JimsAstronomy: September 2021

Thursday, September 30, 2021

- 3286 - SUN - exploring the Sun? - The Sun plays a central role in shaping space around us. Its massive magnetic field stretches far beyond Pluto, paving a superhighway for charged solar particles known as the solar wind. When bursts of solar wind hit Earth, they can spark space weather storms that interfere with our GPS and communications satellites and can even threaten astronauts.

--------------------- 3286 - SUN - exploring the Sun?

- A new spacecraft is journeying to the Sun to snap the first pictures of the Sun's north and south poles. The “Solar Orbiter“ was launched from Cape Canaveral on Feb. 7, 2020.

- Up until Solar Orbiter, all solar imaging instruments have been within the ecliptic plane. This space probe will be able to look down on the Sun from above.

- To prepare for arriving solar storms that started again in 2021scientists monitor the Sun's magnetic field. Their techniques work best with a straight-on view; the steeper the viewing angle, the noisier the data. The sidelong glimpse we get of the Sun's poles from within the ecliptic plane leaves major gaps in the data.

- The Sun's poles may also explain centuries-old observations. In 1843, German astronomer Samuel Heinrich Schwabe discovered that the number of sunspots which are dark blotches on the Sun's surface marking strong magnetic fields that waxes and wanes in a repeating pattern.

- Today, we know it as the approximately-11-year solar cycle in which the Sun transitions between solar maximum, when sunspots proliferate and the Sun is active and turbulent, and solar minimum, when they're fewer and it's calmer.

- The Solar Orbiter will pass inside the orbit of Mercury carrying four “in situ” instruments and six remote-sensing imagers, which see the Sun from afar. After years of technology development, it will be the closest any Sun-facing cameras have ever gotten to the Sun.

- Over the mission's seven year lifetime, Solar Orbiter will reach an inclination of 24 degrees above the Sun's equator, increasing to 33 degrees with an additional three years of extended mission operations. At closest approach the spacecraft will pass within 26 million miles of the Sun.

- To beat the heat, Solar Orbiter has a custom-designed titanium heat shield with a calcium phosphate coating that withstands temperatures over 900 degrees Fahrenheit which is thirteen times the solar heating faced by spacecraft in Earth orbit.

- Five of the remote-sensing instruments look at the Sun through peepholes in that heat shield; one observes the solar wind out to the side.

Solar Orbiter is following on August 2018's launch of “Parker Solar Probe“. Parker has completed four close solar passes and will fly within four million miles of the Sun at closest approach.

- The two spacecraft will work together: As Parker samples solar particles up close, Solar Orbiter will capture imagery from farther away, contextualizing the observations. The two spacecraft will also occasionally align to measure the same magnetic field lines or streams of solar wind at different times.

- Continued analysis of Parker Solar Probe data is starting to create a clearer picture of the sun’s magnetic activity, which may bolster our ability to predict dangerous solar events.

- Sensors aboard the spacecraft have produced data suggesting:

--------------------- The sun’s atmosphere, composed of plasma and magnetic fields, moves in a general global circulation pattern. Parker Solar Probe can observe a small section at any given time.

-------------------- Close to the sun, solar wind, the outward stream of charged particles from the surface, is embedded with abrupt changes in magnetic field direction, called switchbacks, along which the solar wind flows at an accelerated speed.

-------------------- The global coronal magnetic field slides over the surface of the sun via a process called interchange reconnection, when closed loops of magnetic field sprouting from the sun’s surface explosively realign with open magnetic field lines that extend out into the solar system.

- Defining that mechanism is key to predicting when a transition from slow to fast solar wind is going to strike Earth and create a geomagnetic storm. The “heliosphere” is the region of space, including our solar system, that the solar wind influences.

------------------- In different areas of the corona, open magnetic lines that stretch from the surface of the sun out into space should circulate in a closed pattern, with motions both in the direction of and opposite to the sun’s rotation.

- As Parker Solar Probe continues to move closer to the sun, the mission will provide ample opportunity to test and validate predictions by the theory.

designed, built and operates the spacecraft

- The first images from Solar Orbiter have revealed omnipresent miniature solar flares, dubbed 'campfires', near the surface of our closest star.

- The Solar Orbiter carries six remote-sensing instruments, or telescopes, that image the Sun and its surroundings, and four ‘in situ’ instruments that monitor the environment around the spacecraft. By comparing the data from both sets of instruments, scientists will get insights into the generation of the solar wind, the stream of charged particles from the Sun that influences the entire Solar System.

- The campfires were captured by the “Extreme Ultraviolet Imager” (EUI) from Solar Orbiter's first perihelion, the point in its elliptical orbit closest to the Sun. At that time, the spacecraft was only 77 million kilometers away from the Sun, about half the distance between Earth and the star.

- The campfires are little relatives of the solar flares that we can observe from Earth, million or billion times smaller. The scientists do not know yet whether the campfires are just tiny versions of big flares, or whether they are driven by different mechanisms. There are already theories that these miniature flares could be contributing to one of the most mysterious phenomena on the Sun, the “coronal heating“.

- The solar corona is the outermost layer of the Sun's atmosphere that extends millions of kilometers into outer space. Its temperature is more than a million degrees Celsius, which is orders of magnitude hotter than the surface of the Sun, a 'cool' 5500 °C. After many decades of studies, the physical mechanisms that heat the corona are still not fully understood, but identifying them is considered the 'holy grail' of solar physics.

- The “Polarimetric and Helioseismic Imager” (PHI) is another cutting-edge instrument aboard Solar Orbiter. It makes high-resolution measurements of the magnetic field lines on the surface of the Sun. It is designed to monitor active regions on the Sun, areas with especially strong magnetic fields, which can give birth to solar flares.

- During solar flares, the Sun releases bursts of energetic particles that enhance the solar wind that constantly emanates from the star into the surrounding space. When these particles interact with Earth's magnetosphere, they can cause magnetic storms that can disrupt telecommunication networks and power grids on the ground.

- Right now, 2021. we are in the part of the 11-year solar cycle when the Sun is very quiet. But because Solar Orbiter is at a different angle to the Sun than Earth, we could actually see one active region that wasn't observable from Earth. That is a first. We have never been able to measure the magnetic field at the back of the Sun.

- The “magneto grams“, showing how the strength of the solar magnetic field varies across the Sun's surface, could be then compared with the measurements from the in situ instruments.

- The four in situ instruments on Solar Orbiter then characterize the magnetic field lines and solar wind as it passes the spacecraft. Using this information, we can estimate where on the Sun that particular part of the solar wind was emitted, and then use the full instrument set of the mission to reveal and understand the physical processes operating in the different regions on the Sun which lead to solar wind formation.

- Solar Orbiter has started a grand tour of the inner Solar System, and will get much closer to the Sun within less than two years. Ultimately, it will get as close as 42 million km, which is almost a quarter of the distance from Sun to Earth. Besides solar flares Solar eclipses are another opportunity to study the Sun.

- Isaac Newton figured out something absolutely remarkable about gravity that no one else had ever realized: that it's universal.

- According to Isaac himself, the thought struck him when he watched an apple fall from a tree. He saw the apple fall in a straight line toward the Earth. He saw the apple accelerate from being still to moving. And all accelerations require a force. So, the Earth was applying a force to the apple even though it wasn't touching it.

- Isaac also knew that every action has an equal and opposite reaction. If the Earth is applying a force to accelerate the apple, then the apple must be applying a force to accelerate the Earth. Whatever this force of gravity is, it must be mutual and in both directions.

- The reason the apple moves more than the Earth is because the mass of the Earth is so much greater. It just appears like that apple is doing all the moving and the Earth is doing all the work, when in Newton's suddenly much clearer vision, all things were equal when it comes to forces.

- So, if the Earth is applying gravity to the apple and the apple is applying gravity to the Earth, then this force of gravity must be operating with all pairs of objects simultaneously all across the universe. In other words, gravity must be universal.

- Newton worked out the implications of this newfound universal force of gravity, and instantly many things clicked into place. He was able to predict the speed of the moon in its orbit. He was able to derive Kepler's laws from much simpler principles. He was able to explain the motions of all the planets and all the moons around those planets.

- Kepler’s writings sat there for years until one of his friends, Edmond Halley, started agitating for him to publish it. Apparently, for Newton, unlocking the secrets of universal gravity was just an idle afternoon pastime and not something worthy of serious academic interest. But Halley knew better. He constantly pressed Newton until he finally published his work.

- Edmond Halley then took this theory of universal gravitation and began solving almost every single problem known to plague astronomers. Most notably, he figured out the regular pattern of a particular comet that now bears his name by digging into the historical records and using that data to feed into calculations of a prediction of its reappearance.

- By digging into the ancient records, Halley was able to predict an upcoming total solar eclipse over his home city of London. Using Newton's theory of universal gravitation, Halley predicted the eclipse of May 3, 1715, to an accuracy of a scant four minutes.

- Without any calculator or computer. Just using historical records and Newton's laws, Halley nailed the first-ever accurate prediction of a solar eclipse.

- When the moon takes on a reddish color, or when the sun's corona shines like a glowing ring aloft in the sky, it's hard to ignore the sight. Lunar and solar eclipses have enchanted and even frightened humans for thousands of years.

- Eclipses aren't limited to one part of the world. In fact, there will be 20 lunar and solar eclipses traversing different places on Earth from now until the next North American cross-continental total solar eclipse on April 8, 2024.

- September 30, 2021 SUN - exploring the Sun? 3286

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

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--------------------- --- Thursday, September 30, 2021 ---------------------------

Monday, September 27, 2021

3285 - GRBs - and Blackholes.

- 3285 - GRBs - and Blackholes. Gamma-ray bursts (GRBs) are the brightest, most energetic blasts of light in the universe. Released by an immense cosmic explosion, a single GRB is capable of shining about a million trillion times brighter than Earth's sun.

--------------------- 3285 - GRBs - and Blackholes.

- Astronomers can not explain how these immense bursts of power is created. Part of the problem is that all known GRBs come from very, very far away, usually billions of light-years from Earth.

- The GRB's home galaxy is so far away that the burst's light appears to come from nowhere at all, briefly blipping out of the black, empty sky and vanishing seconds later. These "empty-sky" gamma-ray bursts have presented an ongoing cosmic mystery for more than 60 years.

- Astronomers are beginning to model the interactions between gamma rays and other powerful energy sources, such as cosmic rays. Those nebulous empty-sky bursts could be the results of massive stellar explosions in the disks of distant galaxies.

- Astronomers favor two leading explanations for the empty-sky gamma-ray mystery. In one explanation, the rays occur when gas falls into the supermassive blackholes that sit at the centers of all galaxies in the universe.

- As gas particles get sucked into the blackhole, a small fraction escape and instead radiate in large, near-light-speed jets of matter. It's thought that these powerful jets could be responsible for gamma-ray bursts.

- Gamma Rays are very high frequency light. With light waves the higher the frequency the more powerful the light packing higher energy. Ultraviolet light is higher frequency than visible light That is why it burns your skin.

- Another explanation points to stellar explosioning supernovas. When large stars run out of fuel and erupt in these violent supernovas, they can send nearby particles blasting away at near-light speed. These highly energetic particles, called cosmic rays, may then collide with other particles sprinkled through the gassy hinterland between stars, producing gamma-rays.

- In this 2021 study, the researchers focused on that second explanation by modeling the interactions between cosmic rays and interstellar gas in various types of star-forming galaxies.

- Astronomers found that the rate of gamma-ray emissions was influenced by the size of the galaxy, the rate of star formation, which affects the rate of supernovas, and the initial energy of the cosmic rays created by each supernova.

- Blackholes are probably still responsible for some of the gamma-rays that our satellites pick up. But the mysterious “empty-sky GRBs“, these blackholes are not necessary, exploding stars in faraway corners of the universe are sufficient to explain the phenomenon.

- Still for the far-out concepts in astronomy, blackholes may be the weirdest. A region of space where matter is so tightly packed that nothing, not even light itself, can escape, these dark behemoths present a pretty terrifying prospect.

- With all the normal rules of physics breaking down inside them, it's tempting to dismiss blackholes as the stuff of science fiction. Yet there's plenty of evidence, both direct and indirect, that they really do exist in our universe.

- Blackholes were predicted as a theoretical possibility, in 1916 by Karl Schwarzschild, who found them to be an inevitable consequence of Einstein's theory of general relativity.

- If Einstein's theory is correct then blackholes must exist. Later Roger Penrose and Stephen Hawking showed that any object collapsing down to a blackhole will form a “singularity”, where the traditional laws of physics break down.

- In the 1930s, Indian astrophysicist Subramanian Chandrasekhar looked at what happens to a star when it has used up all its nuclear fuel. The end result, he found, depends on the star's mass.

- If that star is really big, 20 solar masses, then its dense core, which may itself be three or more times the mass of the sun, collapses all the way down to a blackhole.

- The final core collapse happens incredibly quickly, in a matter of seconds, and it releases a tremendous amount of energy in the form of a gamma-ray burst. This burst can radiate as much energy into space as an ordinary star emits in its entire lifetime.

- Telescopes on Earth have detected many of these bursts, some of which come from galaxies billions of light-years away; so we can actually see blackholes being born.

- Blackholes don't always exist in isolation, sometimes they occur in pairs, orbiting around each other. When they do, the gravitational interaction between them creates ripples in space-time, which propagate outward as gravitational waves which was another prediction of Einstein's theory of relativity.

- With observatories like the “Laser Interferometer Gravitational-Wave Observatory” and “Virgo“, we have the ability to detect these gravitational waves.

- The first gravity wave discovery, involving the merger of two blackholes, was announced in 2016, and many more have been made since then. As detector sensitivity improves, other wave-generating events besides blackhole mergers are being discovered.

- A crash between a blackhole and a neutron star took place beyond our own galaxy at a distance of 0.65 to 1.5 billion light-years from Earth.

- The short-lived, high-energy events that produce gamma-ray bursts and gravitational waves may be visible halfway across the observable universe, but for most of their lives blackholes, by their very nature, will be almost undetectable.

- The fact that they don't emit any light or other radiation means they could be lurking in our cosmic neighborhood without astronomers being aware of it. There's one way to detect the dark beasts, though, and that's through their gravitational effects on other stars.

- When observing the ordinary-looking binary system, or pair of orbiting stars, known as HR 6819 in 2020, astronomers noticed oddities in the motion of the two visible stars that could be explained only if there was a third, totally invisible, object there.

- When they worked out its mass, at least four times that of the sun, the researchers knew there was only one possibility left. It had to be a blackhole. It is the closest yet discovered to Earth, a mere thousand light-years away inside our own galaxy.

- The first “observational” evidence for a blackhole emerged in 1971, and this too came from a binary star system within our own galaxy. Called Cygnus X-1, the system produces some of the universe's brightest X-rays.

- The X-rays don't emanate from the blackhole itself, or from its visible companion star which is 33 times the mass of our own sun, according . Matter is constantly being stripped from the giant star and dragged into an accretion disk around the blackhole, and it's from this accretion disk that the X-rays are emitted.

- As they did with HR 6819, astronomers can use observed star motion to estimate the mass of the unseen object in Cygnus X-1. The latest calculations put the dark object at 21 solar masses concentrated into such a small space that it couldn't be anything other than a blackhole.

- At the center of our galaxy is a supermassive black hole in the region known as Sagittarius A.

- Blackholes are created through stellar collapse. Evidence suggests that supermassive blackholes, each millions or even billions of solar masses, have been lurking in the centers of galaxies since early in the history of the universe.

- In the case of active galaxies, the evidence for these heavyweights is spectacular. The central black holes in these galaxies are surrounded by accretion disks that produce intense radiation at all wavelengths of light.

- Our own galaxy has a blackhole at its center. Astronomers see the stars in that region whizzing around so fast, up to 8% of the speed of light, that they must be orbiting something extremely small and massive. Current estimates put the Milky Way's central blackhole around 4 million solar masses.

- Another piece of evidence for the existence of black holes is … “spaghettification“. Spaghettification is what happens when you fall into a blackhole. You get stretched out into thin strands by the blackhole's extreme gravitational pull.

- Last year, in October 2020, astronomers witnessed this shredding as a flash of light from a star as it was ripped apart. Fortunately, the spaghettifying didn't happen anywhere near Earth, but instead in a galaxy 215 million lightyears away.

- Astronomers have plenty of compelling indirect evidence for blackholes: bursts of radiation or gravitational waves, or dynamical effects on other bodies, that couldn't have been produced by any other object known to science.

- In April 2019 a direct image of the supermassive blackhole at the center of active galaxy Messier 87 was created. This stunning photo was taken by the Event Horizon Telescope which consists of a large network of telescopes scattered all over the world rather than a single instrument.

- The more telescopes that can participate, and the more widely spaced they are, the better the final image quality. The result clearly shows the dark shadow of the 6.5 billion-solar-mass blackhole against the orange glow of its surrounding accretion disk.

- September 26, 2021 GRBs - and Blackholes. 3285

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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” -----------

--------------------- --- Monday, September 27, 2021 ---------------------------

Sunday, September 26, 2021

- 3284 - EINSTEIN RING - distance to far away galaxies? The circle surrounding a constellation of stars is called an “Einstein ring” after the famous physicist who predicted its existence.

--------------- 3284 - EINSTEIN RING - distance to far away galaxies?

- The Einstein ring is actually a light smear created by a lensing effect that occurs when a foreground object with strong gravity magnifies the light of a more distant galaxy behind it.

- The galaxy inside the ring is as it was 9 billion years old, when the universe was only about one-third its present age of 13.8 billion years.

- The detection of molecular gas, of which new stars are born, allowed astronomers to calculate the precise redshift and thus the galaxy distance

- 13.8 billion years ago was a time when the universe was going through a 'baby boom,' forming thousands of stars at a prolific rate.

- In the brightest and very dusty early galaxies saw stars being born at a rate a thousand times faster than occurs within our own galaxy.

- Astronomers are learning even more by observing quasars in the early Universe. They have found a relationship between X-ray and UV luminosities. This relation does not evolve with redshift and therefore astronomers can use the same relation just using fluxes to compute the distance of the objects.

- Whatever quasars are, they’re an exotic feature of the early Universe that we don’t see in the nearby cosmos today. The first quasar discovered was “3C 273” in 1963. With a high redshift (z = 0.158). Astronomers knew they were looking at something extremely distant and therefore intrinsically luminous.

- To give you some idea just how bright 3C 273 actually is, it has an absolute magnitude value of -27. If you placed it at a distance of 10 parsecs away, 32.6 lightyears away , it would compete with the Sun in the sky.

- The first ‘rung’ on the cosmic distance ladder is “parallax“, using observations from two different points in space and basic trigonometry to gauge distance. Using the Earth’s orbit as a baseline is also the basis for the parsec which is a measure of distance, 3.26 light-years long.

- But parallax calculations will only get you so far. The triangle becomes nearly a straight line. The next yardstick out was discovered by astronomer Henrietta Swan Levitt while examining variable stars in the Small Magellanic cloud in 1912. She noticed that a particular type of star known as a Cepheid variable pulses in a fashion that’s directly related to its luminosity.

- For larger distances, brighter standard candles are needed. Astronomers use Type IA supernovae, as they flare and fade in a predictable fashion. Over the immense distances of hundreds of millions of light-years, cosmic expansion and spectroscopic redshift (noted as z) comes into play.

- Hubble’s Law correlates velocity as being proportional to distance due to the expansion of the Universe: the higher the redshift, the more distant the object.

- Type IA supernovae allow calculations back to about three billion years after the Big Bang. Quasars as standard candles would be good to just 700 million years after the Big Bang.

- Quasars have another advantage, as hundreds of thousands of them have been discovered in recent years. As a standard candle, they provide not only a good overlap with more distant Type 1A supernovae, but are also a good backup check for distance, as they are separately distinct cosmological processes.

- You can observe “quasar 3C 273” from your driveway with a good-sized telescope. At magnitude +12.9 it won’t look like much more than a nondescript faint star. It is amazing to think that you’re seeing photons that left their source 2.4 billion years ago.

- Just 50 years since discovery, quasars have gone from mysterious objects to key standard candles for probing the early Universe. A new measurement is coming from gamma ray bursts.

- Gamma-ray bursts (GRBs) are the brightest, most energetic blasts of light in the universe. Released by an immense cosmic explosion, a single GRB is capable of shining about a million trillion times brighter than Earth's sun.

- GRBs are usually billions of light-years from Earth. Sometimes, a GRB's home galaxy is so far-flung that the burst's light appears to come from nowhere at all, briefly blipping out of the black, empty sky and vanishing seconds later.

- These "empty-sky" gamma-ray bursts have presented an ongoing cosmic mystery for more than 60 years. But a new study, published September 15, 2021, offers a compelling mathematical explanation for the powerful bursts' origins

- Studying the interactions between gamma rays and cosmic rays found that all those nebulous empty-sky bursts could be the results of massive stellar explosions in the disks of distant galaxies.

- It is these star-forming galaxies that produce these gamma-ray radiation outbursts. One explanation for these outbursts is that the rays occur when gas falls into the supermassive blackholes that sit at the centers of all galaxies in the universe.

- As gas particles get sucked into the blackhole, a small fraction escape and instead radiate in large, near-light-speed jets of matter. These powerful jets could be responsible for gamma-ray bursts.

- Another explanation points to stellar explosions called supernovas. When large stars run out of fuel and erupt in these violent supernovas, they can send nearby particles blasting away at near-light speed. These highly energetic particles, i.e. cosmic rays, may then collide with other particles sprinkled through the gassy hinterland between stars, producing gamma-rays.

- The astronomer’s calculations fit with the observations that supernovas in star-forming galaxies could explain most, if not all, empty-sky GRBs.

- Blackholes are probably still responsible for some of the gamma-rays that our satellites pick up. But when it comes to the mysterious empty-sky GRBs, the blackholes are simply not necessary; exploding stars in faraway corners of the universe are sufficient to explain the phenomenon.

- September 25 , 2021 EINSTEIN RING - distance to far away galaxies? 3284

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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” -----------

--------------------- --- Sunday, September 26, 2021 ---------------------------

Wednesday, September 22, 2021

- 3283 - COSMIC RAYS - a lot we don’t know? Great mysteries of the universe surround us, all the time. They even permeate us, sailing straight through our bodies. One such mystery is “cosmic rays“, made of tiny bits of atoms. These rays, which are not “rays” but particles, are passing through us at this very moment, are not harmful to us or any other life on the surface of Earth, we think.

--------------------- 3283 - COSMIC RAYS - a lot we don’t know?

- Some of these Cosmic Ray particles carry so much energy that physicists are baffled by what object in the universe could have created them. Many are much too powerful to have originated from our sun. Many are even much too powerful to have originated from an exploding star.

- Because cosmic rays don’t often travel in a straight line, we don’t even know where in the night sky they are coming from. The answer to the mystery of cosmic rays could involve objects and physical phenomena in the universe that no one has ever seen or recorded before.

- Though we don’t know where cosmic rays come from, or how they get here, we can see what happens when these cosmic rays hit our planet’s atmosphere at nearly the speed of light.

- When the particles in cosmic rays collide with the atoms at the top of the atmosphere, they burst, tearing apart atmospheric atoms in a violent collision. The particles from that explosion then keep bursting apart other bits of matter, in a snowballing chain reaction. Some of this atomic shrapnel even hits the ground.

- It’s possible to see this in action by building what’s called a cloud chamber out of a glass jar, felt, dry ice, and isopropyl alcohol (i.e. rubbing alcohol). You soak the felt in the alcohol, and the dry ice (which is super-cold solid carbon dioxide) cools down the alcohol vapor, which is streaming down from the felt. That creates a cloud of alcohol vapor.

- In this chamber, you can see the cosmic rays, particularly those from a particle called a muon. Muons are like electrons, but a bit heavier. Every square centimeter of Earth at sea level, including the space at the top of your head, gets hit by one muon every minute.

- Like electrons, muons carry a negative charge. When the muons zip through the alcohol cloud, they ionize (charge) the air they pass through. The charge in the air attracts the alcohol vapor, and it condenses into droplets. And those droplets then trace the path the cosmic rays made through the cloud chamber.

- When you see the paths these muons make these subatomic particles rocket down to Earth at 98 percent the speed of light, over 650,000,000 miles per hour.

- Cosmic Rays are moving so fast, they experience the time dilation predicted by Einstein’s theory of special relativity. They are supposed to decay, break apart into smaller components, electrons, and neutrinos, in just 2.2 microseconds, which would mean they’d barely get 2,000 feet down from the top of the atmosphere before dying.

- But because they’re moving so fast, relative to us, they age 22 times more slowly. If Einstein’s theory weren’t true, we wouldn’t see any muons in the cloud chamber.

- Our theoretical physicist colleagues are perplexed” about how these particles are energized. They can’t figure out where they are coming from.

- This mystery of cosmic rays began with their discovery in 1912. Victor Hess took a ride on a hot air balloon and discovered the amount of radiation in the atmosphere increases the higher up you go.

- He was on the balloon to isolate his experiment from radiation. But it was only noisier higher up. That led him to conclude that the radiation was coming from space, and not radioactivity from rocks in the earth.

- He also took this balloon ride during a total solar eclipse. With the moon blocking the sun, cosmic radiation coming from the sun ought to have been filtered out. But he still recorded some. That led him to the insight that the radiation was not coming from the sun, but from deeper in space.

- The highest-energy cosmic ray particle ever recorded, the “Oh-My-God” particle, was some 2,000,000 times more energetic than the most energetic proton propelled by the Large Hadron Collider, the world’s most powerful particle accelerator.

- Nobody knows what in the universe is able to give a subatomic particle such an energy. Scientists are baffled to know such a particle can even reach Earth. Particles with such high energies are thought to interact with the radiation leftover from the Big Bang and the creation of the universe, which ought to put the breaks on them before they reach us.

- What created the “Oh-My-God” particle and these powerful cosmic rays is a complete, baffling mystery. Astronomers do know some cosmic rays come from the sun. But the strongest ones, the most mysterious ones, come from the great way-out-there in the galaxy and universe.

- The problem with looking for the sources of these very high energy cosmic rays is that the rays don’t always travel in a straight line. The various magnetic fields of the galaxy and universe deflect them, and put them on bending paths.

- Many of the cosmic rays that hit Earth, particularly the ones that come from our sun, get deflected to the poles due to Earth’s magnetic field. That’s why we have the Northern and Southern Lights near the poles.

- There are a few huge projects underway to better understand where these cosmic rays come from. An enormous block of ice at the South Pole is a giant cosmic-ray detector

Science has built the “IceCube Neutrino Observatory“, forged directly into the ice beneath the surface of the South Pole.

- It is a 1-cubic kilometer, or, 1.3 billion cubic yards, block of crystal-clear ice surrounded by sensors. These sensors are set up to detect when subatomic particles called neutrinos, which travel along with other subatomic particles in cosmic rays, crash into Earth.

- Neutrinos are different from the other components of cosmic rays in one really important way: They don’t interact with other forms of matter much at all. They don’t have any electrical charge. That means they travel through the universe in a relatively straight line, and we can trace them back to a source.

- Every once in a while a neutrino, perhaps every one in 100,000, will hit an atom in the ice at the observatory and break the atom apart. This collision produces other subatomic particles, which are then propelled to a speed faster than the speed of light as they pass through the ice.

- You might have heard that nothing can travel faster than light. That’s true, but only in a vacuum. The photons that make up light actually slow down a bit when they enter a dense substance like ice. But other subatomic particles, like muons and electrons, do not slow down.

- When particles are moving faster than light through a medium like ice, they glow. It’s called “Cherenkov radiation“. And the phenomenon is similar to that of a sonic boom. When particles move faster than light, they leave wakes of an eerie blue light like a speedboat leaves wakes in the water.

- The “Pierre Auger Observatory” uses an array of 1,600 tanks, each filled with 3,000 gallons of water. The tanks are spread across more than 1,000 square miles in Mendoza, Argentina.

- The tanks work like the block of ice at the South Pole. But instead of using ice to record cosmic rays, they use water. The tanks are completely pitch black inside. But when cosmic rays, more than just neutrinos, enter the tanks, they cause little bursts of light, via Cherenkov radiation, as they exceed the speed of light in water.

- If many of the tanks record a burst of cosmic rays at the same time, the scientists can then work backward and figure out the energy of the particle that hit at the top of the atmosphere. They can also make a rough guess on where in the sky the particle was shot from.

- In the Northern Hemisphere, there’s a similar experiment in Utah called the “telescope array“. Like the tanks in South America, the array in Utah has a series of detectors spread out over an enormous area. Currently, it takes up about 300 square miles, but there’s an upgrade in the works expanding it up to 1,200 square miles.

- The detectors in Utah are made up of super-clear acrylic plastic, and are housed in units that kind of look like hospital beds. If many of the detectors record a hit in sequence astronomers can reconstruct the direction from which they came.

- Every square kilometer of Earth only sees about one of these high energy particles per century. And to account for the fact that these rays don’t often travel in a straight line, it’s going to take a mountain of data.

- The Pierre Auger observatory has some data that some of these high-energy particles come from starburst galaxies, which are galaxies that are forming stars at a very fast rate. About a quarter of the most powerful cosmic rays observed come from a circle about 6 percent the size of the night sky, near the Big Dipper constellation.

- Last summer, 2020, scientists at the IceCube observatory published exciting evidence that galaxies called “blazars” generate some of these high-energy particles. Blazars have supermassive blackholes at the center of them that rip apart matter into its constituent parts, and then blast subatomic particles off like a laser cannon into space.

- Smartphone cameras work because photons, the subatomic particle that constitute light, activates a sensor at the back of the lens. Cosmic rays can activate the sensor too. Every once in a while a cosmic ray can interfere with a microprocessor and cause a computer to crash.

- If you put your phone camera face down, most of the light is blocked, and you’d get a black picture. But, particles from space, will pass right through your phone, ceiling, or wall, and hit the camera sensor, and will leave a trace.

- The hope is that millions of users can turn the app on at night while they are asleep, and it will look for these cosmic rays. With enough phones astronomers can get a better picture of where cosmic rays come from.

- The existence of high-energy cosmic rays tells us our understanding of the universe is woefully incomplete.

- September 20, 2021 COSMIC RAYS - a lot we don’t know? 3283

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

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--------------------- --- Wednesday, September 22, 2021 ---------------------------

Sunday, September 19, 2021

3282 - UNIVERSE - how fast is it expanding?

- 3282 - UNIVERSE - how fast is it expanding? Astronomers compared the latest gamma-ray attenuation data from the Fermi Gamma-ray Space Telescope and Imaging Atmospheric Cherenkov Telescopes to devise their estimates from extragalactic background light models. This approach led to a measurement of approximately 67.5 kilometers per second per mega parsec for the rate of expansion of the Universe.

--------------------- 3282 - UNIVERSE - how fast is it expanding?

- Measuring the expanding Universe using known distances of 50 galaxies from Earth to refine calculations in Hubble's constant the estimate for the age of the universe at 12.6 billion years.

- Different approaches are used to measure the date of the Big Bang, which gave birth to the universe They rely on mathematics and computational modeling, using distance estimates of the oldest stars, the behavior of galaxies, and the rate of the universe's expansion.

- A key calculation for dating is the Hubble's constant, named after Edwin Hubble who first calculated the universe's expansion rate in 1929. Another recent technique uses observations of leftover radiation from the Big Bang. It maps bumps and wiggles in spacetime we know as the cosmic microwave background, or CMB and reflects conditions in the early universe as set by Hubble's constant.

- However, the different methods reach different conclusions. Here is a new approach that recalibrates a distance-measuring tool known as the “baryonic Tully-Fisher relation” independently of Hubble's constant.

- The “distance scale problem” is incredibly difficult because the distances to galaxies are vast and the signposts for their distances are faint and hard to calibrate.

- Recalculations using the Tully-Fisher approach, accurately defined distances in a linear computation of the 50 galaxies as guides for measuring the distances of 95 other galaxies.

- The universe is ruled by a series of mathematical patterns expressed in equations. The new approach more accurately accounts for the mass and rotational curves of galaxies to turn those equations into numbers like age and expansion rate.

- The Hubble's constant, or the universe's expansion rate is calculated to be 75.1 kilometers per second per megaparsec, + or - 2.3 km/sec/Mpsec

- A mega parsec is a common unit of space-related measurements, and is equal to one million parsecs. A parsec being about 3.3 light years. In more common units this is 49,300 miles per hour expansion rate for every million miles distance separtion.

- Previously used measuring techniques over the past 50 years have set the value at 75, but CMB computes a rate of 67 km/sec/Megaparsec.

- Calculations drawn from observations of NASA's Wilkinson Microwave Anisotropy Probe in 2013 put the age of the universe at 13.77 billion years.

- The differing Hubble's constant values from the various techniques generally estimate the universe's age at between 12 billion and 14.5 billion years.

- This new study is based on observations made with the Spitzer Space Telescope that adds a new element to how calculations to reach Hubble's constant can be set, This introduces a purely empirical method, using direct observations, to determine the distance to galaxies.

- Cosmology is about understanding the evolution of our universe -- how it evolved in the past, what it is doing now and what will happen in the future.

- The concept of an expanding universe was advanced by the American astronomer Edwin Hubble (1889-1953), who is the namesake for the Hubble Space Telescope.

- In the early 20th century, Hubble became one of the first astronomers to deduce that the universe was composed of multiple galaxies. His subsequent research led to his most renowned discovery: that galaxies were moving away from each other at a speed in proportion to their distance.

- Edwin Hubble originally estimated the expansion rate to be 500 kilometers per second per mega parsec. Hubble concluded that a galaxy two megaparsecs away from our galaxy was receding twice as fast as a galaxy only one megaparsec away. This estimate became known as the Hubble Constant, which proved for the first time that the universe was expanding.

- Astronomers have been recalibrating it -- with mixed results -- ever since.

- With the help of new technologies, astronomers came up with measurements that differed significantly from Hubble's original calculations, slowing the expansion rate down to between 50 and 100 kilometers per second per megaparsec.

- In the past decade, ultra-sophisticated instruments, such as the Planck satellite, have increased the precision of Hubble's original measurements in relatively dramatic fashion.

- Astronomers compared the latest gamma-ray attenuation data from the Fermi Gamma-ray Space Telescope and Imaging Atmospheric Cherenkov Telescopes to devise their estimates from extragalactic background light models. This approach led to a measurement of approximately 67.5 kilometers per second per mega parsec for the rate of expansion of the Universe.

- Gamma rays are the most energetic form of light. Extragalactic background light (EBL) is a cosmic fog composed of all the ultraviolet, visible and infrared light emitted by stars or from dust in their vicinity. When gamma rays and EBL interact, they leave an observable imprint, a gradual loss of flow.

- Matter -- the stars, the planets, even us -- is just a small fraction of the universe's overall composition. The large majority of the universe is made up of dark energy and dark matter.

- Dark energy is pushing things away from each other. Gravity, which attracts objects toward each other, is the stronger force at the local level, which is why some galaxies continue to collide. But at cosmic distances, dark energy is the dominant force.

- It is remarkable that we are using gamma rays to study cosmology. New results show the maturity reached in the last decade by the relatively recent field of high-energy astrophysics. The analysis paves the way for better measurements in the future using the Cherenkov Telescope Array, which is still in development and will be the most ambitious array of ground-based high-energy telescopes ever.

- What we know is that gamma-ray photons from extragalactic sources travel in the universe toward Earth, where they can be absorbed by interacting with the photons from starlight. The rate of interaction depends on the length that they travel in the universe. And the length that they travel depends on expansion.

- If the expansion is low, they travel a small distance. If the expansion is large, they travel a very large distance. So the amount of absorption that we measured depended very strongly on the value of the Hubble Constant.

- What astronomers did was turn this around and use it to constrain the expansion rate of the universe.

- September 19, 2021 UNIVERSE - how fast is it expanding? 3282

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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

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--------------------- --- Sunday, September 19, 2021 ---------------------------

- 3281 - PLUTO - Planets and Baryons Beyond Pluto? Scientists thus discovered some of the Universe's missing baryons, thereby confirming that 80-90% of normal matter is located outside of galaxies, an observation that will help expand models for the evolution of galaxies. The further we look the more we see?

--------------------- 3281 - PLUTO - Planets and Baryons Beyond Pluto?

- Are there planets beyond Pluto? Maybe, the latest surveys have found 461 orbiting objects, but, none so far to be big enough for planets.

- The next-generation telescopes will be the James Webb Space Telescope (JWST) and the Nancy Grace Roman Space Telescope (RST). Improved data mining and machine learning techniques will also allow astronomers to get more out of existing instruments as well as the new telescopes.

- The current Dark Energy Survey (DES ) is a six-year survey of the outer solar system. In addition to gathering data on hundreds of known objects, this survey revealed 461 previously undetected objects as of 2021.

- Between 2013 and 2019, DES used the 4-meter Blanco Telescope at the Cerro Tololo Inter-American Observatory (CTIO) in Chile to study hundreds of millions of galaxies, supernovae, and the large-scale structure of the universe.

- While their primary objective is to measure the accelerating rate of the universe expansion (the Hubble-Lemaître Constant) and the spatial distribution of Dark Matter, the DES Collaboration also reported the discovery of individual TNOs.

- By 2021, the team detected 461 previously undetected objects, which brings the total number of TNOs discovered by DES to 777, and the number of known TNOs to nearly 4,000. They also gained fresh data on many other objects, including the large comet C/2014 UN271.

- Astronomers have long suspected that the population of small bodies orbiting beyond Neptune are remnants left over from the formation of the solar system. The current orbital distribution of these objects is the result of the migration of the giant planets to their current orbits. As they migrated, they kicked these objects into the trans-Neptunian region, outside the orbit o the planet Neptune.

- By having a census of TNOs and constraining their orbital dynamics, astronomers will be able to gain new insight into how our solar system formed and evolved billions of years ago. That knowledge could also inform our understanding of how habitable systems that give rise to life emerge, thus making it easier for us to find it.

- A giant comet from the outskirts of our solar system has also been discovered in six years of data from the Dark Energy Survey. It is estimated to be about 1,000 times more massive than a typical comet, making it arguably the largest comet discovered in modern times.

- This comet has an extremely elongated orbit, journeying inward from the distant Oort Cloud over millions of years. It is the most distant comet to be discovered on its incoming path, giving us years to watch it evolve as it approaches the Sun, though it's not predicted to become a naked-eye spectacle.

- The comet, which is estimated to be 200 kilometers across, or about 10 times the diameter of most comets, is an icy relic flung out of the solar system by the migrating giant planets in the early history of the solar system.

- DES was tasked with mapping 300 million galaxies across a 5,000-square-degree area of the night sky, but during its six years of observations it also observed many comets and trans-Neptunian objects passing through the surveyed field.

- A trans-Neptunian object, or TNO, is an icy body that resides in our solar system beyond the orbit of Neptune. Tracking algorithms have identified over 800 individual TNOs from among the more than 16 billion individual sources detected in 80,000 exposures taken as part of the DES. Thirty-two of those detections belonged to one object in particular, C/2014 UN271.

- Comets are icy bodies that evaporate as they approach the warmth of the Sun, growing their coma and tails.

- This comets current inward journey began at a distance of over 40,000 astronomical units (au) from the Sun, 40,000 times farther from the Sun than Earth is, or 3.7 trillion miles, or 0.6 light-years, 1/7 of the distance to the nearest star. For comparison, Pluto is 39 au from the Sun, on average.

- This means that Comet Bernardinelli-Bernstein originated in the Oort Cloud of objects, ejected during early history of the solar system. It could be the largest member of the Oort Cloud ever detected, and it is the first comet on an incoming path to be detected so far away.

- Comet Bernardinelli-Bernstein is currently much closer to the Sun. It was first seen by DES in 2014 at a distance of 29 au, 2.5 billion miles, or roughly the distance of Neptune, and as of June 2021, it was 20 au or 1.8 billion miles, the distance of Uranus from the Sun and currently shines at magnitude 20.

- The comet's orbit is perpendicular to the plane of the solar system and it will reach its closest point to the Sun, the perihelion, in 2031, when it will be around 11 au away , a bit more than Saturn's distance from the Sun. Despite the comet's size, it is currently predicted that skywatchers will require a large amateur telescope to see it, even at its brightest.

- Comet Bernardinelli-Bernstein will be followed intensively by the astronomical community, including with NOIRLab facilities, to understand the composition and origin of this massive relic from the birth of our own planet.

- Astronomers suspect that there may be many more undiscovered comets of this size waiting in the Oort Cloud far beyond Pluto and the Kuiper Belt. These giant comets are thought to have been scattered to the far reaches of the solar system by the migration of Jupiter, Saturn, Uranus and Neptune early in their history.

- If we look a little further outside our solar system galaxies are receiving and exchanging matter with their external environment due to the galactic winds created by stellar explosions.

- The MUSE instrument has mapped this galactic wind for the first time. This unique observation, as 16 September 16, 2021, helped to reveal where some of the Universe's missing matter is located and to observe the formation of a nebula around a galaxy.

- Galaxies are like islands of stars in the Universe, and possess ordinary or baryonic matter, which consists of elements from the periodic table, as well as dark matter, whose composition remains unknown.

- One of the major problems in understanding the formation of galaxies is that approximately 80% of the baryons that make up the normal matter of galaxies is missing. According to models, they were expelled from galaxies into inter-galactic space by the galactic winds created by stellar explosions.

- The MUSE instrument was used to generate a detailed map of the galactic wind driving exchanges between a young galaxy in formation and a nebula (a cloud of gas and interstellar dust).

- The team chose to observe galaxy due to it’s proximity of a quasar, which served as a "lighthouse" for the scientists by guiding them toward the area of study. They also planned to observe a nebula around this galaxy, although the success of this observation was initially uncertain, as the nebula's luminosity was unknown.

- The perfect positioning of the galaxy and the quasar, as well as the discovery of gas exchange due to galactic winds, made it possible to draw up a unique map. This enabled the first observation of a nebula in formation that is simultaneously emitting and absorbing magnesium, some of the Universe's missing baryons, with this galaxy.

- This type of normal matter nebula is known in the near Universe, but their existence for young galaxies in formation had only been supposed.

- Scientists thus discovered some of the Universe's missing baryons, thereby confirming that 80-90% of normal matter is located outside of galaxies, an observation that will help expand models for the evolution of galaxies.

- September 19, 2021 PLUTO - Planets and Baryons ? 3281