“The three-body problem, which seeks stable orbit configurations among gravitating bodies, is a longstanding challenge in celestial mechanics,” Feng writes. Feng examines ? Centauri AB, our nearest binary neighbour, to understand if the system could host a super Jupiter and what orbit the giant planet could follow.

Feng isn’t the first astronomer to tackle the problem. “As the closest triple stellar system to Earth, Alpha Centauri system has attracted diverse studies in astronomy, including exoplanet stability,” Feng writes. Though the entire Alpha Centauri system is a triple star system, ? Centauri AB are far enough from the third star that they comprise a binary system.

There are some solutions to the three-body problem if one of the bodies has a negligible mass compared to the other two. ? Centauri AB is a pair of Sun-like stars. ? Centauri A is a class G star a little more massive than the Sun, and ? Centauri B is a class K star a little less massive than the Sun.

The study compares the ? Centauri AB system with a similar star system named GJ65AB (Gliese 65). It’s a binary pair known to host a Neptune-mass exoplanet. Though Gliese 65 is a pair of M-dwarfs, the comparison is still valuable because it “shares similar mass ratios and orbital eccentricities,” Feng writes. Gliese 65 is also close at only about 8.8 light-years from Earth. Feng also performed simulations of the ? Centauri AB system to test the idea of it hosting an exoplanet.

“The similarities between GJ65AB and Alpha Centauri AB, together with the newly detected stable super Neptune in the GJ65 system, suggest the stability of the corresponding potential super Jupiter in Alpha Centauri AB,” Feng writes. The Gliese 65 and the Alpha Centauri AB systems have nearly identical mass ratios and eccentricities. If GJ65 can host a planet in a stable orbit, can ? Centauri AB also host one?

Feng used the Mean Exponential Growth factor of Nearby Orbits (MEGNO) method to test the potential stability of a super Jupiter at ? Centauri AB. First, he used it to simulate the GJ65AB system and the newly discovered planet to verify the planet’s orbital stability. Then, he did the same with ? Centauri AB. “For this simulation, we restricted the semimajor axis of the planet to range from 0.1 to 5.0 au, and eccentricities less than 0.5,” Feng writes.

The MEGNO simulations for Gliese 65 showed that the newly discovered Neptune mass planet should be stable.

The next step was to find stable orbits for a planet orbiting ? Centauri AB. To do that, Feng used ? Centauri A as the primary star and injected a 350 Earth-mass planet at a distance of 23.336 AU. All of the other parameters were similar to GJ65 but scaled to ? Centauri AB. “We figured out the stable zone with ?
spanning from 0.1 to ~ 2.2 au, and ? ranges from 0 to 0.5,” Feng writes.

Feng says that the “potentially stable planet” should have ? about equal to 1.189 and ? about equal to 0.33. Those numbers place the planet in the stable zone in MEGNO results.

Of course, none of this means there is a planet there. It just shows that a potential stable orbit is available.

Feng’s work proposes that exoplanets in binary systems with nearly identical mass ratios and eccentricities can exhibit similar stability properties. “From this hypothesis, together with the newly detected Neptune-mass planet in the GJ65 system, which is similar to Alpha Centauri AB, we assume the existence of a potential Jupiter-mass planet with corresponding orbital parameters in Alpha Centauri AB should also be possible,” Feng writes.

No planets have been detected around ? Centauri AB, but that doesn’t mean there isn’t one there. Our planet-hunting methods are far from absolute, and there are bound to be many planets in nearby systems that we haven’t been able to detect yet.

There are many proposals for missions to the region or for telescopes designed to probe the system more deeply. Their neighbour, Proxima Centauri, has two confirmed exoplanets. And there’ve been tantalizing hints that Alpha Centauri A hosts a planet, but it remains only a candidate.

A true detection or emphatic non-detection may be years or decades away. Who knows? But at least Feng’s work shows that there could be a stable orbital home for a super Jupiter in the system.

{ https://www.universetoday.com/ }

06-07-2024 om 21:04 geschreven door peter  

SOURCE : NASA

When looking up into the night sky, you can see millions of stars with the naked eye. When using high-powered telescopes, that number jumps up into the billions.

While most people cannot point out too many specific stars, they know they are always there. Throughout human history, people have even used the consistency of the stars to aid in navigation, planning, and much more.

Of course, today we know that stars do eventually die, often in brilliant explosions known as supernovae. Smaller stars can also simply fade out over time as they exhaust their fuel sources.

Over the past 70 years, however, scientists have documented another phenomenon with stars. They simply disappear without a trace. Astronomers look at the star at one point, then when they return (even just an hour later), and it is gone.

What makes this even more unusual is that the star never returns.

There have been over 800 cases of this documented so far, and they have largely left astronomers baffled.

New research from astronomers at the University of Copenhagen, however, has published a paper that may offer an explanation.

The study’s co-author, Alejandro Vigna-Gomez said in a statement:

“Were one to stand gazing up at a visible star going through a total collapse, it might, just at the right time, be like watching a star suddenly extinguish and disappear from the heavens. The collapse is so complete that no explosion occurs, nothing escapes and one wouldn’t see any bright supernova in the night sky.”

This can happen, they theorize, when massive stars collapse under their own gravity and become black holes, or extremely dense neutron star, immediately.

All detectable evidence that this occurred would be captured by the gravity and sucked back in, leaving nothing for us to see. From our perspective, it would look like the star simply disappeared.

The evidence that they used is from observing a binary star system that is called VFTS 243. In it, a star that is about ten times more massive than our sun is orbiting with a black hole. Vigna-Gomes says of this situation:

“The orbit of the system has barely changed since the collapse of the star into a black hole.”

One obvious problem with this type of theory is that it is difficult to gather any type of hard evidence for it.

All the energy, partials, and even light would be sucked back down into the black hole. in this type of case, scientists can theorize what would happen and compare it to the data that is available.

So far, it seems that things fit well.

Of course, more research is needed before the theory can be widely adopted.

Who knew that stars could disappear?

If you thought that was interesting, you might like to read about a second giant hole has opened up on the sun’s surface. Here’s what it means.

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• The post Astronomers Have Counted Over 800 Stars That Have Disappeared Without A Trace. Now They Think They Know What Happened. first on TwistedSifter.

{ https://www.msn.com/en-us/ }

06-07-2024 om 20:50 geschreven door peter  

Artikel door Heleen Vander Beken

Rood zand, een koepel die je van de rest van de wereld afzondert, en 160 vierkante meter om met z'n vieren in te wonen en werken. Dat is de wereld waarin Anca Selariu, Nathan Jones, Ross Brockwell en Kelly Haston het afgelopen jaar leefden.

De 4 'valse' astronauten leefden om precies te zijn 378 dagen samen in isolatie. En die koepel mogen ze vanavond om 23 uur onze tijd verlaten. Voor het eerst in een jaar zullen ze terug kunnen gaan en staan waar ze willen, hun familie en vrienden vastpakken, en echt alleen zijn wanneer ze dat willen. 

De© Foto: NASA

Met het experiment wil het Amerikaanse ruimteagentschap NASA missies naar Mars voorbereiden, met een focus op de voedselvoorziening tijdens zo'n missie. En ook de gevolgen van die isolatie voor de crew kunnen ze zo onderzoeken, want eerder onderzoek toont aan dat mensen wel degelijk veranderen door een ruimtemissie.

De proefpersonen leefden in omstandigheden die lijken op die van een mogelijke missie naar Mars. Ze hebben geen vers voedsel, behalve de groenten die ze zelf telen, er werden geen nieuwe voorraden geleverd, ze hadden een beperkte hoeveelheid water...

Tomaten die de crew in isolatie gekweekt heeft

© Foto: NASA

Ook de communicatie met het thuisfront was gesimuleerd met een vertraging van 6 tot 22 minuten - zo traag zou het namelijk ook gaan naar Mars - en 2 keer met een black-out (radiostilte) van 2 weken. Ze zagen geen daglicht en werden blootgesteld aan stresssituaties, bijvoorbeeld technische problemen. Ze oefenden er ook op ruimtewandelingen.

Groepsdynamiek als grootste uitdaging

Eerder was er namelijk al een kortere versie van dit soort experiment. 6 mensen verbleven 4 maanden lang onder een plastic koepel op de flank van een berg: de Mauna Loa-vulkaan op Hawaï. In dat verlaten, rotsige landschap moesten ze onder meer ontdekken hoe je kan koken tijdens een marsmissie.

De Belg Angelo Vermeulen, een bioloog gespecialiseerd in ruimtevaart, was er toen bij als gezagvoerder.

Dat brengt ons meteen bij het allermoeilijkste van de missie: de groepsdynamiek. "Ik moest als gezagvoerder de groep bij elkaar houden. Die samenhang is de grootste uitdaging, maar ze is essentieel, niet alleen voor het welzijn van iedereen, maar ook om samen de uitdagingen te kunnen aanpakken die zich voordoen." Denk dan aan problemen met apparatuur, de barre omstandigheden, noem maar op.

Niet evident als je een jaar lang samen opgesloten zit. "Vaak zie je dat één iemand zich in zulke experimenten, of ook tijdens ruimtemissies, wat afzondert van de groep. Logisch, want je hebt behoefte aan wat privacy. Ook tussen de crew in het station en de crew in het controlecentrum ontstond er spanning, wat ook wel vaker gebeurt in ruimtemissies. Je kijkt anders naar de dingen als je daar zit." 

Vier 'astronauten' na fictieve marsmissie van 378 dagen terug in de echte wereld: wat doet 1 jaar isolatie met een mens?

© VRTNWS

Wat staat de 'valse' astronauten te wachten?

Hoe ze zullen reageren als de deur vanavond opengaat, is af te wachten. Maar Vermeulen herinnert zich wel nog wat het met hem deed. "Je kijkt er enorm naar uit, om terug te kunnen buitenstappen, zonder afspraken te maken en een ruimtepak te moeten aandoen. Ik dacht vaak aan het moment dat het voorbij zou zijn."

"Ik herinner me ook nog het uitgebreide ontbijt dat we kregen. We hebben ons allemaal op het verse fruit gestort. Dat trok ons het meeste aan, omdat we dat gemist hadden." Al hebben ze in de simulatie die nu beëindigd wordt een kleine plaats om verse groenten te telen, waarschijnlijk zal ook dit team naar vers voedsel snakken.

Maar de ervaring na de 'bevrijding' ging veel dieper voor Vermeulen, die zich echt had ingeleefd in de idee dat hij op een andere planeet leefde. "We stapten in een busje en zigzagden naar beneden. Het eerste wat je ziet, is de oceaan, nadat je lang in een dor lavalandschap hebt geleefd. Dat water terugzien, dat beroerde me enorm: het feit dat dat water is meegebracht door meteorieten in de geschiedenis van de aarde."

"Ik denk dat het wat lijkt op wat astronauten ervaren als ze de aarde zien vanuit de ruimte: je wordt je zo bewust van de kwetsbaarheid van onze aarde. En hoe uniek die groene planten hier zijn."

Geen daglicht en slapeloze nachten

Los van die emotionele ervaringen, heeft de isolatie ook effect op je lichaam. Vermeulen herinnert zich bijvoorbeeld dat iedereen in het team wel een of andere vorm van slaapproblemen had.

"Dat is zeker ook zo in de ruimte", zegt Angelique Vanomberen, wetenschapscoördinator bij het Europese ruimteagentschap ESA. "Je hebt geen normale blootstelling aan daglicht. In het internationaal ruimtestation ISS zie je bijvoorbeeld 16 keer per dag de zon opkomen, in een simulatie als deze zie je gewoon geen daglicht, terwijl dat de aanmaak van melatonine regelt, een slaaphormoon." 

"En dan heb je nog de psychologische stress van die isolatie. Als ik niet lekker in m'n vel zit, kan ik ook moeilijker slapen", legt Van Ombergen uit.

Verandering in hersenen en bloed

Of je je tijdens die lange maanden samen ook verveelt? "Het is niet zo saai als je zou denken. Je hebt heel veel onderzoek te doen, je moet 1 uur per dag fysieke oefeningen doen om gezond te blijven, en je organiseert samen ontspanningsmomenten zoals een filmavond", blikt Vermeulen terug. 

Maar je lichaam verandert wel door die eentonige isolatie. "We weten van eerder onderzoek, zowel bij dieren als bij mensen dat, wanneer je ze gaat isoleren in een monotone omgeving, dat dat impact heeft op hun brein", zegt Van Ombergen. Bij muizen en ratten veranderde de hippocampus in de hersenen, specifiek een stuk ervan dat belangrijk is voor het vormen van herinneringen en het verkennen van nieuwe omgevingen. 

Dat bleek ook al het geval te zijn bij mensen. Duitse wetenschappers hebben onderzocht wat een verblijf van 14 maanden deed met poolreizigers in het Neumayer-Station III op Antarctica, één van de meest afgelegen, geïsoleerde plekken op aarde. Ook bij hen was dat stukje gekrompen. En dat was ook te zien in hun bloed.

Neumayer-Station III is een afgelegen poolbasis op Antarctica.

© VRTNWS

"Toen ze anderhalve maand uit isolatie waren, was die bloedwaarde wel weer verbeterd, maar nog niet op het oorspronkelijke niveau", vertelt Van Ombergen. "Hoe die op lange termijn evolueert, moet nog blijken uit onderzoek."

Dat kan deze studie misschien prijsgeven, net als nog veel andere effecten van het samenleven in isolement. Maar het zegt niet alles over hoe een Marsmissie zal uitdraaien, want je hersenen veranderen ook door de extreme omstandigheden in de ruimte.

"Het interessante aan dit experiment is dat we nu kunnen zien welke veranderingen de isolatie en psychosociale stress precies geven in je brein. Bij astronauten die uit de ruimte komen, weten we niet wat er een specifieke verandering veroorzaakt."

En je kan in dit soort simulaties ook kritieke situaties nabootsen die op Mars zouden kunnen gebeuren. "Dat geeft al een eerste indruk van hoe mensen ermee omgaan. Al weten ze natuurlijk ergens in hun achterhoofd altijd wel dat het een simulatie is", besluit Van Ombergen.

De NASA plant nog 2 gelijkaardige studies de komende jaren, om in totaal 12 personen te testen, en ook de ESA doet vergelijkbaar onderzoek.

{ https://www.msn.com/nl-be/feed?ocid=msedgdhp&pc=u531 à

 

06-07-2024 om 17:18 geschreven door peter  

Ignatius shies away from calling the novel “science fiction.”

“All of my books really are drawn from my reporting,” he says. “I begin with the real world — the subjects that interest me — and if they seem bigger and more important than I can express in a newspaper column of 800 or 1,200 words, then I think maybe that might be a novel.”

The real-world reporting behind “Phantom Orbit” began in 2017, when Ignatius became intrigued by calls for the creation of the U.S. Space Force. Over the years that followed, he mapped out a spy-novel plot with a Russian satellite researcher as one of the main characters — and made plans for a research trip to Russia’s industrial heartland.

But before he could take that trip, the war in Ukraine broke out in February 2022 — and Russia put Ignatius on its list of banned travelers. “My journalist friends were envious,” he recalls.

Ignatius ended up stealing an assortment of plot points from real-life developments in the war in Ukraine — for example, how Russia jammed Viasat’s satellite internet network at the start of its offensive, how SpaceX’s Starlink network stepped into the breach to help Ukraine fight back, and how commercial satellite imagery contributed to Ukraine’s battlefield awareness.

In response, the Russians have escalated the space-based battle — by interfering with Starlink, scrambling satellite navigation systems and  camouflaging its military assets to hide them from satellite sensors.

If Space War I gets hotter, Ignatius worries that Russia may resort to measures that bring down entire satellite constellations. “We should be very scared about the vulnerability of space systems,” he says.

For more than two decades, policymakers have warned about the potential for a “space Pearl Harbor” — a sneak attack on America’s orbital assets. Ignatius points to U.S. Rep. Mike Turner’s recent warning about the potential for Russia to use nuclear weapons in space. Such weapons might destroy enough satellites to create a crippling debris field in orbit, or shut down electronics with an electromagnetic pulse.

“The Russians understand their vulnerability in space. They understand that the United States and its commercial companies would suffer asymmetric damage. We’d suffer a lot more than Russia or China,” Ignatius says. “So, they’re willing to go forward with this planning, and it ought to scare the heck out of people.”

What is to be done? “What I would say, first, is that our existing systems in space need to be hardened,” Ignatius says. “They need to be less vulnerable to all of the mischief that an adversary could attempt.”

The U.S. Space Force is already well into its effort to make satellite networks more resilient — and more replaceable in the event of an attack. That’s what its “Tactically Responsive Space” initiative is all about. Millions of dollars are being paid out to commercial ventures to demonstrate how they could help the U.S. military send up fresh assets to support existing networks in a matter of days, if not hours.

One rapid-response demonstration mission, known as Victus Nox, was conducted successfully last year with Firefly Aerospace and Millennium Space Systems serving as the Space Force’s commercial partners. Another demonstration, Victus Haze, is currently being readied by Rocket Lab and True Anomaly. In all, a dozen commercial launch providers are on the Space Force’s list for future rapid-response satellite missions.

The Space Force is even supporting the development of new space station architectures — such as the orbital system being built by Gravitics, a Seattle-area startup.

Keeping track of what’s going on in orbit — also known as space domain awareness — is another must-have for ensuring America’s space security. With Pentagon support, True Anomaly, Starfish Space and Northrop Grumman’s SpaceLogistics subsidiary are working on spacecraft that could approach other satellites in orbit to inspect them, refuel them, boost them into different orbits or deorbit them safely.

In the Fiction Science podcast, Ignatius hints that there may be bigger things to come. “I was just hearing about a company that’s going to radically change the way space and other big weapons systems are built,” he says. “It will revolutionize how weapons are built. The Russians and Chinese just don’t have anything remotely like that kind of creativity. So, there are a lot of reasons that I think people should be worried, but that’s a reason people should be reassured.”

Which begs the question: Which company is Ignatius talking about? If I had to guess, I’d put a bet down on a defense-tech startup called Anduril. But Ignatius isn’t telling. At least, not yet.

“It’s coming to a Washington Post near you,” he says with a laugh.

• “Phantom Orbit” is David Ignatius’ 12th novel. Check out DavidIgnatius.com for links to information about his books and about his columns for The Washington Post. He’ll participate in a live online chat with readers on July 15.
• For more about space security policy, check out the resources offered by the Center for Strategic and International Studies, including the center’s latest Space Threat Assessment. Ignatius also recommends resources provided by The Aerospace Corp.
• This report and the accompanying podcast were originally published on Alan Boyle’s Cosmic Log. Stay tuned for future episodes of the Fiction Science podcast via Apple, Spotify, Player.fm, Pocket Casts and Podchaser. If you like Fiction Science, please rate the podcast and subscribe to get alerts for future episodes.

{ https://www.universetoday.com/ }

06-07-2024 om 01:43 geschreven door peter  

Their results are in new research published in Nature Astronomy titled “An estimate of the impact rate on Mars from statistics of very-high-frequency marsquakes.” The lead authors are Géraldine Zenhäusern and Natalia Wójcicka, from the Institute of Geophysics, ETH Zurich, and the Department of Earth Science and Engineering, Imperial College, London, respectively.

Though SEIS was an effective instrument, it couldn’t always tell what each seismic event was. Only a handful of the events it detected were powerful enough to determine their location. However, six events in close proximity to the InSight lander were confirmed as meteorite impacts because they were correlated with acoustic atmospheric signals that meteors make when they enter Mars’ atmosphere. The six events belong to a larger group called very high-frequency (VF) events.

While the source process for a typical marsquake measuring magnitude 3 takes several seconds, an impact-generated quake takes much less time because of the collision’s hypervelocity. These are the VF events.

During about three years of recording time, InSight and SEIS detected 70 VF events. 59 of them had good distance estimates, and according to the researchers, a handful of them were “higher quality B VF events,” meaning their signal-to-noise ratios are strong. “Although a non-impact origin cannot be definitively excluded for each VF event, we show that the VF class as a whole is plausibly caused by meteorite impacts,” the authors explain in their paper.

This led to a new estimate of Mars’s impact frequencies. The researchers say that between 280 and 360 meteoroids about the size of basketballs strike Mars each year and excavate craters greater than 8 meters (26 ft) in diameter. That’s almost one every day at the upper end. “This rate was about five times higher than the number estimated from orbital imagery alone. Aligned with orbital imagery, our findings demonstrate that seismology is an excellent tool for measuring impact rates,” Zenhäusern said in a press release.

Impact rates on different bodies in the Solar System are one way of understanding the age of their surfaces. Earth’s surface is young because the planet is so geologically active. Earth is also much easier to study in greater detail, for obvious reasons. But for bodies like the Moon and Mars, impact rates can tell us the ages of various surfaces, leading to a more thorough understanding of their history.

Orbital images and models based on preserved lunar craters have been the main tools used by planetary scientists to infer impact rates. The data from the Moon was used to extrapolate Mars’ impact rate. But there are problems with that method. Mars has more powerful gravity and is closer to the source of most meteors, the asteroid belt.

That means more meteoroids strike Mars than the Moon, and that had to be calculated somehow. Conversely, Mars has widespread dust storms that can obscure craters in orbital images, while the lunar surface is largely static. Mars also has different types of surface regions. In some regions, craters stand out; in others, they don’t. Trying to accurately account for that many differences when extrapolating impact rates from the Moon to Mars is challenging.

This work shows that seismometers can be a more reliable way to understand impact rates.

“We estimated crater diameters from the magnitude of all the VF-marsquakes and their distances, then used it to calculate how many craters formed around the InSight lander over the course of a year. We then extrapolated this data to estimate the number of impacts that happen annually on the whole surface of Mars,” Wójcicka explained.

“While new craters can best be seen on flat and dusty terrain where they really stand out, this type of terrain covers less than half of the surface of Mars. The sensitive InSight seismometer, however, could hear every single impact within the landers’ range,” said Zenhäusern.

These results extend beyond Mars. Understanding Mars also helps us understand the wider Solar System. “The current meteoroid impact rate on Mars is vital for determining accurate absolute ages of surfaces throughout the Solar System,” the authors write in their paper. Without accurate surface ages, we don’t have an accurate understanding of the Solar System’s history.

Now we know that an 8-metre (26-feet) crater is excavated somewhere on Mars’ surface almost daily, and a 30-metre (98-feet) crater is a monthly occurrence. But it’s about more than just crater size. These hypervelocity impacts create blast zones that dwarf the crater itself. The blast zones can easily be 100 times larger than the crater. So, a better understanding of impact rates can make robotic missions and future human missions safer.

“The higher overall number of impacts and the higher relative number of small ones found in our study show that meteoritic impacts might be a substantial hazard for future explorations of Mars and other planets without a thick atmosphere,” the authors write in their conclusion.

This study is a win for InSight and SEIS and for the researchers who pieced this together.

“This is the first paper of its kind to determine how often meteorites impact the surface of Mars from seismological data – which was a level one mission goal of the Mars InSight Mission,” says Domenico Giardini, Professor of Seismology and Geodynamics at ETH Zurich and co-Principal Investigator for the NASA Mars InSight Mission. “Such data factors into the planning for future missions to Mars.”

{ https://www.universetoday.com/ }

06-07-2024 om 01:32 geschreven door peter  

NASA Finally Revealed Who Will Help Intentionally Destroy The International Space Station

The space agency picked SpaceX to be the space station's grim reaper.

BY DORIS ELÍN URRUTIA

 

Both the vehicle and its cargo would burn up in Earth’s atmosphere. “While the company will develop the deorbit spacecraft, NASA will take ownership after development and operate it throughout its mission. Along with the space station, it is expected to destructively break up as part of the re-entry process,” NASA officials wrote in the announcement.

The mission’s main goal is to ensure there’s no risk of harm to populated areas. The first step is to dock the vehicle to the ISS. Then teams would gradually lower their altitude until they’re ready to perform the deorbit burn. The vehicle would execute that burn, NASA officials told reporters on Friday afternoon.

WHY DESTROY THE SPACE STATION?

The ISS is subject to numerous forces as it orbits 270 miles above the planet’s surface. Year after year, these take their toll. The station currently requires regular maintenance by the astronauts who swap in and out, keeping the station permanently occupied and functional.

What’s more, NASA also seeks to open up its budget for loftier goals. Retiring the ISS may free up resources to develop the Artemis program, which could see the first humans on the Moon since Apollo.

WHAT’S NEXT?

NASA officials said they will be working with SpaceX to execute the design and construction of the U.S. Deorbit Vehicle. The mission’s final price tag also isn’t set. “The single-award contract has a total potential value of $843 million,” according to the announcement.

{ https://www.inverse.com/ }

05-07-2024 om 23:01 geschreven door peter  

Mars orbiter captures Red Planet scar that's longer than the Grand Canyon (image)

The recently published images owe themselves to ESA's Mars Express, Europe's first mission to the Red Planet, which has been orbiting Mars since 2003. Although its lander, Beagle 2, was lost, the orbiter remains conducting a global investigation of Mars. It maps minerals, studies the atmosphere, probes beneath the crust and investigates the planet's blob-shaped moons, Phobos and Deimos.

Related: 

• Largest canyon in the solar system revealed in stunning new images

Mars Express captured the new images of Aganippe Fossa with its high resolution stereo camera and revealed the varied surface features of Mars in great detail, showing both clustered, uneven hills and smooth, gently sloping cliffs covered in debris — referred to as hummocky and lobate terrains, respectively.

These terrains are characteristic of Arsia Mons's ring-shaped "aureole," the ESA press release states, in reference to a 100,000-square-kilometer (38,610-square-mile) disk around the base of the volcano, possibly associated with ancient glaciers.. "Intriguingly," the statement continues, "this aureole has only built up on the northwestern flank of the volcano, likely due to prevailing winds from the opposite direction controlling where ice settled over time.

The team also describes windblown dust and sand dynamics of this region of Mars, which create "zebra-like" patterns on the planet's surface as a result of darker material getting deposited on lighter ground. "The surface here also shows evidence of lava flows, dating from when the volcano was active." the scientists wrote.

Aganippe Fossa is one of many classical albedo features on Mars, which refers to the light and dark features that can be seen on the planet through even an Earth-based telescope. With space-based orbiters, astronomers have been given unprecedented views of the planet's surface and its intriguing topography.

"The mission has been immensely productive over its lifetime, creating a far fuller and more accurate understanding of our planetary neighbor than ever before," ESA scientists said. 

{ https://www.space.com/ }

05-07-2024 om 22:50 geschreven door peter  

Implications of an Expanded or Two-part Kuiper Belt

Beyond simply expanding the limit of the Kuiper Belt, the Subaru observations have profound implications for our understanding of the solar nebula, according to Fumi Yoshida, who led the research for the Subaru observation team. “Looking outside of the Solar System, a typical planetary disk extends about 100 AU from the host star (100 times the distance between the Earth and the Sun), and the Kuiper Belt, which is estimated to extend about 50 AU, is very compact. Based on this comparison, we think that the primordial solar nebula, from which the Solar System was born, may have extended further out than the present-day Kuiper Belt,” said Yoshida.

Let’s say the primordial disk was quite large. Then it’s possible that undiscovered planetary bodies clipped the outer edge of the Kuiper Belt. If that happened, then it makes sense to search the outer limits of the current Belt to find such a cut-off object. It’s also possible that perhaps that truncation created a second Kuiper Belt beyond the currently known belt. What it’s like is anybody’s guess, although it’s probably dusty and very likely has at least a few larger objects. So, even if there’s nothing along the New Horizons trajectory, using Subaru to study the distribution of objects it has found will help scientists to understand the evolution of the Solar System.

Searching for KBOs

Subaru Telescope’s has been searching for more KBOs to explore ever since New Horizons flew past Arrokoth in 2019. The idea is to find additional KBOs along the path of flight. The search focused two Hyper Suprime-Cam fields along the spacecraft’s trajectory through the Belt. The New Horizons team spent about 30 half-nights to find more than 240 outer Solar System objects.

The next step was for a Japanese team to analyze images from those observations. However, they used a different method than the mission team did and found seven new outer Solar System objects. The scientists then analyzed the HSC data with a Moving Object Detection System developed by JAXA. Normally it detects near-Earth asteroids and other space debris. Those types of bodies move very fast, compared to more distant ones. So, looking for very dim, faraway, slow-moving objects was a challenge. That’s because the team had to adjust for the speed of the Kuiper Belt objects. Then they applied some updated image analysis to confirm their findings. Scientists now know the orbits of two of the seven new objects and they’ve been assigned provisional designations by the Minor Planet Center (MPC.

Continuing to Search the Kuiper Belt

The discovery of more KBOs in the outer Solar System (along with New Horizons’ continued dust detection activities) tells scientists that there’s more to the Kuiper Belt than anyone expected. The proof will be in continued Subaru observations to detect and confirm more objects “out there.”

“The mission team’s search for Kuiper Belt objects using Hyper Suprime-Cam continues to this day, and a series of papers will be published in the future, mainly by the North American group,” said Yoshida. “This research, the discovery of sources with the potential to expand the Kuiper Belt region using a method developed in Japan and led by Japanese researchers, serves as a precursor to those publications.”

For More Information

• A New Horizon for the Kuiper Belt: Subaru Telescope’s Wide-Field Observations
• A Deep Analysis of New Horizons’s KBO Search Images
• The PI’s Perspective: Needles in the Cosmic Haystack

{https://www.universetoday.com/ }

05-07-2024 om 01:48 geschreven door peter  

We Might Witness A Star Explode Soon — And It’s Not Betelgeuse

Any day now...

BY KIONA SMITH

 

NASA

TWINKLE, TWINKLE, LITTLE — BOOM

T CrB is actually a pair of stars, trapped in each other’s orbit — and in an extremely messy relationship that sometimes literally explodes.

One member of the pair is an aging red giant, which has burned up all its hydrogen fuel and is now fusing helium atoms together at its core. Helium fusion produces a tremendous amount of heat and radiation pressure, so the aging star’s outer layers have swelled outward to many times its original size (this is the same fate that will eventually befall our Sun in about 5 billion years). The other half of the dynamic duo is a white dwarf: the burned-out remains of a star’s core (this is what our Sun will look like sometime after its red giant phase).

About every 80 years, the red giant shrugs off its outermost layers of gas, and the white dwarf’s gravity grabs them. White dwarfs are nowhere near as dense as neutron stars, but they're still pretty dense, being the remnants of stellar cores — and it doesn't take much to ignite one again, at least temporarily. When the gas discarded by the red giant falls onto the surface of the white dwarf, it puts just enough pressure on the inner layers of the white dwarf to kickstart nuclear fusion.

That sudden burst of fusion triggers a chain reaction that eventually engulfs the outer layers of the star in what's called a runaway thermonuclear reaction. The envelope of gas around the white dwarf (the same envelope it just snatched away from the nearby red giant), heated by the runaway nuclear fusion, explodes outward at roughly 3,700 miles per second. In other words, KABOOM.

And 3,000 light years away, people on Earth will be able to see what looks like a new star in the night sky.

HOW TO SEE THE NOVA IN T. CORONAE BOREALIS

You can’t see the T Coronae Borealis system with the unaided eye right now, because it’s too dim and too far away. When the nova happens, that will change; the now-invisible star will suddenly appear, blazing brightly for about a week. But you’ll need to know where to look.

This occasionally explosive pair of stars is located in a very small, C-shaped constellation called Coronae Borealis (or the Northern Crown if you’re not a fan of conversational Latin). The Northern Crown lies between the big kite-shaped constellation Boötes and the smaller constellation Hercules. Hercules makes a good landmark, because it’s shaped a little like the more familiar Orion, and it’s almost directly overhead after sunset.

If you’re not an experienced stargazer with a clear view of the night sky, though, your best bet might be to download a star-chart app that can help you pinpoint objects in the sky. It’s a good idea to play with the app and find out where T Coronae Borealis is – the better to appreciate its sudden appearance when the nova finally goes off.

HOW DO WE KNOW WHEN T. CORONAE BOREALIS WILL GO SUPERNOVA?

For the last several centuries, astronomers have watched this pair of stars flare up fairly regularly: about once every 80 years. And the last time this happened, in 1946, astronomers had advanced enough equipment to measure changes in the stars’ brightness in specific wavelengths of light, especially during the months and years leading up to the nova.

“Its behavior over the past decade appears strikingly similar to the observed behavior in a similar timeframe leading up to the 1946 eruption,” writes NASA in a recent press release. “If this pattern continues, some researchers say, the nova event could occur by September 2024.”

But there are no guarantees, and predicting a nova in a star system 3,000 light years away is far from an exact science, especially since astrophysicists still don’t understand the mechanics of these explosions in much detail (which is something they’re hoping this year’s nova can shed more light on).

“Recurrent novae are unpredictable and contrarian,” says NASA astrophysicist Koji Mukai in a recent statement. “We’ll see how T Coronae Borealis behaves.”

 { https://www.inverse.com/ }

04-07-2024 om 23:48 geschreven door peter  

Webb Sees Hourglass-Shaped Molecular Cloud around Protostar

Astronomers using the MIRI (Mid-Infrared Instrument) camera aboard the NASA/ESA/CSA James Webb Space Telescope have captured a striking new photo of the molecular cloud L1527.

L1527, shown in this image from Webb’s MIRI instrument, is a molecular cloud that harbors the IRAS 04368+2557 protostar. The more diffuse blue light and the filamentary structures in the image come from organic compounds known as polycyclic aromatic hydrocarbons (PAHs), while the red at the center of this image is an energized, thick layer of gases and dust that surrounds the protostar. The region in between, which shows up in white, is a mixture of PAHs, ionized gas, and other molecules.

Image credit: NASA / ESA / CSA / STScI.

L1527, also known as LDN 1527, is located approximately 447 light-years away from Earth in the constellation of Taurus.

An infant protostar called IRAS 04368+2557 is embedded within the molecular cloud, which is part of the Taurus star-forming region.

IRAS 04368+2557 is only 100,000 years old — a relatively young stellar body.

Given its age and its brightness in far-infrared light, the star is considered a class 0 protostar, the earliest stage of star formation.

IRAS 04368+2557 hosts an edge-on disk with two misaligned parts.

The inner and outer parts of the disk have slightly different orbital planes, connected at 40 to 60 AU (astronomical units) from the protostar, but the disk has point symmetry with respect to the protostar’s position.

Webb’s previous observation of L1527, with NIRCam (Near-Infrared Camera), allowed astronomers to peer into this region and revealed this molecular cloud and protostar in opaque, vibrant colors.

Both NIRCam and MIRI show the effects of outflows, which are emitted in opposite directions along the protostar’s rotation axis as the object consumes gas and dust from the surrounding cloud.

These outflows take the form of bow shocks to the surrounding molecular cloud, which appear as filamentary structures throughout.

They are also responsible for carving the bright hourglass structure within the molecular cloud as they energize, or excite, the surrounding matter and cause the regions above and below it to glow.

“Unlike NIRCam, however, which mostly shows the light that is reflected off dust, MIRI provides a look into how these outflows affect the region’s thickest dust and gases,” the Webb astronomers said in a statement.

“The areas colored here in blue, which encompass most of the hourglass, show mostly carbonaceous molecules known as polycyclic aromatic hydrocarbons.”

“The IRAS 04368+2557 protostar itself and the dense blanket of dust and a mixture of gases that surround it are represented in red.”

“In between, MIRI reveals a white region directly above and below the protostar, which doesn’t show as strongly in the NIRCam view.”

“This region is a mixture of hydrocarbons, ionized neon, and thick dust, which shows that the protostar propels this matter quite far away from it as it messily consumes material from its disk.”

“As IRAS 04368+2557 continues to age and release energetic jets, it’ll consume, destroy, and push away much of this molecular cloud, and many of the structures we see here will begin to fade.”

“Eventually, once it finishes gathering mass, this impressive display will end, and the star itself will become more apparent, even to our visible-light telescopes.”

“The combination of analyses from both the near-infrared and mid-infrared views reveals the overall behavior of this system, including how the central protostar is affecting the surrounding region.”

“Other stars in Taurus, the star-forming region where L1527 resides, are forming just like this, which could lead to other molecular clouds being disrupted and either preventing new stars from forming or catalyzing their development.”

{ https://www.sci.news/ }

03-07-2024 om 22:35 geschreven door peter  

Scientists Revise Famous Drake Equation

Within the uncertainties of involved astronomical and biological parameters, the Drake equation typically predicts that there should be many exoplanets (< 100 to millions) in our Milky Way Galaxy hosting active, communicative civilizations. These optimistic calculations are however not supported by evidence, which is often referred to as the Fermi paradox. University of Texas at Dallas Professor Robert Stern and ETH-Zurich’s Professor Taras Gerya elaborate on this long-standing enigma by showing the importance of long-term plate tectonics as well as oceans and continents for the evolution of active, communicative civilizations.

Stern & Gerya propose that the lack of evidence for active, communicative civilizations reflects the scarcity of long-lived plate tectonics and/or continents and oceans on exoplanets with primitive life.

Image credit: Sci.News.

In 1961, the American astrophysicist and astrobiologist Dr. Frank Drake devised an equation in which several factors are multiplied together to estimate the number of intelligent civilizations in our Galaxy capable of making their presence known to humans:

N = R * f_p * n_e * f_l * f_i * f_c * L

N: the number of civilizations in the Milky Way Galaxy whose electromagnetic emissions (radio waves, etc.) are detectable;

R: the number of stars formed annually;

f_p: the fraction of those stars with planetary systems;

n_e: the number of planets per solar system with an environment suitable for life;

f_l: the fraction of suitable planets on which life actually appears;

f_i: the fraction of life-bearing planets on which intelligent life emerges;

f_c: the fraction of civilizations that develop a technology that produces detectable signs of their existence;

L: the average length of time (years) such civilizations produce such signs.

Assigning values to the seven variables has been an educated guessing game, leading to predictions that such civilizations should be widespread. But if that is true, why is there no conclusive evidence of their existence?

This contradiction is known as the Fermi paradox, named for the Italian and later naturalized American nuclear physicist and Nobelist Dr. Enrico Fermi, who informally posed the question to colleagues.

“Life has been around on Earth for about 4 billion years, but complex organisms like animals didn’t appear until about 600 million years ago, which is not long after the modern episode of plate tectonics began,” Professor Stern said.

“Plate tectonics really jump-starts the evolution machine, and we think we understand why.”

In their paper, Professor Stern and Professor Gerya propose refining one of the Drake equation factors — f_i, the fraction of life-bearing planets on which intelligent life emerges — to take into account the necessity of large oceans and continents and the existence of plate tectonics for more than 500 million years on those planets.

“In the original formulation, this factor was thought to be nearly 1, or 100% — that is, evolution on all planets with life would march forward and, with enough time, turn into an intelligent civilization. Our perspective is: That’s not true,” Professor Stern said.

The researchers propose a revision to the Drake equation that defines f_i as the product of two terms:

f_oc: the fraction of habitable exoplanets with significant continents and oceans;

and f_pt: the fraction of planets that have had long-lasting plate tectonics.

Based on the team’s analysis, the fraction of the exoplanets with optimal water volume is likely very small.

The authors estimate the value of f_oc ranges between 0.0002 and 0.01.

Similarly, they conclude that plate tectonics lasting more than 500 million years is also highly unusual, leading to an estimate of f_pt at less than 0.17.

“When we multiply these factors together, we get a refined estimate of f_i that is very small, between 0.003% and 0.2%, instead of 100%,” Professor Stern said.

“This explains the extreme rareness of favorable planetary conditions for the development of intelligent life in our Galaxy and resolves the Fermi paradox.”

“Biogeochemistry posits that the solid Earth, particularly plate tectonics, speeds up the evolution of species,” he added.

“Studies like ours are useful because they stimulate thinking broadly about larger mysteries and provide an example of how we can apply our knowledge of Earth systems to interesting questions about our Universe.”

• The paper appeared in the April 2024 edition of the journal Scientific Reports.
• R.J. Stern & T.V. Gerya. 2024. The importance of continents, oceans and plate tectonics for the evolution of complex life: implications for finding extraterrestrial civilizations. Sci Rep 14, 8552; doi: 10.1038/s41598-024-54700-x

This article was adapted from an original release by the University of Texas at Dallas.

{ https://www.sci.news/ }

03-07-2024 om 22:17 geschreven door peter  

{ https://www.deseret.com/ }

02-07-2024 om 23:16 geschreven door peter  

To get to the Moon, NASA is building a Lunar Gateway in orbit to facilitate easier access to the Moon. With construction beginning in 2028 as part of Artemis IV there will be an ongoing programme of enhancements and additions. NASA has now released a fabulous new 3D animation of the Lunar Gateway to showcase what the final Gateway will look like. It includes modules from partner nations and an Orion lunar landers dock to carry astronauts. 

NASA’s Artemis program marks a historic return to lunar exploration following on from the Apollo era. It aims to land “the first woman and the next man” on the Moon by 2025 and heralds a new era of space exploration focused on sustainability and international collaboration. This ambitious project will use advanced technologies, including the Space Launch System (SLS) rocket and the Orion spacecraft, to establish a long-term human presence on the surface of the Moon. The program also aims to develop the Lunar Gateway, a space station orbiting the Moon, to support missions and serve as a staging point for future expeditions to Mars. 

The purpose of the Lunar Gateway is to facilitate the exploration of the many scientific mysteries of deep space with Gateway’s first lunar space station. Starting with the Artemis IV mission in 2028, the international teams of astronauts will live, conducting science, and preparing for various lunar missions to the South Pole.

NASA has released a fabulous computer generated video of the Gateway showing its exterior form in amazing detail. You can view the video here.

The propulsion and power systems are prominent in the video and with the solar array will make the most powerful solar electric spacecraft ever flown. The array will power the station’s systems and even ionise the xenon gas that will produce thrust using an ion system to maintain the spacecrafts polar orbit. 

At the hub of the spacecraft though is the Habitation and Logistics Outpost otherwise known as HALO! This element controls and commands the spacecraft and provides communication links back to Earth and the lunar surface. It has been provided by the European Space Station (ESA) and will also support life support systems, exercise equipment and science payload banks. 

Another element provided by ESA with support from the Japan Aerospace Exploration Agency (JAXA) is the environmental control and life support systems. Without it, life on board simply would not survive. 

There are a whole host of other systems on bard from a refuelling capability to ensure the power and propulsion system is topped up, a crew and science airlock system, science payloads and much more. 

Source : 

• Gateway: Up Close in Stunning Detail

{ https://www.universetoday.com/ }

30-06-2024 om 23:46 geschreven door peter  

The study mentions several other locations across Mars where pits or skylights have been observed, including Hebrus Valles, the Pavonis volcano, Ascraeus Mons, Acidalia Planitia (whose surface location was featured The Martian), and Cydonia Mensae. Additionally, the study discusses how lava channels, caves, or tubes close to sources of water ice would also prove beneficial for future astronauts, which could significantly reduce the costs of shipping and storing water on their spacecraft for the initial journey to Mars.

“The best case would be a lava tube with strong walls found next to powerful glacial structures,” the study notes. “The colony itself, most likely, will have the appearance of separate premises, with residential, engineering, elevator and greenhouse compartments. They will have to be connected to each other by small transition tunnels to control the pressure and composition of the artificially created atmosphere in them.”

Lava tubes were featured prominently in the National Geographic television series, Mars, which depicted the first astronauts to the Red Planet and their quest to survive the harsh environment. During their journey, lava tubes provided shelter from the cosmic and solar radiation while also having large deposits of water ice at their disposal which they used for drinking and rocket fuel while drastically reducing the amount of water they initially had to bring during their journey.

The reason why cosmic and solar radiation rains down on to the Martian surface daily is due to the lack of protective ozone layer and magnetic field that exists on Earth and helps deflect this deadly radiation from reaching our surface, enabling life to exist here for billions of years. While Mars might have had both mechanisms billions of years ago, the interior of the Red Planet has since cooled drastically, causing these protective features to be stripped away by the solar wind and lost to space.

This study comes as NASA plans to send humans back to the Moon for the first time in over 50 years, and eventually Mars, as part of the agency’s Moon to Mars Architecture. Therefore, adequate preparation prior to sending the first astronauts to the Red Planet would prove beneficial in increasing their chances of survival throughout the entire journey, and this study highlighted several ways lava tubes could do just that.

How will lava caves help future Mars astronauts 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/ }

30-06-2024 om 23:28 geschreven door peter  

Zijn er andere planeten zoals die van ons?

©Shutterstock

Zijn er andere planeten zoals die van ons?
De zoektocht naar buitenaards leven houdt de wereld al tientallen jaren bezig. Terwijl telescopen naar de hemel kijken en de uithoeken van de ruimte afspeuren, leggen sondes zoals Voyager 1 ongelofelijke afstanden af in de hoop buitenaards leven te vinden. Maar waar kan zulk leven gevonden worden? Wat zijn de ideale omstandigheden voor buitenaardse wezens om in te leven? En hoe vergelijkbaar zijn hun planeten met die van ons?

LEES door deze galerij om de antwoorden te vinden die verborgen liggen in de interstellaire ruimte.

©Shutterstock

Waar te beginnen met zoeken?
Er zijn naar schatting een septiljoen sterren in het bekende heelal (dat is een 1 gevolgd door 24 nullen!). En om elk van deze sterren kunnen wel een dozijn planeten draaien. Dus hoe kunnen we buitenaards leven vinden? De eerste stap is om het dichter bij huis te zoeken.

©Shutterstock

De aarde en haar omstandigheden
De aarde is astronomisch gezien de perfecte plek om te leven. Het bestaan van water en een stabiele atmosfeer heeft een ideale omgeving gecreëerd waarin leven kan floreren.

©Shutterstock

De bewoonbare zone
De afstand van een planeet tot zijn ster is cruciaal voor het begrijpen van de leefbaarheid van een planeet. De aarde bevindt zich perfect in wat de bewoonbare zone wordt genoemd, waar de omstandigheden niet te warm of te koud zijn om te kunnen leven.

©Getty Images

De 'Goldilocks zone'
De bewoonbare zone wordt in het engels ook wel de 'Goldilocks zone' genoemd, vernoemd naar het sprookje. In het verhaal kiest Goudlokje tussen drie sets van items en negeert de items die te extreem zijn (groot of klein, warm of koud), in plaats daarvan neemt ze genoegen met het item dat "precies goed" is.

©Shutterstock

Venus
Venus, dat qua massa vergelijkbaar is met de aarde, staat te dicht bij de zon om levensvatbaar te zijn. Planeetwetenschappers denken dat Venus ooit water aan het oppervlak heeft gehad, maar dat de planeet verstikt is door kooldioxide en een temperatuur van 462°C.

©Shutterstock

Mercurius
Mercurius staat nog dichter bij de zon dan Venus. Daarnaast is het te klein en heeft het niet eens een atmosfeer om leven te ondersteunen.

©Shutterstock

Mogelijkheden beperken
Door de criteria voor de bewoonbare zone te begrijpen, konden astronomen achterhalen dat er zo'n 40 miljard planeten in de bewoonbare zones van de Melkweg zouden kunnen draaien.

©Shutterstock

In de sterren geschreven
Tot nu toe hebben astronomen slechts 1.780 planeten buiten ons zonnestelsel kunnen bevestigen. En van al die planeten bevinden zich er maar 16 in hun bewoonbare zones.

©Reuters

Te groot of te klein
Maar het is niet genoeg voor een planeet om zich op de juiste afstand van een ster te bevinden. De grootte doet er ook zeker toe. Een kleine planeet kan geen atmosfeer behouden, terwijl een te grote planeet een verpletterende atmosfeer zal hebben.

©Shutterstock

De aarde als schaal
Om de juiste atmosferische druk te hebben, moet een planeet tussen 0,1 en 10 keer de massa van de aarde hebben. Dit is een zeer smalle bewoonbare zone, zeker als je bedenkt hoeveel planeten in het heelal honderden keren groter zijn dan de aarde.

©Shutterstock

Gliese 581c
In 2007 werd de wetenschappelijke gemeenschap verblijd met het nieuws over Gliese 581c, de eerste superaarde in de bewoonbare zone. Al snel werd ontdekt dat de omstandigheden aan het oppervlak van de planeet veel leken op die van Venus.

©Shutterstock

Kepler-186f
In 2014 werd een exoplaneet ter grootte van de aarde ontdekt die Kepler-186f heet en in de bewoonbare zone van een rode dwergster rondcirkelt. Astronomen proberen nog steeds vast te stellen of de planeet leefbaar is.

©Shutterstock

Proxima Centauri b
De exoplaneet die het dichtst bij de aarde staat is Proxima Centauri b. Deze planeet draait rond de ster die het dichtst bij de zon staat, op een afstand van ongeveer vier lichtjaar. Hoewel het een gouden planeet is, weten wetenschappers niet zeker of het ook een atmosfeer heeft.

©Shutterstock

Andere belangrijke criteria
Hoewel de bewoonbare zone en de atmosfeer van een planeet belangrijk zijn om de bewoonbaarheid te begrijpen, is dat zeker niet alles. Planeten moeten aan een groot aantal andere criteria voldoen, waaronder het vermogen om vloeibaar water te bevatten.

©Shutterstock

Mars
Mars is de enige andere planeet in ons zonnestelsel die zich binnen de bewoonbare zone bevindt. Maar de juiste atmosferische druk is alleen te vinden op de lage punten van de planeet en er is nog geen bewijs dat de planeet vloeibaar water heeft.

©Shutterstock

Droge planeten
Hypothetisch gezien zouden droge planeten water kunnen vasthouden via oases. Dit zou betekenen dat zulke planeten dichter bij een ster en buiten de bewoonbare zone kunnen draaien.

©Shutterstock

Oceaanplaneten
Er bestaat een theorie dat de oceanen op aarde zijn ontstaan nadat ijslichamen op onze planeet insloegen en vervolgens smolten. Er zouden nog meer van zulke planeten kunnen bestaan.

©Shutterstock

Manen
Natuurlijke satellieten van planeten, of manen, zouden ook bewoonbaar kunnen zijn. Maar deze manen moeten zich binnen de bewoonbare zone van hun gastheerplaneten bevinden en ze moeten ver genoeg rond hun planeet draaien, zodat ze geen vulkanische planeten worden zoals Jupiters maan, Io.

©Shutterstock

Europa
De op drie na grootste maan van Jupiter, Europa, zou een wateroceaan onder het oppervlak van de planeet bevatten, welke mogelijk buitenaards leven zou kunnen herbergen.

©Shutterstock

Magnetische velden
Het magnetische veld van de aarde is een voorbeeld van een ander belangrijk criterium dat de levensvatbaarheid bepaalt, omdat het het oppervlak van de planeet beschermt tegen straling en kosmische stralen. Andere planeten zouden een vergelijkbaar veld moeten hebben om complex leven te kunnen laten floreren.

©Shutterstock

Zonnetweeling
Tot op de dag van vandaag hebben astronomen nog geen ster kunnen vinden die op de zon lijkt, een fenomeen dat een zonnetweeling wordt genoemd. Dit heeft het de wetenschappelijke gemeenschap moeilijker gemaakt om buitenaards leven te vinden dat op het onze lijkt.

©Shutterstock

Buitenaards leven
Maar welke soorten buitenaards leven zouden we kunnen vinden? Het is algemeen aangenomen dat op koolstof gebaseerde levensvormen de enige levensvatbare manieren zijn waarop leven kan bestaan.

©Getty Images

Koolstof-chauvinisme
Veel wetenschappers hebben kritiek geuit op het idee dat buitenaards leven gebaseerd moet zijn op koolstof. Hypothetisch gezien zouden buitenaardse wezens uit heel andere elementen kunnen bestaan die hen in staat stellen om op plekken te overleven die voor mensen onherbergzaam zijn.

©Shutterstock

Titan
Titan, de grootste maan van Saturnus, bezit koolwaterstofmeren die mogelijk leven zouden kunnen ondersteunen. Titan is het enige andere object in de ruimte waarvan is ontdekt dat het oppervlak vloeistof bevat.

©Getty Images

Zijn we uniek, of alleen de eerste?
Natuurkundige Enrico Fermi (1901-1954) kwam met de theorie dat we nog geen buitenaards leven zijn tegengekomen omdat intelligent leven ofwel zeldzaam is, ofwel nog maar net was onstaan in het universum.

©Shutterstock

Dicht bij het einde
Andere natuurkundigen hebben beweerd dat we nog geen buitenaards leven hebben gevonden omdat we al te laat zijn. In feite zeggen ze dat de meeste buitenaardse wezens al dood zijn en dat het heelal te ver uitbreidt om hun overblijfselen nog te kunnen vinden.

©Shutterstock

Het Grote Filter
Veel antropologen en astronomen geloven dat de mensheid alleen is in het universum, vanwege Het Grote Filter. Dit betekent in feite dat er zoveel onwaarschijnlijke stappen nodig zijn voor leven om intelligentie te ontwikkelen, dat het onwaarschijnlijk is dat dit nog eens zal gebeuren.

©Getty Images

De 'dierentuin hypothese'
Andere wetenschappers veronderstellen dat buitenaards leven wel degelijk bestaat, maar dat ze de mensheid vermijden om ons primitieve bestaan zonder tussenkomst te laten verlopen. Hoe dan ook, de ruimte is een grote grens die heel goed buitenaards leven zou kunnen herbergen.

Bronnen:

• (National Geographic)
• (NASA)
• (Astronomy.com)
• (Earth How)
• (Harvard John A. Paulson School of Engineering and Applied Sciences)

{ https://www.msn.com/nl-be/feed?ocid=msedgdhp&pc=u531 }

30-06-2024 om 23:01 geschreven door peter  

{ https://www.universetoday.com/ }

30-06-2024 om 00:30 geschreven door peter  

Mars is Bombarded by Meteoroids At More Frequent Rates than Previously Thought

Current impact rates at Mars could be 2-10 times higher than previously estimated, depending on the size of the meteoroids, according to new research.

Mars; the center of the scene shows the entire Valles Marineris canyon system.

Image credit: NASA Goddard Space Flight Center.

“It’s possible Mars is more geologically active than we thought, which holds implications for the age and evolution of the planet’s surface,” said Brown University’s Dr. Ingrid Daubar.

“Our results are based on a small number of examples available to us, but the estimate of the current impact rate suggests the planet is getting hit much more frequently than we can see using imaging alone.”

Dr. Daubar and colleagues used the highly sensitive seismometer onboard NASA’s InSight lander to identify eight new impact craters from meteoroids not previously seen from orbit.

The frequency of these cosmic collisions challenges existing notions about how often meteoroids hit the surface of Mars and suggests a need to revise current Martian cratering models to incorporate higher impact rates, especially from smaller meteoroids.

The findings could ultimately reshape current understandings of the Martian surface — as batterings from small meteoroids continue to sculpt it — and the impact history of not just Mars, but other planets.

“This is going to require us to rethink some of the models the science community uses to estimate the age of planetary surfaces throughout the entire Solar System,” Dr. Daubar said.

Six of the craters the researchers detected were near the site where the stationary InSight set down.

NASA/JPL-Caltech/University of Arizona

The two distant impacts they identified from the data were the two biggest impacts ever detected by scientists, even after decades of watching from orbit.

The larger impacts, each leaving a crater roughly the size of a football field, came just 97 days apart, underscoring the higher frequency of these types of geological events.

“This size impact, we would expect to happen maybe once every couple of decades, maybe even once in a lifetime, but here we have two of them that are just over 90 days apart,” Dr. Daubar said.

“It could just be a crazy coincidence, but there’s a really, really small likelihood that it’s just coincidence.”

“What’s more likely is that either the two big impacts are related, or the impact rate is a lot higher for Mars than what we thought it was.”

“Planetary impacts are happening all across the Solar System all the time.”

“We’re interested in studying that on Mars because we can then compare and contrast what’s happening on Mars to what’s happening on the Earth,”

“This is important for understanding our Solar System, what’s in it and what the population of impacting bodies in our Solar System looks like — both as hazards to the Earth and also historically to other planets.”

NASA/JPL-Caltech/University of Arizona

NASA/JPL-Caltech/University of Arizona

• The study appeared today in the journal Science Advances.
• Ingrid J. Daubar et al. 2024. Seismically detected cratering on Mars: Enhanced recent impact flux? Science Advances 10 (26); doi: 10.1126/sciadv.adk7615

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29-06-2024 om 15:39 geschreven door peter  

NASA benadrukt dat astronauten Starliner niet geblokkeerd zitten in ISS

NASA benadrukt dat astronauten Starliner niet geblokkeerd zitten in ISS

© Aangeboden door Belga

De twee astronauten die met de Boeing-ruimtecapsule Starliner drie weken geleden aankwamen in het internationale ruimtestation ISS, zitten daar "niet geblokkeerd". Dat heeft het Amerikaanse ruimteagentschap NASA vrijdag benadrukt. De terugkeer van de Starliner naar de aarde is ondertussen herhaaldelijk uitgesteld en zal er nu pas komen na nieuwe tests.

NASA benadrukt dat astronauten Starliner niet geblokkeerd zitten in ISS

© Aangeboden door Belga

De terugvlucht was aanvankelijk ten laatste op 26 juni gepland. NASA gaf geen nieuwe datum, maar liet eerder al weten dat de terugkeer van de Starliner met de twee astronauten Butch Wilmore en Suni Williams niet meer voor juni zou zijn.

Onderweg naar het ISS had de Starliner te maken gekregen met talrijke technische problemen. Er waren bijvoorbeeld heliumlekken opgetreden. Na problemen met de motoren slaagde het ruimteschip er pas bij de tweede poging in om aan te meren bij het ISS.

"Butch en Suni zijn niet geblokkeerd in de ruimte", benadrukte Steve Stich, een hoge verantwoordelijke van NASA, vrijdag tijdens een ongewoon gespannen persconferentie. De twee astronauten zouden aanvankelijk slechts iets meer dan een week in de ruimte blijven. In Amerikaanse media werd dan ook de vraag gesteld of de astronauten nog wel konden terugkeren naar aarde.

"We kunnen Starliner op elk moment terughalen", benadrukte Mark Nappi, een hoge verantwoordelijke bij Boeing. De eerste bemande vlucht van de Starliner was de ultieme testvlucht van de Boeing-ruimtecapsule, alvorens er reguliere vluchten mee uitgevoerd kunnen worden van en naar het ISS.

De Starliner, ontwikkeld en gebouwd door de Amerikaanse vliegtuigbouwer Boeing, maakte zijn eerste succesvolle onbemande vlucht in 2022.

NASA benadrukt dat astronauten Starliner niet geblokkeerd zitten in ISS

© Aangeboden door Belga

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29-06-2024 om 01:41 geschreven door peter  

De terugvlucht was aanvankelijk ten laatste op 26 juni gepland. NASA gaf geen nieuwe datum, maar liet eerder al weten dat de terugkeer van de Starliner met de 2 astronauten Butch Wilmore en Suni Williams niet meer voor juni zou zijn. 

Onderweg naar het ISS had de Starliner te maken gekregen met talrijke technische problemen. Er waren bijvoorbeeld heliumlekken opgetreden. Na problemen met de motoren slaagde het ruimteschip er pas bij de tweede poging in om aan te meren bij het ISS.

De capsule kon pas bij een tweede poging aanmeren bij het ISS

© Foto: AP

"Butch en Suni zijn niet geblokkeerd in de ruimte", benadrukte Steve Stich, een hoge verantwoordelijke van NASA, vrijdag tijdens een ongewoon gespannen persconferentie. De 2 astronauten zouden aanvankelijk slechts iets meer dan een week in de ruimte blijven. In Amerikaanse media werd dan ook de vraag gesteld of de astronauten nog wel konden terugkeren naar aarde.

"We kunnen Starliner op elk moment terughalen", benadrukte Mark Nappi, een hoge verantwoordelijke bij Boeing. De eerste bemande vlucht van de Starliner was de ultieme testvlucht van de Boeing-ruimtecapsule, alvorens er reguliere vluchten mee uitgevoerd kunnen worden van en naar het ISS.

De Starliner, ontwikkeld en gebouwd door de Amerikaanse vliegtuigbouwer Boeing, maakte zijn eerste succesvolle onbemande vlucht in 2022.

{ https://www.msn.com/nl-be/feed?ocid=msedgdhp&pc=u531 }

29-06-2024 om 01:30 geschreven door peter  

Scientists were eager to analyze the 4.3-ounce (121.6-gram) sample, and now, less than a year after its arrival on Earth, a new study published in Meteoritics & Planetary Science has revealed the discovery of vital prebiotic compounds and minerals on Bennu’s rocky surface.

Jason Dworkin, OSIRIS-REx project scientist at NASA’s Goddard Space Flight Center and a co-author of the new paper, said the OSIRIS-REx mission “gave us exactly what we hoped: a large pristine asteroid sample rich in nitrogen and carbon from a formerly wet world.”

The asteroid’s composition, represented in the samples retrieved by OSIRIS-REx, offers scientists a look into the formation of the solar system and the components that may have played a role in the formation of life on Earth.

The analysis is key to confirming carbon and nitrogen-rich dusts and organic compounds essential for life. However, the sample also revealed a few surprises, including the presence of magnesium-sodium phosphate, which had not been detected in data obtained from the asteroid through remote sensing.

This significant finding points to the likelihood that Bennu may have its origins in a small, primitive ocean world since magnesium-sodium phosphate is a water-soluble phosphate that plays a crucial role in Earth’s biochemistry. The detections made in the Bennu samples were also very pure and of a size that set them apart from similar phosphates found in asteroid samples retrieved by JAXA’s Hayabusa2 mission.

Although it seems likely, based on the new data, that Bennu has a history involving interactions with water, the asteroid is still relatively chemically primitive, and somewhat paradoxically, researchers compare the elements it possesses to those of the Sun.

Confirming the presence of carbon and nitrogen in the asteroid samples obtained from Bennu’s surface allows researchers to glean new insights into environments where those elements formed, as well as how they became complex molecules over time. These processes would have once occurred early in Earth’s history, also a process that would have been fundamental in the formation of life.

Retrieving the samples directly from the surface of an asteroid also offered NASA scientists access to a veritable “time capsule” where the materials remained preserved for billions of years. Given their low density, such materials are destroyed when asteroids collide with Earth’s atmosphere, burning up during reentry.

Studying the preserved samples retrieved by OSIRIS-REx has already provided new insights toward understanding the intricate processes of solar system formation and prebiotic chemistry, but researchers involved in the ongoing analysis believe there will likely be more surprises in the near future.

“Each week, analysis by the OSIRIS-REx Sample Analysis Team provides new and sometimes surprising findings,” said Harold Connolly, co-lead author of the new study and OSIRIS-REx mission sample scientist at Rowan University.

Connolly said the ongoing discoveries Bennu’s samples are revealing “are helping place important constraints on the origin and evolution of Earth-like planets.”

The new paper by lead-author Dante Lauretta and colleagues, “Asteroid (101955) Bennu in the laboratory: Properties of the sample collected by OSIRIS-REx,” was published on June 26. Additional information about NASA’s OSIRIS-REx mission can be found on its official web page.

• 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.

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28-06-2024 om 22:37 geschreven door peter