4204 - MILKY WAY'S VIOLENT PAST?

 

-    4204   -  MILKY  WAY'S  VIOLENT PAST?     Galactic archaeology reveals Milky Way's neighbor Andromeda has a violent past.  Chemical analysis of stars in our galaxy next door has revealed its upbringing was more chaotic than our own galaxy's.

---------------------  4204  -  MILKY  WAY'S  VIOLENT PAST?   

-    Astrophysicists looked at the chemical compositions of stars in Andromeda, which is the closest large galaxy to our own. The goal was to reconstruct its past.   After examining the abundance of elements in Andromeda and considering the fact this galaxy possesses both planetary nebulae ,  gas and dust blown away from dying low-mass stars, and red giant stars,  researchers concluded that  it experienced dramatic and forceful formation.

-

-    In fact, astronomers thinks the creation of the Andromeda galaxy was more turbulent than the origins of the Milky Way. They theorize that Andromeda initially experienced a burst of intense star formation that created the galaxy's foundation, with a secondary period of star birth happening between 2 billion and 4.5 billion years ago.

-

-    Although in many ways Andromeda is similar to our own Milky Way,  it's a similarly-sized, spiral disc galaxy , new research confirms that its history is far more intense and dramatic, with bursts of activity forming stars in abundance, and two distinct eras of star formation.

-

-    The idea is the second starburst period was triggered when the gas-rich Andromeda collided and merged with another galaxy, also replete with gas, in an event that astronomers call a "wet merger." The influx of gas in such a merger acts as the fuel to kick-start yet more bouts of star formation.

-

-    Andromeda isn’t finished clashing with other galaxies.  Scientists have long thought that Andromeda experienced collisions and mergers with other galaxies in its past, because the positions and motions of its individual stars,  the stars started out in another galaxy.

-

-   By looking at the chemical compositions of these stars, astronomers found two distinct signatures in the disc components of Andromeda. One family of stars appeared to have ten times more oxygen than iron, while the other group appeared to have similar amounts of both elements. This bit adds a new dimension to the understanding of this galaxy’s past, revealing more about the nature of the suggested collision and its effect on Andromeda’s stellar population.

-

-    Galactic archaeology can provide fresh new insights into the history of our universe.   By analyzing the chemical abundance in different ages of stars in Andromeda, astronomers can bring to life its history and better understand its origins.

-

-    Andromeda likely has a history of violence and  its future looks to be equally turbulent, with our own galaxy set to become part of its neighbor’s chaotic existence. This is because the Milky Way and Andromeda are currently on a collision course, set to slam into each other in around 4.5 billion years. This titanic collision will give both galaxies a severe makeover, wiping out the distinctive arms of both spiral galaxies.

-

-    The stellar population of the Milky Way and Andromeda, which is currently about 2.5 billion light years away from us, will not slam into each other but will survive to be thrown into new orbits around a new galactic center. Our own star, the sun, and the entire solar system are likely to be pushed away from the new galactic core, moving toward the outskirts of the resultant new galaxy.

-

-    Oxygen is one of the so-called alpha-elements produced by massive stars. The others are neon, magnesium, silicon, sulfur, argon, and calcium.  Oxygen and argon have been measured with planetary nebulae, but Andromeda is so far away that the James Webb Space Telescope (JWST) is required to measure other elements, including iron.

-

-    In coming years, JWST and ground-based large telescopes will keep looking at Andromeda  giving further weight to the new findings.

-

-

October 30,  2023              MILKY  WAY'S  VIOLENT PAST?        4204

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--------------------- ---  Monday, October 30, 2023  ---------------------------------

 

 

 

 

 

           

 

 

4203 - FREE FLOATING PLANETS?

 

-    4203 -  FREE  FLOATING  PLANETS?    Hundreds of Free-Floating Planets have been found in the Orion Nebula.  It appears that rogue planets, free floating worlds that aren’t gravitationally bound to a parent star, might be more common than we thought.   The James Webb Space Telescope have revealed 540  planetary-mass objects in the Orion Nebula and Trapezium Cluster.

---------------------  4203  -  FREE  FLOATING  PLANETS?

-   This discovery would be by far the largest sample of rogue planets ever discovered.  Last year, astronomers found 70 free floating worlds throughout the Milky Way.   A near-infrared survey from JWST allowed astronomers to discover and characterize a large sample of 540 planetary-mass candidates.

-

-   The team says these planetary mass objects (PMOs) are too small to be stars, as their masses are well below the traditional cutoff for a deuterium-burning brown dwarf, even down to 0.6 Jupiter mass, not much more massive than Saturn.

-

-    Within the large group of rogue planets are 42 pairs of planets that are gravitationally bound together, something that’s never been observed before. The astronomers named them Jupiter Mass Binary Objects, or JuMBOs.

-

-   How pairs of young planets can be ejected simultaneously and remain bound, weakly at relatively wide separations, remains quite unclear.

-

-    The Jupiter Mass Binary Objects or JuMBOs are a really big discovery.  The conventional definition of a planet is that it is in orbit around a star. Additionally, current theories of planetary formation suggest that Jupiter-sized objects can only be formed through the process that gives rise to stars inside the clouds of dust and gas found in a nebula.

-

-   How can a substantial population of objects form below 5 Jupter masses and how a significant fraction of them can end up in multiple systems?.  The exact mechanisms for how planets go “rogue” are unknown.

-

-    The theories include that planets are pulled away from one star by gravitational interactions with other passing stars, or that supernovae kick them out, or that they free float into space after their sun dies.  Alternatively planetary ejections can be caused through planets scattering in a planetary disk or by dynamical interactions between stars.

-

-    Rogue planets are usually impossible to image in visible light, which makes JWST’s sensitive infrared vision the perfect tool to look for them.

-

-    The Orion Nebula has been studied for decades to observe the formation and early evolution of stars and other celestial objects. It lies 1,350 light years away from Earth and is visible to the naked eye as a misty smudge at the bottom of the Orion constellation, part of the ‘sword’ of the mythical Greek hunter after whom the constellation is named.

-

-

October 27,  2023            FREE  FLOATING  PLANETS                4300

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--------------------- ---  Monday, October 30, 2023  ---------------------------------

 

 

 

 

 

           

 

 

4202 - MILKY WAY GALAXY - is it still a spiral

 

-    4202   -   MILKY  WAY  GALAXY  -    is it still a spiral?     The Milky Way wasn't always a spiral  and astronomers may finally know why it 'shape-shifted'.  A century-old mystery of how galaxies change shapes has been solved by considering 'survival of the fittest' collisions between cosmic titans.

---------------------  4202  -  MILKY  WAY  GALAXY  -    is it still a spiral

-   A 100-year-old mystery surrounding the "shape-shifting" nature of some galaxies has been solved, revealing in the process that our Milky Way galaxy did not always possess its familiar spiral appearance.

-

-   The evolution of galaxies from one shape to another takes place is a process known as “galactic speciation” . The research shows that clashes and subsequent mergers between galaxies are a form of "natural selection" that drives the process of cosmic evolution.

-

-    The Milky Way's history of cosmic violence is the survival of the fittest out there. "Astronomy now has a new anatomy sequence and finally an

evolutionary sequence in which galaxy speciation is seen to occur through the inevitable marriage of galaxies ordained by gravity.

-

-    Galaxies come in an array of shapes. Some, like the Milky Way, are composed of arms of well-ordered stars revolving in a spiral shape around a central concentration or "bulge" of stellar bodies. Other galaxies like Messier 87 (M87) are composed of an ellipse of billions of stars chaotically buzzing around a disordered central concentration.

-

-    Since the 1920s, astronomers have classified galaxies based on a sequence of varying galaxy anatomy called the "Hubble sequence." Spiral galaxies like ours sit at one end of this sequence, while elliptical galaxies like M87 sit at the other. Bridging the gap between the two are elongated sphere-shaped galaxies, lacking spiral arms, called “lenticular galaxies”.

-

-    To understand our evolutionary paths on the Hubble sequence astronomers looked at 100 galaxies near to the Milky Way in optical light images collected by the Hubble Space Telescope and compared them to infrared images from the Spitzer Space Telescope. This allowed him to compare the mass of all the stars in each galaxy to the mass of their central supermassive black holes.

-

-   This revealed the existence of two different types of bridging lenticular galaxies: One version that is old and lacks dust, and the other that is young and rich in dust.

-

-   When dust-poor galaxies accrete gas, dust, and other matter, the disk that surrounds their central region is disrupted, with said disruption creating a spiral pattern radiating out from their hearts. This creates spiral arms, which are over-dense rotating regions that create gas clumps as they turn, triggering collapse and star formation.

-

-    The dust-rich lenticular galaxies are created when spiral galaxies collide and merge. This is indicated by the fact that spiral galaxies have a small central spheroid with extending spiral arms of stars, gas and dust. Young and dusty lenticular galaxies have notably more prominent spheroids and black holes than spiral galaxies and dust-poor lenticular galaxies.

-

-   The surprising result of this is the conclusion that spiral galaxies like the Milky Way actually lie between dust-rich and dust-poor lenticular galaxies on the Hubble sequence. The lenticular galaxies are not the single bridging population they were long portrayed.

-

-    The history of the Milky Way is believed to be punctuated with a series of "cannibalistic" events in which it devoured smaller surrounding satellite galaxies to grow.   In addition to this, our galaxy's cosmic "acquisitions" also included it accreting other material and gradually transforming from a dust-poor lenticular galaxy to the spiral galaxy we know today.

-

-    Our galaxy is set for a dramatic merger with its closest large galactic neighbor, the Andromeda galaxy, in between 4 billion and 6 billion years. This collision and merger will see the spiral arm pattern of both galaxies erased and the new research indicates that the daughter galaxy created by this union is likely to be a dust-rich lenticular galaxy still possessing a disk, albeit without a spiral structure carved through it.

-

-   Should the Milky Way-Andromeda daughter galaxy encounter a third, dust-rich lenticular galaxy and merge with it, then the disk-like aspects of both galaxies will also be wiped clean. This would create an elliptical-shaped galaxy without the ability to harbor cold gas and dust clouds.

-

-    Just as this new galaxy will carry the story of its evolution for astronomers in the far-future, the dust-poor lenticular galaxies could serve as fossil records of the processes that transformed old and common disk-dominated galaxies in the early universe.

-

-    This could help explain the discovery by the James Webb Space Telescope (JWST) of a massive spheroid-dominated galaxy just 700 million years after the Big Bang. The new research could indicate that the merging of elliptical galaxies is a process that could explain the existence of some of the universe's most massive galaxies, which sit at the heart of clusters of over 1,000 galaxies.

-

-

October 28,  2023      MILKY  WAY  GALAXY  -    is it still a spiral?               4202

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--------------------- ---  Sunday, October 29, 2023  ---------------------------------

 

 

 

 

 

           

 

 

4201 - GRAPH OF THE UNIVERSE?

 

-    4201   -  GRAPH  OF  THE  UNIVERSE?   What if we put on one graph all the masses, sizes, and relative densities of all the objects in our entire Universe, and more. What would it look like?  Everything in the Universe fits in this one graph including you and me!

-

---------------------  4201  -  GRAPH  OF  THE  UNIVERSE?

-    The Universe has physical constants, such as the force of gravity that define everything. If these constants were any different, our Universe would look quite different. When you consider the types of objects that exist in our Universe from quarks and bacteria to fleas and superclusters different forces dominate their existence.

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-   This single graph defines the types of objects that are prohibited by the laws of physics as we understand them.  The graph is designed to get people to think about all the unanswered questions we have about the Universe.

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-    The graph provides an overview of the thermal history of the Universe and the sequence of objects ( protons, planets, and galaxies) that condensed out of the background as the Universe expanded and cooled.

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-  The graph shows the general process that has happened multiple times as the hot dense universe cooled down as it expanded and condensed into various objects.   As the hot dense plasma of quarks and gluons cooled, it condensed into protons and neutrons. And as the hot dense plasma of protons and electrons cooled down it condensed into atoms.

-

-   This general process of “condensation” seems to be underappreciated as a simple way to understand what happened as the universe cooled: the hot dense big bang condensed into objects.

-

-   The middle strip in the middle section of the graph marked “BBN” or Big Bang Nucleosynthesis has atoms and elements, with the atomic densities of things like bacteria, fleas, humans, whales, the Earth, Sun and stars.

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-   As the main sequence stars, which when they run out of fuel, become white dwarfs, which eventually collapse into neutron stars, which eventually collapse into black holes. On this graph the black holes exist on the dark black line.

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-    Does that mean the whole universe is a black hole? This graph seems to imply this might be true!  It’s plausible that what we see from inside our Universe is simply the result of being inside a black hole that formed from some parent Universe?   Contrary to common knowledge, black holes are not the densest things in the universe.

-

-    The bigger the black hole, the less dense it is.   That is why the whole universe could be a huge low-density black hole. Another interesting fact is when you trace the evolution of the whole universe back along the black hole line, all the way back to the beginning of the universe, the plot suggests that the initial condition of the universe was  the smallest possible black hole.  It is an object that instantaneously evaporates (through Hawking radiation) and explodes at the highest possible temperature (the Planck temperature: 10^32 K).

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-    The area of the graph that might be most intriguing are two triangular regions that are ‘forbidden.  This is where objects cannot be denser than black holes, or are so small, quantum mechanics blurs the very nature of what it really means to be a singular object.

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-   The boundaries of the plots and what lies beyond them are also a major mystery, as the triangular regions forbidden by “general relativity” and “quantum mechanics uncertainty” and help navigate the relationship between gravity and quantum mechanics.

-

-   This graph should help both students and experts talk about some very profound questions that we don’t know the answers to.

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-

October 28,  2023        GRAPH  OF  THE  UNIVERSE?             4201

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

--------------------- ---  Sunday, October 29, 2023  ---------------------------------

 

 

 

 

 

           

 

 

4200 - MILKY WAY GALAXY - is not a flat disk as we thought.

 

-    4200   -  MILKY  WAY  GALAXY   -  is not a flat disk as we thought.      We normally thing of our  Milky Way Galaxy as a flat disk.  Almost like a phonograph record with a bulge in the middle.  But our galaxy disk appears to be warped and wavy. If our entire galaxy is warping a gigantic blob of dark matter could be to blame.

-------  4200  -  MILKY  WAY  GALAXY   -  is not a flat disk as we thought.

-    An invisible halo of misaligned dark matter could explain the warps at the Milky Way's edges.  Scientists initially believed that the Milky Way was a flat disk dominated by two spiral arms trailing stars from a central bar, but measurements taken since the mid-20th century reveal that it's bent inexplicably out of shape.

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-    The warping occurs mostly at our galaxy's borders, where some regions bend downward while others flare upward giving it the look of a crushed sombrero. Now, computer simulations may have revealed the cause to be a mysterious event that knocked our galaxy's invisible halo of dark matter out of alignment.

-

-    These computer results provide compelling evidence that our Galaxy is embedded in a tilted dark matter halo.   Dark matter is a mysterious and somewhat contradictory type of matter. It makes up 85% of the universe's matter; but because it doesn't directly interact with light, it is completely invisible.

-

-    However, scientists can observe its gravitational effects on its surroundings. Dark matter makes its presence known by accelerating stars to otherwise inexplicable speeds as they orbit galactic centers; warping distant starlight; and by giving shape to the Milky Way's galactic halo.

-

-    The galactic halo is a vast sphere of stars floating like leaves on a dark matter pond.  It rests just beyond the spiral arms of the Milky Way.  Astronomers investigated this region using the European Space Agency's Gaia spacecraft, which maps the positions and movements of the Milky Way's roughly 2 billion stars. By poring through Gaia's data, they discovered that the stars suspended in the galactic halo were strangely off-kilter.

-

-    A computer model  recreated a young Milky Way-like galaxy with a dark matter halo tilted 25 degrees with respect to its disk. After simulating the galaxy over 5 billion years, the researchers found that they had created a very similar galaxy to our own.

-

-    A dark halo tilted in the same direction as the stellar halo can induce a warp and flare in the Galactic disk at the same amplitude and orientation as the data.  What caused the dark matter around our galaxy to fall out of tilt isn't clear.

-

-    The researchers' simulations suggest it is likely to have been a gigantic collision, likely from another galaxy flying into our own.  This collision could have caused the dark matter halo to tilt up by as much as 50 degrees before slowly swinging down to its current 20-degree angle elevation.

-

-

October 27,  2023     MILKY  WAY  GALAXY   -  is not a flat disk?               4200

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--------------------- ---  Sunday, October 29, 2023  ---------------------------------

 

 

 

 

 

           

 

 

- 4100 - Index of Reviews 4100 to 4150

            -  4100  -   Index of Reviews 4100 to 4150

            -     This index is of the 50 reviews from 4050  to 4100.  Indices of all previous reviews is available upon request.      Writing style is stochatto with each paragraph an idea and limited to a few pages in total.  Comments are always welcome.  See https:://jimdetrick@blogspot.net

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

            -

            ------------------  4100-  Index of Reviews 4100 to 4150

            -

            -

            -     4100  -   WEBB TELESCOPE  -  sees most distant galaxy?      As astronomers push our views of the Universe further back in time, their telescopes keep uncovering surprises. That’s the case with a supermassive black hole in CEERS 1019, a distant very early galaxy.

            -

            -     4101  -   LIFE  ON  MARS?  -    The search for life on Mars has been a long a confusing one. Inconclusive experiments abound, but one thing is certain, there is definitely “organic” material on the Red Planet.

            -

            -    4102  -  DARK  STARS  -  did Webb just discover them?     Current theories about the Universe will need updating.  Webb has revealed what our universe looked like 13.5 billion years ago, when the first stars and galaxies took shape after the Big Bang.

            -

            -     4103  -    UNIVERSE  -  how old is it, really?     Well, it depends on the speed of light? The Universe could be twice as old if light is “tired” and physical constants change. When the James Webb Space Telescope started collecting data, it gave us an unprecedented view of the distant cosmos. Faint, redshifted galaxies seen by Hubble as mere smudges of light were revealed as objects of structure and form.

            -

            -     4104  -    ICE CUBE NEUTRINOS  -  seeing without photons?   The “IceCube Neutrino Observatory” has used 60,000 neutrinos to create the first map of the Milky Way made with matter and not light.  Seeing with neutrinos!

            -

            -     4105  -   LIGHT  SPEED  -  is it constant?    The phenomenon of light slowing down as it passes through a material like glass or air is one of the most fascinating areas of physics, involving a complex interaction between light and materials. There are three ways to look at the same situation, and each employs a different understanding of physics.

            -

            -     4106  -   LIFE  ON  MARS  -   Perseverance  explorations?  What happens if Perseverance finds life on Mars?   On February 18, 2023,  NASA’s Perseverance rover set landed in the Jezero crater on Mars and almost immediately transmitted its first image of the Martian.

            -

            -     4107  -   ATLANTIC  OCEAN  -  is heating up, why?       The ocean system, known as the “Atlantic Meridional Overturning Circulation” (AMOC) had previously been measured to be dramatically weakening in conjunction with rising ocean temperatures.

            -

            -     4108  -   PLANETARY  NEBULAE  -  the future for our sun?      Planetary nebulas are clouds of gas that are expelled by dying stars at the end of their lives. These can resemble butterflies or hourglasses with the smoldering remains of the star at their heart.

            -

            -     4109  -   DARK  MATTER  and  DARK  ENERGY ?    Dark energy and dark matter, constitute some of the biggest and most fascinating questions to exist in astronomy today. Neither phenomena can be seen by human eyes, yet still appear to be holding our universe together.

            -

            -    4110  -   EINSTEIN  CROSS  -   a new model for the Universe?     Astronomers have discovered a stunning, rare example of an "Einstein cross" splitting and magnifying light from the far depths of the universe.  One foreground elliptical galaxy, around 6 billion light-years from Earth, has warped and quadrisected a bright beam of light from a background galaxy about 11 billion light-years from our planet.

            -

            -     4111  -   RING  NEBUBLA  -  new studies using JWST?    The James Webb Space Telescope has imaged the “Ring Nebula” as a glowing green and purple eye, presenting the familiar panetary nebula in an altogether new light.  The James Webb Space Telescope (JWST) images show the Ring Nebula, known as Messier 57 (M57), located around 2,200 light-years away, in intricate detail that will surprise even astronomers who are familiar with the object.

            -

            -     4112  -   MILKYWAY  -  new chemicals and ghost stars?       “Chemical cartography”, has unveiled new regions of our galaxy's stunning radial features populated by dense patches of young stars.   This could be crucial for astronomers seeking to understand our galaxy's evolution, shape and structure.

            -

            -    4113  -  NEUTRINOS  -  where do they come from?     Pinpointing cosmic neutrino sources opens up the possibility of using the particles as a new probe of fundamental physics. Researchers have shown that the neutrinos can be used to open cracks in the reigning Standard Model of particle physics and even test quantum descriptions of gravity.

            -

            -     4114 -   MODIFIED  GRAVITY  -  does MOND replace Dark Matter?   There is a smoking-gun evidence for modified gravity at low acceleration from Gaia observations of wide binary stars.   Evidence for the breakdown of standard gravity equation in the low acceleration limit from a verifiable analysis of the orbital motions of long-period, widely separated, binary stars, usually referred to as wide binaries.

            -

            -     4115 -    ROGUE  PLANETS  -    roaming without a sun?     There could be trillions of “Rogue Planets” wandering the Milky Way galaxy?   Rogue planets are free-floating exoplanets that drift through space unbound by the gravitational tug of a star. They can form within their own solar system and get ejected, or they can form independently.

            -

            -     4116 -  RING  NEBULAE  -   future of our solar systrem?  -    When dense patches of these clouds condense and collapse under their own gravity, they birth new stars that contain the material from stellar predecessors. That means objects like the Ring Nebula can weave a tale of stellar life and death.

            -

            -     4117 -   MOST  DISTANT  GALAXY?     Astronomers have begun measuring of the most distant star ever detected.  That star, known as “Earendel”, was discovered last year by the Hubble Space Telescope. It has taken 12.9 billion years for Earendel's light to reach Earth, meaning the star was shining less than a billion years after the Big Bang spurred our universe into existence.

            -

            -    4118  -   SUN  -  high energy flares?     Scientists discover the highest-energy light coming from the sun.  The sun is more surprising than we knew.  Astronomers thought we had this star figured out, but that's not the case.

            -

            -     4119 -   COMET  NEAR  EARTH?    Astronomers discover 'potentially hazardous' asteroid 600 feet wide.  This dangerous space rock was discovered for the first time by an Artificial  Intelligence”,AI algorithm.  August 13, 2023.

            -

            -     4120 -   WATER  ON  PLANETS?      Liquid water on Rocky Planets could be 100 times more likely than we thought.   It’s easy to think of Earth as a water world, with its vast oceans and beautiful lakes, but compared to many worlds, Earth is not particularly wet.

            -

            -     4121 -    MUON  AND  HIGGS - BOSON  PHYSICS.      The discovery of wobbling muons promises to spark a revolution in physics.  This tiny wobbling particle may be about to reveal a fifth force of nature.  Physicists have found more evidence that the muon, a subatomic particle, is wobbling far more than it should, and they think it's because an unknown force is pushing it.

            -

            -     4122 -   EARTH'S ORBITS  -  how many, how fast?     You'll travel nearly a trillion miles in your lifetime.  Everything in the universe is moving, and fast.   So how far, on average, does a person travel in their lifetime? The answer depends on whether you consider Earth as your vehicle.

            -

            -     4123   -  MILKYWAY  GALAXY  - what shape it's in?    The Milky Way wasn't always a spiral, and astronomers may finally know why it 'shape-shifted'.  A century-old mystery of how galaxies change shapes has been solved by considering 'survival of the fittest' collisions between galaxies.

            -

            -     4124 -   MARS  -  heliocopter explorations?      After 63 Days of silence, NASA has restored communications with the Mars Helicopter.  “Ingenuity” helicopter not only racked up several firsts for humanity, most notably the first powered flight of a craft on another planet, but it has provided both a new perspective and new scientific data to its operations team.

            -

            -     4125 -  REDSHIFT   -  tell us distance to galaxies?      Astronomers can't directly measure the distance of galaxies billions of light years away. Instead, they measure what is known as “redshift”, or “z”. In this case, they measured a particular wavelength of light emitted by oxygen known as “OIII”.

            -

            -    4126 -   OLDEST GALAXY  -  looking back in time?      Born less than 400 million years after the Big Bang, 'Maisie's galaxyz' is officially one of the four oldest galaxies ever discovered.  A fiery orange smudge representing Maisie's galaxy, one of the earliesrt galaxies in the known universe.

            -

            -     4127 -    STARS and  Magnetars?     On a basic level, a star is pretty simple. Gravity squeezes the star trying to collapse it, which causes the inner core to get extremely hot and dense. This triggers nuclear fusion, and the heat and pressure from that pushes back against gravity. The two forces balance each other while a star is in its main sequence state.

            -

            -     4128 -   GRAVITY  -   how gravity works?   There is evidence for “modified gravity” at low acceleration from Gaia observations of wide binary stars.   A new study reports conclusive evidence for the breakdown of standard gravity in the low acceleration limit from a verifiable analysis of the orbital motions of long-period, widely separated, binary stars.

            -

            -     4129 -   DARK  MATTER  EXISTS  -    Even though scientists are certain that dark matter exists because as all our universe's normal matter simply can't account for the way galaxies are held together.  Still we don't know what it is. We also don't really know where it is (though they have some ideas). And we definitely don't know what it looks like.

            -

            -     4130  -  MAGNETARS  -  the death of massive stars?     At least 29 known magnetars exist in the Milky Way Galaxy, visible to us through their X-ray and gamma-ray emissions. Eventually, the magnetic fields relax and fade and the emissions stop. That leaves behind a dead core. It’s likely that our galaxy has tens of millions of inactive magnetars.

            -

            -    4131  -  JAMES  WEBB  TELESCOPE  -  easrly galaxy discoveries?     Why is James Webb Telescope seeing in the infrared wsvelengths?  Why is this powerful infrared observatory key to seeing the first stars and galaxies that formed in the universe? Why do we even want to see the first stars and galaxies that formed?

            -

            -    4132  -  LIGHT  -  the fastest known thing.     Light is faster than anything else in the known universe, though its speed can change depending on what it's passing through. Light slows down when it passes through air, glass, water, etc.  It is only fastest in a vacuum.

            -

            -     4133  -  EARLY  UNIVERSE -  is the same?    Scientists have made amazing progress in uncovering more and more information on how the Universe began and what conditions were like all those billions of years ago. Powerful infrared telescopes, especially the ground-breaking James Webb Space Telescope, have let astronomers study the ancient light from the early Universe.

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            -    4134  - DARK  MATTER  -  exists?    Our solar system is in a spiral arm of the Milky Way that is spinning, the Earth is orbiting the sun and the Earth rotates on its axis. This astronomical motion means the Earth is passing through the sea of dark matter particles, but from our perspective, that looks like dark matter particles are constantly bombarding the Earth and our detectors.

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            -    4135  - BLACK  HOLES  - many more found?  -   What has the new James Webb Space Telescope (JWST) was discovering about black holes in one of its surveys of the Universe?    Six distant galaxies captured by JWST are wowing astronomers.  It’s truly studying parts of the Universe that just weren’t available to us technologically.

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            -     4136 -   COSMIC  MICROWAVE  BACKGROUND  -      The cosmic microwave background radiation (CMB Radiation) verifies the fact that the universe is expanding. This is one of the most profound discoveries of the 20th century. This means that the universe was much smaller, denser, and hotter in the distant past.

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            -    4137  -    OLDEST  POPULATION  -  evidence of oldest humans?    86,000-year-old human bone found in Laos cave hints at 'failed population' from prehistory.  The discovery of a skull and shin bone fragment in a cave in Laos pushes back the earliest known date of Homo sapiens in Southeast Asia.

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            -    4138  - WHIRLPOOL  GALAXY  -   with the James webb telescope.    The team behind that whirlpool portrait stated that "although Hubble is providing incisive views of the internal structure of galaxies such as M51, the planned James Webb Space Telescope is expected to produce even crisper images.

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            -     4139  - SPIRAL  GALAXIES  -  how to explain them?     The Milky Way wasn't always a spiral, and astronomers may finally know why it 'shape-shifted'.  A century-old mystery of how galaxies change shapes has been solved by considering 'survival of the fittest' collisions between cosmic titans.

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            -     4140  -   EARLIEST  GALAXY  -  rewriting the birth of the Universe?     Before the Webb telescope switched on in 2022, we could not even dream of confirming such faint galaxies.   The combination of JWST and the magnifying power of gravitational lensing is a revolution. We are rewriting the book on how galaxies formed and evolved in the immediate aftermath of the Big Bang.

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            -     4141   -   SUPERNOVA  -  how exploding stars evolve?    The Pinwheel Galaxy, Messier 101 was observed on May 21, 2023, just four days after the light from the supernova “2023ixf “.  It was the nearest supernova since 2014,  21 million light years from Earth.

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            -    4142   -  EINSTEIN  CROSS  -  what causes it?        In 2021, the Gaia satellite found a dozen more “Einstein crosses” And, astronomers predict that more will be found as more powerful instruments and techniques perform surveys like Gaia’s.   More lenses like these will extend astronomy’s view to earlier epochs. They could perform as excellent probes of the dark matter distribution in the different epochs of cosmic time.

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            -     4143   -  GRAVITATIONAL  WAVES  - tell us about the Universe -    Scientists are reporting the first evidence that our Earth and the universe around us are awash in a background of spacetime undulations called “gravitational waves”. The waves oscillate very slowly over years and even decades and are thought to originate primarily from pairs of supermassive black holes leisurely spiraling together before they merge.

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            -     4144   -   MILKY WAY  -  birth of spiral galaxies?  -   The Milky Way wasn't always a spiral.  A century-old mystery of how galaxies change shapes has been solved by considering 'survival of the fittest' collisions between cosmic titans.  The "shape-shifting" nature of some galaxies has been solved, revealing in the process that our Milky Way galaxy did not always possess its familiar spiral appearance.

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            -    4145   -  OLDEST  METEORITE  -  older than the Earth?  -    Scientists have analyzed one of the oldest space rocks ever discovered. The data could reveal secrets about the solar system in its infancy during the birth of the planets and also help scientists better determine the ages of the oldest meteorites that fall to Earth.

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            -     4146   -    GRAVITATIONAL  WAVES  - changing our Universe?     The James Webb Spaxe Telescope is showing astronomers more of the Universe than we have ever seen before.  Problem is what we see is not what the theories say we should be seeing.  Maybe how the universe started is different than what we thought?

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            -     4147   -   EARLIEST  GALAXIES  -  James Webb new discoveries?   Before the Webb telescope switched on we could not even dream of confirming such a faint galaxy.  The combination of JWST and the magnifying power of gravitational lensing is a revolution. We are rewriting the book on how galaxies formed and evolved in the immediate aftermath of the Big Bang.

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            -     4148   -   UNIVERSE  -   model of the beginning?     Our understanding of the Universe is rooted in a cosmological model known as LCDM. The CDM stands for Cold Dark Matter, where most of the matter in the universe isn’t stars and planets, but a strange form of matter that is dark and nearly invisible.

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            -      4149   -   BLACK HOLE  -   switched on?     A Black Hole switched on in the blink of an eye?   In 2019, astronomers discovered one of the most powerful transients ever seen, where astronomical objects change their brightness over a short period.  Astronomers were searching for the source of a gravitational wave (GW) that was thought to be caused by two massive objects merging in our galaxy.

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            June 13,2023        Index of Reviews 4100 to 4150                          4150                                                                                                                          

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