https://bigthink.com/starts-with-a-bang/milky-way-andromeda-merger-uncertain/?utm_sourc...

"Instead of moving away, Andromeda is headed toward us at an impressive 109 km/s: about twice as fast as Halley’s comet moves at its maximum speed. Because of this speed, its distance of about 2.5 million light-years from us, and the mass-based gravitational attraction of the Milky Way and Andromeda, it was simple and straightforward to conclude that in about four billion years, the Milky Way and Andromeda would collide and merge.

"Only now, with new data from Hubble and Gaia about galaxies from all across the Local Group, it looks like that picture is too simple and naive, and may not be right at all. Here’s what the newest data teaches us.

***

"When we take the best position and velocity data that we have from Hubble and Gaia of these objects, and when we include what we know about their masses from a variety of lines of evidence, we can then look at the probability and timescale of a collision-and-merger occurring between the two most massive galaxies in the entire Local Group: Andromeda and the Milky Way.

***

"The authors correctly conclude that this implies that the conventional story — of an inevitable merger between the Milky Way and Andromeda in ~4 billion years — is too naive to be true, and in fact their analysis supports a low likelihood for this scenario. (Something that can only be known when we include the gravitational effects of the LMC, which was not known until well into the Gaia era.) By adding in new data, as well as using both simulation and semi-analytical techniques, they confirm that while including the Triangulum galaxy makes a near-term merger more likely, adding in the LMC both pushes out the merger timescale and makes a collision-and-merger less likely overall within the next ~10 billion years.

***

"In practically all of the models and simulations — even the most dramatic ones that include the LMC and that experience high-speed near-misses between the Milky Way and Andromeda — the Milky Way and Andromeda remain gravitationally bound to one another and to the greater Local Group, implying that a collision-and-merger will still occur.

"Our entire Local Group eventually should turn into a single galaxy, Milkdromeda, but the timescale for this fate is still largely unknown. It may still be ~4 billion years from now; it’s more likely that it will be ~8 billion years from now; it’s plausible that it will be ~10+ billion years from now, and maybe even tens of billions of years into the future. However, it’s extremely unlikely that either of these galaxies will be ejected from the Local Group, and thus an eventual merger really is inevitable. The question of when this will occur, however, just got a whole lot more interesting."

Comment: We have always been told the Milky Way and Andromeda will join a few million years from now. Now we might not merge at all or do it in many million more years. dhw will comment why did God make such a big universe if His only interest is us on Earth? My answer is God knows what He is doing and for some reason unknown to us the universe's size is required.

https://www.sciencealert.com/light-travels-across-the-universe-without-losing-energy-bu...

"Light is electromagnetic radiation: basically, an electric wave and a magnetic wave coupled together and traveling through space-time. It has no mass. That point is critical because the mass of an object, whether a speck of dust or a spaceship, limits the top speed it can travel through space.

"But because light is massless, it's able to reach the maximum speed limit in a vacuum – about 186,000 miles (300,000 kilometers) per second, or almost 6 trillion miles per year (9.6 trillion kilometers). Nothing traveling through space is faster. To put that into perspective: In the time it takes you to blink your eyes, a particle of light travels around the circumference of the Earth more than twice.

"As incredibly fast as that is, space is incredibly spread out. Light from the Sun, which is 93 million miles (about 150 million kilometers) from Earth, takes just over eight minutes to reach us. In other words, the sunlight you see is eight minutes old.

"Alpha Centauri, the nearest star to us after the Sun, is 26 trillion miles away (about 41 trillion kilometers). So by the time you see it in the night sky, its light is just over four years old. Or, as astronomers say, it's four light years away.

***

"...most light just goes and goes, without colliding with anything. This is almost always the case because space is mostly empty – nothingness. So there's nothing in the way.

"When light travels unimpeded, it loses no energy. It can maintain that 186,000-mile-per-second speed forever.

***

"...when you're traveling at or close to the speed of light, the distance between where you are and where you're going gets shorter. That is, space itself becomes more compact in the direction of motion – so the faster you can go, the shorter your journey has to be. In other words, for the photon, space gets squished.

"Which brings us back to my picture of the Pinwheel galaxy. From the photon's perspective, a star within the galaxy emitted it, and then a single pixel in my backyard camera absorbed it, at exactly the same time. Because space is squished, to the photon the journey was infinitely fast and infinitely short, a tiny fraction of a second.

"But from our perspective on Earth, the photon left the galaxy 25 million years ago and traveled 25 million light years across space until it landed on my tablet in my backyard."

Comment: the universe is so large we must measure distance in light-years. The massless photon allows us to do that without varying the measurements of distance.

https://www.sciencealert.com/major-problem-in-physics-could-be-fixed-if-the-whole-unive...

"Earth rotates, the Sun rotates, the Milky Way rotates – and a new model suggests the entire Universe could be rotating. If confirmed, it could ease a significant tension in cosmology.

"The Universe is expanding, but exactly how fast is a contentious question. Two different methods of measurement return two very different speeds – and as the measurements become more precise, each becomes more certain. This discrepancy is known as the Hubble tension, and it's reaching crisis levels in physics.

"So for a new study, physicists in Hungary and the US added a small rotation to a model of the Universe – and this mathematical massage seemed to quickly ease the tension.

"'Much to our surprise, we found that our model with rotation resolves the paradox without contradicting current astronomical measurements," says István Szapudi, an astronomer at the University of Hawaii.

"'Even better, it is compatible with other models that assume rotation. Therefore, perhaps, everything really does turn."

"According to their calculations, the Universe could take trillions of years to complete a single spin – and given that it's less than 14 billion years old, it still has a long way to go to finish even its first rotation.

***

"...this is the first time the idea has been applied to the Hubble tension.

"It might sound like semantics, but solving this tension is crucial for our understanding of the cosmos. It's based around a value known as the Hubble constant, which represents the rate of the expansion of the Universe.

"Astronomers use the Hubble constant to calculate the age and size of the Universe, the distances to objects beyond our galaxy, and the influence of dark energy. If we start whacking recklessly at this foundational block, the whole Jenga tower that is the Standard Model of Cosmology could come crashing down.

***

"If the entire Universe is spinning, it could raise some fascinating questions about reality. What force could possibly set this in motion? One particularly mind-boggling hypothesis suggests our Universe is located in the center of a black hole inside another Universe. After all, black holes also rotate at close to the maximum possible speed.

"It's fun to think about, but before we embark down that rabbit hole, the team says the next step is to produce a full computer model incorporating a rotating Universe. This could help identify predictions that astronomers can search for in real-world observations, to confirm or rule out the idea."

Comment: if it makes Hubble strictly measurable it may be a correct theory.

https://www.sciencealert.com/nasas-unexpected-discovery-of-the-largest-organics-on-mars...

"NASA's Curiosity Mars rover has detected the largest organic (carbon-containing) molecules ever found on the red planet.

"The discovery is one of the most significant findings in the search for evidence of past life on Mars. This is because, on Earth at least, relatively complex, long-chain carbon molecules are involved in biology.

"These molecules could actually be fragments of fatty acids, which are found in, for example, the membranes surrounding biological cells.

***

"The organic molecules found by Curiosity consist of carbon atoms linked in long chains, with other elements bonded to them, like hydrogen and oxygen.

"They come from a 3.7-billion-year-old rock dubbed Cumberland, encountered by the rover at a presumed dried-up lakebed in Mars's Gale Crater. Scientists used the Sample Analysis at Mars (Sam) instrument on the NASA rover to make their discovery.

***

"Among the molecules were decane, which has 10 carbon atoms and 22 hydrogen atoms, and dodecane, with 12 carbons and 26 hydrogen atoms. These are known as alkanes, which fall under the umbrella of the chemical compounds known as hydrocarbons.

***

"Organic molecules preserved in ancient Martian rocks provide a critical record of the past habitability of Mars and could be chemical biosignatures (signs that life was once there).

"The sample from Cumberland has been analysed by the Sam instrument many times, using different experimental techniques, and has shown evidence of clay minerals, as well as the first (smaller and simpler) organic molecules found on Mars, back in 2015.

"These included several classes of chlorinated and sulphur-containing organic compounds in Gale crater sedimentary rocks, with chemical structures of up to six carbon atoms. The new discovery doubles the number of carbon atoms found in a single molecule on Mars.

"The alkane molecules are significant in the search for biosignatures on Mars, but how they actually formed remains unclear. They could also be derived through geological or other chemical mechanisms that do not involve fatty acids or life. These are known as abiotic sources.

***

"It is possible the sample contains even longer chain organic molecules. It may also contain more complex molecules that are indicative of life, rather than geological processes.

"Unfortunately, Sam is not capable of detecting those, so the next step is to deliver Martian rock and soil to more capable laboratories on the Earth.

"Mars Sample Return would do this with the samples already gathered by the Perseverance Mars rover. All that's needed now is the budget."

Comment: it seems carbon compounds are spread all around as if God made the option to start life amywhere.

https://www.sciencedaily.com/releases/2025/03/250326154430.htm

"'This study is the first to demonstrate, using a physical model, that the first-order features of Earth's lower mantle structure were established four billion years ago, very soon after the planet came into existence," says lead author Faculty of Science Assistant Professor Charles-Édouard Boukaré in the Department of Physics and Astronomy at York.

"The mantle is the rocky envelopment that surrounds the iron core of rocky planets. The structure and dynamics of the Earth's lower mantle play a major role throughout Earth's history as it dictates, among others, the cooling of the Earth's core where the Earth's magnetic field is generated.

***

"Boukaré's model is based on a multiphase flow approach that allows for capturing the dynamics of magma solidification at a planetary scale. Using his model, he studied how the early mantle transitioned from a molten to a solid state. Boukaré and his team were surprised to discover that most of the crystals formed at low pressure, which he says creates a very different chemical signature than what would be produced at depth in a high-pressure environment. This challenges the prevailing assumptions in planetary sciences in how rocky planets solidify.

"'Until now, we assumed the geochemistry of the lower mantle was probably governed by high-pressure chemical reactions, and now it seems that we need to account also for their low-pressure counterparts."

"Boukare says this work could also help predict the behaviour of other planets down the line.

"'If we know some kind of starting conditions, and we know the main processes of planetary evolution, we can predict how planets will evolve.'"

Comment: this is in the very early formation. Later on life appears and makes major transformations on Earth's surface, as previously discussed here : 2020-10-10, 19:09

https://www.astronomy.com/science/the-first-stars-may-have-flooded-the-early-universe-w...

"New research, published today in Nature Astronomy, found that water may have formed in the first 200 million years of the universe’s lifetime. The life-giving molecule may have been created so quickly by the deaths of the universe’s first stars. The study also found that rocky planets could be built in the water-rich environment left behind, all before the first galaxies even existed.

"Principal investigator Daniel Whalen of Portsmouth University in the United Kingdom and his colleagues found that a rare type of supernova created only by the earliest stars formed enough water to drench the surrounding regions where the next generations of stars and their planets would be born.

"The very first stars formed from the hydrogen and helium that filled the universe after the Big Bang. These suns weren’t in galaxies — those didn’t exist yet — but instead at the intersections where cobweblike filaments of dark matter, strung between empty voids, met. Gravity drew gas to these intersections and when the density was high enough, the first stars were born.

"These stars were huge, as much as 300 times as massive as our Sun. Their temperatures were high and they burned through their fuel quickly. And they died in supernovae that spewed new elements across the galaxy.

"Whalen and his colleagues simulated two types of supernovae thought to be prevalent among the first generation of stars by following the lives of stars with 13 and 200 solar masses. “We watched primordial stars form … and then they blew up,” Whalen says.

***

"When the first stars exploded, they were surrounded by leftover hydrogen gas from the star. Whalen’s simulations showed that the leftover material included small clumps bound together by gravity. As hot ejecta from the supernova raced outward, the metals within it — including oxygen — mixed with the hydrogen, accelerating their gravitational collapse. The added metals also helped the clumps to cool, allowing the oxygen to combine with hydrogen to form water."

Comment: life requires water. That it appeared so early fits the theory of design.

https://mail.google.com/mail/u/0/#inbox/FMfcgzQXKhDwlBzZRkPGmjcBlljKJwxF

"Consider for a moment our friends around us in the inner solar system. I don’t mean friends on Earth, but the pristine surfaces from long ago on planetary bodies. We know that many surfaces in our region of the solar system have resurfacing mechanisms like erosion, tectonic plates, etc., including Earth and Venus. But some surfaces show their battered histories, like Mercury and our own Moon.

"The incredible array of craters on the Moon’s surface, for example, presents a record of the early history of the inner solar system. Planetary scientists know that a distant period of incredible violence occurred long ago, as countless small bodies in this part of the solar system cleared themselves away, mostly by colliding with larger bodies. This cosmic shooting gallery happened largely between 4.1 and 3.8 billion years ago. Scientists call this period the Late Heavy Bombardment, during which an inordinately large number of asteroids and comets slammed into the larger bodies, driven by both post-accretion processes and the instability of early planetary orbits." (my bold)

Comment: the history of this period is quite clear and amazingly life appeared as it was ending

https://www.livescience.com/space/cosmology/what-is-the-universe-expanding-into-if-its-...

"The expansion of the universe is, in some ways, similar. But this analogy gets one thing wrong — while the dough expands into the baking pan, the universe doesn't have anything to expand into. It just expands into itself.

"It can feel like a brain teaser, but the universe is considered everything within the universe. In the expanding universe, there is no pan. Just dough. Even if there were a pan, it would be part of the universe and therefore it would expand with the pan.

***

"Scientists know the universe is expanding because they can track other galaxies as they move away from ours. They define expansion using the rate that other galaxies move away from us. This definition allows them to imagine expansion without needing something to expand into.

***

"...the name Big Bang is misleading. It wasn't a giant explosion, as the name suggests, but a time where the universe expanded rapidly.

***

"...in 1929, Hubble published his famous paper that confirmed the entire universe was expanding, and that the rate it's expanding at is increasing.

"This discovery continues to puzzle astrophysicists. What phenomenon allows the universe to overcome the force of gravity keeping it together while also expanding by pulling objects in the universe apart? And on top of all that, its expansion rate is speeding up over time.

***

"Scientists haven't been able to directly measure where the energy causing this accelerating expansion comes from. They haven't been able to detect it or measure it. Because they can't see or directly measure this type of energy, they call it dark energy.

"According to researchers' models, dark energy must be the most common form of energy in the universe, making up about 68% of the total energy in the universe. The energy from everyday matter, which makes up the Earth, the Sun and everything we can see, accounts for only about 5% of all energy.

***

"One way to make these theories work together is the multiverse theory. There are many theories that look beyond our current universe to explain how gravity and the quantum world work together. Some of the leading theories include string theory, brane cosmology, loop quantum theory and many others.

"Regardless, the universe will continue to expand, with the distance between the Milky Way and most other galaxies getting longer over time."

Comment: so we are left with the concept that the universe expands into itself. There is nothing out there to expand into. Wow! In creating the universe God has left us with puzzles. Not just that the basis of our universe is quantum mechanics.

https://bigthink.com/starts-with-a-bang/fabric-space-cheshire-cat/?utm_source=rejoiner&...

"As absurd as it may seem, what we think of as “empty space” doesn’t have the properties fundamental to all media that waves travel through, making the fabric of space the Cheshire Cat of the very Universe itself.

***

"When it comes to how waves work, one of the simplest examples you can experiment with for yourself is to simply drop a stone into an otherwise still body of water, such as a pond or a puddle. As the stone strikes the water, it pushes the water down and out-of-the-way. This leads to a crest (or high point) forming in a circular pattern around where the stone struck the water, followed by a trough (or low point) behind it. Most often, a series of crests-and-troughs are produced: what physicists understand as a wave or a wave pattern. These waves are disturbances in the water itself: the water serves as a medium for this wave to travel through, and the wave propagates at a particular speed dependent on the properties of the water itself.

***

"Although there are many types of waves we encounter in our daily lives — sound waves, water waves, seismic waves, etc. — these are all examples of the same class of wave: traveling waves, which propagate across or through a medium, as opposed to standing waves. Water waves travel through the body of water itself; seismic waves on our planet travel through the Earth; sound waves typically travel through the air. The sensation of hearing arises when that air, full of compressions (peaks) and rarefactions (troughs) in density, then pushes against our eardrums, causing the hairs within our cochlea to vibrate, stimulating the nerves that detect sound.

***

"If light travels through a medium, and Earth is in motion, then we should be able to detect that motion with a sensitive enough experiment. That’s precisely what the Michelson-Morely experiments did in the 1880s: the same experiment we thought about with water ripples created in a river, but with light and the moving Earth rather than with water and a flowing river.

"Remarkably, the experiments found no evidence for this medium — or any medium — at all. Light traveled neither slower nor faster whether it moved with, against, or perpendicular to the Earth; it traveled at the same speed (the speed of light) no matter what experiment was performed.

***

"Einstein’s great insight was to consider the Cheshire Cat-like possibility that the medium does not exist! This was the great insight of special relativity: that light didn’t travel through a medium like other waves, where the motion of the medium (or the motion of the observer relative to the light wave) would change the wave’s speed. Instead, the speed of light itself was the constant, unchanging, universal property, and while a moving observer might see the light’s crests-and-troughs passing them more or less frequently dependent on their motion, the speed of light itself never changed.

"Ten years later, in 1915, Einstein incorporated gravity into the theory of relativity: giving rise to general relativity. Similar to how light is a wave in the electromagnetic field — even though the field itself can have any value, including zero, and even though there’s no medium needed for it to travel through — the gravitational field can have waves in it too: gravitational waves. Once again, as gravitational waves propagate, they can do so:

"...through any gravitational field, including in places where the gravitational field is zero,
and always move at the same speed — the speed of gravity — regardless of the motion of the source or the observer. As with light, there’s no evidence for the existence of a medium that appears in any experiment or observation, even though we’ve now detected hundreds of gravitational waves directly.

***

"Empty space (or spacetime) is certainly “real” in the sense that it exists; it’s where everything in the Universe lives! We’re certain that a medium isn’t necessary, and that if space itself is such a medium, it doesn’t have any of the traditional properties that we associate with any other known medium. All massless waves — light waves, gravitational waves, even gluon waves — travel at the same speed, as the speed of light and the speed of gravity are equal, but whether this is a hint of an underlying medium or just a fact of reality remains undetermined.

***

"It still may be the case that there is a medium, or some type of unknown aether, that truly does underlie all of reality, but if it does, we have no evidence for it. Nature is telling us that we have waves propagating in our Universe without the need for a medium at all: the most mysterious Cheshire Cat we’ve ever encountered."

Comment: space may be empty as far as a medium material is concerned but remember, it is filled with virtual particles according to quantum theory, popping into and out of existence all the time. Obviously God works as a quantum mechanic.

https://mail.google.com/mail/u/0/#inbox/FMfcgzQXKWkpMLZFMXTdkJFfZbJhhLjz

"In 2013, an asteroid exploded just 15 miles above Earth’s surface, creating a huge fireball that briefly outshone the sun in the sky. The resulting shock wave shattered windows in the nearest town, more than 40 miles away in Chelyabinsk, Russia. The impactor had escaped detection by astronomers.

"What's new: Since the 2013 impact, scientists have discovered an additional 200,000 near-Earth asteroids, more than had been found in all of history up to 2013. In 2022 NASA’s Double Asteroid Redirection Test (DART) slammed a spacecraft into a small asteroid and slowed its orbit by about a half hour, successfully altering the cosmic body’s trajectory.

"The future: The Chelyabinsk asteroid took us by surprise but it won’t be the last, writes Phil Plait, astronomer and science communicator. Bigger impactors are rare, but we’re sharpening our detectors and tools to be able to deal with them. In fact, “thanks to new projects such as NEO Surveyor and the Vera Rubin Observatory, within a decade or two we’ll have found upward of 90 percent of the asteroids that may threaten Earth in the next hundred years,” says science journalist Robin George Andrews, who this year published a new book, How to Kill an Asteroid: The Real Science of Planetary Defense."

Comment: the Chixculub asteroid demonstrated how dangerous they are. If we are on our way to 90% detection, we are in good shape to protect ourselves. dhw will ask why God allowed this menace. The answer is our planet came from accretion of many planetoid bodies like the asteroids. Earth would not exist without them. Then dhw will ask why God did not do it differently for safety. Perhaps by some other method. The possibility is there is no other method, but dhw continuously knows better than God.

https://www.sciencealert.com/giant-study-confirms-the-milky-way-really-is-an-unusual-ga...

"...new research that examines 101 of the Milky Way's kin shows how it differs from them.

"One powerful way to understand things is to compare and contrast them with others in their class, a technique we learn in school. Surveys are an effective tool to compare and contrast things, and astronomical surveys have contributed an enormous amount of foundational data towards the effort.

***

"The studies are all based on 101 galaxies similar in mass to the Milky Way, and each study tackles a different aspect of comparing those galaxies to ours.

"The SAGA Survey. III. A Census of 101 Satellite Systems around Milky Way–mass Galaxies
The SAGA Survey. IV. The Star Formation Properties of 101 Satellite Systems around Milky Way–mass Galaxies

The SAGA Survey. V. Modeling Satellite Systems around Milky Way–Mass Galaxies with Updated Universe Machine

"Research shows that galaxies form inside gigantic haloes of dark matter, the elusive substance that doesn't interact with light. 85% of the Universe's matter is mysterious dark matter, while only 15% is normal or baryonic matter, the type that makes up planets, stars, and galaxies.

***

"The comparison between the Milky Way and the 101 others revealed some significant differences.

"'Our results show that we cannot constrain models of galaxy formation just to the Milky Way," said Wechsler, who is also professor of particle physics and astrophysics at the SLAC National Accelerator Laboratory.

"'We have to look at that full distribution of similar galaxies across the universe."

"The SAGA Survey's third data release includes 378 satellites found in 101 MW-mass systems, and the first paper focuses on the satellites.

***

"SAGA found that the number of satellites per galaxy ranges from zero to 13. According to the first paper, the mass of the most massive satellite is a strong predictor of the abundance of satellites.

"One-third of the SAGA systems contain LMC-mass satellites, and they tend to have more satellites than the MW," the paper states. The Milky Way is an outlier in this regard, which is one reason it's atypical.

"The second study focuses on star formation in the satellites. The star formation rate (SFR) is an important metric in understanding galaxy evolution.

"The research shows that star formation is still active in the satellite galaxies, but the closer they are to the host, the slower their SFR. Is it possible that the greater pull of the dark matter halo close to the galaxy is quenching star formation?

"Our results suggest that lower-mass satellites and satellites inside 100 kpc are more efficiently quenched in a Milky Way–like environment, with these processes acting sufficiently slowly to preserve a population of star-forming satellites at all stellar masses and projected radii," the second paper states.

"However, in the Milky Way's satellites, only the Magellanic Clouds are still forming stars, with radial distance playing a role.

"'Now we have a puzzle," Wechsler said.

"'What in the Milky Way caused these small, lower-mass satellites to have their star formation quenched? Perhaps, unlike a typical host galaxy, the Milky Way has a unique combination of older satellites that have ceased star formation and newer, active ones – the LMC and SMC – that only recently fell into the Milky Way's dark matter halo.'"

"This is another reason that our galaxy is atypical."

Comment: this is another study showing the Milky Way is very unusual. I think it is because we are here protected by God.

https://www.newscientist.com/article/mg26435180-800-the-universe-could-vanish-at-any-mo...

"...there is a more immediate cataclysm that may already be barrelling towards us at the speed of light: they call it the big slurp.

"The slurp in question starts with a quantum fluctuation that sets a bubble rolling across the universe like a cosmic tidal wave, obliterating everything in its path. We should take this possibility seriously, says John Ellis at King’s College London. In fact, it is less a matter of if this apocalypse will play out, but when. “It could happen while we’re talking,” he says.

"Theorists like Ellis are actually surprised that such a catastrophe hasn’t already occurred in the observable universe. But rather than taking our precarious existence for granted, they are using the plain fact we are still here as a tool. The thinking is that there could be some exotic physics preserving us.

***

"The Higgs had been hypothesised for decades, but we were in for a surprise when the particle was finally measured at CERN’s Large Hadron Collider (LHC) near Geneva in 2012. The result suggested that the Higgs field isn’t stable because it isn’t in its lowest possible energy state. We know that objects like atoms or particles tend to want to minimise their energy, so in theory the Higgs could suddenly drop to its lowest possible state in a process known as a phase transition.

***

"As a bubble formed, the quantum fields inside would suddenly shift, effectively rewriting the laws of physics and creating chaos. Terrifyingly, the bubbles would expand at light speed, swallowing everything around them.

"The appearance of this apocalyptic bubble comes down to chance. As an analogy, imagine the Higgs field is a ball at the top of a hill that has several valleys of differing heights beneath it. The ball could roll down into one of the higher valleys and stay there happily, while still not being at the lowest possible point. This is the situation the Higgs field is in now, which we call a “metastable state”. A ball in such a valley can’t roll out of it without a kick. But because this field conforms to the rules of the quantum world, it can mysteriously “tunnel” to a lower valley, or energy state. This is a quantum process akin to a ghost walking through a wall. We can make estimates for how likely the Higgs field is to do this in a given time period, but we can’t predict exactly when it will occur.

***

"Recent measurements of these particles at the LHC aren’t comforting. Aside from the Higgs itself, the heaviest known fundamental particle, called the top quark, has the greatest influence on the stability of the Higgs field. The heavier it is, the less stable the field is. In recent years, as measurements of the top quark mass have become more precise, it has become clearer that the Higgs is – according to the standard model – metastable. “The measurements are now so good that we pretty much know that we are in that metastable range,” says Rajantie.

"Assuming there’s no mistake, the universe is doomed – we just don’t know when the big slurp will happen. Based on the shape of these valleys, it is likely to be in billions of years. But it could be tomorrow.

***

"There is, however, an alternative explanation for why the Higgs field hasn’t transitioned. Despite the precise measurements of the top quark and the Higgs boson, we can’t be certain that the Higgs is in a precarious metastable state after all. It might be that there are unknown particles and forces stabilising the Higgs field in a way that protects us from the big slurp. “If there’s some other particle that comes into play at some higher energy, then that will change the story again – we just don’t know yet,” says Katy Clough at Queen Mary University of London.

***

"The alternative, he says, is to resort to “special pleading” arguments, whereby most of the cosmos already flopped into its lowest-energy state, but a few regions, such as ours, were left in a metastable state on the brink of collapse. In this view, a metastable state is necessary for life, so we must find ourselves living in one of these precarious patches. (my bold)

***

"But for all that the end of the universe depends on the whims of the Higgs, we may well owe our existence to it in the first place. Last year, Clough and her colleagues published research suggesting that quantum tunnelling effects could prevent a contracting universe from collapsing in a big crunch. In their model, this contraction squeezes a Higgs-like field in such a way that its lowest-energy state becomes negative. This would cause a collapsing universe to bounce outwards, creating a new, expanding universe perhaps not unlike our own."

comment: We have been here 13.78 billion years. That is stability despite all the smoke and mirrors in current far out cosmology. My thought is not to worry, but this is a theoretical area that is fun to learn about.

"...the Milky Way is only one system and may not be typical of how other galaxies formed. That's why it's critical to find similar galaxies and compare them."

"To achieve that goal, Wechsler cofounded the Satellites Around Galactic Analogs (SAGA) Survey dedicated to comparing galaxies similar in mass to the Milky Way.

"After more than a decade of scanning the universe, the SAGA team identified and studied 101 Milky Way-like analogs as a first step in its ongoing research. The results, published in three studies in the Nov. 18 issue of The Astrophysical Journal, reveal that, in many ways, the evolutionary history of the Milky Way is different from other comparable-sized galaxies.

"'Our results show that we cannot constrain models of galaxy formation just to the Milky Way," said Wechsler, who is also professor of particle physics and astrophysics at the SLAC National Accelerator Laboratory. "We have to look at that full distribution of similar galaxies across the universe."

***

"Studies show that galaxies form inside massive regions of dark matter called halos. A dark matter halo may be invisible, but its enormous size creates a gravitational force strong enough to pull in ordinary matter from space and transform it into stars and galaxies.

"A key objective of the SAGA Survey is to determine how dark matter halos impact galactic evolution. To begin, the SAGA team focused on galactic satellites—small galaxies that orbit much larger host galaxies like the Milky Way.

"The researchers identified four of the Milky Way's brightest satellite galaxies, including the two biggest, known as the Large and Small Magellanic Clouds (LMC and SMC). The scientists then conducted a painstaking search for satellites around other host galaxies similar in mass. Using telescopic imaging, they eventually identified 378 satellite galaxies surrounding 101 Milky Way-like hosts.

***

"In one of the three new SAGA studies, researchers found that the number of satellites per host galaxy ranges from 0 to 13. The Milky Way's four observable satellites fit within that range.

"The study also revealed that host galaxies with large satellites, similar in size to the Milky Way's massive LMC and SMC galaxies, tend to have more satellites overall. But the Milky Way actually hosts fewer satellites than similar galaxies, making it an outlier among its peers.

"A second study focused on star formation in satellite galaxies—an important metric for understanding how galaxies evolve. The study found that in a typical host galaxy, smaller satellites are still forming stars. But in the Milky Way, star formation only occurs in the massive LMC and SMC satellites. All the smaller satellites have stopped forming stars.

"'Now we have a puzzle," Wechsler said. "What in the Milky Way caused these small, lower-mass satellites to have their star formation quenched? Perhaps, unlike a typical host galaxy, the Milky Way has a unique combination of older satellites that have ceased star formation and newer, active ones—the LMC and SMC—that only recently fell into the Milky Way's dark matter halo."

"The study also found that star formation typically stops in satellite galaxies located closer to the host, perhaps because of the gravitational pull of dark matter halos in and around the host galaxy.

"'To me, the frontier is figuring out what dark matter is doing on scales smaller than the Milky Way, like with the smaller dark matter halos that surround these little satellites," Wechsler said.

"The third study, led by Stanford doctoral scholar Yunchong "Richie" Wang, compares the new data to computer simulations and calls for the development of a new model of galaxy formation based in part on the SAGA Survey."

Comment: as usual the Milky Way stands out as unusual. From the designer standpoint the Milky Way must protect the Earth and that explains the differences.

https://www.sciencedaily.com/releases/2024/10/241016115629.htm

"An international team led by three researchers...has successfully demonstrated that 70% of all known meteorite falls originate from just three young asteroid families. These families were produced by three recent collisions that occurred in the main asteroid belt 5.8, 7.5, and about 40 million years ago. The team also revealed the sources of other types of meteorites; with this research, the origin of more than 90% of meteorites has now been identified. This discovery is detailed in three papers.

***

"While more than 70,000 meteorites are known, only 6% had been clearly identified by their composition (achondrites) as coming from the Moon, Mars, or Vesta, one of the largest asteroids in the main belt. The source of the other 94% of meteorites, the majority of which are ordinary chondrites2, had remained unidentified.

"Why are these three young families the source of so many meteorites?

"This can be explained by the life cycle of asteroid families. Young families are characterised by an abundance of small fragments left over from collisions. This abundance increases the risk of collisions between fragments and, coupled with their high mobility, their escape from the belt, possibly in the direction of Earth. The asteroid families produced by older collisions, on the other hand, are "depleted" sources of meteorites. The abundance of small fragments that once made them up has naturally eroded and finally disappeared after tens of millions of years of successive collisions and their dynamic evolution. Thus, Karin, Koronis and Massalia will inevitably coexist with new sources of meteorites from more recent collisions and eventually give way to them.

***

"Thanks to this research, the origin of more than 90% of meteorites has now been identified. It has also enabled scientists to trace the origin of kilometre-sized asteroids (a size that threatens life on Earth). These objects are the focus of many space missions (NEAR Shoemaker, Hayabusa1, Chang'E 2, Hayabusa2, OSIRIS-Rex, DART, Hera, etc.). In particular, it appears that the asteroids Ryugu and Bennu, recently sampled by the Hayabusa2 (Japanese Aerospace Exploration Agency JAXA) and OSIRIS-REx (NASA) missions and studied in laboratories around the world, particularly in France, are derived from the same parent asteroid as the Polana family."

Comment: the more we learn is vital. The big ones, kilometer-size, are every dangerous to us. Maybe God is not so perfect at all! OR, this is the way it had to be as we see in the issue of why life has so many problems. Can there be limits God cannot traverse?

"If you want to pinpoint your place in the Universe, start with your cosmic address. You live on Earth->Solar System->Milky Way Galaxy->Local Cluster->Virgo Cluster->Virgo Supercluster->Laniakea. Thanks to new deep sky surveys, astronomers now think all those places are part of an even bigger cosmic structure in the “neighborhood” called The Shapley Concentration.

"Astronomers refer to the Shapley Concentration as a “basin of attraction”. That’s a region loaded with mass that acts as an “attractor”. It’s a region containing many clusters and groups of galaxies and comprises the greatest concentration of matter in the local Universe. All those galaxies, plus dark matter, lend their gravitational influence to the Concentration. There are many of these basins in the Universe, including Laniakea. Astronomers are working to survey them more precisely, which should help provide a more precise map of the largest structures in the Universe.

"One group, led by astronomer R. Brent Tully of the University of Hawai’i measured the motions of some 56,000 galaxies to understand these basins and their distribution in space. “Our universe is like a giant web, with galaxies lying along filaments and clustering at nodes where gravitational forces pull them together,” said Tully. “Just as water flows within watersheds, galaxies flow within cosmic basins of attraction. The discovery of these larger basins could fundamentally change our understanding of cosmic structure.”

"Tully’s team is called CosmicFlows and they study the motions through space of those distant galaxies. The team’s “redshift” surveys revealed a possible shift in the size and scale of our local galactic basin of attraction. We already know that we “live” in Laniakea, which is about 500 million light-years across. However, the motions of other clusters indicate there’s a larger “attractor” directing the cluster flow. The CosmicFlows data suggest that we could be part of the Shapley Concentration, which could be 10 times the volume of Laniakea. It’s about half the volume of the largest structure in space, known as “the Great Wall”, which is a string of galaxies stretching across 1.4 billion light-years.

***

"The main actor in all these galaxies, clusters, and superclusters, is gravity. The more mass, the more gravity influences motions and matter distribution. For these basins of attraction, Tully’s research team examined their impact on galaxy motions in the region. The basins exert a sort of “tug of war” on galaxies that lie between them. That influences their motions. In particular, redshift surveys like Tully’s team is doing will map the radial motion (along the line of sight), velocities (how fast they’re moving), and other related motions. By mapping the velocities of galaxies throughout our local Universe, the team can define the region of space where each supercluster dominates.

Comment: we are the red dot in one of the illustrations. Be sure to see them to understand the text. It shows how gravity is the magic sculptor of these massive structures. And it comes back to dhw's wonderment-questioning about the universe's enormous size and structure. He asks why God made it so big if we humans are His purpose.

https://www.sciencealert.com/giant-magnetic-halo-discovered-wrapped-around-the-milky-wa...

"By studying hot gas glowing in circumgalactic space, astrophysicists have found evidence of enormous magnetic fields that wind through and around our galaxy's dark matter 'halo'.

"'This work provides the first detailed measurements of the magnetic fields in the Milky Way's X-ray emitting halo and uncovers new connections between star-forming activities and galactic outflows," explains astrophysicist He-Shou Zhang of the National Institute for Astrophysics (INAF) in Italy.

"'Our findings show that the magnetic ridges we observed are not just coincidental structures but are closely related to the star-forming regions in our galaxy."

"The study was performed on the X-ray light emitted by two huge structures that extend above and below the plane of the Milky Way. Discovered in 2020, these 'eROSITA bubbles' extend more than 45,000 light-years either side of the galactic center. They're powered by huge outflows of gas and plasma; shocks in this medium cause the bubbles to glow brightly in the X-ray range.

***

"Light, when it travels through a magnetic field, becomes oriented according to the direction of the magnetic field in what's referred to as polarization. We can examine the light collected by our telescopes to see not just evidence of its polarization, but the direction of the magnetic field that produced it.

"When the researchers studied the polarization of the broad spectrum of light emitted by the eROSITA bubbles, they found huge, long filaments of magnetization. If we could see these filaments with our eyes, they would stretch across the sky up to 150 times longer than the width of a full Moon, the researchers say.

"And the filaments suggest that the origin of the eROSITA bubbles was star formation. [eROSITA is the name of the instrument.] At a distance between around 10,000 and 16,000 light-years from the galactic center, a ring of star formation could have produced the heat and winds that caused hot gas and plasma to billow out into the galactic halo over a distance of tens of thousands of light-years and counting.

***

"'What I find fascinating in this case is to note that even the Milky Way, a quiescent galaxy like many others, can expel powerful outflows, and in particular that the star formation ring at the end of the rotational center contributes significantly to the galactic outflow. Perhaps the Milky Way is revealing to us a phenomenon common in galaxies similar to ours, thus helping us to shed light on the growth and evolution of these objects."

"It is not a certainty, of course; it's going to take a lot more analysis to make a solid determination on the source of the bubbles. The team's findings are consistent with recent simulations, but more detailed ones will be needed to determine whether star formation can produce the kinds of outflows we observe in the eROSITA bubbles.

"But the magnetic fields represent a significant piece of the puzzle.

"'The study opens new frontiers in our understanding of the galactic halo," Zhang says, "and will contribute to deepening our knowledge of the complex and dynamic star-forming ecosystem of the Milky Way.'"

Comment: not so quiescent. Our galaxy has lots of processes in very active ways. The Earth is placed in a very quiet spot two-thirds of the way out the second spiral arm.

https://phys.org/news/2024-10-earliest-galaxies-amazingly-fast-big.html

"...observations from JWST agree with our current understanding of cosmology—the scientific discipline that aims to explain the universe—and of galaxy formation. But they also reveal aspects we didn't expect. Many of these early galaxies shine much more brightly than we would expect given that they existed just a short time after the Big Bang.

"Brighter galaxies are thought to have more stars and more mass. It was thought that much more time was needed for this level of star formation to take place. These galaxies also have actively growing black holes at their centers—a sign that these objects matured quickly after the Big Bang. So how can we explain these surprising findings? Do they break our ideas of cosmology or require a change to the age of the universe?

***

"Our understanding of cosmology and galaxy formation rests on a few fundamental ideas. One of these is the cosmological principle, which states that, on a large scale, the universe is homogeneous (the same everywhere) and isotropic (the same in all directions). Combined with Einstein's theory of general relativity, this principle allows us to connect the evolution of the universe—how it expands or contracts—to its energy and mass content.

"The standard cosmological model, known as the "Hot Big Bang" theory, includes three main components, or ingredients. One is the ordinary matter that we can see with our eyes in galaxies, stars and planets. A second ingredient is cold dark matter (CDM), slow-moving matter particles that do not emit, absorb or reflect light.

"The third component is what's known the cosmological constant (Λ, or lambda). This is linked to something called dark energy and is a way of explaining the fact that the expansion of the universe is accelerating. Together, these components form what is called the ΛCDM model of cosmology.

***

"While dark matter and dark energy remain mysterious, the ΛCDM model of cosmology is supported by a wide range of detailed observations. These include the measurement of the universe's expansion, the cosmic microwave background, or CMB (the "afterglow" of the Big Bang) and the development of galaxies and their large-scale distribution—for example, the way that galaxies cluster together.

"The ΛCDM model lays the groundwork for our understanding of how galaxies form and evolve. For example, the CMB, which was emitted about 380,000 years after the Big Bang, provides a snapshot of early fluctuations in density that occurred in the early universe. These fluctuations, particularly in dark matter, eventually developed into the structures we observe today, such as galaxies and stars.

***

"One of the simpler models of galaxy formation assumes that the rate at which stars form in a galaxy is directly tied to gas flowing into those galaxies. This model also proposes that the star formation rate in a galaxy is proportional to the rate at which dark matter halos grow. It assumes a fixed efficiency at converting gas into stars, regardless of cosmic time.

"This "constant star formation efficiency" model is consistent with star formation increasing dramatically in the first billion years after the Big Bang. The rapid growth of dark matter halos during this period would have provided the necessary conditions for galaxies to form stars efficiently. Despite its simplicity, this model has successfully predicted a wide range of real observations, including the overall rate of star formation across cosmic time.

***

"In the first year of JWST's operation, it was claimed that some of the earliest galaxies had extremely high stellar masses (the masses of stars contained within them) and a change in cosmology was needed to accommodate bright galaxies that existed in the very early universe. They were even dubbed "universe-breaker" galaxies.

"Soon after, it was clear that these galaxies do not break the universe, but their properties can be explained by a range of different phenomena. Better observational data showed that the distances to some of the objects were overestimated (which led to an overestimation of their stellar masses).

"The emission of light from these galaxies can be powered by sources other than stars, such as accreting black holes. Assumptions in models or simulations can also lead to biases in the total mass of stars in these galaxies.

"As JWST continues its mission, it will help scientists refine their models and answer some of the most fundamental questions about our cosmic origins. It should unlock even more secrets about the universe's earliest days, including the puzzle of these bright, distant galaxies."

Comment: the more we see, the more we learn and have to modify theories and models. Not at all surprising. In a fast-moving areas of study like this one theories have to be liquid, not fixed. We still do not know why the universe has to be as it is. I assume it is all purposeful.

https://www.sciencealert.com/a-nearby-supernova-may-have-sparked-diverse-life-on-earth?...

"Supernovae explosions are responsible for creating some of the heavy elements, including iron, which is blasted out into space by the explosion.

"On Earth, there are two accumulations of the iron isotope Fe60 in seafloor sediments that scientists trace back about two or three million years ago and about five to six million years ago.

"The explosions that created the iron also dosed Earth with cosmic radiation.

***

"'Life on Earth is constantly evolving under continuous exposure to ionizing radiation from both terrestrial and cosmic origin," the authors write.

"Terrestrial radiation slowly decreases over billions of years. But not cosmic radiation. The amount of cosmic radiation that Earth is exposed to varies as our Solar System moves through the galaxy.

"'Nearby supernova (SN) activity has the potential to raise the radiation levels at the surface of the Earth by several orders of magnitude, which is expected to have a profound impact on the evolution of life," they write.

"The authors explain that the two million-year-old accumulation is directly from a supernova explosion, and the older accumulation is from when Earth passed through a bubble.

"The bubble in the study's title comes from a particular type of star called OB stars. OB stars are massive, hot, and short-lived stars that usually form in groups.

"These stars emit powerful outflowing winds that create "bubbles" of hot gas in the interstellar medium. Our Solar System is inside one of these bubbles, called the Local Bubble, which is almost 1,000 light-years wide and was created several million years ago.

"The Earth entered the Local Bubble about five or six million years ago, which explains the older Fe60 accumulation. According to the authors, the younger Fe60 accumulation from two or three million years ago is directly from a supernova.

"'It is likely that the 60Fe peak at about 2-3 Myr originated from a supernova occurring in the Upper Centaurus Lupus association in Scorpius Centaurus (~140 pc) or the Tucana Horologium association (~70 pc). Whereas the ~ 5-6 Myr peak is likely attributed to the Solar System's entrance into the bubble," the authors write.

"The Local Bubble is not a quiet place. It took multiple supernovae to create it. The authors write that it took 15 SN explosions over the last 15 million years to create the LB.

"'We know from the reconstruction of the LB history that at least 9 SN exploded during the past 6 Myrs," they write.

"The researchers took all the data and calculated the amount of radiation from multiple SNs in the LB.

"'It is not clear what would the biological effects of such radiation doses be," they write, but they do discuss some possibilities.

"The radiation dosage may have been strong enough to create double-strand breaks in DNA. This is severe damage and can lead to chromosomal changes and even cell death. But there are other effects in terms of the development of life on Earth.

"'Double-strand breaks in DNA can potentially lead to mutations and jump in the diversification of species," the researchers write. A 2024 paper showed that "the rate of virus diversification in the African Tanganyika lake accelerated 2-3 Myr ago." Could this be connected to SN radiation?

"'It would be appealing to better understand whether this can be attributed to the increase in cosmic-radiation dose we predict to have taken place during that period," the authors tease.

"The SN radiation wasn't powerful enough to trigger an extinction. But it could've been powerful enough to trigger more mutations, which could lead to more species diversification.

***

"The study shows that, whether we can see it in everyday life or not, or even if we're aware of it or not, our space environment exerts a powerful force on Earth's life. SN radiation could have influenced the mutation rate at critical times during Earth's history, helping shape evolution.

"Without supernova explosions, life on Earth could look very different. Many things had to go just right for us to be here. Maybe in the distant past, supernova explosions played a role in the evolutionary chain that leads to us."

Comment: it is fascinating how much information we have about our local area in space. This all part of the way the universe evolved. I assme with God in charge, Her prefers to evolve all of His creations.

https://www.livescience.com/space/earth-once-wore-a-saturn-like-ring-study-of-ancient-c...

"Earth may have had a giant ring of space rocks surrounding it, similar to those around Saturn, which could have led to chaotic meteorite strikes on our planet's surface, new research suggests.

"The hypothesized ring may have formed roughly 466 million years ago and was the remains of a gigantic asteroid tugged apart by Earth's tidal forces after passing our planet's Roche limit.

"Casting a shadow across Earth's equator, the ring may have contributed to a global cooling event by blocking sunlight, while bombarding the surface with meteorites.

***

"'Over millions of years, material from this ring gradually fell to Earth, creating the spike in meteorite impacts observed in the geological record," study lead author Andy Tomkins, a professor of planetary science at Monash University in Australia, said in a statement. "We also see that layers in sedimentary rocks from this period contain extraordinary amounts of meteorite debris."

"The scientists arrived at the startling hypothesis by studying a period in Earth's history known as the Ordovician (485 million to 443 million years ago). The Ordovician was a tumultuous time for our planet — it was one of the coldest periods in the last 500 million years and saw a dramatic uptick in the rate of meteorites striking Earth.

"To investigate what could have caused these effects, the scientists mapped the positions of 21 Ordovician asteroid impact craters, which revealed that all the impacts occurred within 30 degrees of Earth's equator."

Comment: the grouping of the craters is highly suggestive. It could be interpreted as a way to bring deposits of useful materials to Earth for eventual human use.

https://www.universetoday.com/168165/life-needs-black-holes-to-survive/

"Life is rare, and it requires exactly the right environmental mix to establish itself. And there’s one surprising contributor to that perfect mix: gigantic black holes.

"Life requires a certain combination of elements to make itself possible: hydrogen, nitrogen, carbon, oxygen, phosphorus, and sulfur. Hydrogen has been hanging around the universe since the first few minutes of the big bang, but the other elements only come from fusion processes inside of stars. Galaxies need several generations of stellar lives and deaths before a solar system like our own can be possible.

"But left to its own devices, star formation in a galaxy can proceed far too rapidly, burning through material too quickly, the stellar generations coming and going in a blink. One thing that can put the brakes on this kind of out-of-control star formation is the activity tied to supermassive black holes.

"Giant black holes sit in the hearts of almost every single galaxy. Their intense gravitational strength can pull material towards it. The swirl and turbulence of gas will send material careening towards the galactic center, where the waiting black hole is more than eager to devour it. As the gas crams itself down the throat of the vent horizon, it will heat up to over a trillion degrees, releasing a flood of high-energy radiation in the process.

"That radiation floods the rest of the galaxy, heating up the rest of the gas. To make stars, the gas in a galaxy has to be cool, allowing it to collapse to high densities. But if it’s heated by outbursts from the central black hole, it can’t make new stars. After enough time, however, the gas cools off and resumes star formation, and the entire cycle starts again.

"This feedback process from the central black hole keeps star formation in a galaxy regulated. Without the black hole, galaxies would use up their available material much quicker, possibly before the ingredients needed for life can circulate and spread throughout the galaxy."

Comment: every part of a galaxy has reasons to exist. dhw complains God didn't need such a large universe to make life appear for us.