3614 - BLACKHOLES - at the center of Milky Way Galaxy?

  -  3614 -   BLACKHOLES  -  at the center of Milky Way Galaxy?   The supermassive black hole at our galaxy's core, Sagittarius A*, is modest in size with only 4,150,000  solar-masses. The Event Horizon Telescope (EHT) recently released a dramatic submillimeter image of it as seen illuminated by its glowing environment.

---------------  3614  - BLACKHOLES  -  at the center of Milky Way Galaxy?

-   Many galaxies have nuclear black holes at their center that are a thousand times bigger than the Milky Way black hole.  The nucleus of M87 image was taken by the EHT in 2020. But SagA* is relatively close to us, only about 25,000 light-years, and its proximity offers astronomers a unique opportunity to probe the properties of black holes.

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-  As gas and dust slowly accrete onto a black hole's surrounding hot, disk-like environment they radiate across the electromagnetic spectrum. The accretion and variable radiation bursts offer clues to the nature of the accretion, the dimensions and locations of each event in the black hole's complex environment. and how the episodes might be related to one another and to properties of the black hole, like its spin. 

-

-  Each wavelength carries its own information, and one of the key tools is the time difference between flares at different wavelengths which trace where in the outburst the different production mechanisms occur. 

-

-  Sag A* is close enough that it has been monitored at radio wavelengths since its discovery in the 1950's; on average Sgr A* accretes material at a very low rate, a few hundredths of an Earth-mass per year, but enough to produce variability as well as more dramatic flares.

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-  Flaring events were seen July, 2019.   The 2019 activity seems to reflect an unusually high accretion rate. While some of the events were observed to occur simultaneously, the submillimeter flaring (ALMA) appeared roughly 20 minutes after the infrared and X-ray flares (Chandra).

-

-  The scientists consider three scenarios: 

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-  (1)  The infrared and X-ray emission in these flares arose from charged particles spiraling in powerful magnetic fields; 

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-  (2)  The infrared and submillimeter came from this first process, but the X-ray emission was produced when infrared photons collided with charged particles moving near the speed of light.

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-  (3)  Only the submillimeter radiation came from the first process and all the other bands were produce by the second. 

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-  Unfortunately ground-based observations cannot be continuous, and as a result the time of the peak of the submillimeter emission flare was not observed, making it hard to pin down any time-delay between it and the X-rays that could signal its arising in a different location or from a different process. 

-

-  The combining its results with earlier variability studies, finds one consistent picture in which the infrared and X-rays originate via the second process followed by submillimeter emission from the first in an expanding, cooling magnetized plasma.

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-  Looks can be deceiving. The light from an incandescent bulb seems steady, but it flickers 120 times per second. Because the brain only perceives an average of the information it receives, this flickering is blurred and the perception of constant illumination is a mere illusion.

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-  While light cannot escape a black hole, the bright glow of rapidly orbiting gas has its own unique flicker.   Astronomers are able to use this subtle flickering to construct the most accurate model to date of our own galaxy's central black hole providing insight into properties such as its structure and motion.

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-   Gas travels in the center of the Milky Way from being blown off by stars to falling into the black hole.    The black hole feeding in the galactic center involves directly infalling gas from large distances, rather than a slow siphoning off of orbiting material over a long period of time.

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-  Although the existence of black holes was predicted about 100 years ago by Karl Schwarzschild, based on Albert Einstein's new theory of gravity, researchers are only now starting to probe them through observations

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-  For a long time, we thought that we could largely disregard where the gas around the black hole came from. Typical models imagine an artificial ring of gas, roughly donut shaped, at some large distance from the black hole. We found that such models produce patterns of flickering inconsistent with observations.

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-    A “stellar wind model” takes a more realistic approach, in which the gas consumed by black holes is originally shed by stars near the galactic center. When this gas falls into the black hole, it reproduces the correct pattern of flickering.  

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-   When we study flickering, we can see changes in the amount of light emitted by the black hole second by second, making thousands of measurements over the course of a single night.  

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-  Like an incandescent light bulb when we slow it down we learn it is not a continuous light.  Astronomers hope to learn more by studying this flickering at many different frequencies coming from the center of our galaxy.

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June 28, 2022        BLACKHOLES  -  at the center of Milky Way Galaxy?         3614                                                                                                                                           

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--------------------- ---  Tuesday, June 28, 2022  ---------------------------

3613 - MERCURY - we sent a messenger to learn?

  -  3613 -   MERCURY -  we sent a messenger to learn?    Our space probe, “BepiColombo“, just flew passes the planet Mercury. But, it is going too fast to stop.  It is scheduled to make six more passes around the Sun before settling down in Mercury orbit.   

---------------------  3613  -   MERCURY -  we sent a messenger to learn?

-  We all know the planet Mercury is closest to the sun.  The Sun’s gravity should help us send a space probe there.  There is only Venus between us and Mercury.  Getting there is not so hard using the Sun’s gravity as an assistant.  But, stopping once you get  there is not so easy.  

-

-  The BepiColombo spacecraft on Thursday, June 23, 2022,  passed just 200 kilometers from the surface of our innermost world. During that brief encounter, BepiColombo got a brief glimpse of its final destination.

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-  This completes a second of six Mercury flybys. It will be back this time next year for the third before arriving into a Mercury orbit in 2025.

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-  The spacecraft approached Mercury from the planet’s night side, then began imaging the cratered surface about five minutes after closest approach as the Sun rose over the illuminated terrain below. 

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-  This,  the second Mercury flyby for the spacecraft of six overall that BepiColombo must perform before arriving in orbit around Mercury in December 2025. Launched on October 20, 2018,  from Guiana Space Center atop an Ariane-5 rocket, the spacecraft also performed an Earth flyby on April 10, 2020, and two Venus flybys in 2020 and 2021.

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-   Getting deep into the inner solar system and entering orbit around an inner planet is a complex and time-consuming process, as the spacecraft must bleed off momentum during each successive planetary flyby.  It cannot not carry enough fuel to use thruster to slow down.  

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-  The probe is a stacked pair of satellites that will separate after orbital insertion, and will probe Mercury once science operations begin in 2026. The pair of probes will examine the planet from its core, interior and surface terrain, out through its magnetosphere and tenuous atmospheric sodium ‘tail’. 

-

-   BepiColombo provided science observations during its first Mercury flyby on October 1, 2021, and we can expect to see more data gathered from this pass.

-

-  It is now the third spacecraft to reach Mercury, after the Mariner 10 flyby in 1973 and NASA’s Mercury Messenger in 2011 to 2015. The spacecraft will also become the second mission to enter orbit around Mercury, after Messenger.

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-   BepiColombo will build upon data and science collected by Messenger, which completed its mission by crashing into Mercury on April 30, 2015, becoming the first human artifact to touch this innermost world.

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-  The images from the second flyby reveal the ancient cratered surface of Mercury, appearing much like our own Moon. Prominent features such as the “Caloris Basin”, a massive 1,550 kilometer-wide impact feature are visible. The volcanic lavas around the basin are thought to predate the basin itself by several hundred million years, and could provide crucial clues to the geological history of Mercury.

-

-  You can see Mercury now low in the dawn sky in June, 2022, as the most challenging planet in the current dawn solar system lineup because its smaller orbit does not carry it much above the horizon.  

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-  It’s amazing that we live in an era where we can now discuss topics like the ‘planetary geology’ of Mercury. Thanks to spacecraft like BepiColombo, these enigmatic worlds that have remained mere points of light for centuries have now become dynamic and exciting worlds in their own right.

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-  We have a lot more to learn.  Maybe my grandchildren will read this?  And, tell more of the story.

-

June 26, 2022                    3613                                                                                                                                           

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--------------------- ---  Monday, June 27, 2022  ---------------------------

3612 - GAIA Space Telescope - data is pouring in?

  -  3612 -   GAIA  Space Telescope  -  data is pouring in?   The “Gaia space mission” will make the largest, most precise three-dimensional map of our Milky Way Galaxy by surveying more than a thousand million stars.  Gaia will monitor each of its target stars about 70 times over a five-year period.

---------------------  3612  -  GAIA  Space Telescope  -  data is pouring in?

-  Gaia will precisely chart star positions, distances, movements, and changes in brightness. It is expected to discover hundreds of thousands of new celestial objects, such as extra-solar planets and brown dwarfs, and observe hundreds of thousands of asteroids within our own Solar System. 

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-  The mission will also study about 500,000 distant quasars and will provide stringent new tests of Albert Einstein’s General Theory of Relativity.  It will create an extraordinarily precise three-dimensional map of more than a thousand million stars throughout our Galaxy and beyond, mapping their motions, luminosity, temperature and composition. 

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-  This huge stellar census will provide the data needed to tackle an enormous range of important problems related to the origin, structure and evolutionary history of our Galaxy. Gaia will identify which stars are relics from smaller galaxies long ago ‘swallowed’ by the Milky Way.

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-    By watching for the large-scale motion of stars in our Galaxy, it will also probe the distribution of dark matter, the invisible substance thought to hold our Galaxy together.

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-  Gaia will achieve its goals by repeatedly measuring the positions of all objects down to magnitude 20 which is about 400,000 times fainter than can be seen with the naked eye.

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-  For all objects brighter than magnitude 15 (4,000 times fainter than the naked eye limit), Gaia will measure their positions to an accuracy of 24 micro-arcseconds. This is comparable to measuring the diameter of a human hair at a distance of 1,000 kilometers.

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-  It will allow the nearest stars to have their distances measured to the extraordinary accuracy of 0.001%. Even stars near the Galactic center, some 30,000 light-years away, will have their distances measured to within an accuracy of 20%.

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-  Gaia contains two optical telescopes that work with three science instruments to precisely determine the location of stars and their velocities, and to split their light into a spectrum for analysis.

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-  During its five-year mission, the spacecraft spins slowly, sweeping the two telescopes across the entire celestial sphere. As the detectors repeatedly measure the position of each celestial object, they will detect any changes in the object’s motion through space.

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-  After launch, Gaia unfolded a ‘skirt’ just over 10 meters in diameter. This acts as both a sunshade to permanently shade the telescopes and allow their temperatures to drop to below –100°C, and as a power generator for the spacecraft. The underside of the shield is partially covered with solar panels and will always be facing the Sun, generating electricity to operate the spacecraft and its instruments.

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-  Gaia is mapping the stars from an orbit around the Sun, at a distance of 1.5 million km beyond Earth’s orbit. This special location, known as the L2 Lagrangian point, keeps pace with Earth as we orbit the Sun. It offers a clearer view of the cosmos than an orbit around Earth, which would result in the spacecraft passing in and out of Earth's shadow and causing it to heat up and cool down, distorting its view. Free from this restriction and far away from the heat radiated by Earth, L2 provides a much more stable viewpoint.

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-  Gaia has its roots in ESA’s Hipparcos mission (1989-1993), which catalogued more than 100,000 stars to high precision, and more than a million to lesser precision. Now, some 20 years later, Gaia will catalogue a thousand million stars, measuring each star's position and motion 200 times more accurately than Hipparcos, and producing 10,000 times more data than its predecessor.

-

-  Gaia's massive third data release is out, June, 2022.  This data release called (DR3) by the ESA’s Gaia Observatory.  DR3 contains new and improved details for almost two billion stars in our galaxy, including the chemical compositions, temperatures, colors, masses, ages, and the velocities at which stars move. 

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-   Much of this information consists of newly released spectroscopy data, a technique in which starlight is split into the color spectrum and analyzed to determine how it is being shifted. This technique is known as “radial velocity” ( Doppler Spectroscopy), where light is shifted towards the red or blue end of the spectrum ( redshift and blueshift) based on whether the object is moving towards or away from Earth (respectively). Astrophysicists use this technique to determine how a star is moving relative to our own and also for the sake of detecting exoplanets.

-

-  This latest release also includes data on special subsets of stars, like those that undergo changes in brightness over time ( variable stars). The DR3 also contained the largest catalog of binary star systems, thousands of Solar System objects (asteroids and moons), and millions of galaxies and quasars outside the Solar System (like Andromeda). Other major discoveries include the ability of Gaia to detect tiny motions on the surface of a star (Starquakes) and improved data on the chemical compositions of stars.

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-  Starquakes are a phenomenon where the crust of a star undergoes a sudden adjustment that changes its shape. This was a surprise to astronomers since it is not something the observatory was not originally built for. Previously, Gaia data pointed towards radial oscillations that cause stars to swell and shrink periodically but leave their shape unaffected. The latest data demonstrates that Gaia can also detect nonradial oscillations that are far more powerful but harder to detect because they change the star’s shape globally.

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-  Gaia detected strong nonradial starquakes on the surface of thousands of stars, even where conventional theory states that none should exist. Much like how Earthquakes and similar phenomena on other bodies allow astronomers to learn more about the interior of planets and moons, these starquakes can tell astronomers a great deal about the internal workings of different star types.

-

-  By studying the chemical composition of stars, astronomers can place tighter constraints on where the stars were born and how they migrated over time. This, in turn, can reveal interesting details about the history of the Milky Way and how it has evolved since. 

-

-  With the DR3, Gaia has revealed the largest chemical map of the galaxy from our solar system to smaller galaxies surrounding the Milky Way. Coupled with proper motion and velocity measurements (astrometry) in the catalog, this information has provided a 3D map of where stars originated and got to where they are today.

-

-  The key aspect of stellar composition is the amount of heavy metals they contain, “metallicity.” The first stars in the Universe, which formed roughly 100 million years after the Big Bang, were composed of hydrogen and helium, reflecting the composition of the Universe at the time. 

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-  These Population III stars  formed heavier elements in their interiors through a slow process of nuclear fusion, where fusion and helium were merged to create boron, carbon, nitrogen, oxygen, silicon, and eventually iron.

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-  When these stars collapsed at the end of their life cycles and exploded in massive supernovae, these elements were dispersed through the interstellar medium from which new stars formed. This active cycle of star formation and death slowly enriched the interstellar medium with metals over time. 

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-  Subsequent generations of stars, known as Population II and I, contained greater and greater amounts of these elements, which can be used to determine their age. In this respect, a star’s chemical composition is like its DNA.

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-  Gaia has revealed that some stars in our galaxy are “metal-poor” and composed of primordial material, while others like our Sun are rich in metal. The data also showed that stars closer to the center and plane of our galaxy have higher metallicities than those farther from the center and outside the galactic disk.

-

-    Based on their compositions, Gaia also identified numerous stars that formed in different galaxies but were captured by the Milky Way or became part of it through galactic mergers.

-

-   This diversity is extremely important, because it tells us the story of our galaxy’s formation. It reveals the processes of migration within our galaxy and accretion from external galaxies. It also clearly shows that our Sun, and we, all belong to an ever changing system, formed thanks to the assembly of stars and gas of different origins.

-

-  The new binary star catalog contains data on the mass and evolution of more than 800,000 binary systems. 

-

-  Another breakthrough is a new asteroid survey that provides data on the origins of 156,000 thousand rocky bodies in our Solar System.

-

-   Gaia‘s observations have revealed about 10 million variable stars, macro-molecules in the medium, and quasars and galaxies.  While surveying the entire sky with billions of stars multiple times, Gaia is bound to make discoveries that other more dedicated missions would miss. 

-

-  The mission has been approved until the end of 2022, and there are indications that it will be extended further to 2025.  This final product will contain the most precise astronomical measurements ever made and will include:

-

-----------------------  Full astrometric, photometric, and radial-velocity catalogs

-

-----------------------  All available variable-star and non-single-star solutions

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-----------------------  Source classifications (probabilities) plus multiple astrophysical parameters for stars, unresolved binaries, galaxies, and quasars.

-

-----------------------  An exo-planet list

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-----------------------  All epoch and transit data for all sources

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-   This data should keep astronomers busy for along time.  Many more astronomical papers to be published.  More JimsAstronomy Reviews to follow:

-

June 25, 2022      GAIA  Space Telescope  -  data is pouring in?              3612                                                                                                                                           

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

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

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

--------------------- ---  Saturday, June 25, 2022  ---------------------------

3611 - SUNSPOTS - affects on satellites?

 -  3611 -   SUNSPOTS  -  affects on satellites?    There is a lot of complex physics that we still don't fully understand going on in the upper layers of the atmosphere where it interacts with the solar wind.   This interaction causes an upwelling of the atmosphere. That means that the denser air shifts upwards to higher altitudes.

---------------------  3611  - SUNSPOTS  -  affects on satellites?

-   In late 2021, operators of the European Space Agency's (ESA) Swarm constellation noticed something worrying: The satellites, which measure the magnetic field around Earth, started sinking toward the atmosphere at an unusually fast rate, up to 10 times faster than before. The change coincided with the onset of the new solar cycle, and experts think it might be the beginning of some difficult years for spacecraft orbiting our planet. 

-

-  In the last six years, the satellites were sinking about 1.5 miles a year.   But since December, 2021, they have been virtually diving. The sink rate between December and April has been 12 miles per year.

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-  Satellites orbiting close to Earth always face the drag of the residual atmosphere, which gradually slows the spacecraft and eventually makes them fall back to the planet. They usually don't survive this re-entry and burn up in the atmosphere.

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-   This atmospheric drag forces the International Space Station's controllers to perform regular "reboost" maneuvers to maintain the station's orbit of 250 miles above Earth. 

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-  This drag also helps clean up the near-Earth environment from space junk. Scientists know that the intensity of this drag depends on solar activity which is the amount of solar wind spewed by the sun that varies depending on the 11-year solar cycle. 

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-  The last cycle, which officially ended in December 2019, was rather sleepy, with a below-average number of monthly sunspots and a prolonged minimum of barely any activity. But since last fall, our star has been waking up, spewing more and more solar wind and generating sunspots, solar flares and coronal mass ejections at a growing rate. And the Earth's upper atmosphere has felt the effects.

-

-   There is a lot of complex physics that we still don't fully understand going on in the upper layers of the atmosphere where it interacts with the solar wind.   This interaction causes an upwelling of the atmosphere. That means that the denser air shifts upwards to higher altitudes.

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-  Denser air means higher drag for the satellites. Even though this density is still incredibly low 250 miles above Earth, the increase caused by the upwelling atmosphere is enough to virtually send some of the low-orbiting satellites plummeting. 

-

-  The “Swarm constellation“, launched in 2013, consists of three satellites, two of which orbit Earth at an altitude of 270 miles , about 20 miles above the International Space Station. The third Swarm satellite circles the planet somewhat higher about 320 miles  above ground. The two lower-orbiting spacecraft were hit more by the sun's acting out than the higher satellite was.   The situation with the lower two got so precarious that by May, operators had to start raising the satellites' altitude using onboard propulsion to save them. 

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-  ESA's Swarm satellites are not the only spacecraft struggling with worsening space weather. In February, SpaceX lost 40 brand-new Starlink satellites that were hit by a solar storm just after launch.

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-  The sun unleashed a major X1.1 class solar flare from an active sunspot cluster on its eastern limb on April 17, 2022.   In such storms, satellites suddenly drop to lower altitudes. The lower the orbit of the satellites when the solar storm hits, the higher the risk of the spacecraft not being able to recover, leaving operators helplessly watching as the craft fall to their demise in the atmosphere.

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-  Starlink satellites have operational orbits of 340 miles, which is above the most at risk region. However, after launch, Falcon 9 rockets deposit the satellite batches very low, only about 217 miles  above Earth.   SpaceX then raises the satellites' orbits using onboard propulsion units. The company says that approach has advantages, as any satellite that experiences technical problems after launch would quickly fall back to Earth and not turn into pesky space debris. However, the increasing and unpredictable behavior of the sun makes those satellites vulnerable to mishaps. 

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-  The International Space Station will have to perform more frequent reboost maneuvers to keep afloat.  Also the hundreds of “cubesats” and small satellites that have populated low Earth orbit in the past decade. Those satellites are a product of the new space movement spearheaded by private entrepreneurs pioneering simple, cheap technologies.  They are particularly vulnerable.

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-  Many of these new satellites don't have propulsion systems.  They don't have ways to get up higher. That basically means that they will have a shorter lifetime in orbit. They will reenter sooner than they would during the solar minimum.

-

-  By coincidence, or beginner's luck, the onset of the new space revolution came during that sleepy solar cycle. These new operators are now facing their first “solar maximum“.  The sun's activity in the past year turned out to be much more intense than solar weather forecasters predicted, with more sunspots, more coronal mass ejections and more solar wind hitting our planet.

-

-  The solar activity is even a lot higher than the official forecast suggested.  In fact, the current activity is already quite close to the peak level that was forecasted for this solar cycle, and we are still two to three years away from the solar maximum.

-

-  The “solar cycle 25” that we are entering now is currently increasing very steeply. We do not know if this means that it will be a very tough solar cycle. It could slow down, and it could become a very weak solar cycle. But right now, it's increasing fast.

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-  While the harsh solar activity is bad news for satellite operators, who will see the lifetimes of their missions shortened.  Even satellites with onboard propulsion will run out of fuel much faster because of the need for frequent altitude boosts.  The situation will have some welcome purifying effects on the space around Earth. 

-

-  In addition to becoming populated with hundreds of new satellites over the past decade, this region of space is  cluttered with a worrying amount of space debris, old satellites, spent rocket stages and collision fragments. 

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-  This omnipresent junk hurtling around the planet threatens the safety of satellite services, forcing operators to conduct frequent avoidance maneuvers. Moreover, the debris might trigger an out-of-control situation known as “Kessler syndrome“, an unstoppable cascade of collisions.

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-  Increasing solar activity and its effect on the upper atmosphere is good news from a space debris perspective, as it reduces orbital lifetimes of the debris and provides a useful “cleaning service“.  The positive effect can already be observed, as fragments produced by the November 2021 Russian anti-satellite missile test are now coming down much faster than before. 

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-  However, there is a downside to this cleansing process. The increased rate of decay of debris objects can be perceived almost like rain.  When solar activity is high, the 'rain' rate is higher, and missions at lower altitudes will potentially experience a greater flux of debris.

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-  A greater flux of debris means the need for even more frequent fuel-burning avoidance maneuvers and a temporarily increased risk of collisions, which could potentially generate more dangerous fragments. 

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-  Operators are currently raising the orbit of the two low-orbiting Swarm satellites by 28 miles. The satellites might require even more adjustments later this year.

-

-   The goal is to help the mission, which is currently in its ninth year and beyond its originally planned lifetime, to get through the solar cycle. Whether this team succeeds will largely depend on the behavior of the sun. 

-

June 24, 2022        SUNSPOTS  -  affects on satellites?            3611                                                                                                                                          

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

-----  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”  -----------

--------------------- ---  Saturday, June 25, 2022  ---------------------------

 

3608 - PULSAR - shoots beams of antimatter?

 -  3608 -   PULSAR   -  shoots beams of antimatter?    Astronomers have imaged a beam of matter and antimatter that is 40 trillion miles long with NASA's Chandra X-ray Observatory. The record-breaking beam is powered by a pulsar, a rapidly rotating collapsed star with a strong magnetic field.

---------------------  3608  -    PULSAR   -  shoots beams of antimatter?

-  This beam of particles may help explain the surprisingly large numbers of positrons, the antimatter counterparts to electrons, throughout the Milky Way galaxy.  Astronomers first discovered the beam, or filament, in 2020, but they did not know its full length because it extended beyond the edge of the Chandra detector. 

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-  New Chandra X-ray observations show the filament is about three times as long as originally seen. The filament spans about half the diameter of the full Moon on the sky, making it the longest one from a pulsar as seen from Earth.

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-  It's amazing that a pulsar that's only 10 miles in diameter can create a structure so big that we can see it from thousands of light-years away.   With the same relative size, if the filament stretched from New York to Los Angeles the pulsar would be about 100 times smaller than the tiniest object visible to the naked eye.

-

-  The pulsar, “PSR J2030+4415“,  is located about 1,600 light-years from Earth. This city-sized object is spinning around about three times a second, faster than most ceiling fans.  This result may provide new insight into the source of the Milky Way's antimatter, which is similar to ordinary matter but with its electrical charges reversed. 

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-  The vast majority of the universe consists of ordinary matter rather than antimatter. Scientists, however, continue to find evidence for relatively large numbers of positrons in detectors on Earth, which leads to the question: What are possible sources of this antimatter?

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-  The researchers think that pulsars like PSR J2030+4415 may be one answer. The combination of two extremes, fast rotation and high magnetic fields of pulsars, leads to particle acceleration and high-energy radiation that creates electron and positron pairs. The usual process of converting mass into energy, E = m * c2 equation, is reversed, and energy is converted into mass, m = E / c^2

-

-  The pulsar may be leaking these positrons into the galaxy. Pulsars generate winds of charged particles that are usually confined within their powerful magnetic fields. The pulsar is traveling through interstellar space at about a million miles per hour, with the wind trailing behind it.

-

-   A bow shock of gas moves along in front of the pulsar, similar to the pile-up of water in front of a moving boat. However, about 20 to 30 years ago the bow shock's motion appears to have stalled, and the pulsar caught up to it, resulting in an interaction with the interstellar magnetic field.

-

- This likely triggered a particle leak.  The pulsar wind's magnetic field linked up with the interstellar magnetic field, and the high-energy electrons and positrons squirted out through a nozzle formed by connection.

-

-  As the particles then moved along that interstellar magnetic field line at about one third the speed of light, they lit it up in X-rays. This produced the long filament seen by Chandra.

-

-  Astronomers have observed large halos around nearby pulsars in gamma-ray light that imply energetic positrons generally have difficulty leaking out into the galaxy. This undercut the idea that pulsars explain the positron excess that scientists detect. 

-

-  However, pulsar filaments that have recently been discovered, like PSR J2030+4415, show that particles actually can escape into interstellar space, and eventually could reach Earth.

-

-  We have more to learn!

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June 23, 2022        PULSAR   -  shoots beams of antimatter?            3608                                                                                                                                           

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

-----  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 24, 2022  ---------------------------

 

3609 - ANTIMATTER - discovered by x-ray telescopes?

  -  3609 - ANTIMATTER  - discovered by x-ray telescopes?  Astronomers have imaged a beam of “matter and antimatter” that is 40 trillion miles long with NASA's Chandra X-ray Observatory. The record-breaking beam is powered by a pulsar, a rapidly rotating collapsed star with a strong magnetic field.

---------------------  3609  -  ANTIMATTER  - discovered by x-ray telescopes?

-  With its tremendous scale, this pulsar beam may help explain the surprisingly large numbers of positrons, the antimatter counterparts to electrons, throughout the Milky Way galaxy?

-

-  Astronomers first discovered the beam, or filament, in 2020, but they did not know its full length because it extended beyond the edge of the Chandra detector. New Chandra observations taken in February and November 2021 show the filament is about three times as long as originally seen. The filament spans about half the diameter of the full Moon on the sky, making it the longest one from a pulsar as seen from Earth.

-

-  It's amazing that a pulsar that's only 10 miles across can create a structure so big that we can see it from thousands of light-years away.  With the same relative size, if the filament stretched from New York to Los Angeles the pulsar would be about 100 times smaller than the tiniest object visible to the naked eye.

-

-  The pulsar, “PSR J2030+4415“, is located about 1,600 light-years from Earth. This city-sized object is spinning around about three times a second, faster than the ceiling fans now over my head.  

-

-  This result may provide new insight into the source of the Milky Way's antimatter, which is similar to ordinary matter but with its electrical charges reversed.   A “positron” is the positively charged equivalent to the electron.

-

-  The vast majority of the universe consists of ordinary matter rather than antimatter. Scientists continue to find evidence for relatively large numbers of positrons in detectors on Earth, which leads to the question: What are possible sources of this antimatter?

-

-  Pulsars like PSR J2030+4415 may be one answer. The combination of two extremes, fast rotation and high magnetic fields of pulsars, leads to particle acceleration and high-energy radiation that creates electron and positron pairs. 

-

-  The usual process of converting mass into energy,  E = m * c2 equation, is reversed, and energy is converted into mass, 

-

-----------------------------  m  =  E / c^2.

-

-  The pulsar may be leaking these positrons into the galaxy. Pulsars generate winds of charged particles that are usually confined within their powerful magnetic fields. The pulsar is traveling through interstellar space at about a million miles per hour, with the wind trailing behind it.

-

-   A bow shock of gas moves along in front of the pulsar, similar to the pile-up of water in front of a moving boat. However, about 20 to 30 years ago the bow shock's motion appears to have stalled, and the pulsar caught up to it, resulting in an interaction with the interstellar magnetic field running in almost a straight line.

-

-  This likely triggered a particle leak.  The pulsar wind's magnetic field linked up with the interstellar magnetic field, and the high-energy electrons and positrons squirted out through a nozzle formed by connection.

-

-  As the particles then moved along that interstellar magnetic field line at about one third the speed of light, they lit it up in X-rays. This produced the long filament seen by Chandra.

-

-  Previously, astronomers have observed large halos around nearby pulsars in gamma-ray light that imply energetic positrons generally have difficulty leaking out into the galaxy. This undercut the idea that pulsars explain the positron excess that scientists detect. 

-

-  However, pulsar filaments that have recently been discovered, like PSR J2030+4415, show that particles actually can escape into interstellar space, and eventually could reach Earth.

-

June 24, 2022        ANTIMATTER  - discovered by x-ray telescopes?           3609                                                                                                                                          

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--------------------- ---  Friday, June 24, 2022  ---------------------------

3610 - SUNSPOTS - activity in 2022?

  -  3610 -  SUNSPOTS  -  activity in 2022?  Astronomers have known since 1775 that solar activity rises and falls according to a roughly 11-year cycle, but recently, the sun has been more active than expected, with nearly double the sunspot appearances predicted. The sun's activity is projected to steadily climb for the next few years, reaching an overall maximum in 2025 before decreasing again.

---------------------  3610  -   SUNSPOTS  -  activity in 2022?

-  June 22, 2022, a  gigantic sunspot has swelled to twice Earth's size, doubling its diameter in 24 hours, and it's pointed right at us.   The sunspot, “AR3038“, grew to 2.5 times Earth's size, making the sunspot 19,800 miles in diameter from Sunday (June 19) to Monday night (June 20;   Spaceweather.com is a website that tracks news about solar flares, geomagnetic storms and other cosmic weather events. 

-

-  Sunspots are dark patches on the sun's surface where powerful magnetic fields, created by the flow of electric charges from the sun's plasma, knot before suddenly snapping. The resulting release of energy launches bursts of radiation called “solar flares” and generates explosive jets of solar material called “coronal mass ejections” (CMEs). 

-

-  Sunspot AR3038 was big. The fast-growing sunspot has doubled in size in only 24 hours.  It has an unstable 'beta-gamma' magnetic field that harbors energy for M-class [medium-sized] solar flares, and it is directly facing Earth.

-

-  When a solar flare hits Earth's upper atmosphere, the flare's X-rays and ultraviolet radiation ionize atoms, making it impossible to bounce high-frequency radio waves off them and creating a so-called radio blackout.

-

-   Radio blackouts occur over the areas on Earth that are lit by the sun while a flare is underway; such blackouts are classified from R1 to R5 according to ascending severity. In April and May, two solar flares caused R3 blackouts over the Atlantic Ocean, Australia and Asia.

-

-   As solar flares travel at the speed of light, they take only 8 minutes to reach us, from an average distance of 93 million miles . 

-

-  If an Earth-facing sunspot forms near the sun's equator, it typically takes just under two weeks for it to travel across the sun so that it is no longer facing Earth. Currently, AR3038 lies slightly to the north of the sun's equator and is just over halfway across, so Earth will remain in its crosshairs for a few days. 

-

-  Despite its alarmingly speedy growth, the giant sunspot is less scary than it may seem. The flares it will most likely produce are M-class solar flares, which "generally cause brief radio blackouts that affect Earth's polar regions, alongside minor radiation storms.

-

-  M-class flares are the most common type of solar flare. Although the sun does occasionally release enormous X-class flares (the strongest category) with the potential to cause high-frequency blackouts on the side of Earth that's exposed to the flare, these flares are observed much less often than smaller solar eruptions.

-

-  Sunspots can also belch solar material. On planets that have strong magnetic fields, like Earth, the barrage of solar debris from CMEs is absorbed by our magnetic field, triggering powerful geomagnetic storms.

-

-   During these storms, Earth's magnetic field gets compressed slightly by the waves of highly energetic particles, which trickle down magnetic-field lines near the poles and agitate molecules in the atmosphere, releasing energy in the form of light to create colorful auroras in the night sky.  (the Northern Lights).

-

-  The movements of these electrically charged particles can disrupt our planet's magnetic field powerfully enough to send satellites tumbling to Earth.  Scientists have warned that extreme geomagnetic storms could even cripple the internet. Erupting debris from CMEs usually takes around 15 to 18 hours to reach Earth.

-

-  Scientists think the largest solar storm ever witnessed during contemporary history was the 1859 Carrington Event, which released roughly the same energy as 10 billion one megaton atomic bombs. After slamming into Earth, the powerful stream of solar particles fried telegraph systems all over the world and caused auroras brighter than the light of the full moon to appear as far south as the Caribbean. 

-

-  If a similar event were to happen today, it would cause trillions of dollars in damage and trigger widespread blackouts, much like the 1989 solar storm that released a billion-ton plume of gas and caused a blackout across the entire Canadian province of Quebec.

-

June 24, 2022           SUNSPOTS  -    activity in 2022?                     3610                                                                                                                                           

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

-----  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”  -----------

--------------------- ---  Friday, June 24, 2022  ---------------------------

3607 - MILKY WAY GALAXY - new developments?

  -  3607 -   MILKY WAY  GALAXY  -  new developments?    Milky Way Galaxy has at least one major collision that happened early in the Milky Way’s development.  History of the Milky Way:

---------------------  3607  -     MILKY WAY  GALAXY  -  new developments?

-  When the Khoisan hunter-gatherers of sub-Saharan Africa gazed upon the meandering trail of stars and dust that split the night sky, they saw the embers of a campfire. Polynesian sailors perceived a cloud-eating shark. The ancient Greeks saw a stream of milk, gala, which would eventually give rise to the modern term “galaxy.”

-                      

-  In the 20th century, astronomers discovered that our silver river is just one piece of a vast island of stars, and they penned their own galactic origin story.  Our Milky Way galaxy came together nearly 14 billion years ago when enormous clouds of gas and dust coalesced under the force of gravity. 

-

-  Over time, two structures emerged, a vast spherical “halo,” and later, a dense, bright disk.   Billions of years after that, our own solar system spun into being inside this disk.  When we look out at night, we see spilt milk which is an edge-on view of the disk splashed across the sky.

-

-  On April 25, 2018, a European spacecraft by the name of “Gaia” released a staggering quantity of information about the sky.  Gaia’s years-long data set described the detailed motions of roughly 1 billion stars. Previous surveys had mapped the movement of just thousands. 

-

-  Astronomers found that parts of the disk appeared impossibly ancient. They also found evidence of epic collisions that shaped the Milky Way’s violent youth, as well as new signs that the galaxy continues to churn in an unexpected way.

-

-  The Gaia satellite has revolutionized our understanding of the Milky Way since its launch in December 2013.  These results have spun a new story about our galaxy’s turbulent past and its ever-evolving future. The theme is that the Milky Way is not a static object. Things are changing rapidly everywhere.

-

-  To peer back to the galaxy’s earliest days, astronomers seek stars that were around back then. These stars were fashioned only from hydrogen and helium, the cosmos’s rawest materials. These smaller stars from this early stock are also slow to burn, so many are still shining.

-

-  Researchers had assembled a catalog of 42 such ancients, known as ultra metal-poor stars.  To astronomers, any atom bulkier than helium qualifies as “metallic“. According to the standard story of the Milky Way, these stars should be swarming throughout the halo, the first part of the galaxy to form. By contrast, stars in the disk, which was thought to have taken perhaps an additional billion years to spin itself flat should be contaminated with heaver elements such as carbon and oxygen.

-

-  Gaia’s data release extracted the 42 ancient stars from the full data set, then tracked their motions. He found that most were streaming through the halo, as predicted. But some, roughly 1 in 4, weren’t. Rather, they appeared stuck in the disk, the Milky Way’s youngest region. 

-

-  Follow-up research confirmed that the stars really are long-term residents of the disk, and not just passing through. From two recent surveys astronomers amassed a library of roughly 5,000 “metal-poor stars“. A few hundred of them appear to be permanent denizens of the disk.

-

-  About 1 in 10 of these stars lie flat in circular, sunlike orbits. And a third research group found stars of various metallic ties, and therefore various ages,  moving in flat disk orbits. 

-

-  How did these anachronisms get there?  Perhaps pockets of pristine gas managed to dodge all the metals expelled from supernovas for eons, then collapsed to form stars that looked deceptively old. Or the disk may have started taking shape when the halo did, nearly 1 billion years ahead of schedule.

-

-  In digital simulations, a Milky Way like galaxy forms and evolves over 13.8 billion years from the early universe to the present day. The distribution calculates the invisible dark matter; the temperature of gas and the density of stars.  In these digital simulations, a Milky Way like galaxy forms and evolves over 13.8 billion years from the early universe to the present day.

-   

-  At the Supercomputing Center, a single simulation required three months of computing time.  It was repeated the exercise six times.  Five produced Milky Way doppelgängers. Two of those featured substantial numbers of metal-poor disk stars.  How did those ancient stars get into the disk?  They were stellar immigrants. 

-

-  Some of them were born in clouds that predated the Milky Way. Then the clouds just happened to deposit some of their stars into orbits that would eventually form part of the galactic disk. Other stars came from small “dwarf” galaxies that slammed into the Milky Way and aligned with an emerging disk.

-

-   With Gaia, astronomers have found direct evidence of these cataclysmic collisions. Astronomers assumed that the Milky Way had a hectic youth.  In every direction, they saw a huge number of halo stars ping-ponging back and forth in the center of the Milky Way in the same peculiar way,  This was a clue that they had come from a single dwarf galaxy.

-

-  The galactic wreckage was everywhere. Perhaps half of all the stars in the inner 60,000 light-years of the halo, extending hundreds of thousands of light-years in every direction, came from this lone collision, which may have boosted the young Milky Way’s mass by as much as 10%. 

-

-  The incoming galaxy was named “Gaia-Enceladus“, after the Greek goddess Gaia, one of the primordial deities, and her Titan son Enceladus.   When the Milky Way and Gaia-Enceladus collided, perhaps 10 billion years ago, the Milky Way’s delicate disk may have suffered widespread damage. 

-

-  Astronomers debate why our galactic disk seems to have two parts: a thin disk, and a thicker one where stars bungee up and down while orbiting the galactic center.  The first ancient disk formed pretty fast, and then we think Gaia-Enceladus destroyed it.

-

-  Hints of additional mergers have been spotted in bundles of stars known as “globular clusters“.  Galaxy simulations to train a neural network to scrutinize globular clusters by their ages, makeup, and orbits. From that data, the neural network could reconstruct the collisions that assembled the galaxies.

-

-   All these mergers have led some astronomers to suggest that the halo may be made almost exclusively of immigrant stars. Models from the 1960s and ’70s predicted that most Milky Way halo stars should have formed in place. But as more and more stars have been identified as galactic interlopers, astronomers may not need to assume that many, if any, stars are natives.

-

-  The Milky Way has enjoyed a relatively quiet history in recent eons, but newcomers continue to stream in. Stargazers in the Southern Hemisphere can spot with the naked eye a pair of dwarf galaxies called the Large and Small Magellanic Clouds. Astronomers long believed the pair to be our steadfast orbiting companions, like moons of the Milky Way.

-

-  Then a series of Hubble Space Telescope observations between 2006 and 2013 found that they were more like incoming meteorites.  The clouds were coming in hot at about 330 kilometers per second, nearly twice as fast as had been predicted. ( 738, 189 miles per hour)

-

-  The speedy clouds were extremely hefty, 10 times bulkier than previously thought.  The problem with looking for galaxy-wide motion is that the Milky Way is a raging blizzard of stars, with astronomers looking outward from one of the snowflakes.

-

-   Calculations were used to neutralize the motions of the Earth and the sun, and to average out the motion of halo stars so that the halo’s outer fringe could serve as a stationary backdrop.  When this calibrated the data formed in this way, they found that the Earth, the sun, and the rest of the disk in which they sit are lurching in one direction, not toward the Large Magellanic Cloud’s current position, but toward its position around a billion years ago.

-

-  The Milky Way is an object in balance. It may spin and slip through space, but most astronomers assumed that after billions of years, the mature disk and the halo had settled into a stable configuration.

-

-   Even after 14 billion years, mergers continue to sculpt the overall shape of the galaxy. This realization is just the latest change in how we understand the great stream of milk across the sky.

-

-  Astronomers produced the most comprehensive image of radio emission from the nearest actively feeding supermassive black hole to Earth.  The emission is powered by a central black hole in the galaxy Centaurus A, about 12 million light years away.

-

-  As the black hole feeds on in-falling gas, it ejects material at near light-speed, causing 'radio bubbles' to grow over hundreds of millions of years.  When viewed from Earth, the eruption from “Centaurus A” now extends eight degrees across the sky, the length of 16 full Moons laid side by side.

-

-  It forms a disc around the black hole, and as the matter gets ripped apart going close to the black hole, powerful jets form on either side of the disc, ejecting most of the material back out into space, to distances of more than a million light years.

-

-  Previous radio observations could not handle the extreme brightness of the jets and details of the larger area surrounding the galaxy were distorted, but our new image overcomes these limitations.

-

-  Astronomers were been able to combine the radio observations with optical and X-ray data, to help us better understand the physics of these supermassive black holes.

-

-   Clouds of cold gas condense in the galactic halo and rain down onto the central regions, feeding the supermassive black hole.  Triggered by this rain, the black hole vigorously reacts by launching energy back via radio jets that inflate the spectacular lobes.

-

June 23, 2022          MILKY WAY  GALAXY  -  new developments?          3607                                                                                                                                         

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

-----  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”  -----------

--------------------- ---  Thursday, June 23, 2022  ---------------------------

3606 - PLANCK TIME - how small can it get?

  -  3606 -   PLANCK  TIME  -  how small can it get?   The Planck time is an incredibly small interval of time that emerges naturally from a few basic quantities in theoretical physics. When it was discovered by Max Planck at the end of the 19th century, it seemed to be no more than a scientific curiosity. But today it plays a tantalizing role in our understanding of the Big Bang and the search for a theory of quantum gravity. 

---------------------  3606  -   PLANCK  TIME  -  how small can it get?

-  Let’s take a minute and divide it by 60 to get seconds.  Now divide seconds by a million and get 10^-6 seconds.  Divide it again and get 10^12 seconds.  How far can you go to get the smallest interval of time?  When you get there it is called “Planck Time”.

-

-   The Planck time was first described in a scientific paper written by Max Planck in 1899, in a section called “Natural Measurement Units”.  In everyday use, measurement units are no big deal. We use whatever is convenient – ounces or tons for mass, miles or inches for distance, minutes or days for time. Scientists tend to use SI units of kilograms, meters and seconds, because they simplify complex calculations , but only up to a point. The math can still get tortuously complicated.

-

-  In Newton’s equation for the force of gravity the gravitational constant G has brain-twisting units of “cubic meters per kilogram per second squared,” . In these units, G – which is one of the most fundamental numbers in the universe has the arbitrary-looking value of 0.0000000000667 m^3/(kg/sec2)

-

-  Planck wanted to find a more “natural” set of units in which G, and similar fundamental constants, are exactly equal to 1.

-

-  Max Planck may not be a household name, but he gave the world a household phrase: quantum theory. According to the European Space Agency, which named its Planck spacecraft after him, the breakthrough came in 1900 when he discovered that energy can only be transmitted in small packets of prescribed size, which he termed “quanta.”

-

-   This was decades before Werner Heisenberg and Erwin Schrödinger discovered all the quantum weirdness we’re familiar with today, but none of that would have been possible if Planck hadn’t paved the way first. As such, he’s described as the father of quantum physics.

-

-  The second parameter Planck chose was the speed of light “c“, in meters per second. This was known to be an important constant even in 1899, despite the fact that Einstein’s theory of relativity, with which it’s closely associated, still lay several years in the future. 

-

-  The third parameter was a brand-new constant Planck himself had just discovered, now known simply as Planck’s constant. Usually represented by the letter “h“, it’s the ratio of a photon's energy to its frequency, with units of kilograms multiplied  square meters per second.

-

-  Taking these three constants as his starting point, Planck was able to find a new set of measurement units in which they’re all precisely equal to one. These basic units are referred to as the Planck mass, Planck length and Planck time. 

-

-  The Planck length is equal to the Planck time multiplied by the speed of light. 

-

-  The U.S. National Institute for Standards and Technology gives the value of the Planck time as 5.391247 × 10^-44 seconds. In other sources, including Planck’s original paper, you may find a slightly bigger value around 1.35 × 10^-43 seconds. As explained on Eric Weisstein’s World of Physics site, this is due to the use of two different versions of Planck’s constant. The larger value uses Planck’s original quantity, “h“, while the smaller, more common value uses a parameter called “h-bar“, which is h divided by 2 pi.

-

-  Whichever value is used, the result is a time interval that is unimaginably tiny in the context of everyday experience. A nanosecond, often used colloquially to mean “a very short time,” is 0.000000001 seconds, with 8 zeros between the decimal point and the first significant figure.

-

-   The Planck time has no fewer than 43 zeroes. It’s the time it takes light to travel one Planck length, which is around a hundredth of a millionth of a trillionth of the diameter of a proton.

-

-  Because the Planck time is so impractically small, it was largely ignored by scientists prior to the 1950s.  At best it was considered an interesting curiosity with no real physical significance. Then, when physicists started looking for a “theory of everything” that would encompass both gravity and quantum mechanics, they realized that the Planck time might have enormous significance after all.

-

-  The key lies in the fact that the Planck time, along with the other Planck units, incorporates both the gravitational constant “G” and Planck’s constant “h“, which is central to quantum theory. 

-

-  Planck’s original motivation in devising his measurement system was to define a set of units that weren’t Earth-centric, in the way our units usually are. That’s even true of the so-called “astronomical unit,” which is the average distance from the Earth to the Sun, according to the University of Surrey, or the light year, which is the distance light travels in the time it takes the Earth to orbit once around the Sun.

-

-   In contrast, Planck’s units  have no such ‘anthropocentric’ connections. As Planck himself put it, his units “necessarily retain their meaning for all times and for all civilizations, even extraterrestrial and non-human ones“.

-

-  For any given mass, Einstein’s theory of gravity ( i.e. general relativity) gives a characteristic length scale called the “Schwarzschild radius” But quantum theory has its own length scale for that mass, which is termed the “Compton wavelength”.

-

-   So, is there any mass for which the Schwarzschild radius is exactly equal to the Compton wavelength? It turns out there is, and,  it’s the Planck mass, for which those two parameters, one from quantum theory and one from general relativity, both equal the Planck length.

-

-  Is this just a coincidence, or does it mean that gravitational and quantum effects really do start to overlap at the Planck scale?   The general consensus is that Planck units really do play a key role in connecting these two areas of physics. One possibility is that spacetime itself is quantized at the level of a Planck length and Planck time. If this is true, then the fabric of spacetime, when looked at on that scale, would appear “chunky” rather than smoothly continuous.

-

-  Planck time is the shortest measurable time interval and could be applied to the time the universe started to evolve after the Big Bang.   In the universe we see today, there are four fundamental forces: gravity, electromagnetism and the strong and weak nuclear forces. 

-

-  But as we look backward in time through the first moments after the Big Bang, the universe becomes so hot and dense that these forces gradually merge into each other. It all happened very quickly; from ten microseconds onward, the four forces looked just as they do today.

-

-  Before that, however, there was no distinction between the electromagnetic and weak forces, and prior to 10^-36 seconds, these were joined by the strong force as well.

-

-  At this point, gravity was still a separate force.  We can’t look back any further in time than this. But it’s widely believed that, given a better understanding of quantum gravity, we’d find that prior to the Planck time gravity was also merged into the other forces.

-

-   It was only at the Planck time, around 5 × 10^-44 seconds after the Big Bang, that gravity became the separate force we see today.  I know, it happened so quick you did not even notice.  

-

June 18, 2022       PLANCK  TIME  -  how small can it get?             3606                                                                                                                                           

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

-----  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, June 20, 2022  ---------------------------