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The most widely recognized explanation for planet formation is the accretion theory. It states that small particles in a protoplanetary disk accumulate gravitationally and, over time, form larger and larger bodies called planetesimals. Eventually, many planetesimals collide and combine to form even larger bodies. For gas giants, these become the cores that then attract massive amounts of gas over millions of years.

But the accretion theory struggles to explain gas giants that form far from their stars, or the existence of ice giants like Uranus and Neptune.

The accretion theory dates as far back as 1944 when Russian scientist Otto Schmidt proposed that rocky planets like Earth formed from ‘meteoric material.’ Another step forward happened in 1960 when English astronomer William McCrea proposed the ‘protoplanet theory,’ stating that planets form in the solar nebula. In the decades since then, the accretion theory was refined and added to, and in modern times, astronomers have gathered more observational evidence that supported it.

However, the theory has some holes that still need plugging.

According to the theory, forming a core large enough to become a gas giant takes several million years, and protoplanetary disks dissipate too soon for that to happen. Protoplanets also tend to migrate toward their star as they grow, and they may not gather enough mass before the star consumes them.

The accretion theory faces another problem that’s surfaced since we’ve discovered more exoplanets in other solar systems. It struggles to explain hot Jupiters and super-Earths.

Over the years, the development of streaming instability and pebble accretion has overcome some of these problems. Streaming instability explains how particles in a gas disk experience drag and accumulate into clumps, which then collapse gravitationally. Pebble accretion explains how particles from centimetres to meters in diameter experience drag and form planetesimals. Both of these have strengthened the accretion theory, but astronomers still hunger for a complete theory of planet formation.

Researchers have developed a new model that incorporates all the physical processes involved in planet formation. Their work, which is published in the journal Astronomy and Astrophysics, is titled “Sequential giant planet formation initiated by disc substructure.” The lead author is Tommy Chi Ho Lau, a doctoral candidate at Ludwig-Maximilians-University in München, Germany.

The new model shows that substructures in a protoplanetary disk called annular perturbations can trigger the formation of multiple gas giants in rapid succession. Critically, this model matches up with some of the most recent observations.

Planets form in unstable gas disks around stars. The researchers show how small, millimetre-sized dust particles accumulate in the disk and become trapped in the annular perturbations. The authors call these migration traps. Since they’re trapped, the particles can’t be gravitationally drawn toward the star. A lot of material from which planets form accumulates in these compact regions in the disk, which creates the conditions for rapid planet formation.

“We find rapid formation of multiple gas giants from the initial disc substructure,” the researchers write in their paper. “The migration trap near the substructure allows for the formation of cold gas giants.”

This is an image of the HL Tau planet-forming disk taken with the Atacama Large Millimeter Array (ALMA). ALMA has imaged many of these protoplanetary disks with gaps. The gaps have been interpreted as rings carved out of the disk by forming planets, but this new model has a different explanation. Credit: ALMA (ESO/NAOJ/NRAO)

The process creates a new pressure maximum at the outer edge of the planetary gap, which triggers the next generation of planet formation. This results in a compact chain of giant planets, which is what we see in our Solar System. The process is efficient because the first gas giants that form prevent the dust needed to form the next planet from drifting inward toward the star.

“When a planet gets large enough to influence the gas disk, this leads to renewed dust enrichment farther out in the disk,” explains Til Birnstiel, co-author and Professor of Theoretical Astrophysics at LMU and member of the ORIGINS Cluster of Excellence. “In the process, the planet drives the dust—like a sheepdog chasing its herd—into the area outside its own orbit.”

These panels are snapshots from five different times in one of the simulations that show sequential planet formation. The solid line represents gas density, and the dashed line represents dust density. Each dot is a formed planet. As time passes, the dust density peak moves further from the star, shepherded along by newly formed planets. Image Credit: Lau et al. 2024.

The process then repeats itself. “This is the first time a simulation has traced the process whereby fine dust grows into giant planets,” said Tommy Chi Ho Lau, the study’s lead author.

The Atacama Large Millimetre-submillimetre Array (ALMA) specializes in observing protoplanetary disks. It can see through the dust that obscures planet formation around young stars. It’s found gas giants in young disks at a distance beyond 200 AU. In our Solar System, Jupiter is at about 5 AU, and Neptune is at about 30 AU. The authors say that their model can explain all of these different architectures. It also shows how our Solar System stopped forming planets after Neptune because the material was all used up.

“This work demonstrates a scenario of sequential giant planet formation that is triggered by an initial disc substructure,” the authors write in their conclusion. “Planetary cores are formed rapidly from the initial disc substructure, which can then be retained at the migration trap and start gas accretion.” The results show that “… up to three cores can form and grow into giant planets in each generation.”

How the substructures form is beyond the scope of this work. More research is needed to investigate this.

This work can explain how gas giants form, but it can’t explain how the timing worked in our Solar System. That requires more research into how gas accretion works, which the astronomical community is actively pursuing.

“Further investigations specifically on gas accretion are required to model the formation time of the Solar System’s giant planets,” the authors conclude.

The post A New Model Explains How Gas and Ice Giant Planets Can Form Rapidly appeared first on Universe Today.

Let others bang on about Trump; I’ve passed my judgment and have nothing to say about the loon. My brief this morning, as it is so often (sorry!) is New Zealand, which I see as the country of the world most captured by woke ideology (in this case, what we call DEI). In NZ, this takes the form of holding everything indigenous as sacred, and any criticism of such things cannot and will not be tolerated within the country. (I am safe in America.)  New Zealand may be a model of what will happen in countries like the US and UK, so we should pay attention.

What really burns my onions in when this kind of capture affects science, so that schoolkids—all the way up to college—are taught that science is not only compatible with the local “way of knowing” (Mātauranga Māori, or MM), but almost coequal, despite the fact that MM is a composite of empirical trial-and-error knowledge, spirituality, religion, myth and legend, and morality.

Today’s example, sent to me by yet another anonymous Kiwi (not the same one as yesterday!) puts the lie to the fact that this kind of capture is trivial and should be ignored. There are actually two articles, both from a government geological agency, GNS Science.

GNS Science is, according to Wikipedia,

. . . .a New Zealand Crown Research Institute. It focuses on geology, geophysics (including seismology and volcanology), and nuclear science (particularly ion-beam technologies, isotope science and carbon dating).

GNS Science was known as the Institute of Geological and Nuclear Sciences (IGNS) from 1992 to 2005. Originally part of the New Zealand Government’s Department of Scientific and Industrial Research (DSIR), it was established as an independent organisation when the Crown Research Institutes were set up in 1992.

As well as undertaking basic research, and operating the national geological hazards monitoring network (GeoNet) and the National Isotope Centre (NIC), GNS Science contracts its services to various private groups (notably energy companies) both in New Zealand and overseas, as well as to central and local government agencies, to provide scientific advice and information.

It’s analogous to the U.S. Geological Survey.

Click to read the summary page on “Minerals and Metals in New Zealand”:

After informing us that New Zealand is home to many minerals and metals (which are “not rocks”), and that these minerals and metals have many different uses, the page segues into spirituality and religion, which occupies fully half the page. Here you go:

Mātauranga Māori and minerals

Over hundreds of years, through interaction with and adaptation to the environment, Māori have developed a deep understanding and knowledge of minerals.

Māori believe that each rock and mineral type emerges from the Earth with its own story, its own whakapapa (genealogy) relating to its origin – hei koha tū, hei kura huna a Papa.

According to Māori tradition (pūrākau), Pūtoto, the god of magma, constantly seeks outward paths towards the Earth’s surface. On his upward journey, Pūtoto leaves many deposits — koha (gifts) for the guardians of the Earth’s bedrock and crust. Through the natural processes of heating, compression, solidification, weathering and erosion, Pūtoto’s deposits generate new varieties of stones, rocks, sand and minerals.

Pounamu (also known as jade or greenstone) is one of New Zealand’s most iconic mineral material. Pounamu is the Māori collective term for the semi-precious stone scientifically referred to as nephrite (kawakawa, kahurangi, inanga) or semi-nephrite. Ngāi Tahu are the kaitiaki (guardians) of pounamu and have a desire for it to be managed under the principle of ‘Tiakina he tino taonga Pounamu mō tātou, ā, mo kā uri ā muri ake nei’ (Care for the precious treasure Pounamu for all of us and our children who follow us). GNS Science provides scientific research and information to assist Ngāi Tahu with achieving these aspirations for now and for the benefit of future generations.

Well, I’m prepared to believe that the Māori know what uses metals and minerals have, but of course without modern science they don’t know how to make them into compounds or even the chemical composition of these substances. The geological origin of minerals, as recounted above, comes not from indigenous “ways of knowing” but also from modern science.  What distresses me is that the bit above mixes geology with legend. That isn’t science but anthropology—or even religion.  Seriously, are the things that traditional knowledge tells us of any use in a geology institute, or is it simply a form of virtue signaling? (They are, of course, of some use in anthropology or sociology.)

As the reader who sent this to me remarked,  “They’re trying to be both scientists and not at the same time!”

I have no idea whether the next article has anything to do with diluting geology with religion, but it’s an indication of what’s happening to science in New Zealand. Click to read:

The bad news:

GNS Science is proposing to axe dozens of jobs – the latest in a rolling series of shake-ups that have rocked the public and science sectors.

The Crown Research Institute has begun consulting staff on its cost-cutting proposals, which would disestablish 103 positions, of which one-quarter were vacant.

While 77 staff were affected by the plans, GNS was also proposing to establish 37 new roles, which it said would help the institute to “address its challenges and rise to its opportunities”.

“The change process anticipates these new positions will offer redeployment opportunities for some of our impacted staff,” GNS said in a statement.

The agency said it’d been focused on operating with fiscal prudence, seeking cost savings where possible and looking hard at any discretionary spending.

“Now, considering the size of our workforce alongside other cost-saving measures is a difficult but necessary step on a longer journey to financial sustainability,” it said.

“We are now encouraging staff to engage and provide feedback on the issues we face and our change proposals.”

It wasn’t yet clear how some of the agency’s vital functions – such as monitoring natural hazards or climate change research – might be affected.

Now I’m sure that New Zealand, a country of immense geological interest (it sits atop two tectonic plates) is full of excellent science-oriented geologists. I wonder what they think when their own governmental organization says stuff like this:

Ngāi Tahu are the kaitiaki (guardians) of pounamu and have a desire for it to be managed under the principle of ‘Tiakina he tino taonga Pounamu mō tātou, ā, mo kā uri ā muri ake nei’ (Care for the precious treasure Pounamu for all of us and our children who follow us). GNS Science provides scientific research and information to assist Ngāi Tahu with achieving these aspirations for now and for the benefit of future generations.

Is that the job of geologists?

On another page, you can see the “Framework of GNS”, described as “MAHIA Framework – the values that guide our work at GNS Science”.  These articles always have colorful diagrams for those who need pictures.

Today we have a collection of photos from several readers. All of their captions and IDs are indented, and you can click on the photos to enlarge them.

First, three from Martin Riddle:

I take lots of nature photos around the campus of Brooksby Village, a retirement community in Peabody,Ma.

Ruby-Throated Hummingbird  (Archilochus colubris):

Hummingbird hawk-moth (Macroglossum stellatarum). [JAC: this is a great example of convergent evolution when taken together with hummingbirds]

American Painted Lady butterfly (Vanessa virginiensis):

From Norm Gilinsky:

This is perhaps more of a conversation starter than an actual wildlife photo, but we found this seemingly unique sunflower in a field of sunflowers. This one is from a farm in Woodinville, Washington. It’s a cultivar of the Common Sunflower (Helianthus annuus).

What’s up with that? It’s a well-formed flower within the main flower. Since sunflowers are in the Asteraceae (Formerly the Compositae), it’s a composite within a composite. Strange and interesting:

From Simon Badderley:

Lin was walking down Democracy Street in our village when she saw this on the step of a derelict house in the middle of Ano Korakiana, Corfu.It’s a Giant Peacock Moth (Saturnia pyri), the largest moth in Europe, having a wingspan close to five and a half inches (140mm). It’s often thought to be a bat when flying at night. This is the female without the male’s feather-like antennae. The adult moth does not feed, but the caterpillar feeds on various deciduous trees including fruit trees and is regarded as a nuisance by fruit tree owners. These moths are active from March to late June. This one was almost inert, willing to be touched.

From Bryan Lepore:

 A photo of a green burgundy stink bug.  Wikipedia says it’s “Banasa dimidiata, the green burgundy stink bug, is a species of stink bug in the family Pentatomidae.”  Photo details: Taken in mid-Massachusetts: Middlesex county, July, 2024 – i.e. just a couple weeks ago. Mid-day, sunny, dry… on the recycle bin lid. iPhone 13 mini; enhanced photo:

And a lovely mountain from Larry Zelenak:

Not a wildlife photo, but maybe you can use it anyway, perhaps in a new series of best views from commercial plane flights.  This is Mt. Rainier on the morning of July 9 from an Alaska Airlines flight from SEA to RDU, taken with an older iPhone.

A strain of green algae has been artificially evolved to turn carbon dioxide into sustainable fuel and plastic

Let me start out by saying that I think the answer to that question is no – but this requires lots of clarification. This was, however, the discussion here, while although poorly informed, does raise some interesting questions. This is a Tik Tok video of a popular podcast which is mainly personalities chatting. The host, Logan, asks the question of whether or not it is possible that Jesus was essentially a con artist – a charismatic speaker who essentially started a cult of personality, and may or may not have believed his own rhetoric about being the son of God.

I think the question touches on something interesting, although historical context is critical. As I have discussed before, I think the evidence for a historical Jesus is thin. In the end, it doesn’t really matter because what is clear is that the mythology of Jesus evolved in a typical way involving all the elements known to fuel such mythologies. There were many stories of Jesus which are mutually exclusive, involving wildly different archetypes and story details. The themes followed the mythology themes that were already prominent in that time and place. The story evolved in a pattern of obvious embellishment. Eventually a canon was imposed from the top down, and all other versions became heresy and actively destroyed. What is left is almost entirely mythology, and the question of whether or not the life of a real person is in the mix is mostly irrelevant (from a historical point of view).

Unfortunately this renders the Logan conversation mostly irrelevant also, one giant non sequitur. Everyone in the conversation assumes that the details in the New Testament are historically accurate (if not the interpretation of those details), but that assumption is not justified. So the conversation takes the form of – could those details be the result of a charismatic con artist, or do they require an actual son of God.

For example, at one point, responding to the question, one person asks – has Trump ever walked on water? The point is that modern cult-like followings are not an adequate analogy to Jesus, because Jesus performed actual miracles. Another person raises the point (one which I have heard often before) that the disciples all faced persecution and death for their beliefs, and they would not have done so their belief was not genuine and intense. The unstated major premise here is that such belief can only come from a genuine Jesus.

The same person also argues no eyewitness to Jesus ever recanted. First, we do not have any direct eye witness accounts of Jesus. Paul, who wrote earliest about Jesus, never met him and only allegedly saw him 25 years after his death in visions (keep that in mind – the ultimate source of Christian belief is visions). The earliest gospels were written about 40 years after the death of Jesus. The writings that we have were all written by the faithful, to tell a story of faith, so why would they include accounts of recants. Any disagreement was purged as heresy. We don’t even know who wrote the gospels. They were authored anonymously and only later attributed to characters in the story.

I also found it interesting that the point was raised that there were a hundred such prophets walking around the middle east at the time claiming to be the son of god, and yet only one spawned a world religion. I actually think this point works against the claim of authenticity for Jesus. That’s right – there were lots of messiahs and prophets at the time. The concept of a messiah, a person with some kind of divinity, with a special message for humanity, who must make a personal sacrifice in order to save us, was the standard myth of the time. Why would we think that, by an amazing coincidence, one of these people was an actual messiah while the rest were fake?

The fact that one messiah myth emerged and persisted is not surprising. This is partly due to the notion that some messiah myth had to win and fill that mythology niche. It’s also possible that the Jesus myth that emerged contains elements of many of the false messiahs – any stories about any messiah that resonated could survive and would likely become attached to the most famous messiah story. Eventually Theodosius made Christianity the official religion of Rome, and that is the primary reason why it is a world religion today. Essentially, one version of the messiah myth emerged, mainly through luck and happenstance. This doesn’t mean that it has to be the one real messiah.

I am approaching this question from a neutral historical perspective, one not relying on faith. As a historical question, there is still some discussion about whether there is an element of historicity to the Jesus myth. But there is no debate about whether or not the story is a myth – it is. It emerged out of the mythology of that time and place, it evolved like a myth, and all of the references to Jesus either emerge from the early religious tradition itself or are a reference to that religious tradition (yes, even Josephus – he was not giving any first hand account, just referring to Christian belief).

But there is still an element of legitimacy to Logan’s question – it is very likely that many of the messiahs who were walking around at that time were charismatic cult leaders. We see this today, and we can see how such leaders can create new religions (Mormonism, Scientology). The process of creating mythology and mythology evolving into religion is not mysterious, but rather is well documented.

The post Was Jesus a Con Artist? first appeared on NeuroLogica Blog.

Bigger antennas are better, at least according to researchers interested in geospatial monitoring. That’s because higher resolution in monitoring applications requires larger apertures. So imagine the excitement in the remote sensing community when a researcher from Leidos, a government consulting firm, developed an idea that dramatically increased the effective aperture size of a remote radio-frequency monitoring system simply by tying a rotating antenna to a flat “sparse” array. That’s exactly what Dr. John Kendra did, and it has garnered him not only two NASA Institute for Advanced Concepts (NIAC) grants to advance the technology but also a prize paper award at a technical conference on remote sensing. In other words, if implemented correctly, the Rotary-Motion Extended Array Synthesis (R-MXAS) technology could be a game changer for remote sensing applications.

To understand why, it is best to understand the underlying concept of synthetic aperture radar (SAR). In a SAR system, multiple images of a single area are collected as a sensor moves past that area. Those images are then combined using a specially designed algorithm to create a single image composition. These images can see through clouds and are commonly used in remote sensing, especially in ground monitoring applications, such as tracking ocean levels.

R-MXAS is an implementation of a synthetic aperture imaging radiometer (SAIR), which combines the movement aspect of a typical SAR system and stitches together data from at least three separate antennas. One antenna is a large, 2-D plane that is, in fact, a 1-D “sparse” antenna. Two antennas are attached to either end of a tether that rotates at a right angle to the flat plane.

Scott Manley explains the basics of Synthetic Aperature Radar (SAR).
Credit – Scott Manley YouTube Channel

Data from those antennas are captured and combined in a specialized signal processing algorithm, some of which would occur in a remote sensing satellite, while some would have to occur on the ground. Those signal-processing algorithms effectively create an aperture area much larger than the sum of the physical components comprising it, which is precisely what remote sensing enthusiasts are looking for.

One particular application of this technology is ground moisture monitoring. Currently, there is a mission known as the Soil Moisture and Ocean Salinity (SMOS) mission, which ESA runs. It does an excellent job of monitoring overall soil moisture content at a resolution of about 35 km per “pixel.” But it does so from a low-Earth orbit, meaning it can only update those estimates once every few days. That update rate is frustrating to end data customers, who would like to see a faster cycle time and a higher resolution to allow for more specific tailoring of responses to conditions on the ground.

R-MXAS can help with both of those desires. First, according to calculations by Dr. Kendra, it can map the same 35 km resolution from geostationary orbit, allowing it to monitor an entire hemisphere simultaneously and continuously. While this particular final report didn’t dive into the detail of how R-MXAS could improve the resolution to 5-10 km rather than 35km, the idea is addressed, at least in theory, to show that the same multi-antenna configuration could be used as a high-gain phased array to increase the resolution even more.

R-MXAS Boom Design depiction
Credit – John Kendra

Given the novel nature of the idea and the enthusiastic acceptance by other researchers in the remote sensing community, R-MXAS was one of the lucky projects selected to receive a NIAC Phase II grant in 2019, immediately after its original Phase I grant in 2018. A brief search shows the most recent paper as being from 2021 and no further adopted plans or missions that implement the concept, but it would seem that a project somewhere would do so. Given the wide variety of use cases for a technology such as R-MXAS, it remains to be seen what that use case might be.

Learn More:
John Kendra – Rotary-Motion-Extended Array Synthesis (R-MXAS) FINAL REPORT
UT – There’s a Cloud of Space Debris Around Earth. Here’s how we Could get a Better Picture of it
UT – How a Single Atomic Sensor Can Help Track Earth’s Glaciers
UT – Astrobiologists Detect a Signature of Life Remotely. Don’t get too Excited, Though, it was With a Helicopter Here on Earth

Lead Image:
Artist’s conception of the R-MXAS system.
Credit – John Kendra

The post A Unique Combination of Antennas Could Revolutionize Remote Sensing appeared first on Universe Today.

Many people enjoy the experience of using AIs like ChatGPT or voice assistants like Alexa to find out information, but it turns out doing so makes it less likely you will spot inaccurate information

Josh Malerman, James S. A. Corey and Neal Asher all have new science fiction novels out in August, making it a bumper month for fans

Opponents of birth control don't object to condoms because they think they don't work, and Dr. Vinay Prasad doesn't object to masks because he thinks they don't work.

The post Dr. Adam Cifu Should Recognize, Dr. Vinay Prasad Will Never Admit Measures to Limit Viruses “Work” first appeared on Science-Based Medicine.

Scientists have made significant strides in understanding the properties of a ferroelectric material under an electric field. This breakthrough holds potential for advances in computer memory, lasers and sensors for ultraprecise measurements.

Scientists have made significant strides in understanding the properties of a ferroelectric material under an electric field. This breakthrough holds potential for advances in computer memory, lasers and sensors for ultraprecise measurements.

Scientists develop next-generation semiconductor technology for high-efficiency, low-power artificial intelligence.

Scientists develop next-generation semiconductor technology for high-efficiency, low-power artificial intelligence.

The temperature of the Sun’s corona is a minimum of 100 times hotter than the Sun’s surface, despite the corona being far less dense and extending millions of miles from the Sun’s surface, as well. But why is this? Now, a recent study published in The Astrophysical Journal could eliminate a longstanding hypothesis regarding the processes responsible for the corona’s extreme heat, which could help them better understand the Sun’s internal processes. This study holds the potential to help scientists gain greater insight into the formation and evolution of our Sun, which could lead to better understanding stars throughout the universe, as well.

For the study, the researchers analyzed data from the first 14 laps conducted by NASA’s Parker Solar Probe around the Sun with the goal of ascertaining how the magnetic field causes S-shaped bends, often called magnetic switchbacks due to their behavior in causing sudden reversals in the magnetic field’s direction. The goal of the study was to determine the source of the switchbacks, which are known to store energy from the magnetic field, to better understand how they could potentially heat the corona and solar wind.

“That energy has to go somewhere, and it could be contributing to heating the corona and accelerating the solar wind,” said Dr. Mojtaba Akhavan-Tafti, who is an assistant research scientist of climate and space sciences and engineering at the University of Michigan and lead author of the study.

The debate regarding the origin of the switchbacks has been disputed for some time within the scientific community, with scientists currently favoring two potential hypotheses: switchbacks originate from the magnetic field bending due to the solar wind’s extreme activity that occurs past the corona, and the other origin being from the surface of the Sun.

The results of the study show switchbacks do not originate from the surface of the Sun, which the researchers attribute to the lack of the number of switchbacks inside the corona. In contrast, if the Sun’s surface was the origin of the switchbacks, it is hypothesized the switchback numbers inside the corona would be far greater. Therefore, the study’s results eliminate one of the two competing hypotheses regarding the origin of switchbacks in the Sun.

“Our theory could fill the gap between the two schools of thought on S-shaped switchback generation mechanisms,” said Dr. Akhavan-Tafti. “While they must be formed outside the corona, there could be a trigger mechanism inside the corona that causes switchbacks to form in the solar wind.”

He follows this with, “The mechanisms that cause the formation of switchbacks, and the switchbacks themselves, could heat both the corona and the solar wind.” 

The study of the Sun’s magnetic field reversal dates to the 1970s when the two German-US Helios spacecraft, dubbed Helios-1 and Helios-2, observed this reversal behavior when Helios-2 traveled just over 43.432 million kilometers (26.99 million miles) from the Sun with Helios-1 being 3 million kilometers (1.9 million miles) behind it. This distance record was broken by the Parker Solar Probe in October 2018 and has since achieved a jaw-dropping distance of 7.26 million kilometers (4.51 million miles) from the Sun, which was accomplished in September 2023.

The Helios missions were followed by the first observations of switchbacks conducted by the NASA/ESA Ulysses probe that studied the Sun’s southern and northern polar regions in 1994 and 1995, respectively. More recently, remnants of switchbacks were observed by the ESA/NASA Solar Orbiter in September 2020 when the spacecraft was just over 146 million kilometers (91 million miles) from the Sun.

As noted, discovering the origin of switchbacks could help scientists better understand the internal processes of the Sun, and specifically the behavior of the solar wind, which contributes to space weather that can cause massive damage to orbiting satellites and electronic ground stations on Earth.

What new discoveries will scientists make about the origins of switchbacks on the Sun in the coming years and decades? Only time will tell, and this is why we science!

As always, keep doing science & keep looking up!

The post Why is the Sun’s Corona So Hot? One Hypothesis Down, Many to Go appeared first on Universe Today.

Interest in interstellar objects (ISOs) was ignited in 2017 when ‘Oumuamua flew through our Solar System and made a flyby of Earth. Roughly two years later, another ISO passed through our Solar System – the interstellar comet 2I/Borisov. These encounters confirmed that ISOs are not only very common, but pass through our Solar System regularly – something that astronomers have suspected for a long time. Even more intriguing is that some of these objects are captured and can still be found orbiting our Sun.

In a recent study, a team of researchers described a region in the Solar System where objects can be permanently captured from interstellar space. Their analysis determined that once objects are captured by our Sun’s gravitational pull and fall into this region—which could include comets, asteroids, and even rogue planets—they will remain in orbit around the Sun and not collide with it. These findings could have drastic implications for ISO studies and proposed missions to rendezvous with some of these objects in the near future.

The research was conducted by Edward Belruno, a professor of mathematics with the Katz School of Science and Health at Yeshiva University, New York, and James Green, the Director of the Planetary Science Division at NASA Headquarters. Their findings were presented in a paper titled “Permanent Capture into the Solar System” that appeared online and was recently presented at Heidelberg University and to the trajectory dynamics group at the European Space Agency’s Operations Centre (ESOC).

‘Oumuamua (l) and 2I/Borisov (r) are the only two ISOs we know of for certain. Credit: ESO/M. Kornmesser (left) NASA/ESA/D. Jewitt (right)

As noted, previous research has indicated that ISOs regularly visit our Solar System and could even be responsible for seeding Earth with the building blocks of life. In addition, researchers have attempted to simulate how many of these objects are captured by our Solar System over time, which yielded estimates in the thousands. Last, but not least, the arrival of ‘Oumuamua and 2I/Borisov also led to numerous proposals for spacecraft that could rendezvous with future ISOs and study them up close – such as the Interstellar Object Explorer (IOE) concept – or fly to those that our System has captured.

For their study, Belbrundo and Green performed simulations using a simplified model involving three masses – a captured ISO, the Sun, and the Milky Way – which allowed them to recreate the motion of the captured object. As they describe in their paper, when ISOs get caught by the Sun’s gravitational pull, they can enter a state known as “permanent capture,” where captured objects will remain in orbit around the Sun indefinitely. In addition, these objects will also enter a state known as “weak capture,” where they are slowly drawn into a stable orbit around the Sun but never collide with it.

Their simulations showed that captured objects in this region can exhibit chaotic motion, making their orbits appear highly unpredictable. However, they also noted that the region exhibits a complex, repeating pattern, similar to a fractal (or the patterns seen in the Mandelbrot set in mathematics) that contributes to the stability of the captured object’s orbit. As Belbruno explained to Astrobiology contributor Keith Cowing:

“The combined gravitational forces of the Sun and the Milky Way play a crucial role in this process. The galaxy’s gravitational field, including the effects of dark matter, significantly influences how objects are captured. Previous studies mainly focused on comet captures, which weren’t always permanent. This new research, however, describes a mechanism that ensures a permanent capture.”

Their study also suggests that in addition to asteroids and comets, the Sun could capture rogue planets throughout eons. Recent research has shown that there could be trillions of rogue planets in the Milky Way that were kicked from their solar systems over time. The gravitational influence of captured rogue planets and other objects would cause perturbations in the orbits of other bodies in the Solar System.

Similar to how astronomers have used the orbits of Kuiper Belt Objects to search for evidence of Planet 9 (aka. Planet X), astronomers could use these perturbations to infer the presence of captured bodies. Said Belbruno:

“The discovery not only enhances our understanding of gravitational dynamics but also opens up new possibilities for detecting and studying these fascinating celestial bodies. As we continue to explore the cosmos, who knows what other secrets the universe holds about the objects that have joined our solar family?”

Further Reading: Astrobiology, arXiv

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Space is big, really big! Finding new asteroids which are usually dark against the inky blackness of space is harder than looking for a needle in a cosmic haystack. Back in 1991 an astronomer discovered a kilometre wide asteroid which was subsequently found to have a smaller moon half its size. It was given the snappy name of 1991 VH which , after follow up observations was revealed to have a tumbling, chaotic rotation. This was the first binary asteroid that has been seen to exhibit this behaviour. A paper just published suggests that a close encounter with Earth as recently as 12,000 years ago could have started its tumbling motion. 

Asteroid 1991 VH was discovered by Robert McNaught at the Siding Spring Observatory. The asteroid was subject to high resolution imaging from Goldstone and the Arecibo Observatory in 2008 and showed a roughly spherical object. There is an equatorial ridge which gives the whole thing the appearance of a classical spinning top. It’s shape is not what makes the system unique, instead it is the chaotic tumbling nature of the binary system. 

The Arecibo Radio Telescope Credit: UCF

The satellite of 1991 VH has been dubbed S/2008 (35107) 1 and it was discovered on 27 February 1997 by a team of astronomers at Ondrejov Observatory. It was detected through photometric observations of the system’s dip in brightness caused by the eclipses and occultations as the two components rotate about each other. 

The binary asteroid pair have captured attention of astronomers because it comes from a class of asteroids known as Near Earth Binary Asteroids. Usually they consist of an oblate primary asteroid that is rotating rapidly and around it is a tidally locked elongated secondary asteroid. The tidal locking of the system is the result of tidal forces just like those that have tidally locked the Moon to Earth.  

In a paper published by Alex J Meyer from the University of Colorado Boulder and the team of researchers discuss that a past close encounter with Earth could have provided the necessary gravitational influence to disturb the binary system. It has been known that near-Earth asteroids develop chaotic orbital; properties at some point in their life. This is due to orbital resonances with some of the outermost gas giants and on occasions close passages by terrestrial planets. 

The team theorise that a single close passage by Earth could have been enough to impose a chaotic nature to the asteroids orbit. To facilitate their research, the team undertake a series of Monte-Carlo simulations where a stable binary asteroid is perturbed by a series of different orbital geometries. The resultant orbital parameters from the simulations are then compared with real observations from 1991 VH. 

Their results showed that a close fly-by of Earth by 1991 VH could most definitely alter the state. They propose that the flyby would have occurred within the last 100,000 years, possibly as close as within the last 12,000 years. The new altered chaotic state could remain until current day unless further encounters counteract the perturbations. 

Source : An Earth Encounter As the Cause of Chaotic Dynamics in Binary Asteroid (35107) 1991VH

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Two studies have linked "problematic smartphone use" to higher rates of anxiety, depression and insomnia among teenagers, but the researchers haven't shown that excessively using such devices directly causes these issues

Being trapped in space sounds like the stuff of nightmares. Astronauts on board the International Space Station have on occasion, had their return delayed by weather or equipment malfunction. We find ourselves again, watching and waiting as two astronauts; Juni Williams and Butch Wilmore have been stuck for months instead of their week long mission. The delays came as the Starliner system required fixes to be implemented. NASA successfully fired up 27 of its 28 thrusters in a hot-firing test and now, ground teams are preparing finally, to bring them home.

The Boeing Starliner spacecraft is officially known as the CST-100 Starliner. It was developed by Boeing as part of NASA’s Commercial Crew Program. Its purpose is to transport astronauts to the International Space Station and other low orbit craft. Starliner hit the headlines with its reusable design aimed at reducing costs and increasing launch frequency. It was first launched on 20 December 2019 as an uncrewed test flight to demonstrate docking capability with ISS. 

Boeing’s CTS-100 Starliner taking off from Cape Canaveral, Florida, on June 5th, 2024. Credit: NASA

Since 2019 Starliner has had issues along the way but has largely seen a successful progression to becoming a key part of NASA’s launch capability. Just recently however there have been issues with the manoeuvring jets used to adjust the attitude. Engineering teams at NASA and Boeing have been working on and running tests with Mexico a new configuration. Part of the thruster system controls the flow of helium, these are the helium manifolds and they were opened to allow engineers to monitor any helium supply issues and leaks. 

The team ran a hot fire test of the reaction control system jets on 27 July to see if there were any problems with the propulsion system. They test fired 27 out of 28 jets while astronauts Wilmore and Williams sat inside the docked Starliner. The tests involved firing the jets for short bursts, one at a time. They revealed that all thrusters were back to performing well and the helium manifolds were within operational margins that were needed for a return trip from ISS. The engineering teams closed the manifolds ahead of undocking and returning the astronauts home. 

The work is not over for the engineering teams however as they are now reviewing data from the tests and from ground based testing at the White Sands Test Facility in New Mexico. Once the review of data is complete, NASA and Boeing will identify a date to return the astronauts. 

Meanwhile back on board the ISS Wilmore and Williams wait. They have been checking other Starliner systems in preparation for return, working with other Boeing teams to prepare and have been undertaking pressure tests of their space suits. They have been working alongside Expedition 71 members and have recently helped setup the BioServe centrifuge in the Harmony Module. The centrifuge supports a wide range of biological, physical and materials science projects. Facilitating the separation of substances with different densities it can work with cell cultures, DNA, protein, blood and sedimentary samples.

Source : NASA, Boeing Complete Second Docked Starliner Hot Fire Test

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An analysis of people who were hospitalised with covid-19 in the first wave of the pandemic has revealed that the ongoing decline in their cognitive abilities is the equivalent to losing 10 IQ points

Fourteen modifiable risk factors are behind nearly half of all dementia cases worldwide, a report claims, but genetics and old age are the main causes of the condition