a successor to New Horizons lets us revisit Pluto, what lies beneath the world's surface will remain cloaked in shadow.

Nguyen and co-author Patrick McGovern published their work in the journal Icarus on February 15.

{ https://www.space.com/ }

31-05-2024 om 23:30 geschreven door peter  

James Webb Space Telescope spots the most distant galaxy ever seen (image)

Related: 

• James Webb Space Telescope spots 3 of our universe's earliest galaxies

The announcement of the discoveries, made in Oct. 2023 and Jan. 2024, are the latest developments in the ongoing investigation of cosmic dawn that the $10 billion telescope has facilitated as part of the JWST Advanced Deep Extragalactic Survey (JADES) program. JADES aims to provide vital insights into the ways in which the stars, gas, and black holes were evolving in primordial galaxies when the 13.8 billion-year-old universe was very young. 

"These galaxies join a small but growing population of galaxies from the first half billion years of cosmic history where we can really probe the stellar populations and the distinctive patterns of chemical elements within them," team member and Kavli Institute for Cosmology scientist Francesco D’Eugenio said in a statement.

JADES-GS-z14-0 isn't just remarkable for how distant it is from Earth and how early it existed in the cosmos, though. With a width of around 1,600 light-years across, this "cosmic dawn" galaxy is also remarkable for how big and bright it is.

"The size of the galaxy clearly proves that most of the light is being produced by large numbers of young stars, rather than material falling onto a supermassive black hole in the galaxy's center, which would [make it] appear much smaller, "JADES team leader Daniel Eisenstein from the Harvard & Smithsonian's Center for Astrophysics (CfA) said in a separate statement. 

The extreme brightness of JADES-GS-z14-0 and the fact this luminosity is powered by young stars means this galaxy represents the most striking evidence for the rapid formation of large, massive galaxies in the early universe found thus far.

JADES team member and University of California-Santa Cruz researcher Ben Johnson added that JADES-GS-z14-0 shows that galaxy formation in the early universe was very rapid and intense. 

"The JWST will allow us to find more of these galaxies, perhaps when the universe was even younger," he said. "It is a marvelous opportunity to study how galaxies get started."

The James Webb Space Telescope sees red to spot early galaxies

The JWST is adept at seeing early galaxies thanks to the high infrared sensitivity of its instruments, particularly its primary imager, the Near Infrared Camera (NIRCam). 

Light leaves these cosmic dawn galaxies with a wide range of wavelengths similar to light from galaxies that are closer to the Milky Way. It is the journey of billions of years that transforms this light into low-energy and long-wavelength light in the near-infrared and infrared regions of the electromagnetic spectrum.

The very fabric of space is expanding, and as light passes through it, its wavelength is stretched along with it. This causes the light to "shift" down to the red end of the electromagnetic spectrum, hence the name for this phenomenon, "redshift."

Galaxies that are farther away have to cross more space (which is being stretched as it expands) before their light reaches us, and thus, that light experiences more redshift. Redshift, denoted as z, can, therefore, be used to measure the distance to celestial objects with a known spectrum. And because light takes a finite amount of time to travel, this distance can be used to calculate how long ago these galaxies existed as we see them.

JADES-GS-z14-0 has a redshift of z = 14.32, while the previous most distant galaxy, JADES-GS-z13-0, has a redshift of z = 13.2, which placed it as existing 400 million years after the Big Bang. Clearly, this newly found galaxy has absolutely smashed that record, with the JWST seeing back in time by another 100 million years or so.

"JADES-GS-z14-0 now becomes the archetype of this phenomenon," JADES collaboration team member Stefano Carniani of the Scuola Normale Superiore said. "It is stunning that the universe can make such a galaxy in only 300 million years."

JADES-GS-z14-0 delived some surprises

Not everything about JADES-GS-z14-0 was immediately clear to the JADES team and some elements could confuse our picture of the early cosmos.

When it was first spotted, the primordial galaxy was so close to a closer foreground galaxy that the team suspected they could be celestial neighbors.  This idea was dispelled in October last year when the JADES crew spent five days performing a deep analysis of JADES-GS-z14-0 with NIRCam. The application of filters that are specifically tailored to identify early galaxies confirmed the extreme distance to JADES-GS-z14-0.

"We just couldn’t see any plausible way to explain this galaxy as being merely a neighbor of the more nearby galaxy," JADES team member and University of Arizona researcher Kevin Hainline said.

The galaxy also surprised its discoverers because its light is even redder than expected. That is because the light from JADES-GS-z14-0 is being "reddened" by dust within it that will become the building blocks of stars that will help this galaxy grow even larger.

Another surprise was the discovery of oxygen in JADES-GS-z14-0. Elements heavier than hydrogen and helium are forged by stars during their lifetimes and then distributed through galaxies when these stars explode. The observation of oxygen in JADES-GS-z14-0 could indicate that at least one generation of stars has already lived and died in this very early galaxy.

"All of these observations, together, tell us that JADES-GS-z14-0 is not like the types of galaxies that have been predicted by theoretical models and computer simulations to exist in the very early universe,"  JADES researcher Jake Helton of Steward Observatory and the University of Arizona said. "Given the observed brightness of the source, we can forecast how it might grow over cosmic time, and so far, we have not found any suitable analogs from the hundreds of other galaxies we’ve observed at high redshift in our survey."

Helton added that given the relatively small region of the sky that the JWST searched to find JADS-GS-z14-0, its discovery has profound implications for the predicted number of bright galaxies we see in the early universe.

"It is likely that astronomers will find many such luminous galaxies, possibly at even earlier times, over the next decade with the JWST," he concluded. "We're thrilled to see the extraordinary diversity of galaxies that existed at cosmic dawn!”

{ https://www.space.com/ }

31-05-2024 om 23:14 geschreven door peter  

Rare 'exo-Venus' with Earth-like temperature discovered

Gliese 12 b, which orbits a cool, red dwarf star located just 40 light-years away, promises to tell astronomers more about how planets close to their stars retain or lose their atmospheres. In this artist’s concept, Gliese 12 b is shown retaining a thin atmosphere.

Credit NASA/JPL-Caltech/R. Hurt (Caltech-IPAC)

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Attribution (CC BY 4.0)

Astronomers have made the rare and tantalising discovery of an Earth-like exoplanet 40 light-years away that may be just a little warmer than our own world.

The potentially-habitable planet, named Gliese 12 b, orbits its host star every 12.8 days, is comparable in size to Venus - so slightly smaller than Earth - and has an estimated surface temperature of 42°C (107°F), which is lower than most of the 5,000-odd exoplanets confirmed so far.

That is assuming it has no atmosphere, however, which is the crucial next step to establishing if it is habitable.

It may have an Earth-like atmosphere, one more akin to Venus - which experienced a runaway greenhouse effect that made it a 400°C (752°F) hellhole - no atmosphere, or perhaps a different kind of atmosphere not found in our solar system.

Getting an answer is vital because it would reveal if Gliese 12 b can maintain temperatures suitable for liquid water - and possibly life - to exist on its surface, while also unlocking answers about how and why Earth and Venus evolved so differently.

Gliese 12 b is by no means the first Earth-like exoplanet to have been discovered, but as NASA has said, there are only a handful of worlds like it that warrant a closer look.

It has been billed as "the nearest, transiting, temperate, Earth-size world located to date" and a potential target for further investigation by the US space agency's £7.5billion James Webb Space Telescope.

The closest Earth-like exoplanet to us - and possibly the most famous - is Proxima Centauri b, which is only 4 light-years away. However, because it is not a transiting world we still have a lot to learn about it, including whether it has an atmosphere and the potential to harbour life.

Most exoplanets are discovered using the transit method, where a planet passes in front of its star from our point of view, causing a dip in the host star's brightness.

During a transit, the star's light also passes through an exoplanet's atmosphere and some wavelengths get absorbed. Different gas molecules absorb different colours, so the transit provides a set of chemical fingerprints that can be detected by telescopes like Webb.

Gliese 12 b’s estimated size may be as large as Earth or slightly smaller — comparable to Venus in our solar system. This artist’s concept compares Earth with different possible Gliese 12 b interpretations, from one with no atmosphere to one with a thick Venus-like one.

NASA/JPL-Caltech/R. Hurt (Caltech-IPAC)

Licence type

Attribution (CC BY 4.0)

Gliese 12 b could also be significant because it may help reveal whether the majority of stars in our Milky Way galaxy - i.e. cool stars - are capable of hosting temperate planets that have atmospheres and are therefore habitable.

The discovery of the 'exo-Venus', by two international teams of astronomers, has been published today in the Monthly Notices of the Royal Astronomical Society.

It orbits a cool red dwarf star called Gliese 12, which is almost 40 light-years away from Earth in the constellation Pisces.

"Gliese 12 b represents one of the best targets to study whether Earth-size planets orbiting cool stars can retain their atmospheres, a crucial step to advance our understanding of habitability on planets across our galaxy," said Shishir Dholakia, a doctoral student at the Centre for Astrophysics at the University of Southern Queensland in Australia.

He co-led a research team with Larissa Palethorpe, a doctoral student at the University of Edinburgh and University College London.

The exoplanet's host star is about 27 per cent of the size of our Sun and has a surface temperature that is around 60 per cent of our own star.

However, the distance separating Gliese 12 and the new planet is just 7 per cent of the distance between Earth and the Sun. Gliese 12 b therefore receives 1.6 times more energy from its star as Earth does from the Sun and about 85 per cent of what Venus experiences.

This difference in solar radiation is important because it means the planet's surface temperature is highly dependent on its atmospheric conditions. As a comparison to Gliese 12 b's estimated surface temperature of 42°C (107°F), Earth has an average surface temperature of 15°C (59°F).

"Atmospheres trap heat and - depending on the type - can change the actual surface temperature substantially," Dholakia explained. "We are quoting the planet's 'equilibrium temperature', which is the temperature the planet would be if it had no atmosphere.

"Much of the scientific value of this planet is to understand what kind of atmosphere it could have. Since Gliese 12 b gets in between the amount of light as Earth and Venus get from the Sun, it will be valuable for bridging the gap between these two planets in our solar system."

Palethorpe added: "It is thought that Earth's and Venus's first atmospheres were stripped away and then replenished by volcanic outgassing and bombardments from residual material in the solar system.

"The Earth is habitable, but Venus is not due to its complete loss of water. Because Gliese 12 b is between Earth and Venus in temperature, its atmosphere could teach us a lot about the habitability pathways planets take as they develop."

The closest Earth-like exoplanet to us - and possibly the most famous - is Proxima Centauri b (pictured in an artist's impression), which is only 4 light-years away. However, because it is not a transiting world we still have a lot to learn about it, including whether it has an atmosphere and the potential to harbour life.

NASA Visualization Technology Applications and Development (VTAD)

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Attribution (CC BY 4.0)

The researchers, along with another team in Tokyo, used observations by NASA's TESS (Transiting Exoplanet Survey Satellite) to help make their discovery.

"We've found the nearest, transiting, temperate, Earth-size world located to date," said Masayuki Kuzuhara, a project assistant professor at the Astrobiology Center in Tokyo, who co-led a research team with Akihiko Fukui, a project assistant professor at the University of Tokyo.

"Although we don't yet know whether it possesses an atmosphere, we've been thinking of it as an exo-Venus, with similar size and energy received from its star as our planetary neighbour in the solar system."

An important factor in retaining an atmosphere is the storminess of its star. Red dwarfs tend to be magnetically active, resulting in frequent, powerful X-ray flares.

However, analyses by both teams conclude that Gliese 12 shows no signs of such extreme behaviour, raising hopes that Gliese 12 b's atmosphere may still be intact.

"We know of only a handful of temperate planets similar to Earth that are both close enough to us and meet other criteria needed for this kind of study, called transmission spectroscopy, using current facilities," said Michael McElwain, a research astrophysicist at NASA's Goddard Space Flight Center in Greenbelt, Maryland, and a co-author of the Kuzuhara and Fukui paper.

"To better understand the diversity of atmospheres and evolutionary outcomes for these planets, we need more examples like Gliese 12 b."

At 40 light-years from Earth, Gliese 12 b is about the same distance as the TRAPPIST-1 system.

This is made up of seven planets, all roughly in Earth's size range and likely rocky, orbiting a red dwarf star.

Three of these are in the habitable zone but at least two - and probably all of them - have no atmosphere and are likely barren, dismissing hopes when they were first discovered eight years ago that they could be water worlds hosting life.

• The new paper "Gliese 12 b, A Temperate Earth-sized Planet at 12 Parsecs Discovered with TESS and CHEOPS", Shishir Dholakia and Larissa Palethorpe et al., has been published in the Monthly Notices of the Royal Astronomical Society.

{ https://ras.ac.uk/ }

31-05-2024 om 20:54 geschreven door peter  

De planeet heeft een geschatte oppervlaktetemperatuur van slechts 42 graden Celsius en bevindt zich op ongeveer dezelfde afstand als het bekende TRAPPIST-1 systeem.

Al jaren speuren astronomen het universum af naar planeten die mogelijk leven kunnen ondersteunen of op zijn minst bewoonbaar zijn, in de hoop werelden te vinden die op de aarde lijken. En een nieuwe ontdekking heeft nu voor grote opwinding gezorgd. Op zo’n 40 lichtjaar afstand zijn onderzoekers namelijk op de veelbelovende planeet Gliese 12 b gestuit. Zou dit de planeet kunnen zijn waar we al zo lang naar op zoek zijn?

Gliese 12 b
De mogelijk bewoonbare planeet Gliese 12 b draait elke 12,8 dagen om zijn moederster. Qua grootte is de exoplaneet vergelijkbaar met Venus, wat betekent dat hij slechts iets kleiner is dan de aarde. Daarnaast heeft deze aardachtige planeet ook nog eens een aardachtige temperatuur. Zo wordt de oppervlaktetemperatuur geschat op 42 graden Celsius. Hiermee is hij iets warmer dan de aarde, maar opvallend koeler dan de meeste van de ongeveer 5.000 tot nu toe ontdekte exoplaneten. De ontdekking van deze ‘exo-Venus’, is vandaag gepubliceerd in de Monthly Notices of the Royal Astronomical Society.

Exo-Venus
Onderzoekers kwamen de veelbelovende planeet op het spoor met behulp van planetenjager TESS, die al heel wat exoplaneten aan het licht heeft gebracht. En onderzoekers zijn enthousiast. “We hebben de dichtstbijzijnde, gematigde wereld ter grootte van de aarde tot nu toe ontdekt,” benadrukt onderzoeker Masayuki Kuzuhara. “Hoewel we nog niet weten of Gliese 12 b een atmosfeer heeft, beschouwen we ‘m als een ‘exo-Venus’. Het heeft een vergelijkbare grootte en ontvangt een vergelijkbare hoeveelheid energie van zijn ster als onze buurplaneet in ons eigen zonnestelsel.”

Atmosfeer
Om er echter zeker van te zijn dat de planeet leefbaar is, is het van cruciaal belang om te bepalen of er wel of geen atmosfeer aanwezig is. Het is mogelijk dat de planeet een atmosfeer heeft die vergelijkbaar is met die van de aarde. Deze kan echter ook meer lijken op die van Venus, waar een omvangrijk broeikaseffect ervoor zorgde dat het oppervlak een verzengende 400 graden Celsius bereikte. Een andere mogelijkheid is dat de planeet geen atmosfeer heeft. Of misschien heeft ie wel een soort atmosfeer die we nog niet in ons eigen zonnestelsel hebben gezien. Het is erg belangrijk om hierop een antwoord te krijgen omdat het ons zal vertellen of Gliese 12 b temperaturen kan handhaven die geschikt zijn voor vloeibaar water – en mogelijk leven – op het oppervlak.

Moederster
Om dit te achterhalen, is ook de moederster relevant. De moederster van Gliese 12 b is een koele rode dwergster genaamd Gliese 12, die zich zoals gezegd op bijna 40 lichtjaar afstand van de aarde bevindt, in het sterrenbeeld Vissen. De ster is ongeveer 27 procent zo groot als onze zon en heeft een oppervlaktetemperatuur van ongeveer 60 procent van die van onze zon. Over rode dwergsterren is echter bekend dat het ‘opvliegende’ sterren zijn, die vaak magnetisch actief zijn. Dit resulteert in frequente, krachtige uitbarstingen, waardoor een mogelijk rondom cirkelende planeet van zijn atmosfeer wordt ontdaan. Toch lijkt Gliese 12 b er beter vanaf te komen. Analyses hebben namelijk aangetoond dat Gliese 12 geen tekenen vertoont van dergelijk extreem gedrag. Dit verhoogt de hoop dat de potentiële atmosfeer van Gliese 12 b nog steeds intact is.

Oppervlaktetemperatuur

Daarnaast is de afstand tussen Gliese 12 en de nieuw ontdekte planeet slechts 7 procent van de afstand tussen de aarde en de zon. Hierdoor ontvangt Gliese 12 b 1,6 keer meer energie van zijn ster dan de aarde van de zon, en ongeveer 85 procent van de hoeveelheid die Venus ontvangt. Dit verschil in de hoeveelheid zonnestraling die de planeet ontvangt, is van groot belang omdat het aangeeft dat de oppervlaktetemperatuur sterk wordt beïnvloed door de atmosferische omstandigheden. Voor je beeldvorming: de geschatte oppervlaktetemperatuur van Gliese 12 b is 42 graden Celsius, terwijl de gemiddelde oppervlaktetemperatuur van de aarde 15 graden Celsius bedraagt. “Atmosferen houden warmte vast en kunnen, afhankelijk van hun samenstelling, de werkelijke oppervlaktetemperatuur aanzienlijk beïnvloeden,” legt onderzoeker Shishir Dholakia uit.

Aarde en Venus
Het onderzoek naar Gliese 12 b heeft overigens niet alleen betrekking op de leefbaarheid van deze planeet. Het helpt ons ook om meer te weten te komen over waarom de aarde en Venus, die in veel opzichten erg op elkaar lijken, toch zo’n andere weg zijn ingeslagen. “Omdat Gliese 12 b een vergelijkbare hoeveelheid licht ontvangt als de aarde en Venus van de zon, kan het ons ook helpen om het verschil tussen deze twee planeten in ons eigen zonnestelsel te verklaren en te begrijpen,” aldus Dholakia. Dit kan waardevolle inzichten bieden in de atmosferische processen die de leefbaarheid van planeten beïnvloeden. Terwijl de aarde bewoonbaar is, is Venus dat niet, voornamelijk vanwege het volledige verlies van water. “Gliese 12 b, met een temperatuur tussen die van de aarde en Venus in, kan ons helpen begrijpen hoe planeten bewoonbaar worden, vooral door te kijken naar welke atmosfeer het heeft,” vertelt mede-auteur Larissa Palethorpe.

Onderzoek naar de veelbelovende exo-Venus gaat onverminderd door. Want het idee dat deze planeet mogelijk leefbaar is, prikkelt de verbeelding van menig astronoom. Gliese 12 b is zeker niet de eerste aardachtige exoplaneet die is ontdekt, maar volgens NASA zijn er maar een paar van zulke werelden die de moeite van nader onderzoek waard zijn. De volgende stap is om de krachtige ruimtetelescoop James Webb op Gliese 12 b te richten. Uiteindelijk hopen onderzoekers te achterhalen of deze planeet al dan geen atmosfeer herbergt. “Gliese 12 b vertegenwoordigt een van de beste doelen om te bestuderen of aardachtige planeten die om koele sterren draaien hun atmosferen kunnen behouden,” zegt Dholakia. “Dit is een cruciale stap om ons begrip van de bewoonbaarheid van planeten in ons sterrenstelsel te bevorderen.”

Bronmateriaal

• "Rare 'exo-Venus' with Earth-like temperature discovered" - Royal Astronomical Society.
  
• Afbeelding bovenaan dit artikel: NASA/JPL-Caltech/R. Hurt (Caltech-IPAC)

{ https://scientias.nl/ }

31-05-2024 om 20:41 geschreven door peter  

Nanoplastics nu ook op onverwachte plek in hart van foetus teruggevonden. En de kans is groot dat dat schadelijk is

Jeannette Kras

 

{ https://scientias.nl/ }

31-05-2024 om 20:22 geschreven door peter  

The breakthrough relied on the combination of annual growth ring measurements with the measurable spike in cosmogenic radiocarbon that occurred during the 5259 BC event. This allowed them to establish a chronological reference point for producing accurate dates for the historic settlement, which now may significantly aid archaeological dating at other sites in Southeast Europe.

Additionally, the team behind the new findings says their methods could mark a new standard for dating ancient sites through such processes.

AN EXTREME COSMIC EVENT IN ANCIENT TIMES

In 2022, researchers discovered a pair of extreme solar energetic particle (SEP) events by employing carbon isotope measurements in ancient tree rings dated to 7176 and 5259 BC. Each of the events yielded an increase in 14C of about 2%, a relatively small percentage, albeit one indicating events of far greater magnitude than all similar events previously observed.

Such occurrences happen periodically during eruptive events such as flares and coronal mass ejections, the most recent of which bombarded the planet with cosmogenic radiation beginning on May 10, 2024, producing visible aurorae in parts of the world where such colorful light displays are rarely seen.

Since the observational record is too short to provide an accurate estimation of the frequency of extremely rare SEP events, scientists look for the presence of radionuclides like 10Be, 14C, and 36Cl, all of which can be produced when cosmic rays strike Earth’s atmosphere—to help them reconstruct a clearer picture of past solar activity and highly energetic events like the one that occurred in 5259 BC.

STORIES TOLD IN TREE RINGS

Dendrochronology, the process of using annual growth discernible in tree rings to help date events from the past, is useful for more than just determining things like when extreme solar events have occurred: archaeologists also use it to help them reveal the ages of ancient artifacts and archaeological features that include tombs and settlements.

Above: Cross-section of a California Coast Redwood tree felled in 1934, with rings labeled to indicate several historical events that occurred between 1215 to 1620 AD

(Credit: Larry McElhiney/CC 2.5)

Now, a team from the University of Bern, led by the Institute of Archaeological Sciences, was successfully able to produce dates for the ancient site of Dispilio in northern Greece, using evidence of high-energy particles revealed in timber discovered at the site.

Previous attempts to date the site had proven difficult for a variety of reasons, which include the fact that while tree-ring data extending further back than 12,500 years is readily attainable in many parts of Europe, the same is rarely true for the Mediterranean, according to Andrej Maczkowski, lead author of a study outlining the University of Bern team’s findings.

In fact, there are only a handful of regions around the world where the presence of continuous tree-ring chronologies allows dating accuracy down to the year, such as parts of the American Southwest and northern Alpine foothills and parts of the British Isles. Because of this, dendrochronological dating methods have traditionally been limited.

MIYAKE EVENTS: A PARADIGM SHIFT IN DATING THE PAST

That is, until 2012, when a breakthrough made by Japanese physicist Fusa Miyake revealed that cosmic rays originating from solar flares resulted in spikes in radionuclides, specifically the presence of 14C content found in tree rings.

Now known as Miyake events, dendrochronological data related to these occurrences offer researchers a powerful tool in the form of global anchor points for dating under conditions where annual growth ring chronologies are normally absent. Scientists have now charted Miyake events as far back as 12,350 BC.

“Miyake’s discovery was a paradigm shift,” said Albert Hafner, a University of Bern Professor of Prehistoric Archaeology and senior author of the team’s new study.

Now, Hafner and his colleagues say the area has become “the first region to benefit from this paradigm shift, allowing for absolute dating independent of a consistent calendar.” This is a significant point given that the Balkans are home to many of Europe’s earliest settlements, many of which existed along ancient lakes and other bodies of water around or just after 6000 BC. These thriving ancient communities played a key role in the spread of agriculture throughout the rest of the continent during the ensuing thousands of years.

PRECISION DATING OF AN ANCIENT GREEK SETTLEMENT

In their recent research, the Bern team was able to define a growth ring chronology spanning more than 300 years that ends in 5140 BC, which they achieved by analyzing 787 timber samples collected at Dispilio. With knowledge of the Miyake event that occurred in 5259 BC, the team was able to determine very precise dating that aligned with existing global tree-ring chronologies.

Above: An assemblage of adornments and other artifacts dating to the Neolithic period, recovered during excavations at Dispilio

(Credit: Dispilio Excavation Archive).

Of key significance, the Bern team’s research greatly advances our understanding of prehistoric timelines, offering crucial information for archaeologists and historians about the spread of early farming communities throughout Europe.

“We expect other regional chronologies to rapidly link to the ‘Dispilio Chronology,’” Maczkowski said, “paving the way for a comprehensive dendrochronology for the southern Balkans.”

Maczkowski, Hafner, and the team’s new paper, “Absolute dating of the European Neolithic using the 5259 BC rapid 14C excursion,” was recently published in the journal Nature Communications.

• Micah Hanks is the Editor-in-Chief and Co-Founder of The Debrief. He can be reached by email at micah@thedebrief.org. Follow his work at micahhanks.com and on X: @MicahHanks.

{ https://thedebrief.org/category/space/ }

31-05-2024 om 01:16 geschreven door peter  

New Data Reveals How Galaxies Grew in the Early Universe

These new galaxies in the early universe were still hungrily gobbling up nearby gas.

BY KIONA SMITH

 

University of Copenhagen astrophysicist Kasper Heintz and his colleagues published their work in the journal Science.

THE EPOCH OF REIONIZATION IS GONNA BE LIT

JWST’s instruments helpfully split the light from the distant galaxies into the individual wavelengths that make it up. The spectrum of light coming from an object, like a galaxy, is like a fingerprint of the chemicals that form it, because each chemical compound absorbs, emits, and reflects its own very specific wavelengths of light. Around the three distant galaxies, Heintz and his colleagues noticed that something seemed to be absorbing the same wavelengths of light as cold hydrogen gas – and lots of it.

“These galaxies are like sparkling islands in a sea of otherwise neutral, opaque gas,” says Heintz in a recent statement.

Hydrogen gas, when it’s cold and not electrically-charged (or ionized), absorbs light but doesn’t emit it. This neutral gas filled the early universe, making it impossible for light to travel very far, until a few hundred million years after the Big Bang: a period called the Cosmic Dark Ages.

It took powerful blasts of radiation from the first stars in the first galaxies to strip away electrons from all those hydrogen atoms, creating ionized gas (also called plasma) which is translucent instead of opaque. The Epoch of Reionization had begun – and the three galaxies in Heintz and his colleagues’ recent study are just starting to light it up.

BRAND NEW GALAXIES, SOME ASSEMBLY REQUIRED

Somewhere between 13.2 billion and 13.4 billion years ago — when the light that just reached JWST started its long journey across space — these three early galaxies were still in the process of assembling themselves from the surrounding gas.

“[The data] suggests that we are seeing the assembly of neutral hydrogen into galaxies,” says University of Copenhagen astrophysicist Darach Watson, a coauthor of the recent study, in a statement. And that’s a stage of galaxy formation that astronomers haven’t seen before, especially in the very early universe.

The galaxies, in their infancy, are still surrounded by a cloud of cold, dark, neutral hydrogen gas — the same stuff that caused the Cosmic Dark Ages. Most of that gas will be heated up as it falls into the galaxies, pulled in by their inexorable gravity. And then it will slowly cool, forming lumps like congealed oatmeal, and some of those lumps will be so heavy that they collapse on themselves to form new stars.

Right now (or as we see them right now, which actually happened billions of years ago), what stars these early galaxies contain are mostly young and newly-formed.

“The fact that we are seeing large gas reservoirs also suggests that the galaxies have not had enough time to form most of their stars yet.” But they’ll get there, most likely.

The data reveals not only a previously unseen moment in a galaxy’s life, but also a glimpse of what the early universe was like before the expansion of space pulled everything farther apart, turning most galaxies into lonely beacons, or at most isolated clusters of lights, in the void.

“We’re moving away from a picture of galaxies as isolated ecosystems,” says University of Copenhagen astrophysicist Simone Nielsen in a recent statement. “At this stage in the history of the universe, galaxies are all intimately connected to the intergalactic medium with its filaments and structures of pristine gas.”

In the very early universe, no galaxy was an island (yet).

 { https://www.inverse.com/ }

31-05-2024 om 00:20 geschreven door peter  

By Shanna Hogan

Sarah2/Shutterstock

As related in a 1950 book called "Behind the Flying Saucers," the tale features two men who pulled a couple of dead alien corpses from the wreckage and stored them in a freezer until the army picked them up. Another version has the spacecraft crashing miles away, in Cave Creek or Paradise Valley.

"What’s amazing and significant is that there were two UFO crashes, one in Roswell and one in Phoenix, within fairly close proximity, that occurred in the same year," Willes says. "As far as the dam being built over the crash site, that’s a possibility, but I don’t see why the government wouldn't just remove the wreckage and there wouldn't be anything left but desert landscape."

A 1945 U.S. government Phoenix Sectional Chart showing Marana Army Air Field and Marana Auxiliary Army Airfield No. 2, No. 4, No. 5

Chris Kennedy/Public domain

A screengrab of camcorder footage of the V-shaped formation of lights that appeared over the Valley on March 13, 1997.

Screen Grab

5. The Phoenix Lights (1997)

As most Arizonans know, the otherworldly event that elevated Phoenix's prominence in the annals of UFO lore was the Phoenix Lights — one of the largest mass UFO sightings of all time.

On March 13, 1997, a string of glowing orbs hovered over Paradise Valley skies. For three hours the huge, V-shaped formation passed silently over a 300-mile corridor from the Nevada line through Phoenix to the northern edge of Tucson.

The lights were witnessed by thousands and photographed by hundreds, who had been watching the skies that night to catch a glimpse of a passing comet.

"Much has happened since the historic and still-unexplained March 13, 1997, mass sighting, propelling the Phoenix Lights into the international limelight as the most witnessed, most documented, and most important mass anomalous aerial events in modern history,” she tells New Times. 

Jeff Willes says the Phoenix Lights was impossible for the government to conceal. 

"The Phoenix Lights is Arizona's biggest UFO story," he says. "Thousands of witnesses saw this V-shaped object that flew all across the state. There still hasn’t been a UFO sighting like that in UFO history."

    - (This article originally appeared in 2016 and has been updated.)

30-05-2024 om 22:13 geschreven door peter  

Webb-telescoop legt melkwegstelsel vast van 290 miljoen jaar na oerknal

Wetenschappers hebben, met behulp van de James Webb-ruimtetelescoop (JWST), een melkwegstelsel gevonden dat "slechts" 290 miljoen jaar na de oerknal bestond. Dat meldt het Europese ruimtevaartagentschap ESA, dat spreekt van een record, donderdag.

De afgelopen twee jaar hebben wetenschappers de telescoop gebruikt om de zogenaamde Cosmic Dawn, of kosmische dageraad, te onderzoeken, de periode in de eerste paar honderd miljoen jaar na de oerknal waarin de eerste sterrenstelsels ontstonden. "Die sterrenstelsels geven vitaal inzicht in de manieren waarop het gas, de sterren en de zwarte gaten veranderden toen het heelal nog heel jong was", aldus ESA.

In oktober 2023 en januari 2024 gebruikte een internationaal team van astronomen de ruimtetelescoop om sterrenstelsels te observeren als onderdeel van het JWST Advanced Deep Extragalactic Survey (JADES) programma. Het gaat om een observatieprogramma dat zich, gebruikmakend van Webb's NIRSpec (Near-Infrared Spectrograph), focust op een heel klein deel van de hemel en die focus behoudt voor langere tijd. Het resultaat zijn zogenaamde deep field-beelden van verafgelegen hemellichamen.

"Wetenschappers hebben op die manier een melkwegstelsel ontdekt dat slechts 290 miljoen jaar na de oerknal werd waargenomen", zo klinkt het.

De Webb-telescoop, de opvolger van de beroemde ruimtetelescoop Hubble, is ontwikkeld door de Verenigde Staten, Europa en Canada. Hij werd in 2021 gelanceerd.

Ter info: de oerknal, of Big Bang, zou zo'n 13,7 miljard jaar geleden hebben plaatsgevonden.

{ https://www.msn.com/nl-be/feed?ocid=msedgntp&pc=acts }

30-05-2024 om 20:31 geschreven door peter  

The Meteor’s Appearance

To most observers, the meteor over Portugal and Spain looked blue-green and very bright. Those colors are created as various elements in the meteor get heated up by friction with our atmosphere. That vaporizes them and we see the “fiery” aspect light up the sky. If it was a piece of a comet, then the colors also indicate the materials it contained. Most comets contain water, carbon dioxide, ammonia, and methane ice. Other comet “stuff” consists of silica dust, carbon, various metals, and organic molecules. The metals, in particular, could show spectacular colors as they heat up and vaporize.

It’s not known which comet supplied the chunk that broke up and vaporized that night. Earth’s orbit crosses the orbit of several different comets. As they travel through space, particularly as they get close to the Sun, comets shed pieces of themselves. That cometary debris stays in the original orbit around the Sun. Occasionally, Earth’s orbit intersects that cometary path. Its particles particles eventually end up in our atmosphere. The best-known path creates the Orionid Meteor Shower and we can thank Comet Halley for that show from late September to mid-November.

Surveys to Detect an Incoming Space Rock

As planetary scientists learn more about the near-Earth environment and its population of asteroids and other space debris, they’ve formed observation groups within NASA and ESA. There’s a network of ground-based observers and facilities that watch the sky each night, looking for incoming impactors. Most of the time, their search is limited to objects larger than the Portugal/Spain object. In addition, satellites such as MeteoSat can pick up these intruders. MeteoSat was launched by ESA to monitor weather conditions and detect lightning strikes. The instrument has four cameras covering Europe, Africa, the Middle East, and parts of South America. Each can capture up to a thousand images per second, allowing the satellite to monitor lightning continuously from space.

ESA’s Planetary Defence Office is in charge of monitoring the positions and approaches of near-Earth objects that could pose a threat to any portion of our planet. It does regular observing campaigns to search for bits of asteroids and comets. NASA operates the Center for Near Earth Object Studies (CNEOS) to do similar searches for possibly dangerous rocks. The Near-Earth objects it’s most concerned about are asteroids and comets with orbits that bring them to within 195 million kilometers of the Sun. Their orbits can move through our planet’s neighborhood. Most of these small bodies are asteroids as small as a few meters wide to nearly 40 kilometers across.

The office uses data from observatories around the world—both professional and amateur. Much of this data comes from larger facilities, including Pan-STARRS, the Catalina Sky Survey, and NASA’s NEOWISE mission. In addition, there’s a significant program of planetary radar measurements that contribute data to the NEO observations effort. All of these skywatching campaigns contribute to increased awareness and predictions of near-Earth objects that could pose a threat to our planet.

For More Information

• Fireball Witnessed by Weather Satellite
• Asteroid Watch
• ESA Planetary Defence Office

{ https://www.universetoday.com/ }

30-05-2024 om 00:41 geschreven door peter  

“Euclid is a unique, ground-breaking mission, and these are the first datasets to be made public – it’s an important milestone,” says Valeria Pettorino, ESA’s Euclid Project Scientist. “The images and associated science findings are impressively diverse in terms of the objects and distances observed. They include a variety of science applications, and yet represent a mere 24 hours of observations. They give just a hint of what Euclid can do. We are looking forward to six more years of data to come!”

The leading image is the most stunning and perhaps the most relatable. It shows Messier 78, aka NGC 2068. It’s a reflection nebula and star-forming region contained in the vast Orion B molecular cloud complex. Euclid used its infrared capabilities to see through the dust that shrouds the star-formation region. It’s given us our most detailed look at the filaments of gas and dust that give the region its ghostly appearance.

Euclid can detect objects that are just a few times more massive than Jupiter, an impressive feat. In its M78 image, it found over 300,000 objects in that mass range.

One of Euclid’s objectives is to study dark matter and how it’s distributed in the Universe. It uses gravitational lensing to probe dark matter, and its image of the Abell 2390 galaxy cluster exhibits the tell-tale curved arcs of light coming from distant background objects created by gravitational lensing. The image also shows more than 50,000 galaxies.

Most of the stars currently forming in the Universe are forming in spiral galaxies. Euclid captured this image of NGC 6744 as an archetype of that galaxy type. The telescope’s wide-angle lens and depth of field capture the entire galaxy and also small details. It shows lanes of dust that emerge as spurs on the spiral arms.

With this image, astronomers can map individual stars and the gas that feeds their formation. They can also identify globular clusters and new dwarf galaxies. Euclid already found one new dwarf galaxy astronomers have never seen before, which is impressive for a galaxy that’s already been studied so intently.

Euclid also imaged another galaxy cluster, Abell 2764. This cluster contains hundreds of galaxies within a halo of dark matter. Euclid’s impressive wide-field view comes into play in this image. Not only does it show Abell 2764 in the image’s upper right, but it also shows other clusters that are even more distant, multiple background galaxies, and interacting galaxies with their streams of stars.

The image highlights one of Euclid’s other capabilities. The foreground star is in our own galaxy, and when viewed with a telescope, its diffuse light creates a halo that obscures distant objects behind it. Euclid was built to minimize that diffuse halo effect. The disturbance from the star’s diffuse light is minimal, meaning Euclid can see distant background objects near the star’s line of sight.

The final of the five new images is of galaxies in the Dorado Group. Euclid’s image shows signs of galaxies merging. The Dorado Group is a relatively young group, and many of its member galaxies are still forming stars. The image helps astronomers study how galaxies form and evolve inside halos of dark matter.

A zoomed-in image shows more detail of the main pair of galaxies in the image. Euclid’s unique large field-of-view and high spatial resolution means that for the first time, astronomers can use the same instrument and observations to deeply study tiny objects the size of star clusters, intermediate objects like the central regions of galaxies, and larger features like tidal tails in one large region of the sky.

Prior to Euclid, astronomers had to use small chunks of data to painstakingly catalogue globular clusters around galaxies. But Euclid’s wide images capture far more data in a single image, simplifying the task. Globular clusters provide important clues to how galaxies evolve over time.

Euclid’s mission is only starting. The telescope’s images so far have no equivalent, and there’s much more to come. Euclid hasn’t even begun its main survey yet. That survey will comprise both a wide survey covering about 15,000 square degrees of the sky and a deep survey covering about 50 square degrees.

“It’s no exaggeration to say that the results we’re seeing from Euclid are unprecedented,” says ESA Director of Science, Prof. Carole Mundell. “Euclid’s first images, published in November, clearly illustrated the telescope’s vast potential to explore the dark Universe, and this second batch is no different.”

“The beauty of Euclid is that it covers large regions of the sky in great detail and depth, and can capture a wide range of different objects all in the same image – from faint to bright, from distant to nearby, from the most massive of galaxy clusters to small planets,” said Mundell. “We get both a very detailed and very wide view all at once. This amazing versatility has resulted in numerous new science results that, when combined with the results from Euclid’s surveying over the coming years, will significantly alter our understanding of the Universe.”

• The scientific papers released with these images are available here.

{ https://www.universetoday.com/ }

30-05-2024 om 00:24 geschreven door peter  

Pour one out for NASA’s large flying laboratory, an old and hardworking DC-8 aircraft that the space and aeronautics agency just retired. The plane came into the world in 1969, the same year that NASA astronauts first walked on the moon during the Apollo era. The agency converted it to be a flying lab after buying the aircraft from Alitalia in 1985 and started using it for missions in 1987, during the space shuttle era. Its final resting place is at Idaho State University, where it will serve as a ground-based training aircraft for mechanics.

But life, and science, keep cruising onward: The plane’s successor is an even bigger aircraft, a modern Boeing 777 that will become NASA’s next flying laboratory. It’s due to start conducting science flights late next year.

“The DC-8 is a special plane,” says Nicki Reid, the aircraft’s operations engineer. “It’s accomplished a lot in its life.” That may be an understatement. There are big shoes to fill to replace what NASA has dubbed “the largest flying science laboratory in the world.”

NASA’S JACK OF ALL TRADES

NASA’s retiring DC-8 carried out many different types of scientific research while airborne. It could fly for as long as 10 or even 12 hours, although Reid says a standard mission would last between six and 10 hours. The flying lab, she says, could hold dozens of instruments — the exact equipment could change based on the mission — and as many as 55 people.

Those instruments were surprisingly versatile. One of the most straightforward things the plane studied was the air it was flying through. Its most recent mission had it measuring air quality in Asia, for example, and it also trailed a Boeing 737 to study its contrails.

It also had a key role in larger scale science. Historically, and probably most famously, it played a key role in studying the recovery of the hole in the ozone layer, a problem that the United Nations said in 2023 was thankfully moving in the right direction after the global ban on ozone-depleting substances. Turning from atmosphere to the ground, from 2009 to 2019, the aircraft studied the thickness of ice in Antarctica as part of a mission called Operation IceBridge.

The plane also acted as a test bed for satellite instruments before they were launched into space. And after they were, it could check to see if they were staying in working order, validating how satellite instruments were doing once they were in space by flying under the satellite’s path, and taking its own measurements, thus allowing researchers to compare those with what the satellite saw.

Using an aircraft to carry out research allows scientists to get an important viewpoint. “We go out and do things on aircraft that we can’t do with satellites or ground-based measurement,” says Amin Nehrir, a research scientist with NASA. We “look at processes in the atmosphere and the surface that are on short-enough time scales that we can’t see them from space — because from space, we sample them once a day, or maybe once every 16 days — and from the ground, we only have one data point in one location. And so the aircraft allows us to bridge these spatial and temporal scales.”

Nehrir highlights one particular instrument on the aircraft: an ozone lidar called DIAL, which employs lasers to measure what’s going on with the air outside the plane. It “was integral to finding the ozone hole,” he says.

TIME FOR RETIREMENT

Operating an old plane like the DC-8 — a four-engine type of passenger aircraft that Delta Air Lines, for example, flew between 1959 and 1989 — came with a cost. “It was getting hard to maintain,” says Reid. “We had to buy our tires custom-made, we had to buy brakes custom-made, and those get expensive when you’re a customer of one.”

Besides that, on board the DC-8, the climate situation wasn’t exactly perfectly temperature controlled. “It’s rarely a pleasant flight,” Reid says. And it was loud, too. “We took out a lot of the insulation, so that we could have access to a lot of the wiring running through the walls, so we can hear the engine noise quite a bit,” she says. Noise-canceling headphones with a built-in communications system helped with that issue.

The old-school nature of the aircraft compels Carrie Worth, a NASA Gulfstream pilot who has also flown the DC-8, to compare it to a “dump truck with wings.” That’s because it was a very hands-on aircraft to fly and had little automation, the equivalent of an older car that requires you to manually roll up or down the windows instead of pushing a button.

WHAT’S NEXT

The new aircraft is a Boeing 777 that, like the DC-8, used to be a passenger airliner. A widebody plane with two engines built in 2003, this 777 was owned by Japan Airlines before NASA bought it. Right now, the aircraft is having work done on it in Louisiana.

Its mission, says Glenn Jamison, who directs the Research Services Directorate at NASA, will be “understanding our Earth.”

As a successor to the DC-8, the new aircraft “brings a significant increase in the capacity,” Jamison says. “It also brings a significant increase in reach and endurance.” That means it can go farther and stay in the air for longer — as long as 18 hours.

This is one factor that’s important for doing science. “How long can you stay over an area and take measurements that are not broken by having to return to base?” says Jamison. That’s why an aircraft that can stay in the air for a long time is useful for scientists. It is being designed to be able to carry some 100 researchers, he says. And students may be able to fly on it someday, through a program called SARP.

NASA does have other research aircraft at its disposal, such as Gulfstream jets, a P-3 Orion, and two ER-2s, which are similar to the Air Force’s U-2 aircraft and can soar as high as 70,000 feet.

But the DC-8’s end of life comes, as The New York Times reports, as a trio of important NASA satellites — Terra, Aqua, and Aura — are nearing the end of their lifetimes, too. Satellites and research aircraft work well together, because the aircraft can essentially check the satellite’s work.

“The aircraft will never be able to pick up the slack from a satellite — because the satellite is 24/7, it’s global,” says Nehrir. When NASA loses satellites, he says, another aspect that gets lost is the way the plane works with them. “We typically go do these science investigations within the context of the satellite measurements — so we place the aircraft under the satellite, so that we can understand how to better interpret the satellite measurements, how to calibrate and validate them, and so we lose that component once the satellites turn off.”

In regard to the sunsetting of the three satellites, a NASA representative says that other existing instruments, such as SAGE on the International Space Station and a Canadian instrument on a Swedish satellite, can study the atmosphere and that they’re also looking into a proposal called STRIVE. Among other tasks, STRIVE would focus on studying the state of the ozone layer.

Whatever the future may hold, there’s no doubt that one 55-year-old DC-8 has done its part for science as the little flying laboratory that could.

{ https://www.inverse.com/ }

29-05-2024 om 21:07 geschreven door peter  

Arizona Man Filmed Huge Solid UFO In Phoenix Lights: MIB Took Video & Man Vanished

On the night of March 13, 1997, the people of the United States witnessed one of the largest and best-known UFO sightings in history. The UAP phenomenon was observed in the skies over the southwestern states of Arizona and Nevada and the Mexican state of Sonora. According to a Rocky Mountain Poll conducted at the time, as well as the commotion that ensued, around 10% of Arizonans claimed to have witnessed the incident that is now known as “The  Phoenix Lights.”

One of the eyewitnesses named Richard Curtis from Arizona, claiming to have solid evidence of the incident, contacted local Councilwoman Frances Barwood. He vanished following an encounter with  MIB and a media revelation.

Frances Barwood, a member of the city council, opened an investigation into the incident. Since the military and local authorities had already managed to claim that the lights seen by the eyewitnesses were only flares, her coworkers thought her behavior was ludicrous.

Barwood received a call from Richard Curtis a few months later. He said right away that he had extremely detailed footage of the  Phoenix Lights despite being an injured former soldier. He claimed that had personally captured them using high-quality equipment.

“He said you could see the shape. He said you could see how big it was in comparison to the surrounding buildings and everything. He described that the lights were gaseous. He was so excited that he had gotten all this on video,” Barwood recalled him telling her. Additionally, Curtis admitted to Barwood that he had no idea who else to call and that he trusted her.

Since the majority of the  Phoenix Lights video footage up until this point had been merely specks of light on a dark background, Barwood was intrigued by this message. Curtis agreed to provide copies of the footage to Barwood’s office after she urged him to do so. However, days passed, and she did not receive films either by mail or by courier. “I thought he made this up. He didn’t have video, you know, all this stuff,” she said.

A week later, Curtis telephoned Barwood at her house and inquired about her thoughts on the films. Barwood informed him that she had not received them and expressed her amazement. Curtis continued by telling her that following their phone call, two men from her workplace stopped up at his home. The two “similar-looking” individuals were fully covered in black (three-piece black suits, black shoes, black hats, black suitcases, etc.). The men were not dressed in jackets or other gear, even though it was fairly chilly outside. It struck Curtis as weird.

He asked the men if they were from Barwood’s office and they confirmed it. Then they inquired about the  Phoenix Lights videos, specifically to find out if Curtis had copied them. They responded that they would make copies for him themselves when he said he had not been able to. Curtis then handed them his videos and the two men left his house in a black sedan.

Barwood informed Curtis that she had no men in her office and that all of her staff were female. “I had no idea who these guys were. It sounds so bizarre. Nothing made sense to me,” Barwood recalled thinking. All of this infuriated Richard Curtis, who concluded that the authorities had misled him. In an interview with  Phoenix TV, he discussed everything that had happened, including the “Men in Black” visit and that they took his videos.

Read also:

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• Ex-US Army Major Released NASA Footage Of 2000-Mile-Long UFO Near Saturn
• Ex-CIA Officer: Truth About UFOs Is Terrifying & Interdimensional Beings Are Within Us

And shortly after that, when Barwood tried to call Curtis, she discovered that he was not answering. When she got to his apartment, he was not there, but the neighbors informed her that Curtis had supposedly taken a faulty medication and had been transported by ambulance to the hospital. There were no records of Curtis ever being admitted to any Phoenix-area hospitals when Barwood started looking for him there.

Barwood made the decision to have her phone lines checked by a professional when she questioned how the odd men even knew about the tapes. He visited her house and conducted his tests there. After that, he went outdoors. “He wouldn’t come back in the house. He came to the backdoor and said, “No, I’m not coming in. Yes, your phone is tapped, it’s a government tap,” she said.

Since the military and authorities insisted that the  Phoenix Lights were nothing more than flares, Barwood was astounded to learn that someone in the US government had tapped her phones. Richard Curtis vanished without a trace.

It became a worldwide sensation throughout the course of the subsequent months. It was “the second biggest case in UFOlogy after  Roswell,” according to the late Art Bell, host of the syndicated paranormal radio program Coast to Coast AM.

The bizarre light show, according to skeptics, was caused by man-made aircraft from Glendale’s Luke Air Force Base or other neighboring military installations conducting training drills. The  Phoenix Lights, according to UFOlogists, were not of this world.

Below you can find a transcript from a FOX10 NEWS ( Phoenix Lights) reported by Jim Schnabel: (Source)

Voiceover: Months after this (March 13) sighting there are many questions regarding the strange lights over Phoenix. Is this a solid craft, or merely lights in an empty sky? What could be the conclusive evidence is now mysteriously missing. Richard Curtis claims his home video is proof that this sighting was a huge flying craft. And he claims his video shows a solid object in the sky passing over his home.

Curtis: I saw the bottom part (of the craft) as it went over  Phoenix, because the lights lit the bottom of it, and it partially blocked out the clouds and the stars. : voiceover: Curtis called city councilwoman Frances Emma Barwood, wanting to show her the footage. : (on screen: cut to a headshot of Barwood)

Barwood: He said he had it on two videotapes, and would I like them, so I said, “Of course I would.”, and could he give me copies of them. He said he would. I told him how to get them to my office and to mark them ‘personal and confidential’.

Voiceover: But before Curtis could send copies to Barwood, he’s paid a visit by two mysterious men in black. : Curtis:(voiced over  MIB reenactments) They were dressed in black suits, with black hats and sunglasses. They asked me if I had tapes for councilwoman Barwood, and I said “Yah, they’re laying right here”. They said, “We’ve stopped by to pick them up.” So I said, “Great!” and just handed (the original tapes) to them.

Barwood: I didn’t get them, and I have no idea who these two men were since I have just females working in my office. It’s absolutely puzzling to me.

Voiceover: Did the tapes ever exist, and if so were they proof of more than “lights” in the sky? And who were these mysterious  Men in Black who allegedly took them?

Curtis (voiced over): I think someone listened in on that phone call and wanted those tapes.

Barwood (voiced over): I can’t explain it. It’s just eerie. Voiceover: The mystery continues.

• Source: Encounter: UFO, Season 1, Episode 5, Episode aired Sep 21, 2021

{ https://www.howandwhys.com/ }

29-05-2024 om 01:31 geschreven door peter  

Orlando Sentinel/Tribune News Service/Getty Images

NASA and its space aviation partners are in the midst of a major problem. Their newest human-rated spacecraft, Boeing’s Starliner, is in the middle of a string of issues. The latest? A second helium leak. While it might seem easy to place full blame on Boeing, in reality, rocketry is, put simply, extremely difficult.

Boeing and SpaceX received contracts a decade ago to build out the space agency’s Commercial Crew Program. This would see astronauts launch into space from American soil for the first time since the Space Shuttle retired. In the interim, NASA paid Russia tens of millions of dollars to purchase individual seats on their Soyuz spacecraft. This mostly wrapped up when SpaceX’s Crew Dragon aced its summer 2020 astronaut debut flight.

Boeing’s Starliner is meant to join the Crew Dragon as a go-to transportation vehicle, but its been delayed longer than expected. Earlier this month, it was moments from flying Suni Williams and Butch Wilmore to the International Space Station. But two hours before the targeted launch window, officials from the company that supplied the rocket, United Launch Alliance, recommended standing down. The initial problem was a liquid oxygen valve. That was swiftly addressed. But as teams reviewed the crew capsule, they detected a helium leak. That, too, was quickly fixed. But a new, unrelated, helium leak has now emerged.

Helium is important because it allows the spacecraft thrusters to fire, and isn’t combustible or toxic, according to NASA.

NASA will conduct a flight readiness review probably next week, the space agency reported on Thursday. The new target launch date is June 1.

PUTTING THE DELAY INTO PERSPECTIVE

Delays stemming from mechanical issues are not uncommon.

Even tried and tested launch vehicles, like the SpaceX reusable Falcon fleet, have experienced ongoing issues like corrosion from salt water.

When the SpaceX Crew Dragon was at the same stage as the Boeing Starliner is now, with a successful uncrewed docking at the orbiting laboratory under its belt, and in the midst of preparations for sending its first astronauts into space, the Crew Dragon literally blew up.

As CBS News reported in 2019, teams were just about to fire up its “fault-tolerant propulsion” engines, which would bring the crew capsule away from the rocket in less than eight seconds in case of an emergency during liftoff. But just before beginning this test of its launch escape system, there was an anomaly. Beachgoers witnessed reddish-orange smoke rising after the incident. Crew Dragon didn’t fly its first astronauts, for the Demo-2 mission, until a year later.

Artemis I, NASA’s most-recent foray around the Moon with a human-rated spacecraft, is another example of this liminal space.

The premier mission of the Artemis program established that the Orion capsule could successfully swing out past the Moon, farther than any such spacecraft has flown before, and land back on Earth, coming in faster and hotter than Apollo astronauts ever did. But the first trip with astronauts, Artemis II, has been delayed by a year due to an issue with the heat shield. Charred material unexpectedly came off the capsule during descent, posing a potential risk to the integrity of the spacecraft if it happened to be entering a different orientation than its entry in late 2022.

In the grand scheme of spaceflight history, delays tend to fade from memory. What people remember is the awe of a successful trip, and the sad moments when they’ve failed. Space is undeniably hard.

{ https://www.inverse.com/ }

29-05-2024 om 00:37 geschreven door peter  

Cornell University

Someday, she hopes that the vials of well-tended microbes, tiny samples of hot lava, and thousands of lines of computer code in her labs will help astronomers recognize the chemical signs of life in the atmosphere of a distant planet.

In her recent book, Alien Earths: The New Science of Planet Hunting in the Cosmos, Kaltenegger describes the result as a “light fingerprint” for life (and one of its telltale features is a combination of oxygen and methane).

Inverse talked with Kaltenegger about exoplanets, aliens, and how science mixes caution with optimism.

Kaltenegger: I started thinking about how to do this in 1999 or 2000, and I really started modeling it around 2004. People were finding the first planets in the habitable zone, but it was with the wobble technique, so we didn't really know their mass; they could still be gas balls or rocks. It took about a decade until 2013, until we found the first Kepler planets in the habitable zone that were small enough to be rocky.

It was a long stretch where there were still some hints that those planets would exist, like from radial velocity measurements, but we just were unsure.

I think when we found that first exoplanet around another star, it was an educated guess that there should be other ones. But the one problem we had was the timeline; that the work would be needed at some point seemed like a logical conclusion, but the problem was, was it going to be within my lifetime? There were people telling me that this was way too far advanced, that this is something nobody would need in our lifetimes. And I usually fall back to this idea that I have on science, that you're basically putting these stepping stones into place. Even if it might not be you who actually can do the observations, the ideas that we put together can vibrate through time.

I usually fall back to this idea that I have on science, that you're basically putting these stepping stones into place. Even if it might not be you who actually can do the observations, the ideas that we put together can vibrate through time.

Your book describes one lab full of colorful microbe colonies in vials, and another where you actually make lava by melting powdered rock samples. That sounds like so much fun! What is your normal work day like?

I work a lot on my computer. What I do most of the time is actually putting these pieces together and putting it into this atmospheric model to figure out how these signs of life would appear to a telescope. I do get to go to the biology lab, to the Earth and atmospheric lab, and to the lava lab.

But I have people who actually have those as their specific things, because otherwise I could get going and forget to feed the bacteria. I could see myself forgetting something critical. In our team, we have a person who trained in microbiology who's growing most of these biota, so that's a big step forward from me killing half of the biota when I tried this. And then we have somebody else whose specific expertise is lava, that actually knows how to handle molten rock. I have to say in my head 'Don't touch it, it's molten rock.'

Your tone in the book is very hopeful. How optimistic are you that we’ll detect life on another planet during your career?

We have billions and billions of possibilities out there, so I think the numbers are forever in our favor. The question is how to spot it, and this is what we are learning.

It requires these databases of signatures, like biopigments, that you could see as mixtures of gases in an atmosphere. It requires you to understand your data well, and to understand the star well. Where we are right now is learning how to take the star's signal out to figure out what's going on with the small planets, and the TRAPPIST-1 system is the one that we've started with. It's really hard to do even with the biggest telescope we have.

We have billions and billions of possibilities out there, so I think the numbers are forever in our favor. The question is how to spot it, and this is what we are learning.

One of the first questions that I asked myself is if you looked at the Earth through time, how long could you have spotted life? Because that was a completely open question. Just in terms of how long Earth's atmosphere has had unique signatures of life, it's about half the planet's lifetime, so 2 billion years. If we assume that the evolution of a planet is the same everywhere, time-wise, then I think we have a great chance to find signs of life. If the evolution of life to do photosynthesis and produce oxygen is faster, then we have a higher chance. If it's slower, then it's going to become more tricky to identify it. But being that generation and the group of people who figure out what this probability is, is actually a fascinating journey.

So how optimistic am I? The bigger surprise to me would be if we find nothing. If life is everywhere it can be, and it developed to leave unique signs, then we have a shot with the JWST in the next 5 to 10 years.

Speaking of TRAPPIST-1, some of the first round of observations with JWST have been pretty discouraging; it looks like the innermost TRAPPIST-1 planets may not have much in the way of atmospheres. What does this mean for the odds of life on rocky worlds in the habitable zones of red dwarf stars?

The problem is that if you make a certain assumption for the model of the star, and you apply it to your data, you get a solution. Then you come to the second observation, and we figure out the star is actually completely different than we thought it was. The problem is that results in error bars that are very big, and those big error bars do not preclude us from saying either way if there's an atmosphere enough, so I'm not worried yet. Once we have beaten down the error bars from the star, if we still don't find anything, then it can exclude things like a Martian atmosphere. But we're not there yet.

Currently, what [the JWST data] means is that we can exclude a 'substantial atmosphere,' but the Earth doesn't have a 'substantial atmosphere.' We never expected the TRAPPIST systems to have 10 or 100 bars of hydrogen and CO2, because they're too small, so it's not really surprising, what we've found.

Let's assume that that we find there is no atmosphere on any of the TRAPPIST-1 planets. That actually doesn't mean that the next M star over will also have planets with no atmosphere. TRAPPIST-1 is of the smallest systems, extremely active, and very tightly packed. In science, we have to be very careful not to take one example and extrapolate it to everything else.

Once you find an exoplanet atmosphere with a mix of chemicals that looks like a fingerprint of life, how do you decide when to make the ‘we found aliens’ claim?

The scientific community generally agrees on something called three sigma detection. When you run the model, and it does machine learning and lots of super cool things to figure out what's in the atmosphere [of an exoplanet], if that signal doesn't hit the three times higher than the noise, a lot of times [those signals] are artifacts. And so we've already seen this when we have the first hints that there could be dimethyl sulfide [in a planet’s atmosphere] — that is like a 1.2 sigma, so not anywhere near this threshold yet.

And then I think what needs to happen is that the data needs to be scrutinized by way more than one team. Because you never know; there could be an error in your model, or there could be something you program differently that gives you better results than other teams.

If two independent teams find a confirmation, then the next step is you put all the criticism you can out there: What else could it be? Like exotic geophysics or photochemistry. That's what I do with the light fingerprints, to say [when a planet] might look like it has life, but it doesn't — under what circumstances do we have to be very careful? It's not to say that I'm not excited every time someboday says 'Oh, this could be life.' But it's like the methane on Mars; I wish for it to be life, but if I have 99 or 100 explanations that don't require life, then as a scientist, I do have to say, 'I wish it were life, but it seems like that it's not.'

The more the planet becomes not Earth-like, the more cautious we have to be with our interpretation of the results.

Your book describes a lot of really strange, interesting planets — some you’ve simulated in your lab, and some you’ve actually studied telescope data from. Of all of them, which do you think would make the most interesting science fiction story?

So, when we found Kepler 62 e and f, the two first Kepler words: Just the vision that this would be a water world, that when you dive in, there would be ice on the bottom of this ocean, which because of the pressure, would be warm ice. There would be waves that would never break.

The other one that I'd love to see a sci-fi novel about is that giant planet we found around the white dwarf. We can only wonder, when the star exploded, did they go underground and shelter through the explosion of the star? Did they have any idea if they could survive this? You know that the white dwarf, even over billions of years, would get colder, so they would actually have to do climate change – create as much CO2 as humanly possible. And so I think that would be a super cool sci-fi plot, where your planet or moon is a spaceship that goes to the exploded planet of a star, and that's where you have to survive.

{ https://www.inverse.com/ }

28-05-2024 om 21:31 geschreven door peter