4506 - UNIVERSE'S OLDEST STARS?

 

-    4506  -  UNIVERSE'S  OLDEST  STARS?    -    The oldest stars in the universe were found hiding near the Milky Way's edge.  Astronomers reanalyzed the chemical composition of three stars in the Milky Way's halo and found that they are between 12 and 13 billion years old. They may have also been stolen from other galaxies.

---------  -----------------------  4506  -  UNIVERSE'S  OLDEST  STARS?

-

-    Three alien stars circling the Milky Way could be some of the oldest ever found in the universe.  The ancient celestial objects may have been among the first to form after the Big Bang and were likely stolen by our galaxy during gravitational tugs-of-war billions of years ago.

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-    Researchers reanalyzed three previously observed stars each located around 30,000 light-years from Earth in the Milky Way's halo which is a massive cloud of stars that orbit beyond our galaxy's main galactic disk. The basic chemical composition of these stars suggests they are all between 12 and 13 billion years old, making them almost as old as the universe itself, which formed around 13.8 billion years ago.

-

-    The trio's respective trajectories through the Milky Way also hint that these stars did not originate in our galaxy but were instead stolen from the periphery of some of the universe's oldest galaxies as the Milky Way brushed past them billions of years ago.

-

-    Group of 60 ultra-faint stars orbiting the Milky Way could be new type of galaxy never seen before  The ancient balls of gas, which researchers have dubbed “Small Accreted Stellar System” (SASS) stars, are "part of our cosmic family tree.

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-   Normally, stars this old can only be studied by spying on galaxies from the other side of the known universe or by reverse-engineering ancient stars from their descendants. However, the discovery of ancient stars on our cosmic doorstep gives scientists a rare opportunity to study them directly, and,  researchers are now confident there are more stars like these toward our galaxy's edge.

-

-   The new discovery of the stellar trio, which each had an unusually low abundance of heavy metals such as iron, strontium and barium in its atmosphere.   One of the stars had around 10,000 times less iron than the sun.

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-   These heavy metals are forged over eons in the heart of stars, and are also found in the exteriors of younger stars, which suck up ingredients that were dispersed by exploding dead stars. The fact that this trio has few heavy metals, means they were formed before most other stars had exploded.

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-    The stars' compositions hinted that they did not originate in the Milky Way. But to confirm this, the students traced the orbital trajectories of the three stars and found that they all had a retrograde motion, meaning they are circling our galaxy's supermassive black hole in the opposite direction from a majority of the other stars.

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-    The only way you can have stars going the wrong way from the rest is if you threw them in the wrong way.    These stars were likely ripped from other galaxies by the Milky Way.  nBased on the stars' compositions, researchers also believe that each star was ripped from a different galaxy.

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-   Another 65 retrograde stars have similarly simple compositions. These stars will now be studied further to determine if they are also SASS stars.

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-

June 13, 2024          UNIVERSE'S  OLDEST  STARS?                  4506

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---  to:  ------    jamesdetrick@comcast.net  ------  “Jim Detrick”  -----------

--------------------- ---  Friday, June 21, 2024  ---------------------------------

 

 

 

 

 

           

 

 

UNIVERSE'S EXPANSION RATE - is speeding up?

 

-    4505  -  UNIVERSE'S  EXPANSION  RATE  -  is speeding up?  -    The universe is expanding faster than theory predicts, and physicists are trying to explain the mismatch.   Astronomers have known for decades that the universe is expanding. When they use telescopes to observe faraway galaxies, they see that these galaxies are moving away from Earth.

-------------------------  4505  -   UNIVERSE'S  EXPANSION  RATE  -  is speeding up?

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-    To astronomers, the wavelength of light a galaxy emits is longer the faster the galaxy is moving away from us. The farther away the galaxy is, the more its light has shifted toward the longer wavelengths on the red side of the spectrum, so,  the higher the "redshift."

-

-    Because the speed of light is finite, fast, but not infinitely fast, seeing something far away means we're looking at the thing how it looked in the past. With distant, high-redshift galaxies, we're seeing the galaxy when the universe was in a younger state. So "high redshift" corresponds to the early times in the universe, and "low redshift" corresponds to the late times in the universe.

-

-   But as astronomers have studied these distances, they've learned that the universe is not just expanding, its rate of expansion is accelerating. And that expansion rate is even faster than the leading theory predicts it should be, leaving cosmologists puzzled and looking for new explanations.

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-   Scientists call the source of this acceleration “dark energy”. We're not quite sure what drives dark energy or how it works, but we think its behavior could be explained by a “cosmological constant”, which is a property of spacetime that contributes to the expansion of the universe.

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-   Albert Einstein originally came up with this “constant”.   He marked it with a lambda in his theory of general relativity. With a cosmological constant, as the universe expands, the energy density of the cosmological constant stays the same.

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-   Imagine a box full of particles. If the volume of the box increases, the density of particles would decrease as they spread out to take up all the space in the box. Now imagine the same box, but as the volume increases, the density of the particles stays the same.

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-   It doesn't seem intuitive, right? That the energy density of the cosmological constant does not decrease as the universe expands is, but,  this property helps explain the accelerating universe.

-

-    Right now, the leading theory, or standard model, of cosmology is called "Lambda CDM." Lambda denotes the “cosmological constant” describing dark energy, and CDM stands for “cold dark matter”. This model describes both the acceleration of the universe in its late stages as well as the expansion rate in its early days.

-

-   The Lambda CDM explains observations of the cosmic microwave background, which is the afterglow of microwave radiation from when the universe was in a "hot, dense state" about 300,000 years after the Big Bang. Observations using the Planck satellite, which measures the cosmic microwave background, led scientists to create the Lambda CDM model.

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-   Fitting the Lambda CDM model to the cosmic microwave background allows physicists to predict the value of the Hubble constant, which isn't actually a constant but a measurement describing the universe's “current” expansion rate.

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-   But the Lambda CDM model isn't perfect. The expansion rate scientists have calculated by measuring distances to galaxies, and the expansion rate as described in Lambda CDM using observations of the cosmic microwave background, don't line up. Astrophysicists call that disagreement the “Hubble tension”.

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-   Over the past few years, I've been researching ways to explain this Hubble tension. The tension may be indicating that the Lambda CDM model is incomplete and physicists should modify their model, or it could indicate that it's time for researchers to come up with new ideas about how the universe works.

-

-   One way to explain the Hubble tension is to modify the Lambda CDM model by changing the expansion rate at low redshift, at late times in the universe. Modifying the model like this can help physicists predict what sort of physical phenomena might be causing the Hubble tension.

-

-   For instance, maybe dark energy is not a cosmological constant but instead the result of gravity working in new ways. If this is the case, dark energy would evolve as the universe expands, and the cosmic microwave background, which shows what the universe looked like only a few years after its creation, would have a different prediction for the Hubble constant.

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-   To study what types of solutions could explain the Hubble tension, we developed statistical tools that enabled us to test the viability of the entire class of models that change the expansion rate in the late universe. These statistical tools are very flexible, and we used them to match or mimic different models that could potentially fit observations of the universe's expansion rate and might offer a solution to the Hubble tension.

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-    The models that were tested include evolving dark energy models, where dark energy acts differently at different times in the universe. We also tested interacting dark energy-dark matter models, where dark energy interacts with dark matter, and modified gravity models, where gravity acts differently at different times in the universe.

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-   But none of these could fully explain the Hubble tension. These results suggest that physicists should study the early universe to understand the source of the tension.

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June 21, 2024        UNIVERSE'S  EXPANSION  RATE  -  is speeding up?                4505

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--  email feedback, corrections, request for copies or Index of all reviews

---  to:  ------    jamesdetrick@comcast.net  ------  “Jim Detrick”  -----------

--------------------- ---  Friday, June 21, 2024  ---------------------------------

 

 

 

 

 

           

 

 

4503 - MILKY WAY's BLACKHOLE?

 

-    4503  -   MILKY  WAY's  BLACKHOLE?  -    A new view reveals magnetic fields around our galaxy’s giant Black Hole.   Fresh imagery from the “Event Horizon Telescope” traces the lines of powerful magnetic fields spiraling out from the edge of the supermassive black hole at the center of our Milky Way galaxy, and suggests that strong magnetism may be common to all supermassive black holes.

-------------------------------  4503  -   MILKY  WAY's  BLACKHOLE?

-    The newly released image shows the surroundings of the black hole known as Sagittarius A*, which is about 27,000 light-years from Earth. The pictures rely on radio-wave observations from the Event Horizon Telescope’s network of observatories around the world.

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-   Sagittarius A* wasn’t the first black hole whose shadow was imaged by the EHT.   In 2019, astronomers showed off a similar picture of the supermassive black hole at the center of the galaxy M87, which is more than a thousand times bigger and farther away than the Milky Way’s black hole.

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-   In 2021, the EHT team charted the magnetic field lines around M87’s black hole by taking a close look at the black hole in polarized light, which reflects the patterns of particles whirling around magnetic field lines. Researchers used the same technique to determine the magnetic signature of Sagittarius A*, or Sgr A* .

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-     Making a polarized image is like opening the book after you have only seen the cover. Because Sgr A* moves around while we try to take its picture, it was difficult to construct even the unpolarized image. Some models were far too scrambled and turbulent to construct a polarized image, but nature was not so cruel.

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-    What we’re seeing now is that there are strong, twisted and organized magnetic fields near the black hole at the center of the Milky Way galaxy.  Along with Sgr A* having a strikingly similar polarization structure to that seen in the much larger and more powerful M87* black hole, we’ve learned that strong and ordered magnetic fields are critical to how black holes interact with the gas and matter around them.

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-    The structure of the magnetic fields around Sgr A* suggests that the black hole is launching a jet of material into the surrounding environment. Previous research has shown that to be the case for M87’s black hole.

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-   A computer simulation of the disk of plasma around M87’s supermassive black hole shows how magnetic fields help launch jets of matter at near the speed of light. Scientists say the Milky Way’s black hole appears to be doing something similar.

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-   The fact that the magnetic field structure of M87* is so similar to that of Sgr A* is significant because it suggests that the physical processes that govern how a black hole feeds and launches a jet might be universal among supermassive black holes, despite differences in mass, size and surrounding environment.

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-   In the seven years since the EHT began gathering observations, the collaboration has been adding to its array of radio telescopes, which is resulting in the production of higher-quality imagery.  The researchers aim to produce high-fidelity movies of Sgr A* that may reveal a hidden jet. They’ll also look for evidence of similar polarization features around other supermassive black holes.

-

-

June 20, 2024              MILKY  WAY's  BLACKHOLE?                    4503

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---  to:  ------    jamesdetrick@comcast.net  ------  “Jim Detrick”  -----------

--------------------- ---  Friday, June 21, 2024  ---------------------------------

 

 

 

 

 

           

 

 

4502 - MILKY WAY'S - wrinkles with age?

 

-    4502  -     MILKY  WAY'S  -  wrinkles with age?   -  The Milky Way's last major act of galactic cannibalism was surprisingly recent.  We get wrinklier as we age   For the Milky Way it is getting less wrinkly over time.

---------------------------------  4502  -  MILKY  WAY'S  -  wrinkles with age?

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-   New findings from the Gaia space telescope indicate the Milky Way may have cannibalized a small galaxy not too long ago.   The last major collision between our galaxy and another seems to have occurred billions of years later than previously suspected.

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-    The Milky Way has been long understood to have grown via a series of violent collisions, which see smaller galaxies ripped apart by the immense gravitational influence of our solar system's spiral home.

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-   These collisions distribute stars from the devoured galaxy across the halo that surrounds the main disk of the Milky Way and its distinctive spiral arms. These bouts of galactic cannibalism also send "wrinkles" rippling through the Milky Way that affect different "families" of stars, with different origins, in different ways.

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-    With its ability to precisely pinpoint the position and motion of over 100,000 stars local to the solar system within the full catalog of stellar bodies in monitors, Gaia aims to retell the history of the Milky Way by counting its wrinkles. 

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-   By looking at how these wrinkles dissipate over time, we can trace when the Milky Way experienced its last big crash, and, it turns out this happened billions of years later than we thought.

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-   These galactic wrinkles were only discovered by Gaia in 2018; this marks the first time they have been extensively researched to reveal the timing of the collision that created them.   The halo of our galaxy is populated with stars that have strange orbits, with many of these believed to be the "leftovers" of galaxies the Milky Way once devoured.

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-    Many of those stars are believed to be the wreckage of the so-called "last major merger," referring to the last time the Milky Way experienced a significant collision with another galaxy. Scientists think this final major collision may have involved a massive dwarf galaxy, and the event is known as the “Gaia-Sausage-Enceladus” (GSE) merger.

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-    It is thought to have infused the Milky Way with stars on orbits that bring them close to the Galactic Center. The GSE event is thought to have happened between eight and 11 billion years ago when the Milky Way was in its infancy.

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-    The Gaia observations of these strangely orbiting stars, released as part of the space telescope's Data Release 3 in 2022, indicate these odd stellar bodies could have been deposited by a different merger event.

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-    We can see how the shapes and number of wrinkles change over time using these simulated mergers. This lets us pinpoint the exact time when the simulation best matches what we see in real Gaia data of the Milky Way today.   By doing this, we found that the wrinkles were likely caused by a dwarf galaxy colliding with the Milky Way around 2.7 billion years ago. We named this event the “Virgo Radial Merger."

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-    For the wrinkles of stars to be as clear as they appear in Gaia data, they must have joined us less than three billion years ago — at least five billion years later than was previously thought. If they'd joined us eight billion years ago, there would be so many wrinkles right next to each other that we would no longer see them as separate features.

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-   This result that a large portion of the Milky Way only joined us within the last few billion years is a big change from what astronomers thought up until now.  Many popular models and ideas about how the Milky Way grows would expect a recent head-on collision with a dwarf galaxy of this mass to be very rare.

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-   They think that the Virgo Radial Merger brought to our galaxy a family of other small dwarf galaxies and star clusters, all of which would also have been devoured by the Milky Way at around the same time.

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-   This new research is the latest in a treasure trove of results emerging from Gaia data that are rewriting the history of the Milky Way.   Such cosmic revisionism has been made possible thanks to Gaia's unique ability to explore a vast number of stars over Earth, allowing the space telescope to compile an unrivaled map of the positions, distances and motions of around 1.5 billion stars thus far.

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-    Our picture of the Milky Way's past has changed dramatically from even a decade ago, and our understanding of these mergers will continue to change rapidly.

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June 19, 2024           MILKY  WAY'S  -  wrinkles with age?                        4502

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--------  Comments appreciated and Pass it on to whomever is interested. ---

---   Some reviews are at:  --------------     http://jdetrick.blogspot.com ----- 

--  email feedback, corrections, request for copies or Index of all reviews

---  to:  ------    jamesdetrick@comcast.net  ------  “Jim Detrick”  -----------

--------------------- ---  Wednesday, June 19, 2024  ---------------------------------

 

 

 

 

 

           

 

 

4501 - PARTICLE ACCELERATORS - smashing atoms together?

 

-    4501 -  PARTICLE  ACCELERATORS  -  smashing atoms together?

---------------  4501  -  PARTICLE  ACCELERATORS  -  smashing atoms together?

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-   What do we learn by smashing atomic particles together?    It turns ot that much of what physicists know about the fundamental laws of nature has come from building machines to bash particles together.

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-    Physicists began developing particle colliders in the wake of revelations that there was more to the universe than atoms. Ernest Rutherford glimpsed inside the atom in one of the earliest proto-collider experiments in 1909.

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-    Rutherford  and his student put some radioactive material behind a lead shield with a hole in it, so that a stream of alpha particles (now known to be helium nuclei) could shoot through the hole. When they pelted a thin gold foil with this beam of particles, they observed that one in 20,000 bounced straight backward.

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-     Rutherford likened it to an artillery shell reflecting off a sheet of tissue paper. The physicists had discovered that the gold atoms were mostly empty space, but that the alpha particles were occasionally scattering off the atoms’ dense, positively charged nuclei.

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-   Two of Rutherford’s students, John Cockcroft and Ernest Walton, went on to assemble and operate the first proper particle collider in 1932. They used an electric field to speed up protons and slam them into lithium atoms with enough energy to break the lithium atoms in two, splitting the atom for the first time.

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-    In the following decades, physicists built a parade of increasingly capable particle colliders. They increased the density of the projectile particles, added superconducting magnets to steer them better, and bought themselves more runway by designing circular colliders. To produce more violent fireworks, they smashed together beams of particles circulating in opposite directions.

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-    Many of the technological innovations came in pursuit of higher-energy collisions for generating richer varieties of particles. All the matter you’ve ever seen or touched is made up of just three lightweight, fundamental particles: electrons and two types of quarks. Nature allows more than a dozen heavier elementary particles to exist as well, but only for a flash before they transmute into light, stable ones.

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-    To learn what massive particles can exist, physicists leverage the interchangeability of matter and energy discovered by Albert Einstein, expressed in his famous equation, E = mc^2. By generating more energetic collisions, they see heavier particles pop out.

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-    Another way to think of it is that higher-energy collisions push deeper into the subatomic world. All quantum particles have wavelike properties, or wavelengths. And their wavelengths determine what they can interact with.

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-    Sound waves can get around walls because they’re meters long while light waves get stopped by anything larger than their wavelength of a few hundred nanometers. The incredibly tiny waves involved in high-energy collisions are sensitive to equally tiny quantum obstacles. In this way, higher energies let physicists explore the rules of reality at smaller and smaller scales.

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-    The energy of particle collisions increased 10 times every six to eight years for the better part of a century, nearly matching the pace of Moore’s law for computer chips. That progress culminated in the construction of the Large Hadron Collider (LHC) in Europe, a circular underground track 27 kilometers in circumference that crashes protons together at energies some 20 million times higher than what Cockcroft and Walton used to split the atom.

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-    It was at the LHC in 2012 that physicists discovered the Higgs boson, a heavy particle that gives other fundamental particles mass. The Higgs was the final missing piece of the Standard Model of particle physics, a set of equations that accounts for all known elementary particles and their interactions.

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-    The LHC has seen no sign of the particles predicted by supersymmetry, and in 2016 proponents of the theory conceded a bet, acknowledging that our universe is not supersymmetric in the simple way they had thought. The same year, a hint of a new particle turned out to be a statistical mirage, and physicists had to confront the fact that the LHC probably won’t uncover any new phenomena beyond the particles of the Standard Model.

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-    Without hints pointing to the existence of heavier particles that could be conjured up in higher-energy collisions, the case for building another, even bigger multibillion-dollar particle collider is hard to make. Some insist it’s worth doing because there’s still plenty to investigate about the Higgs boson, which might hold clues about any heavier entities beyond the LHC’s reach.

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-   A proposal to construct a next-generation collider in Japan has stalled. Europe is mulling a 100-kilometer successor to the LHC, but if approved and funded, it will take so long to build that today’s grad students will be long retired before it switches on.

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-   American particle physicists got some optimistic news last December when a government panel supported studying the prospects of a muon collider. Muons are bulkier versions of electrons that would pack more punch in collisions, while lacking the substructure of protons, so that a relatively small muon collider could achieve clean, high-energy collisions.

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-     A bleeding-edge muon collider could fit into the footprint of an existing facility, the Fermi National Accelerator Laboratory in Illinois, and so could conceivably be built more quickly and affordably. The catch is that muons decay in a few microseconds, and the technology required to create and control narrow beams of them doesn’t exist yet. Still, if the project goes forward, proponents hope that such a device could be operational around the time today’s kindergartners start getting their doctorates.

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-   In the meantime, physicists have little choice but to come up with alternative experiments and novel ways of piecing together the clues that colliders have already given them.

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June 18, 2024     PARTICLE  ACCELERATORS  -  smashing atoms together?       4501

---------------------------------------------------------------------------------------------------------                                                                                                                       

--------  Comments appreciated and Pass it on to whomever is interested. ---

---   Some reviews are at:  --------------     http://jdetrick.blogspot.com ----- 

--  email feedback, corrections, request for copies or Index of all reviews

---  to:  ------    jamesdetrick@comcast.net  ------  “Jim Detrick”  -----------

--------------------- ---  Wednesday, June 19, 2024  ---------------------------------

 

 

 

 

 

           

 

 

4500 - WEBB DISCOVERIES - giving new science?

 

-    4500  -   WEBB  DISCOVERIES  -   giving new science?     The James Webb Space Telescope was launched at the end of 2021.   New evidence arrive at the speed the JWST is delivering it tells us the early universe are in need of a significant update.

------------------------------  4500  -     WEBB  DISCOVERIES  -   giving new science?

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-   The early universe is one of the JWST's primary scientific targets. Its infrared capabilities allow it to see the light from ancient galaxies with greater acuity than any other telescope. The telescope was designed to directly address confounding questions about the high-redshift universe.

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-    The early universe and its transformations are fundamental to our understanding of the universe around us today. Galaxies were in their infancy, stars were forming, and black holes were forming and becoming more massive.

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-   The Hubble Space Telescope was limited to observations at about z=11. The JWST current high-redshift observations have reached z=14.32. Astronomers think that the JWST will eventually observe galaxies at z=20.

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-   The first few hundred million years after the Big Bang is called the “Cosmic Dawn”. JWST showed us that ancient galaxies during the Cosmic Dawn were much more luminous and, therefore, larger than we expected. The galaxy the telescope found at z=14.32, called    “JADES-GS-z14-0”, has several hundred million solar masses.

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-    This raises the question: How can nature make such a bright, massive, and large galaxy in less than 300 million years?"    They were differently shaped, that they contained more dust than expected, and that oxygen was present. The presence of oxygen indicates that generations of stars had already lived and died.  The presence of oxygen so early in the life of this galaxy is a surprise and suggests that multiple generations of very massive stars had already lived their lives before we observed the galaxy.

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-     Active galactic nuclei (AGN) are supermassive black holes (SMBHs) that are actively accreting material and emitting jets and winds.   “Quasars” are a sub-type of AGN that are extremely luminous and distant, and quasar observations show that SMBHs were present in the centers of galaxies as early as 700 million years after the Big Bang. But their origins were a mystery.

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-    Astrophysicists think that these early SMBHs were created from black hole "seeds" that were either "light" or "heavy." Light seeds had about 10 to 100 solar masses and were stellar remnants. Heavy seeds had 10 to 105 solar masses and came from the direct collapse of gas clouds.

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-   The JWST's ability to effectively look back in time has allowed it to spot an ancient black hole at about z=10.3 that contains between 107 to 108 solar masses. The Hubble Space Telescope didn't allow astronomers to measure the stellar mass of entire galaxies the way that the JWST does.

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-   Thanks to the JWST's power, astronomers know that the black hole at z=10.3 has about the same mass as the stellar mass of its entire galaxy. This is in stark contrast to modern galaxies, where the mass of the black hole is only about 0.1% of the entire stellar mass.

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-    Such a massive black hole existing only about 500 million years after the Big Bang is proof that early black holes originated from heavy seeds. This is actually in line with theoretical predictions.

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-    We know that in the early universe, hydrogen became ionized during the “Epoch of Reionization” (EoR). Light from the first stars, accreting black holes, and galaxies heated and reionized the hydrogen gas in the intergalactic medium (IGM), removing the dense, hot, primordial fog that suffused the early universe.

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-   Young stars were the primary light source for the reionization. They created expanding bubbles of ionized hydrogen that overlapped one another. Eventually, the bubbles expanded until the entire universe was ionized.

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-    This was a critical phase in the development of the universe. It allowed future galaxies, especially dwarf galaxies, to cool their gas and form stars. But scientists aren't certain how black holes, stars, and galaxies contributed to the reionization or the exact time frame in which it took place.

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-      Astronomers knew that reionization ended about 1 billion years after the Big Bang, at about redshift z=5-6. But before the JWST, it was difficult to measure the properties of the UV light that caused it. With the JWST's advanced spectroscopic capabilities, astronomers have narrowed down the parameters of reionization.

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-    We have found spectroscopically confirmed galaxies up to z = 13.2, implying reionization may have started just a few hundred million years after the Big Bang.

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-    JWST results also show that accreting black holes and their AGN likely contributed no more than 25% of the UV light that caused reionization.

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-    There is still significant debate about the primary sources of reionization, in particular, the contribution of faint galaxies.   The JWST is not even halfway through its mission and has already transformed our understanding of the universe's first one billion years. It was built to address questions around the Epoch of Reionization, the first black holes, and the first galaxies and stars.

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-    Among the most fundamental questions in astronomy is: How did the first stars and galaxies form? NASA's James Webb Space Telescope is already providing new insights into this question. The JWST Advanced Deep Extragalactic Survey, or JADES will devote about 32 days of telescope time to uncover and characterize faint, distant galaxies. While the data is still coming in, JADES already has discovered hundreds of galaxies that existed when the universe was less than 600 million years.

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-     For hundreds of millions of years after the Big Bang, the universe was filled with a gaseous fog that made it opaque to energetic light. By one billion years after the Big Bang, the fog had cleared and the universe became transparent, a process known as reionization. Scientists have debated whether active, supermassive black holes or galaxies full of hot, young stars were the primary cause of reionization.

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-     These early bright, massive stars pumped out torrents of ultraviolet light, which transformed surrounding gas from opaque to transparent by ionizing the atoms, removing electrons from their nuclei. Since these early galaxies had such a large population of hot, massive stars, they may have been the main driver of the reionization process. The later reuniting of the electrons and nuclei produces the distinctively strong emission lines.

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-   These young galaxies underwent periods of rapid star formation interspersed with quiet periods where fewer stars formed. These fits and starts may have occurred as galaxies captured clumps of the gaseous raw materials needed to form stars. Alternatively, since massive stars quickly explode, they may have injected energy into the surrounding environment periodically, preventing gas from condensing to form new stars.

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-    Another element of the JADES program involves the search for the earliest galaxies that existed when the universe was less than 400 million years old. By studying these galaxies, astronomers can explore how star formation in the early years after the Big Bang was different from what is seen in current times.

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-    The light from faraway galaxies is stretched to longer wavelengths and redder colors by the expansion of the universe, called “redshift”. By measuring a galaxy's redshift, astronomers can learn how far away it is, and therefore, when it existed in the early universe. Before Webb, there were only a few dozen galaxies observed above a redshift of 8, when the universe was younger than 650 million years old, but JADES has now uncovered nearly a thousand of these extremely distant galaxies.

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-   The gold standard for determining redshift involves looking at a galaxy's spectrum, which measures its brightness at myriad closely spaced wavelengths. But a good approximation can be determined by taking photos of a galaxy using filters that each cover a narrow band of colors to get a handful of brightness measurements. In this way, researchers can determine estimates for the distances of many thousands of galaxies at once.

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-     Webb's NIRCam (Near-Infrared Camera) instrument obtained these measurements, called “photometric redshifts”, and identified more than 700 candidate galaxies that existed when the universe was between 370 million and 650 million years old. The sheer number of these galaxies was far beyond predictions from observations made before Webb's launch.

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-    Previously, the earliest galaxies we could see just looked like little smudges. And yet those smudges represent millions or even billions of stars at the beginning of the universe.   Now, we can see that some of them are actually extended objects with visible structure. We can see groupings of stars being born only a few hundred million years after the beginning of time.

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-   We're finding star formation in the early universe is much more complicated than we thought.

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-   By the time light from the most distant galaxies reaches Earth, it has been stretched by the expansion of the universe and shifted to the infrared region of the light spectrum.  The Webb telescope's NIRCam instrument has an unprecedented ability to detect this infrared light, allowing it to quickly spot a range of never-before-seen galaxies.

-

-   The galaxies are very active in star formation in proportion to their mass.   Those stars were forming at around the same rate as the Milky Way, a speed that was surprising so early in the Universe.   The galaxies were also very poor in metals.

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-    This is consistent with the standard model of cosmology, science's best understanding of how the universe works, which says that the closer to the Big Bang, the less time there is for such metals to form.

-  

-    Those galaxies, observed by the Webb telescope, were bigger than thought possible so soon after the birth of the universe, if confirmed, the standard model could need updating.   The frontier is moving almost every month.  There was now "only 300 million years of unexplored history of the universe between these galaxies and the Big Bang.

-

-

June 18, 2024              WEBB  DISCOVERIES  -   giving new science?              4500

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--------  Comments appreciated and Pass it on to whomever is interested. ---

---   Some reviews are at:  --------------     http://jdetrick.blogspot.com ----- 

--  email feedback, corrections, request for copies or Index of all reviews

---  to:  ------    jamesdetrick@comcast.net  ------  “Jim Detrick”  -----------

--------------------- ---  Wednesday, June 19, 2024  ---------------------------------

 

 

 

 

 

           

 

 

4500 - Index of Reviews 4450 to 4500

            -  4450  -   Index of Reviews 4450  to 4500

            -     This index is of the 50 reviews from 4500 to 4550.  Indices of all previous reviews is available upon request.      Writing style is stocatto with each paragraph an idea and limited to a few pages in total.  Comments are always welcome.  See  https://jimdetrick@blogspot.net

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            ----------------------------------  4500  -   Index of Reviews 4450  to 4500

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            -    4450  -  CONSTELLATION  CASSIOPEIA  -  stars after explosion?  -   When a massive star runs out of fuel, it collapses in on itself and then explodes. It leaves behind a dense core where the protons and electrons are crushed into neutrons. It’s called a “neutron star”, and they’re the smallest and densest stellar objects in the Universe other than black holes.

            -

            -     4451 -  SUN   -  becomes a White Dwarf?  -   In a couple billion years, our Sun will be unrecognizable. It will swell up and become a    “red giant”, then shrink again and become a “white dwarf”. The inner planets aren’t expected to survive all the mayhem these transitions unleash, but what will happen to them? What will happen to the outer planets?

            -

            -     4452  -   MARS &  VENUS -  were they water worlds?   -    Evidence of ancient lake sediments at the base of Mars' Jezero crater offer new hope for finding traces of life in samples collected by NASA's Perseverance rover.  Perseverance touched down on Feb. 18, 2021 inside the Red Planet's 28-mile-wide Jezero Crater, which is believed to have once hosted a large lake and river delta.

            -

            -     4453  - ASTEROID  DISCOVERIES  -  how many are there?   The key to protecting Earth from being hit by asteroids is knowing where all these are. We have discovered over 27,000 overlooked asteroids in old telescope images.   Asteroids in our solar system had been overlooked in existing telescope images.

            -

            -     4454  -  ATOMS  become waves?-   For the first time ever, physicists have captured a clear image of individual atoms behaving like a wave.  The image shows sharp red dots of fluorescing atoms transforming into fuzzy blobs of wave packets and is a stunning demonstration of the idea that atoms exist as both particles and waves.  This concept is one of the cornerstones of “quantum mechanics”.

            -

            -      4455  -   SUPERCONDUCTIVITY  -  can we harness it? -   Last summer, 2023, commentators went wild for LK-99, an alleged room-temperature superconductor that seemed to foreshadow a wondrous age of perfectly efficient power lines and magnetically levitating trains.

            -

            -     4456  -  RING  NEBULA  -  interaction of three stars?  -    Southern Ring Nebula has an unexpected structure.   Submillimeter wavelength radio observations of the Southern Ring Nebula have identified that it's actually a double ring, shaped by the interactions of three stars.

            -

            -      4457  -  MERGING  BLACKHOLES  -   the center of galaxies?  -  The hearts of galaxies can force black holes to collide.  At the hearts of all large galaxies lie cosmic monsters called supermassive black holes, enormous voids that swirl around everything in the galaxies themselves.

            -

            -     4458  -   UNIVERSE  -  and Cosmic Inflation?  -  Our Universe arose in the aftermath of “cosmic inflation”, triggering the hot Big Bang some 13.8 billion years ago that eventually gave rise to us. The Universe passed through many epochs, from free quarks and gluons to stable protons and neutrons to neutral atoms to stars, galaxies, planets, and more.

            -

            -     4459  -    EINSTEIN'S  COSMIC  INFLATION? - is there more to it?  -   Cosmic 'glitch' in gravity challenge Albert Einstein's greatest theory?  There is no denying the awesome predictive power of Albert Einstein's 1915 theory of gravity, “general relativity”.  Yet, the theory still has inconsistencies when it comes to calculating its effect on vast distances. And new research suggests these inconsistencies could be the result of a "cosmic glitch" in gravity itself.

            -

            -     4460  -    DARK  ENERGY  and  DARK   MATTER?  -    20th-century astronomers discovered the first of two invisible continents while observing the motions of stars and galaxies. For outer stars to whip around the center of a galaxy as quickly as they do they must be held by the gravity of something invisible. The galaxy’s bright spiral would have to be a small seed sitting in the center of an unseen cloud of “dark matter.”

            -

            -     4461  -  METEORITES  -  messages from space?  -    Meteorites provide our best information about how the solar system formed and evolved. This includes planet formation. We also obtain information on astrophysics (stellar processes) through studies of pre-solar grains.

            -

            -     4462  -  GALAXY  BLACKHOLE  -  reveals magnetic fields?     A new view reveals magnetic fields around our galaxy’s giant blackhole.   Imagery from the 'Event Horizon Telescope' (EHT) traces the lines of powerful magnetic fields spiraling out from the edge of the supermassive black hole at the center of our Milky Way galaxy, and suggests that strong magnetism may be common to all supermassive black holes.

            -

            -     4463  -   DARK  MATTER  -  could it be blackholes?   -    Tiny black holes left over from the Big Bang may be prime dark matter suspects.  Tiny black holes, created seconds after the birth of the universe, may survive longer than expected, reigniting a suspicion that primordial black holes could account for dark matter, the universe's most mysterious stuff.

            -

            -     4464  -   KEPLER'S  ORBIT  MATH  -  is still used today?    The story of how we understand planetary motion could not be told if it were not for the work of a German mathematician named Johannes Kepler.    Johannes Kepler died Nov. 15, 1630, at age 58. NASA's Kepler space telescope was named for him. The spacecraft launched March 6, 2009, and spent nine years searching for Earth-like planets orbiting other stars in our region of the Milky Way

            -

            -      4465  -  SUNSPOTS  -  we had a big one this week?  -    The behemoth dark patch on the sun's surface has ballooned in recent days, May 10,2024, becoming one of the largest and most active sunspots seen this solar cycle.  “AR3664” caused the Space Weather Prediction Center to issue a warning of increased solar flare risk from the solar giant on Tuesday, May 7.

            -

            -     4466   -   DARK  ENERGY  -  expanding the Universe?   Some 13.8 billion years ago, the universe began with a rapid expansion we call the Big Bang. After this initial expansion, which lasted a fraction of a second, gravity started to slow the universe down. But the cosmos wouldn’t stay this way. Nine billion years after the universe began, its expansion started to speed up, driven by an unknown force that scientists have named “dark energy”.

            -

            -     4467   -  EARTH  -  earliest history?     Our Earth is the only life-supporting planet we know of, so it’s tempting to use it as a standard in the search for life elsewhere. But the modern Earth can’t serve as a basis for evaluating exoplanets and their potential to support life. Earth’s atmosphere has changed radically over its 4.5 billion years.

            -

            -     4468   -  STAR  EXPLOSIONS  -  how astronomers learn?   The tumultuous massive star, in the final year or so of its life, ejected large amounts of matter into space before going supernova.   This massive star that exploded in the Pinwheel Galaxy in May appears to have unexpectedly lost one sun's worth of ejected mass during the final years of its life before going supernova.

            -

            -     4469   -    NORTHERN  LIGHTS  -     May 2024,  a huge solar flare sent a wave of energetic particles from the sun surging out through space.   The wave reached Earth, and people around the world enjoyed the sight of unusually vivid aurora in both hemispheres.  While the aurora is normally only visible close to the poles, this was spotted as far south as Hawaii in the northern hemisphere, and as far north as Mackay in the south.

            -

            -      4470   -     NUCLEAR  ENERGY  -   will it work?  In December 2022, after more than a decade of effort and frustration, scientists at the US National Ignition Facility (NIF) announced that they had set a world record by producing a fusion reaction that released more energy than it consumed , a phenomenon known as “ignition”.

            -

            -     4471   -  EXPANDING  UNIVERSE  -    is it flat?   -    Our cosmic model of the universe, based on quantum mechanics and general relativity, deals with the geometry of the universe as influenced by matter and energy, which for most purposes is considered to be “flat”,  that is the same in all directions..

            -

            -     4472   -  KNOT  THEORY  ORBITS  -   what are they for?  -    When a spacecraft arrives at its destination, it settles into an orbit for science operations. But after the primary mission is complete, there might be other interesting orbits where scientists would like to explore. Maneuvering to a different orbit requires fuel, limiting a spacecraft’s number of maneuvers.

            -

            -      4473   -  OLDEST  STARS  -   may have been captured?  The oldest stars in the universe were found hiding near the Milky Way's edge, and they may not be alone.  Astronomers reanalyzed the chemical composition of three stars in the Milky Way's halo and found that they are between 12 and 13 billion years old. They may have also been stolen from other galaxies.

            -

            -     4474   -  ATOMS  -  have wave particle duality?  -   Atoms squished closer together than ever before, revealing seemingly impossible “quantum effects”.   Using a  laser technique, scientists have squished pairs of atoms closer together than ever before, revealing some truly mind-boggling quantum effects.

            -

            -     4475   -   PHOTON  -  what Einstein discovered.  -    Creating the Photon started with a simple experiment that was all the rage in the early 20th century. And as is usually the case, simple experiments often go on to change the world, leading Einstein himself to open the revolutionary door to the quantum world.

            -

            -     4476   -  DARK  MATTER  -   experiments to learn what is it?      Dark matter makes up over 80% of all matter in the universe, but scientists have never seen it.  We only assume it exists because, without it, the behavior of stars, planets and galaxies simply wouldn't make sense according to laws of gravity

            -

            –     4477   -  BLACKHOLES  -  what have we learned?  -    James Webb Telescope detects most distant black hole merger to date.   Astronomers find evidence for an ongoing merger of two galaxies and their massive black holes when the universe was only 740 million years old. This marks the most distant detection of a black hole merger ever obtained and the first time that this phenomenon has been detected so early in the universe.

            -

            -      4478   -   LIGHT  PHOTONS  -  how were they discovered?   Einstein’s discovery of photons would be just one result in the growing awareness of the microscopic, quantum world.    It was the first to claim that an entity in nature (in this case, the radiation of Maxwell discovered) was really made of quantum particles.  That is photons.

            -

            -     4479   -    EUCLID  TELESCOPE -  will it discover Dark Energy?  -     Europe's Euclid space telescope may see into the dark universe and may put Einstein's famous theory of general relativity into question.  There is a problem with our understanding of the universe: It doesn't make sense if we account only for the matter and energy that we can see, measure or detect.

            -

            -     4480   -    DAYTIME  TELESCOPES  -  really?  -    Stargazing in broad daylight using a multi-lens telescope will change how we do astronomy?   Astronomers at Macquarie University have pioneered a new technique for observing celestial objects during the day, potentially allowing around-the-clock astronomy.

            -

            -     4481   -   EINSTEIN'S  -  theory of relativity?  -    Albert Einstein's famous theory of relativity has been borne out in the real world, measured in eclipses, distorted galaxies and even the universe's structure.  General Relativity (GR), is the “theory of gravity” first cooked up by Albert Einstein in a feat that took him seven years to complete.  It provided amazing insights into how the world works.

            -

            -      4482   -    FREE  FLOATING  PLANETS  -   how many are there?  -   Over 5,000 planets have been found orbiting other star systems. One of the satellites hunting for them is “TESS,” the “Transiting Exoplanet Survey Satellite”. Astronomers using TESS think they are made a  surprising discovery; their first free-floating, or rogue, planet.

            -

            -    4483   -    PLANETS  -   8 or is it now 5,000?  -    The hunt for new exoplanets continues. On May 23rd, 2024,  scientists published the NASA TESS-Keck Catalog, an effort to publicly release over 9,000 radial velocity measurements collected by NASA’s space-based Transiting Exoplanet Survey Satellite (TESS).

            -

            -     4484   -   EARTH'S  MAGNETIC  FIELD  -  what caused it?  -    The image of an atom, with electrons swarming around a central nucleus bulging with protons and neutrons, is as iconic in our perception of science.   Exploring the fundamental forces that govern our world, posing questions along the way that seek to explain how the delicate balance of positive and negative charges paved the way for gravity to shape our universe.

            -

            -      4485   -   SUPERNOVAE  -    close to home?  -   Before exploding, this star puffed out a sun's worth of mass.  The tumultuous massive star, in the final year or so of its life, ejected large amounts of matter into space before going supernova.   The star exploded in the Pinwheel Galaxy in May, 2023.  It unexpectedly lost approximately one sun's worth of ejected mass during the final years of its life before going supernova.

            -

            -      4486  -   SUPERNOVAE  1987A  -  what are the string of pearls?  -      Astronomers finally have an explanation for the “String of Pearls” in Supernova 1987a.  Not long after the explosion of Supernova 1987a, astronomers were making predictions about how it might look in a few years.

            -      4487  -  JAMES  WEBB  -  sees the first stars?  -     Using the James Webb Space Telescope, University of Copenhagen researchers have become the first to see the formation of three of the earliest galaxies in the universe, more than 13 billion years ago.

            -

            -     4488  -     RARE  EARTH  METALS  -  how did they get here?  -   Before exploding, this star puffed out a sun's worth of mass.  This supernova could prove to be a lynchpin in our understanding of massive star deaths.   The massive star, in the final year or so of its life, ejected large amounts of matter into space before going supernova.

            -

            -     4489  -   EINSTEIN  -   how did he get so smart?  -    Albert Einstein was arguably the most famous scientist of the 20th century. Most people are familiar with his iconic E=mc^2 equation, but his life and work encompassed so much more than that. For instance, the brilliant physicist actually won the Nobel Prize for very different work. From his humble beginnings as a patent clerk to the offer to run a small country (that he turned down).

            -

            -    4490  -     BLACKHOLE   DISCOVERIES  -  we keep learning more?  -    Einstein’s theory of general relativity predicted both the existence of black holes and gravitational waves, both of which continued to be scrutinized throughout the 20th century, which includes what’s called the “golden age of general relativity” during the 1960s and 1970s.

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            -

            May 1, 2024             Index of Reviews 4450 to 4500                              4500                                                                                              ---------------------------------------------------------------------------------------

            -----  Comments appreciated and Pass it on to whomever is interested. ---

            ---   Some reviews are at:  --------------     http://jdetrick.blogspot.com ----- 

            --  email feedback, corrections, request for copies or Index of all reviews

            ---  to:  ------    jamesdetrick@comcast.net  ------  “Jim Detrick”  -----------

            --------------------- ---  Friday, June 14, 2024  ---------------------------

 

 

           

 

                                                              4500  -   Index of Reviews 4450  to 4500                 6

-

May 22, 2024                            4472

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--------  Comments appreciated and Pass it on to whomever is interested. ---

---   Some reviews are at:  --------------     http://jdetrick.blogspot.com ----- 

--  email feedback, corrections, request for copies or Index of all reviews

---  to:  ------    jamesdetrick@comcast.net  ------  “Jim Detrick”  -----------

--------------------- ---  Friday, June 14, 2024  ---------------------------------