Space: The Final Frontier

[CaaC (John)+]

A winter’s tale (in the Kuiper belt)

As Pluto’s orbit takes it further from the Sun, scientists get an opportunity to study how the dwarf planet stores heat.

Winter is coming on Pluto. And it is a winter, scientists say, unlike anything imaginable on Earth, a winter in which the dwarf planet’s entire atmosphere is expected to freeze out as frost, leaving it nearly as airless at the Moon.

Not that Pluto has ever had a thick atmosphere. Its current surface pressure is only a bit more than 0.001% that of Earth’s, and there are indications that this is the densest it ever gets.

What’s surprising, says Eliot Young, a planetary scientist at the Southwest Research Institute, Boulder, Colorado, is that Pluto’s nitrogen atmosphere is as actually as dense as it is. Since 1988, when its density was first measured by observing the way it dimmed starlight when Pluto passed in front of a star, it’s actually increased by a factor of nearly three, something that can only occur if frost has been steadily sublimating from the surface during the intervening years.

That would make sense if Pluto’s elliptical orbit was carrying it closer to the Sun. But it reached its closest approach in 1989 and has since moved 10% farther out, which, given the way solar heating works, means it is receiving only 77.8% as much energy from the Sun now, as then.

“It’s a surprise that Pluto’s atmosphere is as big as it is and has been growing for 30 years,” Young said on Monday at a virtual meeting of the American Astronomical Society’s Division for Planetary Sciences.

Now, however, it appears that this trend is on the cusp of reversing itself.

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Read more: In the Kuiper Belt, a baffling lack of small craters

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In August 2018, astronomers realised that Pluto was about to pass in front of a fairly bright star – an occasional event which, like the first one studied in 1988, allows them to probe the density of its atmosphere by watching how the starlight dims before it winks out… and how it brightens as Pluto moves out of the way.

Better yet, this was going to be observable along a broad arc running across much of the US from Texas to Virginia – making it easy for Young’s team to deploy a dozen or so portable telescopes (16- to 20-inch apertures) along that arc in the hope of observing the two-minute event from as many cloud-free locations as possible.

Luck was on their side, and they not only had clear skies, but even managed to predict the centerline of the arc so well that one telescope wound up only six kilometres from the perfect location. “We’ve never gotten that close to the centreline before,” Young says. “It wasn’t long ago where we’d have been happy to have gotten within 100 kilometres.”

When NASA’s New Horizons spacecraft flew by Pluto in 2015, it measured the surface pressure of Pluto’s atmosphere at 11.5 microbars. (One microbar is one millionth the pressure of Earth’s atmosphere).

If Pluto’s atmosphere had continued thickening at the rate seen in prior studies, Young says, his team would have expected to see a pressure of 14.4 microbars. But instead, they got 11.4 microbars, “basically the same thing New Horizons saw.”

That may not sound like the onset of winter, but it’s definitely the beginning of fall. And once Pluto’s temperature starts to drop, Young says, its atmosphere is going to freeze out very quickly, with half of it freezing out with each 1.5°C drop in surface temperature.  

The reason the big freeze has been delayed this long, he adds, is similar to the reason why beach sand continues to heat up after high noon, or why the hottest time of year isn’t the summer solstice, but later on. Even though the solar intensity is waning, heat has penetrated below ground, from where it is slow to dissipate. “It keeps the surface warm,” he says.

Studying the timing of this process as Pluto continues to move outward from the Sun (eventually to about 1.67 times the distance it was in 1989) will teach scientists a lot about how its subsurface retains heat, Young says, including such factors as how porous its materials might be.

“It’s a chance to look below the surface and see how heat is stored,” he says.

Edited October 7, 2021 by CaaC (John)

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China's Moon mission returned youngest ever lavas

The rock samples brought back from the Moon in December by China's Chang'e-5 mission were really young.

It's all relative, of course, but the analysis shows the basalt material - the solidified remnants of a lava flow - to be just two billion years old.

Compare this with the samples returned by the Apollo astronaut missions. They were all over three billion years of age.

The findings are reported in the journal Science.

China's robotic Chang'e-5 mission was sent to a site on the lunar nearside called Oceanus Procellarum.

It was carefully chosen to add to the sum of knowledge gained from previous sample returns - the last of which was conducted by a Soviet probe in 1976.

FULL REPORT - VIDEO & PHOTOS

 

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Pluto should be our ninth planet. A planetary scientist explains why

Astronomers believe they’re closing in on the so-called Planet Nine, but planetary scientist Paul Byrne argues our official definition of what is and isn’t a planet is in need of a long-overdue shake up.

There are some topics that elicit strong opinions from people. Is Die Hard a Christmas movie? (Yes.) Does pineapple belong on pizza? (Also yes.) Is Pluto a planet?

I say that it is. But this isn’t a view that’s universally held.

Those of us born in the latter part of the last century grew up learning that there are nine planets – Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto, in increasing distance from the Sun – and we had clever mnemonics to help.

FULL REPORT

 

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Strange radio waves from the centre of the galaxy

WA radio telescope may have detected a new class of celestial object.

In the West Australian desert, an array of radio telescopes has spotted strange radio signals emanating from somewhere near the heart of the Milky Way.

These signals don’t fit any known patterns produced by familiar radio sources such as pulsars, quasars or radio galaxies. Instead, astronomers think they could come from a new type of stellar object.

According to the lead author of the new study, Ziteng Wang from the University of Sydney, the strangest property of this new signal is its high polarisation.

“This means its light oscillates in only one direction, but that direction rotates with time,” explains Wang.

“The brightness of the object also varies dramatically, by a factor of 100, and the signal switches on and off apparently at random. We’ve never seen anything like it.”

Co-author Tara Murphy, also from the University of Sydney, says this new object is “unique in that it started out invisible, became bright, faded away and then reappeared. This behaviour was extraordinary.”

The discovery was made using the Australian Square Kilometre Array Pathfinder (ASKAP) telescope in WA. Using ASKAP, Wang and team detected six radio signals from the same source over the first nine months of 2020.

They then tried to observe the same signal in visible wavelengths, hoping to “see” the source, but they saw nothing.

Next, they tried with the Parkes radio telescope, again to no avail.

The team then turned to the more sensitive MeerKAT radio telescope in South Africa, checking for the signal for 15 minutes every few weeks.

“Luckily, the signal returned,” says Murphy. “But we found that the behaviour of the source was dramatically different – the source disappeared in a single day, even though it had lasted for weeks in our previous ASKAP observations.”

And it didn’t give the team any further hints about the origin of the mysterious signal.

The team even tried to see the source in X-ray wavelengths, using orbiting observatories such as NASA’s Swift and Chandra telescopes, but spotted nothing.

So what could be creating this signal?

Radio emissions can come from a variety of different sources, many of which are the most energetic and powerful processes in the cosmos. The new signal is variable, which cuts out many options such as stars, normal neutron stars and X-ray binary systems. But there’s still a lot of choice – from pulsars to supernovae to flaring stars to fast radio bursts.

“At first we thought it could be a pulsar – a very dense type of spinning dead star – or else a type of star that emits huge solar flares,” says Wang. “But the signals from this new source don’t match what we expect from these types of celestial objects.”

Another co-author, David Kaplan from the University of Wisconsin-Milwaukee in the US, says “the information we do have has some parallels with another emerging class of mysterious objects known as Galactic Centre Radio Transients (GCRTs), including one dubbed the ‘cosmic burper’.

“While our new object…does share some properties with GCRTs, there are also differences. And we don’t really understand those sources anyway, so this adds to the mystery.”

The fact that the signals are emerging from near the centre of the galaxy is also notable, but it’s unclear whether that’s a coincidence or if the location is related to the nature of the source.

The puzzle remains unsolved. Since no known source fits the observations, it’s possible that the signals represent a new class of celestial objects.

The next generation of radio telescopes, such as the upcoming Square Kilometre Array, will conduct comprehensive surveys that might determine whether this signal is unique, or whether there are many more – and also shed light on its origin.

The discovery is published in the Astrophysical Journal.

Originally published by Cosmos as Strange radio waves from the centre of the galaxy

 

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Fossilised stardust found in meteorites

Tracing ancient elements back to long-gone suns.

Like rocks on Earth preserving records of prehistoric times, some pristine meteorites hold records of ancient grains of stardust, and astronomers are now trying to trace these grains back to their stellar origins.

These specks of stardust were forged in dying stars billions of years ago, becoming part of the debris that helped to form our solar system. The grains were then incorporated into meteorites.

In a new paper published in the Astrophysical Journal Letters, US-led researchers have analysed some of these ‘presolar’ grains extracted from primitive meteorites, giving us new information about the evolution of these long-dead stars.

These grains are just a few thousandths of a millimetre in diameter, so the team used a mass spectrometer to study the grains at a better resolution than ever before.

“Presolar grains have been embedded in meteorites for 4.6 billion years and are sometimes coated with solar materials on the surface,” explains Nan Liu, a physicist from Washington University in St Louis, Missouri, and lead author of the study.

“Thanks to the improved spatial resolution, our team was able to see [aluminium] contamination attached on the surface of a grain and to obtain true stellar signatures by including signals only from the core of the grain during the data reduction.”

Using a plasma ion source, the team exposed the interior part of the stardust grains to measure their isotopes. Specifically, they were looking at carbon (C), nitrogen (N) and magnesium-aluminium (Mg-Al) isotopes in grains made of silicon carbide (SiC).

The isotope ratios measured in the study directly link the grains back to different types of carbon-rich stars, including some with weird chemical compositions.

“The new isotopic data obtained in this study are exciting for stellar physicists and nuclear astrophysicists like me,” says Maurizio Busso, co-author from the University of Perugia, Italy. “Indeed, the ‘strange’ N isotopic ratios of presolar SiC grains have been in the last two decades a remarkable source of concern.

“The new data explain the difference between what was originally present in the presolar stardust grains and what was attached later, thus solving a long-standing puzzle in the community.”

These kinds of studies will also help astrophysicists construct better models of stars, to refine our understanding of how they evolve over time.

“As we learn more about the sources for dust, we can gain additional knowledge about the history of the universe and how various stellar objects within it evolve,” concludes Liu.

https://cosmosmagazine.com/space/astrophysics/grains-of-stardust-in-meteorites/

 

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James Webb super-telescope arrives at launch site

The successor to the Hubble Space Telescope has arrived in French Guiana to prepare for its 18 December launch.

The $10bn (£7.3bn) James Webb observatory was delivered to South America by ship.

Engineers at Europe's Kourou spaceport will spend the coming weeks undertaking a series of final checks before mating the new telescope to its rocket.

Webb is designed to see deeper into the Universe - and further back in time - than Hubble.

The hope is it will detect the light even from the very first population of stars to switch on more than 13.5 billion years ago.

The James Webb Space Telescope (JWST) is a joint venture between the US, European and Canadian space agencies.

• Webb telescope's golden mirror in final test
• James Webb will be the 'launch to watch in 2021'
• Hubble delivers stunning 30th birthday picture

FULL REPORT & MORE PHOTOS

 

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Lucy, the first mission to explore Trojan asteroids, is  scheduled to launch from Cape Canaveral on Saturday for its 12-year-long journey  

 

Interesting fact: in the tradition of Voyager, Lucy spacecraft also carries a plaque as a time capsule - not for the "aliens" though, but for our own descendants. The plaque includes messages from prominent thinkers of our time and a diagram showing the positions of the planets on the date of Lucy’s launch.

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Where’s the edge of the observable Universe? And what’s beyond?

It’s all very well saying the Universe encompasses everything, but everything has to end somewhere, right? Well, not exactly.

 

Does the Universe have an edge? If by ‘Universe’ we mean ‘everything there is’, then the Universe clearly does not have an edge. If we thought it did, we would be guilty of not including everything!

But people often ask the question in a slightly different way, which assumes there is an edge: “If the Universe is expanding,” they say, “what is it expanding into?”

This, though, misunderstands what is meant by ‘expanding Universe’.

In Berlin in 1915, at the height of World War One, Albert Einstein came up with a revolutionary theory of gravity, which supplanted Newton’s and, in 1916, he applied it to be the biggest source of gravitating mass he knew of: the Universe.

What Einstein’s theory showed (it was others who spotted this, not Einstein) was that the Universe could not be still but had to be in motion: either expanding or contracting.

In fact, in 1929, the American astronomer Edwin Hubble discovered that galaxies are flying away from each other like pieces of cosmic shrapnel in the aftermath of a titanic explosion – the Big Bang.

This, in essence, is what we mean by the expansion of the Universe: that the distance between galaxies is growing. Einstein’s theory could easily describe a Universe that goes on forever and therefore has no edge, or one that curves back on itself like a higher-dimensional version of the surface of a ball, and so also has no edge.

In the latter case, confirmation would be to observe the same galaxies on opposite sides of the Universe when we look far enough away with our telescopes.

Of course, others will say the Universe does have an effective edge, because it was born 13.82 billion years ago in the Big Bang. We can therefore see only those galaxies whose light has taken less than 13.82 billion years to reach us (about two trillion).

Those galaxies exist in a sphere of space centred on the Earth that we call the ‘observable Universe’. It’s actually about 92 billion light-years across as the Universe ‘inflated’ far faster than the speed of light in its first split-second of existence.

The observable Universe is bounded by a ‘cosmic horizon’, much like the horizon at sea. Just as we know there’s more ocean over the horizon, we know there are more galaxies (possibly an infinite number) beyond the cosmic horizon. Their light simply hasn’t had time to reach us yet.

https://www.sciencefocus.com/space/the-universe-edge/

 

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NASA Scientist Looks to AI, Lensing to Find Masses of Free-Floating Planets   

Exoplanet hunters have found thousands of planets, most orbiting close to their host stars, but relatively few alien worlds have been detected that float freely through the galaxy as so-called rogue planets, not bound to any star. Many astronomers believe that these planets are more common than we know, but that our planet-finding techniques haven’t been up to the task of locating them.

Most exoplanets discovered to date were found because they produce slight dips in the observed light of their host stars as they pass across the star’s disk from our viewpoint. These events are called transits.

NASA’s Nancy Grace Roman Space Telescope will conduct a survey to discover many more exoplanets  using powerful techniques available to a wide-field telescope. The stars in our Milky Way galaxy move, and chance alignments can help us find rogue planets. When a free-floating planet aligns precisely with a distant star, this can cause the star to brighten. During such events, the planet’s gravity acts as a lens that briefly magnifies the background star’s light. While Roman may find rogue planets through this technique, called gravitational microlensing, there’s one drawback – the distance to the lensing planet is poorly known.

Goddard scientist Dr. Richard K. Barry is developing a mission concept called the Contemporaneous LEnsing Parallax and Autonomous TRansient Assay (CLEoPATRA) to exploit parallax effects to calculate these distances.  Parallax is the apparent shift in the position of a foreground object as seen by observers in slightly different locations. Our brains exploit the slightly different views of our eyes so we can see depth as well. Astronomers in the 19th century first established the distances to nearby stars using the same effect, measuring how their positions shifted relative to background stars in photographs taken when Earth was on opposite sides of its orbit.

It works a little differently with microlensing, where the apparent alignment of the planet and distant background star greatly depends on the observer’s position. In this case, two well-separated observers, each equipped with a precise clock, would witness the same microlensing event at slightly different times. The time delay between the two detections allows scientists to determine the planet’s distance.   

To maximize the parallax effect, CLEoPATRA would hitch a ride on a Mars-bound mission that launches around the same time as Roman, currently scheduled for late 2025. That would place it in its own orbit around the Sun that would achieve a sufficient distance from Earth to effectively measure the microlensing parallax signal and fill in this missing information.

The CLEoPATRA concept would also support the PRime-focus Infrared Microlensing Experiment (PRIME), a ground-based telescope currently being outfitted with a camera using four detectors developed by the Roman mission. Mass estimates for microlensing planets detected by both Roman and PRIME will be significantly improved by simultaneous parallax observations provided by CLEoPATRA.

“CLEoPATRA would be at a great distance from the principal observatory, either Roman or a telescope on Earth,” Barry said. “The parallax signal should then permit us to calculate quite precise masses for these objects, thereby increasing scientific return.”

Stela Ishitani Silva, a research assistant at Goddard and Ph.D. student at the Catholic University of America in Washington, said understanding these free-floating planets will help fill in some of the gaps in our knowledge of how planets form.

“We want to find multiple free-floating planets and try to obtain information about their masses, so we can understand what is common or not common at all,” Ishitani Silva said. “Obtaining the mass is important to understanding their planetary development.”

In order to efficiently find these planets, CLEoPATRA, which completed a Mission Planning Laboratory study at Wallops Flight Facility in early August, will use artificial intelligence. Dr. Greg Olmschenk, a postdoctoral researcher working with Barry, has developed an AI called RApid Machine learnEd Triage (RAMjET) for the mission.

“I work with certain kinds of artificial intelligence called neural networks,” Olmschenk said. “It's a type of artificial intelligence that will learn through examples. So, you give it a bunch of examples of the thing you want to find, and the thing you want it to filter out, and then it will learn how to recognize patterns in that data to try to find the things that you want to keep and the things you want to throw away.”

Eventually, the AI learns what it needs to identify and will only send back important information. In filtering this information, RAMjET will help CLEoPATRA overcome an extremely limited data transmission rate. CLEoPATRA will have to watch millions of stars every hour or so, and there’s no way to send all that data to Earth. Therefore, the spacecraft will have to analyze the data on-board and send back only the measurements for sources it detects to be microlensing events.

“CLEoPATRA will permit us to estimate many high-precision masses for new planets detected by Roman and PRIME,” Barry said. “And it may allow us to capture or estimate the actual mass of a free-floating planet for the first time — never been done before. So cool, and so exciting. Really, it's a new golden age for astronomy right now, and I'm just very excited about it.”

Banner Image: This illustration shows a Jupiter-like planet alone in the dark of space, floating freely without a parent star. CLEoPATRA mission scientists hope to improve the mass estimates of such planets discovered through microlensing. Credit: NASA’s Goddard Space Flight Center Conceptual Image Lab

by Julie Freijat

NASA’s Goddard Space Flight Center in Greenbelt, Md.

Last Updated: Oct 6, 2021

Editor: Karl Hille

 

[Bluewolf]

So lot's of issues surrounding the naming of the new telescope then.... 

Nasa adviser quits and thousands protest at naming of telescope (msn.com)

[nudge]

8 minutes ago, Bluewolf said:

So lot's of issues surrounding the naming of the new telescope then.... 

Nasa adviser quits and thousands protest at naming of telescope (msn.com)

Yeah, it has been brewing for quite a while now, and now is back to the front pages because one of the top scientists quit in protest. I don't know, it's a sensitive topic. On one hand, I can understand people having strong feelings about it, given the purge of homosexuals from NASA in the 60s under Webb's leadership. On the other hand, it comes close to canceling historical characters for being a product of their times and judging them by modern standards. Personally, I can't wait for the telescope being operational; they can call it whatever they want to.

[nudge]

Lucy is on her way

 

[CaaC (John)+]

11 minutes ago, nudge said:

Lucy is on her way

 

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Oct 16, 2021

RELEASE 21-133

NASA, ULA Launch Lucy Mission to ‘Fossils’ of Planet Formation

NASA’s Lucy mission, the agency’s first to Jupiter’s Trojan asteroids, launched at 5:34 a.m. EDT Saturday on a United Launch Alliance (ULA) Atlas V rocket from Space Launch Complex 41 at Cape Canaveral Space Force Station in Florida.

Over the next 12 years, Lucy will fly by one main-belt asteroid and seven Trojan asteroids, making it the agency’s first single spacecraft mission in history to explore so many different asteroids. Lucy will investigate these “fossils” of planetary formation up close during its journey.

“Lucy embodies NASA’s enduring quest to push out into the cosmos for the sake of exploration and science, to better understand the universe and our place within it,” said NASA Administrator Bill Nelson. “I can’t wait to see what mysteries the mission uncovers!”

About an hour after launch, Lucy separated from the second stage of the ULA Atlas V 401 rocket. Its two massive solar arrays, each nearly 24 feet (7.3 meters) wide, successfully unfurled about 30 minutes later and began charging the spacecraft’s batteries to power its subsystems.

“Today’s launch marks a genuine full-circle moment for me as Lucy was the first mission I approved in 2017, just a few months after joining NASA,” said Thomas Zurbuchen, associate administrator for the Science Mission Directorate at the agency’s Headquarters in Washington. “A true mission of discovery, Lucy is rich with opportunity to learn more about these mysterious Trojan asteroids and better understand the formation and evolution of the early solar system.”

Lucy sent its first signal to Earth from its own antenna to NASA’s Deep Space Network at 6:40 a.m. The spacecraft is now traveling at roughly 67,000 mph (108,000 kph) on a trajectory that will orbit the Sun and bring it back toward Earth in October 2022 for a gravity assist.

Named for the fossilized skeleton of one of our earliest known hominin ancestors, the Lucy mission will allow scientists to explore two swarms of Trojan asteroids that share an orbit around the Sun with Jupiter. Scientific evidence indicates that Trojan asteroids are remnants of the material that formed giant planets. Studying them can reveal previously unknown information about their formation and our solar system’s evolution in the same way the fossilized skeleton of Lucy revolutionized our understanding of human evolution.

“We started working on the Lucy mission concept early in 2014, so this launch has been long in the making,” said Hal Levison, Lucy principal investigator, based out of the Boulder, Colorado, branch of Southwest Research Institute (SwRI), which is headquartered in San Antonio. “It will still be several years before we get to the first Trojan asteroid, but these objects are worth the wait and all the effort because of their immense scientific value. They are like diamonds in the sky.”

Lucy’s Trojan destinations are trapped near Jupiter’s Lagrange points – gravitationally stable locations in space associated with a planet’s orbit where smaller masses can be trapped. One swarm of Trojans is ahead of the gas giant planet, and another is behind it. The asteroids in Jupiter’s Trojan swarms are as far away from Jupiter as they are from the Sun.

The spacecraft’s first Earth gravity assist in 2022 will accelerate and direct Lucy’s trajectory beyond the orbit of Mars. The spacecraft will then swing back toward Earth for another gravity assist in 2024, which will propel Lucy toward the Donaldjohanson asteroid – located within the solar system’s main asteroid belt – in 2025.

Lucy will then journey toward its first Trojan asteroid encounter in the swarm ahead of Jupiter for a 2027 arrival. After completing its first four targeted flybys, the spacecraft will travel back to Earth for a third gravity boost in 2031, which will catapult it to the trailing swarm of Trojans for a 2033 encounter.

“Today we celebrate this incredible milestone and look forward to the new discoveries that Lucy will uncover,” said Donya Douglas-Bradshaw, Lucy project manager at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.

NASA Goddard provides overall mission management, systems engineering, plus safety and mission assurance. Lockheed Martin Space in Littleton, Colorado, built the spacecraft. Lucy is the 13th mission in NASA’s Discovery Program. NASA’s Marshall Space Flight Center in Huntsville, Alabama, manages the Discovery Program for the agency.

https://www.nasa.gov/press-release/nasa-ula-launch-lucy-mission-to-fossils-of-planet-formation

 

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Black holes belch out intergalactic smoke

Bubbles, rings and filaments formed over hundreds of millions of years.

Astronomers have just watched the evolution of streamers of gas around an active black hole – and they look a bit like the smoke produced by a volcanic eruption.

The team used the ultra-sensitive Low-Frequency Array (LOFAR) in the Netherlands, as well as the Spektr-RG space observatory, to study a system of 20 galaxies called Nest200047, 200 million light-years away. One of these galaxies has an active black hole at its heart, which produces radio jets that in turn create bubbles and other structures in the surrounding gas.

The researchers found that the galaxy group was home to all different ages of these structures, showing their evolution over hundreds of millions of years.

“Our investigation shows how these gas bubbles accelerated by the black hole are expanding and transforming in time,” says astronomer Marisa Brienza, from the University of Bologna and lead author of the study, published in Nature Astronomy.

“Indeed, they create spectacular mushroom-shaped structures, rings and filaments that are similar to those originating from a powerful volcanic eruption on planet Earth.”

Black holes have a reputation as cosmic monsters, devouring everything they come across. But in that process, they also release enormous amounts of energy, including massive jets of particles moving close to the speed of light. These streams create bubbles of particles and magnetic fields that then influence the intergalactic medium around the black hole.

“LOFAR gave us a unique view of the activity of black holes and their effects on their surrounding environment,” says co-author Annalisa Bonafede, also from the University of Bologna and a member of the Italian National Astrophysics Institute (INAF).

“Our observations of Nest200047 crucially show how magnetic fields and the very old particles accelerated by black holes and consequently aged play a central role in transferring energy to the outer regions of groups of galaxies.”

Credit: University of Bologna

But the study also found that many of these ancient bubbles still haven’t mixed with the surrounding gas even after all this time, likely due to the influence of magnetic fields.

The researchers say this shows that active black holes can have effects on the scale of hundreds of millions of years, as well as on massive spatial scales up to 100 times bigger than the host galaxy.

The team also discovered thin gas filaments around the black hole stretching for as long as a million light-years. The researchers say these are the remnants of gas bubbles produced by the black hole hundreds of millions of years ago. “In the future, we will be able to study the effects of black holes on galaxies and the intergalactic medium with increasing detail,” says Gianfranco Brunetti, co-author and an astrophysicist at the INAF Bologna. “Eventually, we will be able to unveil the nature of the filaments we discovered.”

https://cosmosmagazine.com/space/astrophysics/active-black-hole-intergalactic-smoke/

 

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Mountains of space junk could carry us to Mars

New project aims to recycle and refine space trash into rocket fuel.

Credit: Philipp Igumnov / Getty Images

Space is big. Really big. And there’s not much up there – except all the trash. And that’s suddenly become a valuable resource, as recycling space junk could put an end to the days of fire-and-forget satellite launches.

Thanks to South Australian space-industry start-up Neumann Space, every piece of scrap metal in orbit above us is potential fuel. Now an international partnership is working to cheaply and efficiently salvage orbital cast-offs as the basis of a new space-based industry.

On Wednesday, an international address hosted by the Colorado School of Mines detailed the ambitious plan to turn trash into treasure.

Neumann Space brought its arc-welder-style thruster to the table. Astroscale detailed how it aims to collect and move dead satellites and debris. Nanoracks explained how it could smelt such salvage – in orbit – into pure metal ingots.

Put the three innovative projects together, and a significant challenge for space exploration – getting stuff into orbit in the first place – is dramatically reduced.

US Consul General Kathleen Lively of the US Embassy in Australia called the collaboration “incredible”.

“Watching levitating debris being melted down into shiny goo… I was about to ditch my job and come look for work with you!” she said. “The possibilities are incredible. I challenge anyone to think about the real possibilities of recycling space junk into rocket fuel. And I come away with a smile and a spark of hope that this could be the start of something big.”

Neumann Space CEO Herve Astier told the presentation that the metal-burning thruster would undergo its first proof-of-concept test next year. It will go into orbit as part of the Australian SpIRIT (Space Industry – Responsive – Intelligent – Thermal Nano-satellite) mission.

“This is all about using propellant that we can source in space, to recycle that metal with our partners here,” he said.

Propellants are expensive. Whether it be liquid oxygen for rockets, or Xenon gas for ion engines, the costs of producing them, containing them and transporting them from Earth into space are a significant hurdle.

“The type of technology we’re using with metallic propellant is reasonably cheap compared to others,” Astier said. “They can be stored for a long period of time, they are not subject to radiation, they don’t need tank space – a number of things like that.

“Grabbing satellites with a junk hunter and removing all this debris can lead to this entire value chain from getting the debris, removing the metals and refining them…and, of course, using that metal as propellant.”

As expense and effort had already been invested in getting the ‘junk’ into space, Gary Calnan of CisLunar Industries said it made sense to make use of it. “We see the processing of space debris as a bridge to be able to build the metal processing capability for that full industrial economy that we know is going to emerge probably sooner than you think.”

https://cosmosmagazine.com/space/exploration/recycling-space-junk-could-carry-us-to-mars/

 

Edited October 20, 2021 by CaaC (John)
Spacing correction

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19 minutes ago, CaaC (John) said:

 

Excellent stuff. I read about Neumann Drive as a new concept years ago on the NASA Spaceflight forum, good to see it is becoming an actual reality. The fact that it also makes space junk less of a problem is even better. Would be a massive win-win if it works.

[Bluewolf]

Saturn image captured by NASA's Cassini spacecraft 

Edited October 21, 2021 by Bluewolf

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MORE PHOTOS

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Astronomy Picture of the Day

2021 October 24

Halloween and the Ghost Head Nebula
Image Credit: Mohammad Heydari-Malayeri (Observatoire de Paris) et al., ESA, NASA

Explanation: Halloween's origin is ancient and astronomical. Since the fifth century BC, Halloween has been celebrated as a cross-quarter day, a day halfway between an equinox (equal day / equal night) and a solstice (minimum day / maximum night in the northern hemisphere). With a modern calendar however, even though Halloween occurs next week, the real cross-quarter day will occur the week after. Another cross-quarter day is Groundhog Day. Halloween's modern celebration retains historic roots in dressing to scare away the spirits of the dead. Perhaps a fitting tribute to this ancient holiday is this view of the Ghost Head Nebula taken with the Hubble Space Telescope. Similar to the icon of a fictional ghost, NGC 2080 is actually a star forming region in the Large Magellanic Cloud, a satellite galaxy of our own Milky Way Galaxy. The Ghost Head Nebula (NGC 2080) spans about 50 light-years and is shown in representative colors.

https://apod.nasa.gov/apod/astropix.html

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Pulsating white dwarf spotted

From up in orbit, NASA’s Transiting Exoplanet Survey Satellite (TESS) has recorded an extremely rare sight: a white dwarf star suddenly turning on and off.

White dwarfs are stellar corpses, formed when stars like our Sun run out of fuel to burn and slowly begin to cool and die. This particular star – called TW Pictoris, about 1,400 light-years away – is part of a binary system, and it’s greedily feeding off of its companion. As the white dwarf “eats”, it becomes brighter.

But as astronomers watched, the star lost brightness in just half an hour – which they think might be because its feeding process was interrupted.

Lead author Simone Scaringi from Durham University, UK, says this is “extraordinary”.

“The brightness variations seen in accreting white dwarfs are generally relatively slow, occurring on timescales of days to months,” she says.

“To see the brightness of TW Pictoris plummet in 30 minutes is in itself extraordinary as it has never been seen in other accreting white dwarfs and is totally unexpected from our understanding of how these systems are supposed to feed through the accretion disc.”

The study is published in Nature Astronomy.

https://cosmosmagazine.com/space/astronomy/you-may-have-missed-pulsating-white-dwarf/

 

 

 

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Signs of first planet found outside our galaxy

Astronomers have found hints of what could be the first planet ever to be discovered outside our galaxy.

Nearly 5,000 "exoplanets" - worlds orbiting stars beyond our Sun - have been found so far, but all of these have been located within the Milky Way galaxy.

The possible planet signal discovered by Nasa's Chandra X-Ray Telescope is in the Messier 51 galaxy.

This is located some 28 million light-years away from the Milky Way.

This new result is based on transits, where the passage of a planet in front of a star blocks some of the star's light and produces a characteristic dip in brightness that can be detected by telescopes.

This general technique has already been used to find thousands of exoplanets.

• Exoplanet tally set to pass 4,000 mark
• Giant planet discovery bewilders astronomers

But Dr Roseanne Di Stefano and colleagues searched for dips in the brightness of X-rays received from a type of object known as an X-ray bright binary.

These objects typically contain a neutron star or black hole pulling in gas from a closely orbiting companion star. The material near the neutron star or black hole becomes superheated and glows at X-ray wavelengths.

Because the region producing bright X-rays is small, a planet passing in front of it could block most or all of the X-rays, making the transit easier to spot.

The team members used this method to detect the exoplanet candidate in a binary system called M51-ULS-1.

Future planet-hunting

This binary contains a black hole or neutron star orbiting a companion star with a mass about 20 times that of the Sun.

The X-ray transit lasted about three hours, during which the X-ray emission decreased to zero. Based on this and other information, the astronomers estimate that the candidate planet would be around the size of Saturn, and orbit the neutron star or black hole at about twice the distance Saturn lies from the Sun.

"We are trying to open up a whole new arena for finding other worlds by searching for planet candidates at X-ray wavelengths, a strategy that makes it possible to discover them in other galaxies," said Rosanne Di Stefano, from the Harvard-Smithsonian Center for Astrophysics in Cambridge, US.

The researchers freely admit that more data is needed to verify their interpretation.

One challenge is that the planet candidate's large orbit means it would not cross in front of its binary partner again for about 70 years, quashing any attempts to make a follow-up observation in the near-term.

One other possible explanation that the astronomers considered is that the dimming has been caused by a cloud of gas and dust passing in front of the X-ray source.

However, they think this is unlikely, because the characteristics of the event do not match up with the properties of a gas cloud.

"We know we are making an exciting and bold claim so we expect that other astronomers will look at it very carefully," said co-author Julia Berndtsson of Princeton University, New Jersey.

"We think we have a strong argument, and this process is how science works."

The study has been published in the peer-reviewed journal Nature Astronomy.

https://www.bbc.co.uk/news/science-environment-59044650

 

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WA space radar to spot orbiting objects as small as 2cm

Once, space was all about eyes in the sky. Now, if we hope to combat Kessler Syndrome, we need eyes on the sky.

You can see it unfolding above your head at night – streams of new bright new satellites taking their place in our skies. But this burgeoning new industry is already facing a tipping point.

Which is why a new radar facility is being built in Western Australia. LeoLabs Australia director Terry van Haren says work on the West Australian Space Radar (WASR) will begin in December. The two S-band phased-array radars will scan the Indian Ocean and southwestern Australia to pinpoint as many orbiting objects as possible.

There are already 18,000 items being tracked in low-Earth orbit. Not all of them are benign, and their numbers are exploding.

Former RAAF commander and fighter pilot van Haren says the world’s embryonic commercial exploitation of space is in peril and in danger of succumbing to the Kessler Syndrome.

The Kessler syndrome was a concept first suggested by NASA’s Donald Kessler, that once a critical amount of space junk is reached, space becomes unusable due to bouncing-billiard-ball-style collision risks.

“The sustainability of low-Earth orbit is at a tipping point,” he says. “And we may already be in a position where we can’t stop it.”

The problem is not just space junk. There’s also competition for prime orbital space.

“Right now, in low-Earth orbit, there are nearly 3500 active satellites – with 70 or 80 per cent of them being commercial,” van Haren says.

“We think that, by the end of the decade based just on current registrations of intent by commercial satellite companies, there will be 50,000 satellites in low-Earth orbit. Some people talk of 100,000.”

Collisions are already a disturbingly common occurrence. And in space, size doesn’t matter. A coin-sized piece of debris is capable of creating catastrophic harm.

A small hole was punched in the robotic arm of the International Space Station earlier this year. And, in May, a Chinese satellite was struck by a Russian satellite, sending another cloud of deadly debris cannoning through space.

“And these are just the collisions we know about. Debris-on-debris impacts, which generate more smaller debris, could be occurring quite regularly,” says van Haren. “The Kessler Syndrome is actually occurring very, very slowly, in terms of what we see now.”

LeoLabs says it is currently tracking about 18,000 objects in low-Earth orbit. These are mainly in the range of 10cm in size and above. A real-time visualisation of these objects can be seen on the LeoLabs website.

“We are building a global radar grid because we want to expand our object catalogue down to the limitations of the wavelength of our S-band radar, which is about 2cm across,” says van Haren.

That’s why the WA Bunbury facility is being built.

It improves radar coverage of the world’s skies. And that allows greater fidelity in the tracking of low-orbit objects.

“From our estimates, there are about 250,000 objects in that 2cm to 10cm range,” he says. “And, if you do the math, that represents about 95 per cent of the debris capable of causing a catastrophic collision in low orbit. That’s stuff no one has a track on.”

The Bunbury radar facility will be fully automated, with no staff on site. The data it collects will be injected directly into the “cloud”.

It will be the sixth LeoLabs site in LeoLab’s global radar network. Its specific position in WA is to complement the coverage of another already operating in New Zealand. Other LeoLabs radars are in Costa Rica, the Azores Islands and the United States.

Space junk is a problem that won’t go away any time soon.

Objects up to 650km in altitude will generally take about 20 years to burn up in the Earth’s atmosphere. Higher than that and the lifespan increases exponentially.

“We need to manage that debris problem and stop the slow degradation of space,” van Haren says.

https://cosmosmagazine.com/space/exploration/kessler-syndrome-leolabs-small-objects-orbiting/

 

 

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NASA’s Juno spacecraft probes the depths of Jupiter’s Great Red Spot

The iconic storm stretches down to between 350 and 500km below the giant planet’s swirling clouds.

Since entering Jupiter’s orbit in 2016, NASA’s Juno spacecraft has completed 37 flybys of the giant planet, shedding light on the unseen processes raging beneath its clouds with each pass.

Now, scientists studying data taken by the spacecraft’s microwave radiometer (MWR)  and NASA’s Earth-based Deep Space Network tracking antenna have made new insights into the structure of one of Jupiter’s most iconic features – the Great Red Spot. With its bright crimson hue and diameter wider than the Earth, this enigmatic anticyclone has captured the imagination of astronomers since its discovery two centuries ago.

Data from the MWR shows that cyclones within the giant planet’s atmosphere, large-scale air masses that rotate anticlockwise around a centre of low atmospheric pressure in the northern hemisphere, are warmer near the top and colder near the bottom. While anticyclones, such as the Great Red Spot, rotate in the opposite direction and are colder at the top but warmer at the bottom.

Read more about Jupiter:

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The findings also indicate these storms are far taller than expected, with some extending 100km below the cloud tops and others, including the Great Red Spot, extending over 350km.

“Previously, Juno surprised us with hints that phenomena in Jupiter’s atmosphere went deeper than expected,” said Dr Scott Bolton, principal investigator of Juno from the Southwest Research Institute in San Antonio. “Now, we’re starting to put all these individual pieces together and getting our first real understanding of how Jupiter’s beautiful and violent atmosphere works – in 3D.”

A second team of researchers then used data on Jupiter’s gravity field recorded by NASA’s Earth-based Deep Space Network tracking antenna to produce a second estimate of the Great Red Spot’s depth. As the Great Red Spot is so large, Juno experiences small gravitational tugs as it flies over it.

By measuring tiny changes in Juno’s velocity as small as 0.01 millimetres per second due to the changes in gravitational pull, the team were able to produce an estimate of the Great Red Spot’s depth of around 500km. When combined with the MWR data this suggests the anticyclone is between 350 and 500km deep.

“The precision required to get the Great Red Spot’s gravity during the July 2019 flyby is staggering,” said lead author Marzia Parisi, a Juno scientist from NASA’s Jet Propulsion Laboratory in southern California. “Being able to complement MWR’s finding on the depth gives us great confidence that future gravity experiments at Jupiter will yield equally intriguing results.”

https://www.sciencefocus.com/news/nasas-juno-spacecraft-probes-the-depths-of-jupiters-great-red-spot/

 

Edited October 29, 2021 by CaaC (John)
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