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25-08-2025 om 21:22 geschreven door peter  

The term “geology” should only be used in relation to Earth, since in Greek it means “the science of Earth”. However, when astronomers study other planets in the Solar System, they naturally take the most studied one, i.e., ours, as a “reference point”. Mars has a lot in common with Earth, but in some ways it is very different. Some of its features are strange: although it has the largest volcanoes in the Solar System, there is currently virtually no volcanic activity. Clearly, there is still much we do not know about our neighbor.

Mars as a planet

Mars, like Earth, is a rocky planet. Its shape is nearly spherical, its chemical composition is mainly silicates and aluminates, it has a dense core, and it is covered by a relatively thin crust. This is where the similarities between the two celestial bodies end and their differences begin.

The fourth planet from the Sun is half the size of Earth. The average radius of Mars is only 3,389.5 km. Its surface area is 1.4437×108 km², which is only 28% of that of our world, if we include the oceans. This means that the geological formations found on Earth would appear gigantic on Mars. Incredibly, the mountains, canyons, and depressions there are indeed much larger than those on Earth.

The surface of Mars is very uneven compared to Earth. In particular, its northern hemisphere is almost entirely low-lying, while the southern hemisphere is dominated by mountain ranges and plateaus. To explain this striking difference, some scientists point to the specific mechanism of Martian tectonic plate formation, while others believe it is the result of a collision with a large space object.

Whatever caused this strange dichotomy between the hemispheres of Mars, astronomers are certain that it arose at the dawn of the planet’s existence. Therefore, all subsequent evolution there took place in conditions where there were lowlands in the north and highlands in the south.

Volcanoes of Mars

Approximately 4.5 billion years ago, when Mars was just formed, it was a red-hot ball. Then its crust solidified, but liquid magma remained inside. This created conditions for volcanic activity. However, it occurred in a way that was very different from what we are used to on Earth.

On our planet, the crust consists of separate lithospheric plates that are constantly in motion. Magma erupts mainly through cracks between them, which is why most volcanoes are located along the joints of large sections of the lithosphere. Only occasionally can another type of volcanism be found on Earth, when a flow of hot magma literally melts its way to the surface. Such volcanoes are called shield volcanoes.

It is not known for certain whether lithospheric plates ever moved on Mars. At least, no traces of them have been found there. For billions of years, Martian volcanoes have appeared exclusively due to hot flows that melt the crust, and this happens in a rather strange way. Some volcanoes are indeed similar to those on Earth. However, the largest of them, due to their tendency to group, have formed large provinces that have no analogues not only on Earth, but in the entire Solar System.

Tharsis

The best example of strange Martian volcanism is Tharsis, located in the northwestern part of Mars. Its area is 30 million km², which is larger than Canada, the United States, and China combined. It is here that the largest volcano in the Solar System rises – the 26-kilometer-high Olympus Mons, approximately three times higher than Everest.

However, the most interesting thing about this giant is not its height, but its width. The diameter of Olympus’ base is 624 km, which means that on Earth it would hardly fit in Ukraine. So, despite its dizzying height, it looks almost flat. More precisely, its upper part forms a plain with a minimal slope, while its edges are slopes up to 7 km high.

At the center of the giant volcano is a caldera measuring 85×60 km. Several craters actually merge into one giant pit up to 3 km deep, so large that the entire city of Kyiv could fit inside it.

At the same time, Olympus is the largest, but not the only, giant volcano in Tharsis. To the southeast of it, there are three more very similar structures – the Ascraeus Mons, Pavonis Mons, and Arsia Mons. Each of them is much higher than Everest, and their diameters are measured in hundreds of kilometers.

Incidentally, the highest of the Tharsis Olympus volcanoes is by no means the record holder in terms of area. Alba Mons is “only” 6.8 km high, but its diameter reaches 1,350 km. And in general, it is difficult to call it a mountain, because its slope reaches only 0.5°, which means that it is essentially a sloping elevation. Previously, the term “patera” was used to describe such relief features.

Elysium

Another volcanic province, Elysium, is also located in the northern hemisphere of Mars. There are also several giant shield volcanoes there: the Hecates Tholus, Mount Elysium, and the Albor Tholus. They are significantly smaller than Olympus, but their size is still impressive. For example, Elysium rises 16 km above the Martian surface and has a diameter of 240 km.

Although the two volcanic provinces are very similar, they were formed in completely different periods. Tharsis is extremely ancient, its origin dating back to the Noachian period of Martian history, meaning it is about 4 billion years old. Elysium is much younger. It was formed about 600 million years ago. This is relatively young by the standards of the Red Planet and closer to the time when multicellular life appeared on Earth.

Why shield volcanoes regularly form in such large groups on Mars is still unclear. Apparently, this is related to the peculiarities of the rise of the same hot magmatic flows in its depths, which scientists call plumes. Perhaps the fact that they abut against a solid crust rather than separate plates somehow affects the nature of volcanism.

In addition, Mars’s smaller size plays a role. If there are irregularities in the distribution of heat inside it, they will manifest themselves much more strongly than on Earth. It is quite possible that at a certain depth below the Martian surface, there are large pockets of lava that manifest themselves as volcanic provinces.

Giant faults

In addition to giant volcanoes, Mars has equally amazing surface faults. From a geological point of view, they are very different from those we encounter on Earth, where structures similar to the Dniester Canyon or the Grand Canyon of the Colorado River in the United States are formed as a result of soil particles being washed away by water.

However, liquid water never flowed on the Red Planet long enough to wash out gorges tens and hundreds of meters deep. The nature of canyon formation there is completely different and is related to the same volcanic provinces. Giant mountains of solidified lava are so massive that they literally collapse under their own weight into the depths of the planet. As a result, the much thinner crust around them stretches and cracks.

Over time, cracks formed by erosion and other processes can reach truly enormous sizes. The largest of these is the Valles Marineris. It is often compared to the Grand Canyon in Colorado, but this only complicates its perception. The total length of this structure is 4,500 km, which means that on Earth it would stretch from Great Britain to the Caspian Sea.

In addition, the average width of the Valles Marineris is 200 km. This means that standing on one edge, you are unlikely to see the other. The picture will be more like a giant precipice, the bottom of which is lost somewhere below.

Another feature of the Martian landscape is related to the giant fractures on the surface: chaos terrains. This is the name given to areas where hills and furrows are scattered haphazardly, forming a veritable labyrinth. They appeared at a time when Mars still had plenty of ice and streams flowed across its surface. When the subsurface ice melted, the ground subsided. The water, flowing outwards, went to lower areas and eroded the already damaged rocks along the way. This happened extremely unevenly, resulting in the formation of chaos.

Sedimentary rocks on Mars

Although more large impact craters have been found on Mars than on the Moon or Mercury, smaller traces of collisions are much less common there. This is due to wind and water erosion.

Wind and water cause the destruction of solid rock and transport small particles. Several billion years ago, when the planet’s atmosphere was denser and the northern basin was filled with an ocean into which water flowed, these processes were much more intense. They can still be seen on the surface in the form of dry riverbeds of ancient rivers.

Traces of erosion on Mars include not only certain landforms, but also the presence of rocks that we call sedimentary. These include sand, gypsum, and clay. These conglomerates of extremely fine particles can only form in the presence of large amounts of water, usually near or at the bottom of rivers and lakes.

Despite the similarity between Martian sedimentary rocks and those on Earth, they contain almost no organic matter, which is common on Earth. More precisely, it may be there, and scientists are eager to find it, but this will only be possible after samples of the substance have been brought from Mars to Earth.

Scientists have also not yet found any traces of a developed biosphere on Mars. This means that minerals commonly found on Earth, such as oil, natural gas, and coal, are most likely not present there, as they are the remains of living organisms.

Is Mars really dead?

No matter how spectacular the volcanic eruptions on Mars were, no matter how long water flowed in its streams, forming clay deposits, all this is now a thing of the distant past. This view of the planet has become mainstream over the last few decades.

However, this trend has recently begun to change. One of the main reasons for this is the InSight probe. It operated on the surface of Mars for many months, while the seismograph on board recorded what was happening in the depths of the planet. Imagine the surprise of scientists when it began to register one surface vibration after another!

In general, astronomers had previously assumed the possibility of Marsquakes even in the absence of lithospheric plate movement. After all, tectonic vibrations occur even on the Moon, which is definitely “dead” in this sense. However, the events recorded by InSight turned out to be too frequent and too strong to be caused, for example, by the collapse of some underground cavities. More and more scientists are now inclined to believe that there is still liquid magma inside the Red Planet.

Research on Mars increasingly suggests that our current understanding of its “inner world” is not entirely accurate. However, humanity began exploring our neighboring planet relatively recently, so our knowledge of it is quite limited. It is quite possible that in a few thousand years, it will surprise researchers with active volcanoes… but that is a completely different story.

• Posted in Articles, Questions

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25-08-2025 om 20:07 geschreven door peter  

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24-08-2025 om 21:21 geschreven door peter  

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24-08-2025 om 21:00 geschreven door peter  

If aliens existed on Mars 3.7 billion years ago, they would have needed umbrellas

"Studying Mars, particularly an under-explored region like Noachis Terra, is really exciting because it's an environment which has been largely unchanged for billions of years," said Losekoot. "It's a time capsule that records fundamental geological processes in a way that just isn't possible here on Earth."

Some of the inverted channels appear as isolated segments that have survived the elements for billions of years. Others are more intact, forming systems that run for hundreds of miles and stand tens of yards tall.

Such a widespread network of inverted channels does not suggest these channels were caused by flash floods, argues Losekoot. Rather, they seem to have formed in stable climatic conditions over a geologically significant period of time during the Noachian–Hesperian transition, which was the shift from one geological era into the next around 3.7 billion years ago.

What's particularly intriguing is the most likely source of water to have formed these inverted channels is precipitation — be it rain, hail or snow. Indeed, given the size of the inverted channel network in Noachis Terra, this region of Mars may have experienced lots of rainy days in a warm and wet climate.

It's more evidence that Mars was once more like Earth than the cold and barren desert it is today.

Losekoot presented his findings at the Royal Astronomical Society's National Astronomy Meeting held at the University of Durham in the U.K., which ran between July 7 and July 11.

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{ https://www.space.com/space-exploration }

23-08-2025 om 21:47 geschreven door peter  

Curiosity Finds Coral-Shaped Rocks on Mars

On July 24, 2025, the 4,608th Martian day, or Sol, of the mission, NASA’s Curiosity rover imaged wind-eroded rocks shaped like a piece of coral in the Gale crater on Mars.

This image of the Paposo rock was taken by Curiosity’s MAHLI instrument on July 24, 2025.

Image credit: NASA / JPL-Caltech / MSSS.

One of the wind-eroded rocks was captured by Curiosity’s Mars Hand Lens Imager (MAHLI), a camera on the end of its robotic arm.

“Nicknamed Paposo, the rock was about 5 cm (2 inches) from MAHLI when this image was taken,” members of the Curiosity team wrote in a statement.

On the same day, Curiosity used its Remote Micro Imager, part of its ChemCam instrument, to view another coral-shaped rock.

This image of a wind-eroded rock was taken by Curiosity’s Remote Micro Imager on July 24, 2025.

£Image credit: NASA / JPL-Caltech / MSSS.

“Curiosity has found many small features like these, which formed billions of years ago when liquid water still existed on Mars” the researchers said.

“Water carried dissolved minerals into rock cracks and later dried, leaving the hardened minerals behind.”

“Eons of sandblasting by the wind wore away the surrounding rock, producing unique shapes.”

“This common process is seen extensively on Earth and has produced fantastic shapes on Mars, as well, including a flower-shaped rock.”

Curiosity rover took this selfie on October 11, 2019. The rover drilled twice in this location, nicknamed Glen Etive. Just left of the rover are the two drill holes, called Glen Etive 1 (right) and Glen Etive 2 (left).

Image credit: NASA / JPL-Caltech / MSSS.

Launched November 26, 2011, Curiosity is the fourth rover the United States has sent to Mars.

Led by NASA’s Jet Propulsion Laboratory, the mission involves almost 500 scientists from the United States and other countries.

Curiosity explores the 154-km- (96-mile) wide Gale crater and acquires rock, soil, and air samples for onboard analysis.

The car-size rover is about as tall as a basketball player and uses a 2.1-m- (7-foot) long arm to place tools close to rocks selected for study.

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23-08-2025 om 21:28 geschreven door peter  

Scientists may have found a powerful new space object: 'It doesn't fit comfortably into any known category'

By Keith Cooper

• This content was originally published on Space.

Scientists found a mysterious cosmic object that's between 10 and 100 times more powerful than all known supernovas. What could it be?

NGC 4945 is an edge-on spiral galaxy just 11 million light years away in Centaurus 

(Image credit: ESO)

A bewilderingly powerful mystery object found in a nearby galaxy and only visible so far in millimeter radio wavelengths could be a brand new astrophysical object unlike anything astronomers have seen before.

The object has been named 'Punctum,' derived from the Latin pūnctum meaning "point" or
"dot," by a team of astronomers led by Elena Shablovinskaia of the Instituto de Estudios Astrofísicos at the Universidad Diego Portales in Chile. Shablovinskaia discovered it using ALMA, the Atacama Large Millimeter/submillimeter Array.

"Outside of the realm of supermassive black holes, Punctum is genuinely powerful,” Shablovinskaia told Space.com.

Witnessing the Dawn of a New Solar System: A Historic Discover

Astronomers don't know what it is yet — only that it is compact, has asurprisingly structured magnetic field, and, at its heart, is an object radiating intense amounts of energy.

"When you put it into context, Punctum is astonishingly bright — 10,000 to 100,000 times more luminous than typical magnetars, around 100 times brighter than microquasars, and 10 to 100 times brighter than nearly every known supernova, with only the Crab Nebula surpassing it among star-related sources in our galaxy," Shablovinskaia said.

Punctum is located in the active galaxy NGC 4945, which is a fairly close neighbor of our Milky Way galaxy, located 11 million light-years away. That's just beyond the confines of the Local Group. Yet, despite this proximity, it cannot be seen in optical or X-ray light but rather only millimeter radio wavelengths. This has only deepened the mystery, although the James Webb Space Telescope (JWST) has yet to take a look at the object in near- and mid-infrared wavelengths.

Related: 

• Oops! Earendel, most distant star ever discovered, may not actually be a star, James Webb Telescope reveals

What could Punctum be?

Its brightness remained the same over several observations performed in 2023, meaning it is not a flare or some other kind of transitory phenomenon. Millimeter-wave radiation typically comes from cold objects such as young protoplanetary disks and interstellar molecular clouds. However, very energetic phenomena such as quasars and pulsars can also produce radio waves through synchrotron radiation, wherein charged particles moving at close to the speed of light spiral around magnetic field lines and radiate radio waves.

What we do know about Punctum is that based on how strongly polarized its millimeter light is, it must possess a highly structured magnetic field. And so, Shablovinskaia believes what we are seeing from Punctum is synchrotron radiation. Objects with strong polarization tend to be compact objects, because larger objects have messy magnetic fields that wash out any polarization.

Perhaps that synchrotron radiation is being powered by a magnetar, the team believes, which is a highly magnetic pulsar. However, while a magnetar's ordered magnetic field fits the bill, magnetars (and regular pulsars for that matter) are much fainter at millimeter wavelengths than Punctum is.

Supernova remnants such as the Crab Nebula, which is the messy innards blasted into space of a star that exploded in 1054AD, are bright at millimeter wavelengths. The trouble is that supernova remnants are quite large — the Crab Nebula itself is about 11 light-years across — whereas Punctum is clearly a much smaller, compact object.

"At the moment, Punctum truly stands apart — it doesn't fit comfortably into any known category," said Shablovinskaia. "And honestly, nothing like this has appeared in any previous millimeter surveys, largely because, until recently, we didn't have anything as sensitive and high-resolution as ALMA."

There is the caveat that Punctum could just be an outlier: an extreme version of an otherwise familiar object, such as a magnetar in an unusual environment, or a supernova remnant interacting with dense material. For now, though, these are just guesses lacking supporting evidence. It is quite possible that Punctum is indeed the first of a new kind of astrophysical object that we haven't seen before simply because only ALMA can detect them.

In the case of Punctum, it is 100 times fainter than NGC 4945's active nucleus that is being energized by a supermassive black hole feeding on infalling matter. Punctum probably wouldn't have been noticed at all in the ALMA data if it wasn't for its exceptionally strong polarization.

Further observations with ALMA will certainly help shed more light on what kind of object Punctum is. The observations that discovered Punctum were actually focused on NGC 4945's bright active core; it was just happenstance that Punctum was noticed in the field of view. Future ALMA observations targeting Punctum instead would be able to go to much lower noise levels without worrying about the galaxy's bright core being over-exposed, and it could also be observed across different frequencies.

The greatest help could potentially come from the JWST. If it can see an infrared counterpart, then its greater resolution could help identify what Punctum is.

"JWST's sharp resolution and broad spectral range might help reveal whether Punctum's emission is purely synchrotron or involves dust or emission lines," said Shablovinskaia.

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For now, it's all ifs and buts, and all we can say for sure is that astronomers have a genuine mystery on their hands that has so far left them feeling flummoxed.

"In any case," concluded Shablovinskaia, "Punctum is showing us that there is still a lot to discover in the millimeter sky.”

A paper describing the discovery of Punctum has been accepted by the journal Astronomy & Astrophysics, and a pre-print is available on astro.ph.

{ https://www.livescience.com/space }

23-08-2025 om 21:16 geschreven door peter  

What is the Moon Made Of? (Hint: It’s Not Cheese)

By Paul Sutter 

{ https://www.universetoday.com/ }

22-08-2025 om 21:00 geschreven door peter  

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22-08-2025 om 20:56 geschreven door peter  

Het Langdurige Mysterie van het Ontbrekende Normale Materie in het Universum: Een Doorbraak in de Astrofysica

Een afbeelding van een kunstenaar toont hoe korte, heldere flitsen van radiogolven door de mist tussen sterrenstelsels reizen, bekend als het intergalactische medium. Elke golflengte stelt astronomen in staat om de anders onzichtbare gewone materie te 'wegen'.

Melissa Weiss/CfA

Het universum, zoals wij het kennen, bestaat uit een complexe samenstelling van materie en energie. Hoewel wetenschappers aanzienlijke vorderingen hebben gemaakt in het begrijpen van de kosmische samenstelling, blijft een intrigerend vraagstuk bestaan: waar is al het 'normale' materie dat volgens theorieën en waarnemingen had moeten bestaan, maar tot nu toe grotendeels ontbrak in onze observaties? Recent onderzoek suggereert dat een lang bestaand raadsel over de zogenaamde 'ontbrekende' materie mogelijk opgelost is. Deze ontdekking heeft de potentie om ons begrip van de kosmische structuur en de evolutie van het heelal ingrijpend te veranderen.

Het Probleem van de Ontbrekende Materie

Het concept van 'normale' materie, ook wel baryonische materie genoemd, verwijst naar de materie die opgebouwd is uit baryonen: de elementaire deeltjes zoals protonen en neutronen. Deze vormen de basis van sterren, planeten, gaswolkjes en alles wat we kunnen waarnemen met het blote oog of telescopen. Het is de materie die wij kennen en die zichtbaar is in het universum. Toch bestaat er een fundamenteel probleem dat wetenschappers al decennia bezighoudt: de hoeveelheid baryonische materie die we in het heelal waarnemen, komt niet overeen met de hoeveelheid die we theoretisch verwachten op basis van kosmologische modellen en waarnemingen van de oerknal.

In de jaren 1950 al ontdekten astronomen dat de hoeveelheid baryonische materie in het heelal niet volledig kan worden verklaard door de objecten die we direct kunnen zien, zoals sterren en gaswolken. Toen ze de gegevens vergeleken met de voorspellende modellen van het heelal, bleek dat er een aanzienlijk deel van de baryonen ontbrak. Dit was een opmerkelijk probleem omdat het betekende dat er een grote hoeveelheid materie moest zijn die we niet konden detecteren, hoewel de theorieën en metingen aangeven dat ze aanwezig moesten zijn.

In het begin van de 21e eeuw werden de schattingen van de baryonische inhoud van het heelal verfijnd door middel van geavanceerde observaties. Onderzoek naar de kosmische microgolfachtergrond, de straling die de oerknal herinnert, gaf een eerste indicatie van de hoeveelheid baryonische materie die in het heelal aanwezig is. Daarnaast werden grote schaalstructuren zoals clusters van sterrenstelsels bestudeerd. Deze clusters bevatten enorme hoeveelheden gas dat zich uitstrekt over miljoenen lichtjaren en dat voornamelijk bestaat uit baryonen. Uit deze metingen bleek dat ongeveer 5% van de totale energie-inhoud van het heelal uit baryonische materie bestaat, volgens de standaard kosmologische modellen.

Maar hier ligt het probleem: als we proberen te tellen hoeveel baryonen we daadwerkelijk kunnen waarnemen in het heelal, dan komen we tot de conclusie dat slechts een fractie van die 5% echt zichtbaar is. We kunnen sterren, gaswolken en andere objecten tellen en meten, maar deze waarnemingen laten slechts een deel zien van de baryonen die volgens de modellen aanwezig zouden moeten zijn. Het resterende deel lijkt te 'verdwijnen' in de waarnemingen, wat heeft geleid tot de benaming ‘missing baryons’ of ‘ontbrekende materie’. Met andere woorden, er zou een groot deel van de baryonische materie in het heelal moeten zijn, maar die is tot nu toe niet direct zichtbaar of detecteerbaar met de instrumenten die we tot onze beschikking hebben.

Het ontbreken van deze baryonen vormt een van de grootste raadsels in de moderne kosmologie. Verschillende theorieën en onderzoekslijnen proberen te verklaren waar deze 'verdwenen' materie zich zou kunnen bevinden. Een veelgehoorde hypothese is dat deze baryonen zich in een soort diffuse, hete gaswolk bevinden die zich uitstrekt tussen de sterrenstelsels en clusters van sterrenstelsels, de zogenaamde 'warm-hot intergalactic medium' (WHIM). Dit gas is extreem dun en heet, waardoor het moeilijk te detecteren is met traditionele telescopen die vooral gevoelig zijn voor zichtbaar licht of koud gas.

Het onderzoek naar de ontbrekende baryonen is complex en vereist geavanceerde instrumenten en technieken, zoals X-ray telescopen en spectroscopie om het zwakke signaal van het diffuse gas op te vangen. Het vinden en bestuderen van deze ontbrekende materie is essentieel om een compleet beeld te krijgen van de samenstelling van het heelal en om de evolutie ervan beter te begrijpen. Het oplossen van dit vraagstuk kan ook nieuwe inzichten bieden in de dynamiek van het heelal, de werking van donkere materie en de aard van de kosmische evolutie.

Kortom, het probleem van de ontbrekende baryonische materie is een van de grote raadsels in de hedendaagse astronomie en kosmologie. Het benadrukt dat zelfs de meest fundamentele onderdelen van het universum, de materie die we het beste kennen, nog steeds mysteries bevat die wachten om opgelost te worden. Het zoeken naar deze 'verdwenen' baryonen is niet alleen een zoektocht naar ontbrekende materie, maar ook een zoektocht naar meer inzicht in de fundamentele werking van ons heelal.

De zoektocht naar de ontbrekende baryonen

Gedurende decennia waren astronomen vastbesloten om dit mysterie op te lossen. Verschillende hypothesen werden geopperd over waar deze baryonen zich konden bevinden. Eén van de meest aannemelijke theorieën stelde dat de ontbrekende materie zich bevindt in een diffuse, hete gaswolk die zich uitstrekt over de intergalactische ruimte. Dit heet het Warm-Hot Intergalactic Medium (WHIM), een extreem dunne en hete gasfase met temperaturen tussen 10^5 en 10^7 Kelvin. Vanwege de lage dichtheid en hoge temperatuur is het echter bijzonder moeilijk te detecteren met traditionele telescopen.

Recentelijk is er echter een belangrijke doorbraak geweest. Astronomen hebben gebruikgemaakt van geavanceerde instrumenten zoals de Cosmic Origins Spectrograph op de Hubble-ruimtetelescoop en de X-ray observatoria zoals Chandra en XMM-Newton. Door nauwkeurig te kijken naar de spectra van heldere achtergrondbronnen, zoals quasars, konden ze absorptielijnen identificeren die wijzen op het bestaan van het WHIM.

Een baanbrekende studie, gepubliceerd in 2023, toont aan dat een aanzienlijk deel van de ontbrekende baryonen inderdaad in dit hete, diffuse gas bevindt. Door meerdere lijnen van bevestiging te combineren, konden onderzoekers de hoeveelheid baryonische massa in het WHIM nauwkeurig schatten. Deze metingen suggereren dat ongeveer 60-70% van de 'verdwenen' baryonen nu wordt gevonden in deze intergalactische gaswolken.

Wat deze nieuwe bevindingen bijzonder maakt, is dat ze overeenkomen met de resultaten van recente onderzoeken die gebruikmaakten van Fast Radio Bursts (FRBs). Sinds 2007 zijn meer dan duizend FRBs gedetecteerd, waarvan slechts ongeveer 100 konden worden herleid tot hun galaxieën. Deze korte, krachtige radiosignalen fungeren als kosmische zaklampen die door de intergalactische ruimte reizen. Hun licht wordt beïnvloed door de materie die ze passeren: hoe meer materie, hoe meer de signalen vertragen, vooral in het zogenoemde plasma dispersion effect.

De 69 onderzochte FRBs, waarvan sommige zich op afstanden van 11,74 miljoen tot bijna 9,1 miljard lichtjaar bevinden, bieden een nieuwe manier om de verdeling van materie te bestuderen. Het meest verre FRB, genaamd FRB 20230521B, werd tijdens het onderzoek ontdekt en is momenteel het meest afgelegen waargenomen FRB. Met behulp van het Deep Synoptic Array, een netwerk van 110 radiotelescopen nabij Bishop, Californië, konden de onderzoekers 39 van deze FRBs traceren naar hun oorsprong. Daarnaast werden de afstanden gemeten met telescopen zoals Keck en Palomar in Hawaii en San Diego. De overige 30 FRBs werden gevonden met de Australian Square Kilometre Array Pathfinder en andere telescopen wereldwijd.

Wanneer radiosignalen als FRBs door de ruimte reizen, worden ze beïnvloed door de materie die ze passeren. Hoe meer materie in hun pad, des te meer worden de signalen vertraagd of verspreid in verschillende golflengten. Dit fenomeen, plasma dispersie genoemd, stelt astronomen in staat om de hoeveelheid en verdeling van de intergalactische materie te meten. Door de vertragingen in verschillende golflengten te analyseren, konden de onderzoekers het gas dat de FRBs passeerden in kaart brengen.

Volgens Connor, een van de onderzoekers, fungeren FRBs als korte kosmische lantaarns: “We kunnen heel precies meten hoe de radiosignalen vertraagd worden op verschillende golflengten (plasma dispersie), en dat geeft ons een manier om alle baryon(en) mee te tellen.” Co-auteur Vikram Ravi vergelijkt het met het zien van de schaduw van alle baryonen: “Als je een persoon voor je ziet, kun je veel over hem te weten komen. Maar als je alleen zijn schaduw ziet, weet je nog steeds dat hij er is en ongeveer hoe groot hij is.”

Door deze nieuwe methode konden de onderzoekers de verdeling van het baryonische materie in het heelal beter in kaart brengen. Het resultaat toont aan dat 76% van de kosmische materie zich bevindt als heet, laag-dicht gas tussen de sterrenstelsels, terwijl 15% in galactische halo’s ligt. De rest bevindt zich binnen de sterren, planeten en koud gas in de sterrenstelsels zelf.

Een illustratie van een kunstenaar toont gewone materie als kleurige plekken in de ruimten tussen sterrenstelsels. 

Jack Madden/IllustrisTNG/Ralf Konietzka/Liam Connor/CfA

Impliceert voor ons begrip van het heelal

Deze recente observatiegebaseerde bevindingen bieden een belangrijke aanvulling op ons huidige begrip van het heelal en bevestigen enkele langverwachte theorieën over de verdeling van materie in het kosmos. Ze sluiten naadloos aan bij eerdere voorspellingen uit geavanceerde simulaties en modelleringen, en laten zien dat het 'missing baryon problem'—het probleem dat wetenschappers al decennia lang proberen op te lossen—voor een groot deel een kwestie was van waar de materie zich bevindt in plaats van of die materie überhaupt bestond.

Het 'missing baryon problem' verwijst naar de discrepantie tussen de hoeveelheid baryonische materie (de normale materie die uit protonen en neutronen bestaat) die we zien in sterrenstelsels, gaswolken en andere zichtbare objecten, en de hoeveelheid die we theoretisch verwachten op basis van de kosmische achtergrondstraling en de modellering van het vroege heelal. Voorheen was het onduidelijk waar het grootste deel van deze baryonen zich bevond, want veel ervan was niet zichtbaar met de bestaande instrumenten. Nieuwe observaties, onder andere door middel van snelle radio-observaties en het gebruik van Fast Radio Bursts (FRBs), hebben nu uitgewezen dat een groot deel van deze baryonische materie zich bevindt in het Warm-Hot Intergalactic Medium (WHIM).

William H. Kinney, professor in de fysica aan de Universiteit van Buffalo, benadrukt dat de materie zelf al lang bekend was, maar dat we nu met nieuwe technieken en instrumenten hebben vastgesteld dat het grootste deel ervan in het WHIM ligt. Kinney zegt: “De decennia oude ‘missing baryon problem’ was nooit over of de materie er was, maar vooral over waar die zich bevond.” Het is een belangrijke doorbraak omdat het de lang bestaande onzekerheid wegneemt dat deze materie misschien niet bestond, en in plaats daarvan aantoont dat het zich voornamelijk in diffuse, warm en uitgestrekte gaswolken bevindt die zich tussen de sterrenstelsels uitstrekken.

Connor, een ander wetenschapper die betrokken is bij dit onderzoek, voegt hieraan toe: “Dankzij FRBs weten we nu dat driekwart van de baryonen in het heelal zweeft tussen de sterrenstelsels, in de kosmische webstructuur.” Deze kosmische webstructuur bestaat uit filamenten van gas en donkere materie die de grote schaal van het heelal vormen. De metingen van FRBs—zeer korte en krachtige radiogolven die door het heelal reizen—maken het mogelijk om de hoeveelheid materie die ze doorkruisen te bepalen, doordat de vertraging van het radiosignaal (de dispersie) wordt beïnvloed door de hoeveelheid gas dat het passeert.

Het begrijpen van deze verdeling van baryonische materie is van groot belang voor het verfijnen van onze modellen over de evolutie en structuurvorming van het heelal. Het laat zien dat een aanzienlijk deel van de materie niet zichtbaar is met traditionele telescopen, omdat het zich in een warm, dun gas bevindt dat moeilijk te detecteren is. Dit gas wordt verwarmd tot temperaturen tussen ongeveer 10^5 en 10^7 Kelvin, waardoor het vooral zichtbaar wordt in de röntgenstraling. Dit verklaart waarom eerdere observaties met bijvoorbeeld optische en radiotelescopen niet voldoende waren om deze materie te lokaliseren en te kwantificeren.

De nieuwe inzichten bieden niet alleen antwoorden, maar roepen ook nieuwe vragen op. Hoe wordt het WHIM gevormd en onderhouden? Welke fysische processen zorgen voor de verhitting en dispersie van deze gaswolken? Het lijkt erop dat interacties tussen het gas en de donkere materie, evenals energiebalansen binnen het heelal, een belangrijke rol spelen in de vorming en stabiliteit van het WHIM. Het bestuderen van deze processen is cruciaal voor een volledig begrip van de evolutie van het universum.

De ontwikkeling van nieuwe, gevoeliger instrumenten en observatietechnieken zal een grote rol spelen in het verder ontrafelen van deze mysteries. Zo wordt bijvoorbeeld gewerkt aan de geplande Lynx X-ray observator, die in staat zal zijn om röntgenstraling van het WHIM met hoge precisie te meten en in kaart te brengen. Daarnaast zal de James Webb Space Telescope, vooral bekend om zijn vermogen om in het infrarood te kijken, bijdragen aan het bestuderen van de interactie tussen baryonische materie en donkere materie, en het proces van structuurvorming op grote schaal.

Kortom, deze nieuwe bevindingen helpen ons niet alleen om het 'missing baryon problem' op te lossen, maar bieden ook een dieper inzicht in de complexe dynamiek van het heelal. Ze bevestigen dat het grootste deel van de normale materie zich niet in de sterren en planeten bevindt, maar in een uitgestrekt en warm gas dat zich tussen de sterrenstelsels bevindt en de grote structuur van het heelal vormgeeft. Dit heeft grote implicaties voor ons begrip van de evolutie van het heelal en onderstreept het belang van geavanceerde observatietechnieken voor toekomstige kosmologische ontdekkingen. Het is een belangrijke stap in de richting van een completer en nauwkeuriger beeld van de samenstelling en de dynamiek van ons heelal.

De Deep Synoptic Array hielp astronomen om eerder onbekende snelle radiobroken te vinden.

Vikram Ravi/Caltech/OVRO

Conclusie

Het oplossen van het langlopende raadsel van de 'ontbrekende' baryonische materie markeert een belangrijke mijlpaal in de astrofysica. Dankzij geavanceerde observatietechnieken zoals de studie van FRBs en spectroscopie wordt het mogelijk om het grootste deel van deze mysterieuze materie terug te vinden in het hete intergalactische gas dat zich uitstrekt over grote afstanden. Deze ontdekkingen versterken ons begrip van de dynamiek en evolutie van het heelal en onderstrepen dat zelfs de oudste vragen over de kosmos nieuwe antwoorden kunnen brengen, mits we blijven kijken en innoveren. De combinatie van nieuwe technologieën en methoden brengt ons dichter bij het volledig begrijpen van de complexe structuur van het universum en de verborgen materie die het vormgeeft.

{ PETER2011 }

22-08-2025 om 20:41 geschreven door peter  

Outrigger system traces brightest-ever radio burst to a nearby galaxy's single spiral arm

by Amanda Morris, Northwestern University

The millisecond-long blast—nicknamed RBFLOAT (short for "radio-brightest flash of all time" and, yes, a nod to "root beer float")—was discovered by the Canadian Hydrogen Intensity Mapping Experiment (CHIME) and its newly completed "Outrigger" array. By combining observations from sites in British Columbia, West Virginia and California, scientists traced the burst to a single spiral arm of a galaxy 130 million light-years away—accurate within just 42 light-years.

Because they occur so far away and vanish within the blink of an eye, FRBs are notoriously difficult to study. If scientists can pinpoint an FRB's exact location, however, they can explore its environment, including characteristics of its home galaxy, distance from Earth and potentially even its cause. Eventually, this information could help shed light on the nature and origins of these mysterious, fleeting bursts.

First time FRB was traced to source location was 2015

The study, "FRB 20250316A: A Brilliant and Nearby One-Off Fast Radio Burst Localized to 13 parsec Precision," published in The Astrophysical Journal Letters, marks the first time the full Outrigger array was used to localize an FRB.

"It is remarkable that only a couple of months after the full Outrigger array went online, we discovered an extremely bright FRB in a galaxy in our own cosmic neighborhood," said Northwestern's Wen-fai Fong, a senior author on the study.

"This bodes very well for the future. An increase in event rates always provides the opportunity for discovering more rare events. The CHIME/FRB collaboration worked for many years toward this technical achievement, and the universe rewarded us with an absolute gift."

"This result marks a turning point," said corresponding author Amanda Cook, a postdoctoral researcher at McGill University. "Instead of just detecting these mysterious flashes, we can now see exactly where they are coming from. It opens the door for discovering whether they are caused by dying stars, exotic magnetic objects or something we haven't even thought of yet."

An expert on cosmic explosions, Fong is an associate professor of physics and astronomy at Northwestern's Weinberg College of Arts and Sciences. She is also a member of the Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA) and the NSF-Simons AI Institute for the Sky (SkAI Institute).

Melissa Weiss/CfA

Four days of solar energy packed into a single blink

Flaring up and disappearing within milliseconds, FRBs are brief, powerful radio blasts that generate more energy in one quick burst than our sun emits in an entire year. While most pass unnoticed, every once in a while, an FRB is bright enough to detect. FRB20250316A, or RBFLOAT, was one of these rare events. Detected in March 2025, RBFLOAT released as much energy in a few milliseconds as the sun produces in four days.

"It was so bright that our pipeline initially flagged it as radio frequency interference, signals often caused by cell phones or airplanes that are much closer to home," Fong said. "It took some sleuthing by members of our collaboration to uncover that it was a real astrophysical signal."

And while many FRBs repeat—pulsing multiple times across several months—RBFLOAT emitted all its energy in just one burst. Even in the hundreds of hours after it was first observed, astronomers did not detect repeat bursts from the source. That means astrophysicists couldn't wait for another flare to gather more data. Instead, they only had one shot at pinpointing its location.

"RBFLOAT was the first non-repeating source localized to such precision," said Northwestern's Sunil Simha, a postdoctoral scholar at CIERA and study co-author. "These are much harder to locate. Thus, even detecting RBFLOAT is proof of concept that CHIME is indeed capable of detecting such events and building a statistically interesting sample of FRBs."

Location of RBFLOAT next to its host galaxy.

Credit: Yuxin "Vic" Dong/MMT

FRB forensics hint at a magnetar

To investigate RBFLOAT's origin, the scientists relied on CHIME, a large radio telescope in British Columbia and the world's most prolific FRB hunter. Smaller versions of CHIME, the Outriggers, enable astronomers to triangulate signals to precisely confine the specific locations of FRBs on the sky.

With this array of vantage points, the team traced the burst to the Big Dipper constellation in the outskirts of a galaxy about 130 million light-years away from Earth. The team precisely pinpointed it to a region just 45 light-years across, which is smaller than an average star cluster.

Follow-up observations from the 6.5-meter MMT telescope in Arizona and the Keck Cosmic Web Imager on the 10-meter Keck II Telescope in Hawai'i provided the most detailed view yet of a non-repeating FRB's surroundings. Simha analyzed the optical data obtained from Keck, and Northwestern graduate student Yuxin "Vic" Dong used the MMT to obtain deep optical images of the FRB's host galaxy.

Their investigations revealed the burst occurred along a spiral arm of the galaxy, which is dotted with many star-forming regions. The RBFLOAT occurred near, but not inside, one of these star-forming regions. Although astrophysicists still don't know exactly what causes FRBs, this evidence bolsters one leading hypothesis.

At least some appear to come from magnetars, ultra-magnetized neutron stars born from the deaths of massive stars. Star-forming regions often host young magnetars, which are energetic enough to produce quick, powerful bursts.

"We found the FRB lies at the outskirts of a star-forming region that hosts massive stars," Simha said. "For the first time, we could even estimate how deeply it's embedded in surrounding gas, and it's relatively shallow."

Keck's rich dataset and FRB's precise location enabled the team to perform first-of-its-kind analysis of the galaxy's properties at the FRB's location. These uncovered characteristics include the density of the galaxy's gas, star-formation rate and presence of elements heavier than hydrogen and helium.

"The FRB lies on a spiral arm of its host galaxy," added Dong, who is the principal investigator of the MMT program.

"Spiral arms are typically sites of ongoing star formation, which supports the idea that it came from a magnetar. Using our extremely sensitive MMT image, we were able to zoom in further and found that the FRB is actually outside the nearest star-forming clump. This location is intriguing because we would expect it to be located within the clump, where star formation is happening.

"This could suggest that the progenitor magnetar was kicked from its birth site or that it was born right at the FRB site and away from the clump's center."

The start of something spectacular

With the CHIME Outriggers now fully running, astronomers expect to pin down hundreds more FRBs each year—bringing them closer than ever to solving the mystery of what causes these spectacular flashes. The localization power of the Outriggers, combined with CHIME's wide field of view, marks a turning point for the FRB search.

"For years, we've known FRBs occur all over the sky, but pinning them down has been painstakingly slow," Dong said. "Now, we can routinely tie them to specific galaxies, even down to neighborhoods within those galaxies."

"The entire FRB community has only published about 100 well-localized events in the past eight years," Simha said. "Now, we expect more than 200 precise detections per year from CHIME alone. RBFLOAT was a spectacular source to begin building such a sample."

"Thanks to the CHIME Outriggers, we're now entering a new era of FRB science," said study co-author Tarraneh Eftekhari, who is CIERA's assistant director.

"With hundreds of precisely localized events expected in the next few years, we can start to understand the full breadth of environments from which these mysterious signals emanate, bringing us one step closer to unlocking their secrets. RBFLOAT is just the beginning."

• More information: FRB 20250316A: A Brilliant and Nearby One-off Fast Radio Burst Localized to 13 pc Precision, The Astrophysical Journal Letters (2025). DOI: 10.3847/2041-8213/adf62f on arXiv (2025). DOI: 10.48550/arxiv.2506.19006
• Journal information: arXiv 
• Provided by Northwestern University 

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22-08-2025 om 20:18 geschreven door peter  

The JWST has another feather in its cap. The perceptive space telescope has taken a break from peering into the ancient, distant Universe and probing the formation and evolution of galaxies. It's turned its gaze closer to home, examining Uranus for the presence of undiscovered moons, and it found one.

The discovery of one more tiny moon might not seem like a big deal. But if the Solar System is a puzzle, it can't be completed without the small pieces. As scientists build a more complete understanding of Uranus, the tiny moon S/2025 U1 will be a part of it.

Astronomers found the small moon in JWST NIRCam images from February. It orbits about 56,000 km from Uranus' center, and has an orbital period of 9.6 hours. It follows a nearly circular orbit. That suggests that it formed there, rather than being captured, since captured moons tend to follow eccentric orbits.

“It’s located about 35,000 miles (56,000 kilometers) from Uranus’ center, orbiting the planet’s equatorial plane between the orbits of Ophelia (which is just outside of Uranus’ main ring system) and Bianca,” said Maryame El Moutamid, a lead scientist in SwRI’s Solar System Science and Exploration Division based in Boulder, Colorado. “Its nearly circular orbit suggests it may have formed near its current location.”

“This object was spotted in a series of 10 40-minute long-exposure images captured by the Near-Infrared Camera (NIRCam),” said El Moutamid. “It’s a small moon but a significant discovery, which is something that even NASA’s Voyager 2 spacecraft didn’t see during its flyby nearly 40 years ago.”

Uranus is unique among the Solar System's planets because it's tipped on its side. So instead of a side view, the JWST gets a 'top down' view of the planet, its rings, and its moons.

In 1986, Voyager 2 came to within 81,500 km of Uranus and didn't spot the moon. At that time, only five of the planet's moons had been discovered, and Voyager discovered a sixth, Puck, named after a character in Shakespeare's A Midsummer Night's Dream. Eventually, Voyager 2's images revealed the presence of 11 new moons.

S/2025 U1 is only about 10 km in diameter. That measurement is based on its albedo. If it has the same albedo as Uranus' other moons, then that measurement should stand. At only 10 km diameter, it's easy to see how it's gone undetected for so long.

The tiny moon adds more complexity to one of the Solar System's most complex environments. In fact, its discovery hints at even greater complexity yet to be discovered.

Moons around Saturn and Uranus can act like shepherds that maintain and shape the structure of the rings. Rings can also form from moons that get too close to their planets. When a moon exceeds the Roche Limit, the planet's gravity pulls the moon apart and the debris creates a ring. Around Saturn, there's growing evidence that the same material can then coalesce into another moon, and that this cycle has been repeated. In fact, Saturn's rings contain about 150 moonlets embedded in its rings, which could be evidence of new moons forming.

A similar cycle may happen at Uranus, though on a much shorter timescale. Uranus' moons are more densely packed than Saturn's, and collisions between moons may create the debris that forms rings.

“No other planet has as many small inner moons as Uranus, and their complex inter-relationships with the rings hint at a chaotic history that blurs the boundary between a ring system and a system of moons,” said Matthew Tiscareno of the SETI Institute in Mountain View, California, a member of the research team. “Moreover, the new moon is smaller and much fainter than the smallest of the previously known inner moons, making it likely that even more complexity remains to be discovered.”

This discovery isn't completely unexpected. Astronomers have been studying Uranus' moons and some have concluded that there must be more smaller moons. Only they can explain the sizes and edges of Uranus' rings. A 2020 paper said, "Given that 17 of the 20 sharp ring edges remain unexplained, one would expect several more moons to be required." These moons would be in the 5 to 10 km range, and S/2025 U1 is about 10km in diameter. Though the same paper said that Cassini should've found them, it was incorrect; only the JWST has the power to spot them.

Will the JWST find more tiny moons in the Solar System? Much of the space telescope's observing time is already spoken for. Its observations focus on its four main science themes. But a portion of its time is allocated to General Observer programs, and astronomers compete for this time with observing proposals. It seems likely that more GO programs will focus on the Solar System.

“Through this and other programs, Webb is providing a new eye on the outer solar system. This discovery comes as part of Webb’s General Observer program, which allows scientists worldwide to propose investigations using the telescope’s cutting-edge instruments. The NIRCam instrument’s high resolution and infrared sensitivity make it especially adept at detecting faint, distant objects that were beyond the reach of previous observatories,” said El Moutamid.

“Looking forward, the discovery of this moon underscores how modern astronomy continues to build upon the legacy of missions like Voyager 2, which flew past Uranus on Jan. 24, 1986, and gave humanity its first close-up look at this mysterious world. Now, nearly four decades later, the James Webb Space Telescope is pushing that frontier even farther,” El Moutamid said.

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21-08-2025 om 21:34 geschreven door peter  

An international team of astronomers has published the results of a study of the pulsar nebula MSH 15-52, better known as the Hand of God. The Chandra X-ray telescope participated in these observations.

Hand of God

In 2009, NASA published images of an amazing structure located 17,000 light years from Earth. At its center is the pulsar PSR B1509-58, a rapidly rotating neutron star with a diameter of only 20 km. It was formed as a result of the collapse of a giant star that occurred approximately 1,700 years ago.

Despite its tiny size, the pulsar has a significant impact on its surroundings. It is responsible for the formation of a complex nebula that spans 150 light years. It resembles an X-ray image of a human hand with the palm and fingers extended. This is why the nebula got the nickname “Hand of God.”

Since then, astronomers have continued to study this object using Chandra. Now the Australia Telescope Compact Array (ATCA) has joined the observations. Its data was combined with data from Chandra, allowing for a new look at the exploding star and its surroundings.

Anatomy of a dead star

In the new image of the Hand of God, ATCA radio data is marked in red. In turn, the blue, orange, and yellow colors correspond to Chandra’s X-ray data. Hydrogen gas is shown in gold, and the area where X-ray and radio data intersect is shown in purple. 

The pulsar rotates nearly seven times per second and has a strong magnetic field, approximately 15 trillion times stronger than Earth’s. Rapid rotation and a strong magnetic field make B1509-58 one of the most powerful electromagnetic generators in the Milky Way. Its powerful wind, consisting of electrons and other particles, creates the nebula.

Radio data from ATCA show complex filaments aligned with the magnetic field of the nebula, shown by short straight white lines in the additional image. These filaments may be the result of the pulsar wind colliding with the remnants of a supernova.

By comparing radio and X-ray data, researchers identified key differences between the two types of light sources. In particular, some notable X-ray features, including the jet at the bottom of the image and the inner parts of the three “fingers” at the top, are not detected in radio waves. This indicates that high-energy particles are escaping from the shock wave near the pulsar and moving along magnetic field lines, creating fingers.

Radio data also show that the structure of RCW 89 differs from typical young supernova remnants. Most of the radio emission is uneven and corresponds exactly to the clusters of X-ray and optical emission. It also extends far beyond X-rays. All these characteristics confirm the idea that RCW 89 is colliding with a dense cloud of hydrogen located nearby.

However, not all questions were answered. One of the mysterious areas is the sharp boundary of X-ray radiation in the upper right corner of the image, which appears to be a shock wave from a supernova. Supernova shock waves usually glow brightly in the radio waves of young supernova remnants, so researchers are surprised by the absence of a radio signal at the X-ray boundary.

MSH 15–52 and RCW 89 exhibit many unique features not found in other young pulsar nebulae. However, many questions remain unanswered regarding the formation and evolution of these structures. According to scientists, further research is needed to better understand the complex interaction between the pulsar wind and the supernova remnant.

• According to NASA

• Posted in News, Science

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21-08-2025 om 18:09 geschreven door peter  

It has long been known that water and carbon exist on Ceres, the largest object in the main asteroid belt. Recently, scientists discovered that in the past, it may have had a chemical energy source that could have sustained life on it.

Data on organic molecules on Ceres

A new NASA study has shown that Ceres may have had a constant source of chemical energy: molecules necessary for the metabolism of certain microorganisms. Although there is no evidence that microorganisms ever existed on Ceres, this discovery supports theories that this interesting dwarf planet, which is the largest body in the main asteroid belt between Mars and Jupiter, may once have had conditions suitable for single-celled life forms. 

Scientific data from NASA’s Dawn mission, which ended in 2018, previously showed that the bright, reflective areas on Ceres’ surface are mainly composed of salts left behind by liquid that seeped up from underground. A later analysis in 2020 found that the source of this liquid was a huge deposit of brine, or salt water, beneath the surface. In other studies, the Dawn mission also found evidence that Ceres contains organic matter in the form of carbon molecules, which is necessary, though not sufficient on its own, to support microbial cells. 

Hydrothermal sources on Ceres in the past

The presence of water and carbon molecules are two important pieces of the puzzle regarding Ceres’ suitability for life. New discoveries suggest a third element: a long-term source of chemical energy in Ceres’ distant past that could have sustained microorganisms. This result does not mean that there was life on Ceres, but rather that there was probably “food” that could have sustained life if it had ever arisen on Ceres.

In a study published in the journal Science Advances on August 20, scientists constructed thermal and chemical models simulating the temperature and composition of Ceres’ interior over time. They found that approximately 2.5 billion years ago, Ceres’ underground ocean may have had a stable source of hot water containing dissolved gases rising from metamorphosed rocks in the rocky core. The heat came from the decay of radioactive elements in the rocky inner layer of the dwarf planet when Ceres was young — an internal process that is believed to be common in our Solar System.

Ceres’s temperature evolution drives major interior events.Depending on the extent of internal heating, a mid-sized (~500- to 1000-km radius) icy body such as Ceres may undergo differentiation and then metamorphism of its interior and ocean freezing, leading to the present-day interior structure. After accreting (1), the temperature within Ceres as a function of time and depth controls the events that determine Ceres’s habitability: (2) ice-rock differentiation at ~4 Myr, (3) metamorphic volatiles are added into the ocean ~0.5 to 2 Gyr, and (4) ocean freezing. Here, we assume the ice shell is made of pure water ice.

Credit: Science Advances (2025). DOI: 10.1126/sciadv.adt3283

Suitability for life on the dwarf planet

The Ceres we know today is hardly suitable for life. It has become colder, with more ice and less water than in the past. Currently, radioactive decay inside Ceres does not produce enough heat to prevent water from freezing, and what remains of the liquid has turned into concentrated brine.

The period when Ceres was most likely habitable was between half a billion and 2 billion years after its formation (or approximately 2.5–4 billion years ago), when its rocky core reached its maximum temperature. At that time, warm liquids could have entered Ceres’ underground waters.

The dwarf planet also lacks the advantage of modern internal heating generated by the pull and push of a large planet, as occurs with Saturn’s moon Enceladus and Jupiter’s moon Europa. Thus, Ceres’ greatest potential for providing the energy necessary for life was in the past.

This illustration depicts the interior of dwarf planet Ceres, including the transfer

This result is also significant for water-rich objects throughout the outer Solar System. Many other icy moons and dwarf planets similar in size to Ceres (with a diameter of about 585 miles or 940 kilometers) and lacking significant internal heating from planetary gravitational pull may also have had a window of opportunity for life in the past.

• According to phys.org

• Posted in News, Science

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21-08-2025 om 17:43 geschreven door peter  

Secretive X37-B space plane to test quantum navigation system — scientists hope it will one day replace GPS

In space, especially beyond Earth's orbit, GPS signals become unreliable or simply vanish. The same applies underwater, where submarines cannot access GPS at all. And even on Earth, GPS signals can be jammed (blocked), spoofed (making a GPS receiver think it is in a different location) or disabled — for instance, during a conflict.

This makes navigation without GPS a critical challenge. In such scenarios, having navigation systems that function independently of any external signals becomes essential.

Traditional inertial navigation systems (INS), which use accelerometers and gyroscopes to measure a vehicle's acceleration and rotation, do provide independent navigation, as they can estimate position by tracking how the vehicle moves over time. Think of sitting in a car with your eyes closed: you can still feel turns, stops and accelerations, which your brain integrates to guess where you are over time.

Related: 

• 10 things we know about the secret X-37B space plane

Eventually though, without visual cues, small errors will accumulate and you will entirely lose your positioning. The same goes with classical inertial navigation systems: as small measurement errors accumulate, they gradually drift off course, and need corrections from GPS or other external signals.

Where quantum helps

If you think of quantum physics, what may come to your mind is a strange world where particles behave like waves and Schrödinger's cat is both dead and alive. These thought experiments genuinely describe how tiny particles like atoms behave.

At very low temperatures, atoms obey the rules of quantum mechanics: they behave like waves and can exist in multiple states simultaneously — two properties that lie at the heart of quantum inertial sensors.

The quantum inertial sensor aboard the X‑37B uses a technique called atom interferometry, where atoms are cooled to the temperature of near absolute zero, so they behave like waves. Using fine-tuned lasers, each atom is split into what's called a superposition state, similar to Schrödinger's cat, so that it simultaneously travels along two paths, which are then recombined.

Since the atom behaves like a wave in quantum mechanics, these two paths interfere with each other, creating a pattern similar to overlapping ripples on water. Encoded in this pattern is detailed information about how the atom's environment has affected its journey. In particular, the tiniest shifts in motion, like sensor rotations or accelerations, leave detectable marks on these atomic "waves".

Compared to classical inertial navigation systems, quantum sensors offer orders of magnitude greater sensitivity. Because atoms are identical and do not change, unlike mechanical components or electronics, they are far less prone to drift or bias. The result is long duration and high accuracy navigation without the need for external references.

The upcoming X‑37B mission will be the first time this level of quantum inertial navigation is tested in space. Previous missions, such as NASA's Cold Atom Laboratory and German Space Agency's MAIUS-1, have flown atom interferometers in orbit or suborbital flights and successfully demonstrated the physics behind atom interferometry in space, though not specifically for navigation purposes.

By contrast, the X‑37B experiment is designed as a compact, high-performance, resilient inertial navigation unit for real world, long-duration missions. It moves atom interferometry out of the realms of pure science and into a practical application for aerospace. This is a big leap.

This has important implications for both military and civilian spaceflight. For the US Space Force, it represents a step towards greater operational resilience, particularly in scenarios where GPS might be denied. For future space exploration, such as to the Moon, Mars or even deep space, where autonomy is key, a quantum navigation system could serve not only as a reliable backup but even as a primary system when signals from Earth are unavailable.

Quantum navigation is just one part of the current, broader wave of quantum technologies moving from lab research into real-world applications. While quantum computing and quantum communication often steal headlines, systems like quantum clocks and quantum sensors are likely to be the first to see widespread use.

Countries including the US, China and the UK are investing heavily in quantum inertial sensing, with recent airborne and submarine tests showing strong promise. In 2024, Boeing and AOSense conducted the world's first in-flight quantum inertial navigation test aboard a crewed aircraft.

This demonstrated continuous GPS-free navigation for approximately four hours. That same year, the UK conducted its first publicly acknowledged quantum navigation flight test on a commercial aircraft.

This summer, the X‑37B mission will bring these advances into space. Because of its military nature, the test could remain quiet and unpublicized. But if it succeeds, it could be remembered as the moment space navigation took a quantum leap forward.

• This edited article is republished from The Conversation under a Creative Commons license. Read the original article.

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20-08-2025 om 22:43 geschreven door peter  

Scientists have discovered extraordinary "interstellar tunnels" that create direct pathways from our solar system to distant stellar regions, fundamentally changing our understanding of the space around Earth. Using advanced X-ray telescope data, researchers at the Max Planck Institute have mapped these cosmic channels that stretch across vast regions of the galaxy, revealing an intricate network connecting different star systems.

The breakthrough discovery emerged from analysis of data gathered by the eROSITA X-ray telescope, which orbits the Sun-Earth Lagrangian point L2. This sophisticated instrument provided researchers with the clearest view ever obtained of the soft X-ray background, allowing them to peer deep into the structure of interstellar space without interference from Earth's atmosphere or magnetosphere. The telescope's unique position enables continuous observation of cosmic phenomena that remain invisible to ground-based instruments.

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The Local Hot Bubble Discovery

Our solar system exists within an enormous cavity known as the Local Hot Bubble, a region of space approximately 300 light-years across filled with million-degree plasma. This cosmic bubble was carved out by a series of supernova explosions that occurred between 10 and 20 million years ago, creating what astronomers describe as a "supernova graveyard."

The research team, led by scientists at the Max Planck Institute for Extraterrestrial Physics, analyzed thousands of X-ray measurements to create the most detailed map ever produced of this local cosmic environment. Their findings, published in the journal Astronomy & Astrophysics, reveal that this bubble is far from uniform in temperature and structure, reveals the  Max Planck Institute report.

What makes this discovery particularly remarkable is the identification of tunnel-like structures extending from the Local Hot Bubble toward specific constellations. These channels appear as regions of exceptionally hot, low-density plasma that create pathways through the surrounding cooler interstellar medium.

3D model of the solar neighborhood. The color bar represents the temperature of the LHB as colored on the LHB surface. The direction of the Galactic Centre (GC) and Galactic North (N) is shown in the bottom right. The link to the interactive version can be found at the bottom of the page.

(© Michael Yeung / MPE)

Pathways to Centaurus and Beyond

The most significant tunnel discovery points directly toward the constellation Centaurus, home to some of our nearest stellar neighbors including the Alpha Centauri system. This cosmic highway extends across vast distances, potentially connecting our Local Hot Bubble with distant star-forming regions where new solar systems are being born.

A second interstellar tunnel was identified leading toward the constellation Canis Major, linking our solar system with the Gum Nebula located approximately 1,500 light-years away. Co-author Dr. Michael Freyberg explained the implications: "What we didn't know was the existence of an interstellar tunnel towards Centaurus, which carves a gap in the cooler interstellar medium" explains a Daily Mail report.

These tunnels may form part of an extensive branching network that connects different star-forming regions throughout our local galactic neighborhood. The researchers believe this interstellar highway system is maintained by the explosive births and deaths of massive stars, which create powerful shockwaves and stellar winds that push gas and debris through space.

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3D structure of the LHB with colours indicating its temperature.

 (© Michael Yeung / MPE)

Stellar Feedback and Cosmic Architecture

The formation of these interstellar tunnels demonstrates a process astronomers call "stellar feedback," where the life cycles of massive stars shape the structure of entire galaxies. When extremely massive stars exhaust their nuclear fuel, they collapse and explode as supernovae, creating expanding shells of superheated plasma that sweep through space at tremendous velocities.

Previous research has shown that the supernova explosions that created our Local Hot Bubble also collected gas and debris at their expanding edges, creating ideal conditions for new star formation. These new stars then produce their own jets of hot gases and radiation, which continue pushing outward until they encounter other stellar bubbles and star-forming regions.

The discovery also provides fascinating insights into our solar system's cosmic journey. According to co-author Dr. Gabriele Ponti:

"The sun must have entered the LHB a few million years ago, a short time compared to the age of the sun. It is purely coincidental that the sun seems to occupy a relatively central position in the LHB as we continuously move through the Milky Way."

The Ancient Mysteries of Time and Space ebook available from the Ancient Origins store.

Implications for Galactic Evolution

This network of cosmic tunnels represents a previously unknown aspect of galactic architecture that influences how matter and energy move between different regions of space. The researchers discovered that these pathways exhibit a distinct north-south temperature dichotomy, with the southern regions significantly hotter than their northern counterparts.

The thermal pressure measured within the Local Hot Bubble suggests it may be "open" toward high galactic latitudes, allowing material to flow freely between our local environment and the broader galactic halo. This connectivity could have profound implications for understanding how elements created in stellar cores are distributed throughout the galaxy, potentially affecting the formation of new planetary systems.

The eROSITA telescope's unprecedented sensitivity to soft X-ray emissions has revealed structures that remained invisible to previous generations of instruments. By operating from the L2 Lagrangian point, the telescope avoids contamination from Earth's magnetosphere, providing the cleanest possible view of these faint cosmic phenomena.

• Top image: eROSITA telescope's all sky survey image.
• Source: NASA Scientific Visualization Studio

By Gary Manners

References

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20-08-2025 om 22:23 geschreven door peter  

It's Official: Asteroids Ryugu and Bennu Are Siblings

By Evan Gough 

{ https://www.universetoday.com/ }

20-08-2025 om 18:42 geschreven door peter  

Scientists studied Polana, a fairly large asteroid in the Main Belt, using a spectroscope installed on the James Webb Space Telescope. It turned out to be very similar to Bennu and Ryugu, which had previously been explored by spacecraft.

Asteroid Polana

An article on the spectroscopy of Polana (142) was recently published in the Planetary Science Journal. Its authors claim that it has a common origin and forms a family with well-known objects such as Bennu and Ryugu.

The diameter of Polana is about 55 km. It was discovered back in the 19th century and has not been particularly noteworthy until now. Instead, Ryugu and Bennu were explored by spacecraft at close range, and material from the former was even brought back to Earth.

Spectral analysis of asteroids and their samples

A team of scientists led by Dr. Anicia Arredondo believes that in the early stages of the Solar System’s formation, large asteroids collided and broke into pieces to form a “family of asteroids,” the largest of which was Polana. Theories suggest that the remnants of this collision not only created Polana, but also Bennu and Ryugu. To test this theory, scientists began studying the spectra of all three bodies and comparing them with each other.

Arredondo and her team have applied for time on the James Webb Space Telescope to observe Polana using two different spectral instruments that focus on the near-infrared and mid-infrared spectra. Next, they compared this data with spectral data from physical samples of Ryugu and Bennu collected by two different space missions. The Japanese Aerospace Exploration Agency’s Hayabusa2 spacecraft encountered Ryugu in 2018 and collected samples that returned to Earth at the end of 2020. NASA’s OSIRIS-REx spacecraft encountered Bennu in 2020 and collected samples that returned to Earth in late 2023.

Asteroid sizes

Bennu and Ryugu are considered asteroids on Earth because they orbit the Sun inside the orbit of Mars; however, they are not considered dangerous to Earth, with closest approaches of approximately 1.9 and 1 million miles, respectively. 

Both Bennu and Ryugu are relatively small compared to Polana. Bennu’s diameter is approximately one-third of a mile, or roughly the same as that of the Empire State Building. Ryugu is twice as large, but Polana overshadows them both, being approximately 33 miles wide. Scientists believe that Jupiter’s gravity pushed Bennu and Ryugu out of their orbits near Polana.

• According to phys.org

• Posted in News, Science

{ https://universemagazine.com/en/articles-en/ }

20-08-2025 om 17:33 geschreven door peter  

Moon samples collected by the Apollo 17 mission have revealed new information about the Light Mantle, a distinctive bright band crossing the surface of the Moon. These are the remains of an ancient landslide that may be associated with the Tycho crater.

The last people on the Moon

Launched in December 1972, the Apollo 17 mission was the last flight in the Apollo program. As part of this program, NASA sent a scientist (geologist Harrison Schmitt) to the Moon for the first time, which largely determined its record “catch” of 110 kg of lunar soil samples, which were then delivered to Earth.

Light Mantle was one of the key objectives of the mission. This five-kilometer-long deposit, located at the foot of the two-kilometer-high South Massif mountain, has attracted the attention of scientists since its discovery. It is believed to be the remains of an ancient landslide. However, how exactly it formed and what allowed it to stretch for several kilometers was unknown.

The astronauts studied the Light Mantle by taking a series of cores. Some of them were placed in long-term storage in a sealed container in a special nitrogen storage facility. This was done with the expectation that in the future they could be studied using more advanced technologies and new scientific approaches that did not exist at that time. 

Anatomy of a lunar landslide

This turned out to be the right decision. Over the next half-century, scanning technology took a huge leap forward, making it possible to examine samples in great detail. The research team took advantage of this circumstance. First, scientists simulated how landslides could occur on the Moon using rocks of similar composition. After that, they opened one of the sealed cores, analyzed its contents, and then compared it with the results of computer simulations.

According to the researchers, analysis showed that the finer material covering the fragments in the core originated from them, rather than from the surrounding rock. This suggests that the debris broke apart and helped the landslide to “flow” like a liquid.

Although it is still unclear what exactly caused the landslide, one of the most likely causes was attributed to the impact of an asteroid that formed the Tycho crater. During the impact, countless rocks were thrown outwards and then fell back onto the Moon, forming small secondary craters. They diverge from Tycho with bright rays. Some of them stretch toward the Southern Massif.

Scientists have suggested that some of the material ejected during the formation of Tycho may have struck the South Massif. This could have caused a landslide, which ultimately formed the Light Mantle.

• According to Phys.org

• Posted in News, ScienceTaggedApollo,moon1

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20-08-2025 om 17:19 geschreven door peter  

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19-08-2025 om 21:35 geschreven door peter