4135 - BLACK HOLES - many more found?

 

-    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.

--------------  4135  -  BLACK  HOLES  - many more found?

-   These discoveries could help scientists to answer many long-standing queries about black holes, such as how they managed to form early in the history of the Universe and grow quickly into cosmic vacuums, sucking up everything around them.

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-    Black holes come in several sizes, but the ones JWST has been detecting are massive ones that weigh millions to billions times as much as the Sun. We aren’t sure how these black holes form, but it might involve massive stars or gas clouds collapsing and then beginning to draw in nearby gas and dust. In this scenario, these black-hole ‘seeds’ would grow rapidly, until they become gravitational maws that lurk at the heart of most galaxies.

-

-    Black holes are not themselves visible, their immense gravitational pull means that not even light can escape from them, but they can be spotted by searching for the superheated gas that spirals around them like water going down a drain.

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-    Before JWST, astronomers studied black holes using a range of space- and ground-based telescopes. But these could spot only the brightest black holes, including those that are relatively close to Earth.   JWST is designed to see light coming from the distant Universe and can see black holes lying farther away.

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-   Distance in the Universe can be measured by a quantity known as “redshift”; the higher an object’s redshift, the more distant it is and the earlier it appears in the Universe’s history. Many of JWST’s newfound black holes lie at redshifts of between 4 and 6, which corresponds to a time when the Universe was about 1 billion to 1.5 billion years old.

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-    In JWST images, these faint black holes appear as small and fairly unimpressive blobs, but “they are clearly different” from the galaxies surrounding them.   JWST has discovered roughly ten times as many faint black holes at these intermediate redshifts than would be expected on the basis of the number of black holes previously known.

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-     The confirmed record holder sits at the heart of a well-studied galaxy, called GN-z11, which has a redshift of 10.6.

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-    This suggests that as early as 400 million years after the Big Bang, the seeds for black holes had already formed and were able to create a supermassive object. Upcoming observations aim to probe the details of how superheated gas flows around GN-z11.

-

-    The most distant active supermassive black hole to date found within galaxy CEERS 1019.  It was detected because of the gas and other matter whirling around them. The black hole is more than 13 billion light-years from Earth.

-

-   JWST also spotted a black hole at a redshift of 8.7, in the galaxy CEERS 1019. This black hole somehow managed to accumulate 9 million times the mass of the Sun in the first 570 million years of the Universe.

-

-    This would violate the maximum rate at which black holes can grow, according to theory. But JWST observations suggest that some black holes, such as the one in GN-z11, might grow in this way, and that the theory might need revising.

-

-     Based on the Gravity Wave signal, the event was thought to be the result of a kilonova, where two neutron stars merge (or a neutron star and a black hole), releasing a tremendous amount of energy and gravitational waves in the process.

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-  The spectra indicated that the source was about 10 billion light-years distant, whereas the Gravity Wave signal was detected less than 0.5 billion light-years away.  The key discovery was when the ultraviolet spectrum from Hubble ruled out a Galactic origin.

-    This resulted from an SMBH that consumed surrounding material suddenly and rapidly. It was confirmed by optical and infrared data that previously detected a red galaxy in the vicinity, and the location of the bright burst is consistent with the galaxy’s center.

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-    The UV spectra showed absorption features consistent with a huge release of energy, which pushed and was absorbed by gas and dust surrounding the black hole. Combined with its brightness, the data revealed that J221951 is one of the most dramatic events ever seen where a black hole suddenly “switched on.”

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-   This discovery is part of a growing body of research that shows how SMBHs play a very active role in a galaxy’s star formation. As these behemoths gobble up material, such as gas, dust, and even stars, they release intense bursts of energy that disrupt star-forming material within the galaxy’s central region and disk

-

-    They have identified two possible mechanisms that could explain the sudden and voracious feeding behavior. On the one hand, it is possible that an orbiting star passed close to the SMBH and was pulled apart, known as a tidal disruption event (or more commonly as “spaghettification”).

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-    A second possibility is that J221951 is an active galactic nucleus (AGN), known as a “quasar,” that began feeding on its accretion disk.  The SMBH at the center of this galaxy “woke up” from its previously dormant state.

-

-   In the future, we will be able to obtain important clues that help distinguish between the tidal disruption event and active galactic nuclei scenarios. For instance, if J221951 is associated with an AGN turning on we may expect it to stop fading and to increase again in brightness, while if J221951 is a tidal disruption event we would expect it to continue to fade.

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August 31,  2023          BLACK  HOLES – many mor found?                4135

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

--------------------- ---  Thursday, August 31, 2023  ---------------------------------

 

 

 

 

 

           

 

 

4134 - DARK MATTER - exists?

 

-    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.

--------------  4134  -   DARK  MATTER  -  exists?

-   The quest to find dark matter is a curious one. It is, quite literally, a shot in the dark. Even though scientists are certain that dark matter exists, as all our universe's normal matter simply can't account for the way galaxies are kind of held together, they don't know what it is. They also don't really know where it is.

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-   Dark matter and dark energy of our universe accounts for 95% of our universe,  Dark energy is the unseen force accelerating space's expansion.

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-    But how does one analyze something without truly knowing what to analyze?  Researchers who are dedicated to the hunt recently did by sifting through data captured with a detector buried deep within a mine in Minnesota. While they did not find evidence of dark matter, they say they've created one of the tightest-ever limits for detecting this phenomenon.

-

-   A null result can be as impactful as a positive result.   Scientists managed to rule out a new slice of dark matter parameter space.   SuperCDMS's experimental detector concluded that we can now rule out dark matter particles down to about about a fifth of a proton's mass.

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-   The galaxy cluster 1E 0657-56, the "bullet cluster." was formed after the collision of two large clusters of galaxies, the most energetic event known in the universe since the Big Bang. Most of the matter in the clusters is clearly separate from the normal matter , giving direct evidence that nearly all of the matter in the clusters is “dark matter”.

-

-    To capture proof of these dark matter particles, the SuperCDMS collaboration works with an experiment that basically harnesses the power of detectors that can identify if and when a dark matter particle collides with the atomic nuclei of materials built into the detectors themselves, either germanium or silicon.

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-   SuperCDMS can pick out whether those dark matter particles partake in what are known as "elastic collisions”.  If they do, what would happen is any energy a dark matter particle loses upon its crash would get transferred to the motion of the impacted atomic nucleus. In turn, the two bits would recoil.   It'd be like two billiard balls smashing into one another only to slightly bounce backward on the table.

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-    What if SuperCDMS had been capturing some other type of collision no one's been looking for all this time? Particularly, z”inelastic” collisions.  There are two ways a potential dark-matter-inelastic collision may work. The first, has to do with something called “Bremsstrahlung radiation”.

-

-    In the detector, if this type of inelastic collision happened, the dark matter particle would transfer some of its energy to a light particle, or photon, rather than just recoiling like in the billiard ball example.

-

-   Inelastic collision may occur through something called the “Midgal effect”. If this version happened, the dark matter particle slamming into the nucleus would cause the nucleus itself to get knocked out of position, messing up its electron cloud distribution. Upon getting back into its original spot, some of those jostled electrons would get ejected.

-

-    There are roughly 1 billion dark matter particles passing through you every second, but they interact so rarely that you can't tell.  We're looking for a 1 in a billion billion billion billion chance of interaction.   Their conclusion was about dark matter particles' likely lower mass limits.

-

-   One of those things ripe for interaction is our planet's atmosphere.  If a dark matter particle did interact with our atmosphere, this planetary shield would take away some of the particle's energy by the time we captured its signals.  What do you think we will find?

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August 30,  2023                DARK  MATTER  -  exists?                                4134

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

--------------------- ---  Thursday, August 31, 2023  ---------------------------------

 

 

 

 

 

           

 

 

4133 - EARLY UNIVERSE - is the same?

 

-    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.

--------------  4133  -   EARLY  UNIVERSE -  is the same?

-    One of the mysteries astronomers want to untangle concerns star formation. Has it changed much since the Universe’s early days?  The Universe has evolved a lot since the first stars formed, and astrophysicists want to know if stars form differently now than they did billions of years ago.

-

-      The primary difference between stars that formed billions of years ago and stars  that form now concerns the material available during the process. Not only the amount of material but also how enriched it is. This is referred to as “stellar metallicity”.  Elements heavier than hydrogen and helium are called “metals”. These metals only come from one place: the stars themselves.

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-    Stars create elements heavier than hydrogen and helium through “nucleosynthesis”. The intense conditions inside massive stars create elements like oxygen, iron, carbon, and everything in the periodic table beneath H and He. When these stars explode as supernovae or shed their outer layers as red giants, these elements are cast out into space, available for the next round of star formation.

-

-    We live in a Universe where countless stars have lived and died, synthesized heavy elements and spread them out into space. Consequently, stars in the modern Universe are formed from a variety of elements.  Those elements that make up life on Earth.

-

-     But the Universe’s first stars didn’t have metals available to them and consisted of only hydrogen and helium.  Any planets that formed around these original stars couldn’t have been anything like Earth. Without previous generations of stars and the heavier elements they synthesized, rocky planets wouldn’t exist, and neither would we.

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-   Researchers located a star-forming region in the Milky Way exhibiting low metallicity that’s similar to the primitive Universe, compared to the higher metallicity in the contemporary Universe.

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-    Recaping the broad strokes of the star formation process as science understands it. Things begin in a massive structure in space called a giant molecular cloud. These clouds contain everything available to a nascent star.

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-    The clouds are dominated by hydrogen, the most abundant element in the Universe by far, and also the simplest. They’re called “molecular clouds” because individual hydrogen atoms don’t want to be alone. They bond together as a molecule containing two atoms of hydrogen.

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-    These clouds are not perfectly uniform in their structure. There are irregularities, regions where the gas is more or less dense, and exhibits different temperatures, motions, and velocities. Eventually, small knots or clumps of gas form in these clouds, and over time their gravity draws more gas into them.

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-       Eventually, enough material is drawn in to form a “protostar”, which gives off some energy but hasn’t begun fusion yet. Only when enough mass has gathered to drive the core pressure and temperature to extremes does fusion begin. Then we have a “star”, beginning its long journey along the main sequence.

-

-   But how do differing levels of metallicity affect the stars that result from this detailed process?

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-    Higher metallicity can result in stars with lower temperatures. Stars with higher metallicities can be cooler while they’re on the main sequence and on the giant branch. They can also appear redder.

-

-   None of this is particularly surprising. Even though metals, meaning elements heavier than hydrogen and helium, make up only about 2% of the Universe’s baryons by mass, they have a powerful effect on heating and cooling during star formation. Metallicity is one of the most critical factors in star formation.

-

-    A star’s future is determined by its mass. Huge stars, many times more massive than our Sun, burn hot and don’t last long. These can end as supernovae. Stars much less massive than our Sun are called low-mass stars, and they vastly outnumber high-mass stars. These stars, including the plentiful red dwarf stars, can live for trillions of years.

-

-    Stars seldom form in isolation. Typically, they form in clusters, and in these clusters, the masses of individual stars are similar. Would stars forming in the early low-metallicity Universe maintain this similarity in masses?

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-    Star labelled “S209” can help answer that question because it has another thing going for it other than its low metallicity. It’s close, only about 2.5 parsecs (8.1 light-years) away. This is close enough to enable us to resolve cluster members clearly (~1000 au separation) down to a mass-detection limit of ~ 0.1 solar masses and we have identified two star-forming clusters in S209, with individual cluster scales ~1 pc.

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-    S209 holds two separate star clusters. One is large, and one is small, and the larger one contains up to 1,500 stars. This work marks the first time that astronomers have identified a cluster with this many identifiable members in the Milky Way’s outer regions.

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-    It’s critical because other, similar regions contain only about 100 stars, a sample too small to draw reliable conclusions from.   The Subaru Telescope’s power identified stars as small as 1/10 the Sun’s mass, up to stars 20 times the Sun’s mass.   It all comes down to what’s called the Initial Mass Function (IMF), and its utility in understanding stars, solar systems, and even galaxies.

-

-    The IMF and the stellar metallicity help dictate how stars will form in a given cluster. As stars form, they regulate their own mass through self-radiative feedback. The effect of self-radiative feedback is more pronounced in a low-metallicity environment, so these environments should produce more high-mass stars.

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-    S209 contains a few more stars that are more massive than other star-forming regions in the neighbourhood, but only slightly more. S209 also has slightly more stars that are less massive than the Sun.

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-     The outer part of the Milky Way is known to have properties similar to those of the early Universe.   Results suggest that although a relatively large number of massive stars formed in the early Universe, the number is not dramatically different from that of typical star clusters in the present day.

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-     Weirdness didn’t pervade everything. Stars are the Universe’s basic building blocks, and this research indicates that they formed much the same way back then as they do now.

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August 31,  2023         EARLY  UNIVERSE -  is the same?              4133

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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”  -----------

--------------------- ---  Thursday, August 31, 2023  ---------------------------------

 

 

 

 

 

           

 

 

4132 - LIGHT - the fastest known thing.

 

-    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.

--------------  4132  -   LIGHT  -  the fastest known thing.

-    The universe has a speed limit, and it's the speed of light. Nothing can travel faster than light , according to the laws of physics.

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-    Light moves at an incredible 186,000 miles per second (300,000 kilometers per second), equivalent to almost 700 million mph. That's fast enough to circumnavigate the globe 7.5 times in one second, while a typical passenger jet would take more than two days to go around once (and that doesn't include stops for fuel or layovers!).

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-    Light moves so fast that, for much of human history, we thought it traveled instantaneously. As early as the late 1600s, though, scientist Ole Roemer was able to measure the speed of light (usually referred to as “c”) by using observations of Jupiter's moons.

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-   Around the turn of the 19th century, physicist James Clerk Maxwell created his theories of electromagnetism. Light is itself made up of electric and magnetic fields, so electromagnetism could describe the behavior and motion of light including its theoretical speed.

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-    That value was 299,788 kilometers per second, with a margin of error of plus or minus 30. In the 1970s, physicists used lasers to measure the speed of light with much greater precision, leaving an error of only 0.001. Nowadays, the speed of light is used to define units of length, so its value is fixed; humans have essentially agreed the speed of light is 299,792.458 kilometers per second, exactly.

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-    Light doesn't always have to go so fast.  Depending on what it's traveling through air, water, diamonds, etc. it can slow down. The official speed of light is measured as if it's traveling in a vacuum, a space with no air or anything to get in the way. You can most clearly see differences in the speed of light in something like a prism, where certain energies of light bend more than others, creating a rainbow of light.

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-    The speed of light is no match for the vast distances of space, which is itself a vacuum. It takes 8 minutes for light from the sun to reach Earth, and a couple years for light from the other closest stars (like Proxima Centauri) to get to our planet. This is why astronomers use the unit light-years, the distance light can travel in one year, to measure vast distances in space.

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-    Because of this universal speed limit, telescopes are essentially time machines. When astronomers look at a star 500 light-years away, they're looking at light from 500 years ago. Light from around 13 billion light-years away (equivalently, 13 billion years ago) shows up as the cosmic microwave background, remnant radiation from the Big Bang in the universe's infancy.

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-    The speed of light isn't just a quirk of physics; it has enabled modern astronomy as we know it, and it shapes the way we see the world, literally.

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August 28,  2023              LIGHT  -  the fastest known thing.               4132

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

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

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

--------------------- ---  Monday, August 28, 2023  ---------------------------------

 

 

 

 

 

           

 

 

4130 - MAGNETARS - the death of massive stars?

 

-    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.

--------------  4130  -    MAGNETARS  -  the death of massive stars?

-    The Earth is a magnet with a north and south poles.  Could stars be magnets? Imagine a living star with a magnetic field at least 100,000 times stronger than Earth’s field. That’s the strange stellar “ HD 45166”.

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-    Its field is an incredible 43,000 Gauss. That makes it a new type of object: a “massive magnetic helium star”. In a million years, it’s going to get even stranger when it collapses and becomes a type of neutron star called a “magnetar”.

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-     HD 45166 provides clues to the creation of magnetars.   This object is no ordinary massive star. It is what’s left after the merger of two lower-mass helium stars.  The result is this heavily magnetized helium star which mimics the core of a star that was originally 8 times more massive than our Sun.  It is massive enough to explode as a supernova and collapse into a neutron star.

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-    It is a highly unusual star that is destined to become one of the most magnetic objects in the Universe: a variant of a neutron star known as a magnetar. This finding marks the discovery of a new type of astronomical object, a massive magnetic helium star and sheds light on the origin of magnetars.

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-    Eventually, HD 45166 will explode as a very bright, but not particularly energetic, supernova. Its core will contract, trapping and concentrating the star’s magnetic field lines. The result will be a neutron star with a magnetic field that is far greater.

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-    The newly formed helium object is a highly evolved “Wolf-Rayet star”. Before it becomes a magnetar, it has to go through some more changes. Stellar evolution models suggest that it will eventually explode as a type Ib or IIb supernova.

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-     As it collapses under its own gravity, the already-strong magnetic field will grow. Eventually, the object will become a very compact core with a magnetic field of around 100 trillion Gauss. That would make it one of the most powerful types of magnet in the Universe: a magnetar.

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-    HD 45166 is actually a stellar pair, of which the “Wolf-Rayet star” is one member. Astronomers have observed it for more than a century, but its strange characteristics defied explanation.

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-    In February 2022 the team used an instrument on the Canada-France-Hawaii Telescope that can detect and measure magnetic fields. They also relied on archival data taken with the “Fiber-fed Extended Range Optical Spectrograph” (FEROS) at ESO’s La Silla Observatory in Chile. That’s how the team found out the star had a magnetic field strength of 43 kiloGauss.

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-  The entire surface of the helium star has a magnetic field almost 100,000 times stronger than Earth’s.   This observation marks the discovery of the very first massive magnetic helium star.

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-   How Do Magnetars Form?   Magnetaes neutron stars, the hot leftovers from the deaths of supermassive stars. Essentially, neutron stars are the cores of the once-living supermassive stars. They’re no longer stars with nuclear fusion going on in their cores. Instead, these beasts are spinning spheres of condensed neutrons packed together incredibly tightly. All that mass has very strong gravity.    Something inside is generating a magnetic field that is trillions of times stronger than Earth’s.

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-    Magnetars generate magnetic fields a thousand times stronger than their progenitor neutron stars. The process comes from a magnetohydrodynamic process in conducting “fluids” inside the star. This is roughly similar to what happens in the turbulent center of our planet. Like their neutron star predecessors, magnetars likely have solid, crusty surfaces.

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-   Astronomers continue to probe these objects for clues to the origins of their magnetic fields. As far back as 2009, they entertained the idea that stellar mergers could create conditions for such strong fields.   The origin of the magnetic field in HD 45166 probably goes back to the process that created the proto-magnetar. It gave rise to the hefty magnetic field that got “frozen” into the layers of the star. That field will be the future magnetar.

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August 28,  2023        MAGNETARS   -  the death of massive stars?            4130

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

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---   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”  -----------

--------------------- ---  Monday, August 28, 2023  ---------------------------------

 

 

 

 

 

           

 

 

4129 - DARK MATTER EXISTS

 

-    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.

--------------------------  4129  -   DARK  MATTER  EXISTS

-    We still don't know what dark matter is, but here's what it's not.   Two views from Hubble of the massive galaxy cluster Cl 0024+17 (ZwCl 0024+1652)  show a blue shading that has been added to indicate the location of invisible material called “dark matter” that is mathematically required to account for the nature and placement of the gravitationally lensed galaxies that are seen.

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-    The dark side of our cosmos accounts for an unsettling 95% of our universe when taking into account dark energy, the unseen force accelerating space's expansion.  But, how does we analyze something without truly knowing what to analyze?

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-   Scientists are sifting through data captured with a detector buried deep within a mine in Minnesota. While they did not find evidence of dark matter, they say they've created one of the tightest-ever limits for detecting it.

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-    A null result can be as impactful as a positive result.  Scientists have managed to rule out a new slice of dark matter parameter space.  Using this “SuperCDMS's” experimental detector, they can now rule out dark matter particles down to about about a fifth of a proton's mass.

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-    This SuperCDMS experiment basically harnesses the power of detectors that can identify if and when a dark matter particle (whatever that is) collides with the atomic nuclei of materials built into the detectors themselves, specifically either germanium or silicon.

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-   SuperCDMS can pick out whether those dark matter particles partake in what are known as "elastic collisions." If they do, what would happen is any energy a dark matter particle loses upon its crash would get transferred to the motion of the impacted atomic nucleus. In turn, the two bits would recoil.  SuperCDMS clearly hasn't found any elastic collisions yet.

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-    What if SuperCDMS had been capturing some other type of collision no one's been looking for all this time? Particularly, inelastic collisions.    Searching for elastic collisions is still the main thrust of SuperCDMS, but considering inelastic collisions opened an avenue to dark matter parameter space that the experiment was not previously sensitive to.

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-   There are two ways a potential dark-matter-inelastic collision may work. The first,  has to do with something called “Bremsstrahlung radiation”.  In the detector, if this type of inelastic collision happened, the dark matter particle would transfer some of its energy to a light particle, or photon, rather than just recoiling.

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-    Though on the other hand, an inelastic collision may occur through something called the “Midgal effect”. If this version happened, the dark matter particle slamming into the nucleus would cause the nucleus itself to get knocked out of position, messing up its electron cloud distribution. Upon getting back into its original spot, some of those jostled electrons would get ejected.

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-    This means the team was searching for SuperCDMS signals of either a flying photon or lonely electron straggler.   This analysis used spectral shapes to model the energy profile of the signal as well as the many known background sources.

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-   They used statistics to answer the question 'what is the probability that we see the signal over the known background?  That question is repeated hundreds of thousands of times and we rule out the parameter space where we should've been able to see the signal and didn't.

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-    There are roughly 1 billion dark matter particles passing through you every second, but they interact so rarely that you can't tell.   We're looking for a 1 in a billion billion billion billion chance of interaction.  Their conclusion about dark matter particles is the  likely lower mass limits.

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-   The entire Earth's position in space can affect these dark matter signals.  If dark matter interacts strongly enough with stuff, it'd likely interact with literally everything in its path on the way to our little Earth-based detectors underground. One of those things ripe for interaction is our planet's atmosphere.

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-    And if a dark matter particle did interact with our atmosphere, this planetary shield would take away some of the particle's energy by the time we captured its signals.  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.

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-    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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-   By modeling things like Earth's atmospheric density, working with geologists to figure out what types of rocks are above the Minnesotan mine where SuperCDMS is buried and tons of other variables, they indeed figured out those upper dark matter energy limits.

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-    When you fit a line to some data, there are 2 parameters: Slope and intercept.  In this analysis, we had over 50 parameters being fit simultaneously.  These dark matter hunters surely reached for the stars and managed to softly land on the moon.

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August 28,  2023             DARK  MATTER  EXISTS                     4129

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

--------  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”  -----------

--------------------- ---  Monday, August 28, 2023  ---------------------------------

 

 

 

 

 

           

 

 

4131 - JAMES WEBB TELESCOPE - early galaxy discoveries?

 

-    4131  -  JAMES  WEBB  TELESCOPE  -  early galaxy discoveries?     Why is James Webb Telescope seeing in the infrared wavelengths?  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?

------- 4131  -   JAMES  WEBB  TELESCOPE  -  early galaxy discoveries?    

-     The microwave COBE and WMAP satellites saw the heat signature left by the Big Bang about 380,000 years after it occurred. But at that point there were no stars and galaxies. In fact the universe was a dark place.

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-    After the Big Bang, the universe was like a hot soup of particles, protons, neutrons, and electrons. When the universe started cooling, the protons and neutrons began combining into ionized atoms of hydrogen and eventually some helium. These ionized atoms of hydrogen and helium attracted electrons, turning them into neutral atoms which allowed light to travel freely for the first time, since this light was no longer scattering off free electrons.

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-    The universe was no longer opaque! However, it would still be up to a few hundred million years post-Big Bang before the first sources of light would start to form, ending the cosmic dark ages.

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-    Exactly what the universe's first light when stars that fused the existing hydrogen atoms into more helium.   When these first stars formed is not known. These are some of the questions Webb was designed to help us to answer.

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-    Imagine light leaving the first stars and galaxies nearly 13.6 billion years ago and traveling through space and time to reach our telescopes. We're essentially seeing these objects as they were when the light first left them 13.6 billion years ago. By the time this light reaches us, its color or wavelength has been shifted towards the red, we call a "redshift."

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-    The expansion of the universe means it is the space between objects that actually stretches, causing objects (galaxies) to move away from each other. Furthermore, any light in that space will also stretch, shifting that light's wavelength to longer wavelengths. This can make distant objects very dim (or invisible) at visible wavelengths of light, because that light reaches us as infrared light.

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-    Webb is able to see back to about 100 million to 250 million years after the Big Bang.  Redshift means that light that is emitted by these first stars and galaxies as visible or ultraviolet light, actually gets shifted to redder wavelengths by the time we see it here and now. For very high redshifts, the farthest objects from us, that visible light is generally shifted into the near- and mid-infrared part of the electromagnetic spectrum.

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Webb is addressing several key questions to help us unravel the story of the formation of structures in the Universe such as:

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-----------------------------  When and how did reionization occur?

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-----------------------------  What sources caused reionization?

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-----------------------------  What are the first galaxies?

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-     To find the first galaxies, Webb will make ultra-deep near-infrared surveys of the Universe, and follow up with low-resolution spectroscopy and mid-infrared photometry , the measurement of the intensity of an astronomical object's electromagnetic radiation. -

-    To study reionization, high resolution near-infrared spectroscopy is needed.

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-    After the Big Bang, the universe was like a hot soup of particles (i.e. protons, neutrons, and electrons). When the universe started cooling, the protons and neutrons began combining into ionized atoms of hydrogen and deuterium. Deuterium further fused into helium-4. These ionized atoms of hydrogen and helium attracted electrons turning them into neutral atoms. Ultimately the composition of the universe at this point was 3 times more hydrogen than helium with just trace amounts of other light elements.

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-    This process of particles pairing up is called "Recombination" and it occurred approximately 240,000 to 300,000 years after the Big Bang. The Universe went from being opaque to transparent at this point. Light had formerly been stopped from traveling freely because it would frequently scatter off the free electrons. Now that the free electrons were bound to protons, light was no longer being impeded.

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-    The “era of recombination" is the earliest point in our cosmic history to which we can look back with any form of light. This is what we see as the Cosmic Microwave Background today with satellites like the Cosmic Microwave Background Explorer (COBE) and the Wilkinson Microwave Anisotropy Probe (WMAP).                 -

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-    Following this are the “cosmic dark ages” , a period of time after the Universe became transparent but before the first stars formed. When the first stars formed, it ended the dark ages, and started the next epoch in our universe.

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-    Another change occurred after the first stars started to form. Theory predicts that the first stars were 30 to 300 times as massive as our Sun and millions of times as bright, burning for only a few million years before exploding as supernovae. The energetic ultraviolet light from these first stars was capable of splitting hydrogen atoms back into electrons and protons (or ionizing them).

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-    This era, from the end of the “dark ages” to when the universe was around a billion years old, is known as "the epoch of reionization." It refers to the point when most of the neutral hydrogen was reionized by the increasing radiation from the first massive stars.

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-     Reionization is an important phenomenon in our universe's history as it presents one of the few means by which we can (indirectly) study these earliest stars. But scientists do not know exactly when the first stars formed and when this reionization process started to occur.

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-    Hubble Deep Field is the first significant look back to the era of the universe when early galaxies were forming. The image is a long exposure of a very small area of the sky, which revealed a large number of very faint, and previously unseen, objects. These objects are some of the oldest and most distant galaxies and allowed us to glimpse the first steps of galaxy formation more than 10 billion years ago.

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-    The emergence of these first stars marks the end of the "Dark Ages" in cosmic history, a period characterized by the absence of discrete sources of light.  These first sources is critical, since they greatly influenced the formation of later objects such as galaxies. The first sources of light act as seeds for the later formation of larger objects.

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-    The first stars that exploded as supernovae might have collapsed further to form black holes. The black holes started to swallow gas and other stars to become objects known as "mini-quasars," which grew and merged to become the huge black holes now found at the centers of nearly all massive galaxies.

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-   JWST spies more black holes than astronomers predicted.   JWST’s unprecedented power has allowed it to discover a huge range of these blackholes from many faint, distant black holes to a handful of bright ones raging even farther away.

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-    Black holes come in several sizes, but the ones JWST has been detecting are massive ones that weigh millions to billions times as much as the Sun. Astronomers aren’t sure how these black holes form, but it might involve massive stars or gas clouds collapsing and then beginning to draw in nearby gas and dust. In this scenario, these black-hole ‘seeds’ would grow rapidly, until they become gravitational maws that lurk at the heart of most galaxies.

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-    Black holes are not themselves visible, their immense gravitational pull means that not even light can escape from them,  but they can be spotted by searching for the superheated gas that spirals around them like water going down a drain.

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-    Before JWST, astronomers studied black holes using a range of space and ground based telescopes. But these could spot only the brightest black holes, including those that are relatively close to Earth. JWST is designed to see light coming from the distant Universe and can see black holes lying farther away including ones that astronomers thought would be too dim to detect.

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-    Distance in the Universe can be measured by a quantity known as redshift; the -higher an object’s redshift, the more distant it is and the earlier it appears in the Universe’s history. Many of JWST’s newfound black holes lie at redshifts of between 4 and 6, which corresponds to a time when the Universe was about 1 billion to 1.5 billion years old.

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-    So far, JWST has discovered roughly ten times as many faint black holes at these intermediate redshifts than would be expected on the basis of the number of black holes previously known.

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-    JWST has also found several of the most distant black holes ever seen. The confirmed record holder of the bunch8 sits at the heart of a well-studied galaxy, called GN-z11, which has a redshift of 10.6. This suggests that as early as 400 million years after the Big Bang, the seeds for black holes had already formed and were able to create a supermassive object.

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-     To JWST, distant black holes look like blobs detected because of the gas and other matter whirling around them. The black hole at the center of the CEERS 1019 galaxy lies more than 13 billion light-years from Earth.

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-    Such distant JWST discoveries fit with recent simulations of the birth of early black holes13.  Astronomers have found that big black holes can form in the early Universe if they gobble gas at incredibly high rates in their early stages.

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August 28,  2023   JAMES  WEBB  TELESCOPE  -  early galaxy discoveries?   4131

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