3638 - METEORITES - bringing the materials for life?

  -  3638  -     METEORITES  -    bringing the materials for life?  The Japanese spacecraft Hayabusa2 recently brought the asteroid Ryugu down to Earth.   NASA's OSIRIS-REx probe is due to touch down with samples of the near-Earth asteroid Bennu in 2023.  These will be analyzed to learn if they contain the ingredients for life.

-----------------  3638  -     METEORITES  -    bringing the materials for life? 

-  While studying diamonds inside an ancient meteorite, scientists have found a strange, interwoven microscopic structure that has never been seen before.   The structure, an interlocking form of graphite and diamond, has unique properties that could one day be used to develop superfast charging or new types of electronics. 

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-  The diamond structures were locked inside the “Canyon Diablo meteorite“, which slammed into Earth 50,000 years ago and was first discovered in Arizona in 1891. The diamonds in this meteorite aren't the kind most people are familiar with. 

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-  Most known diamonds were formed around 90 miles beneath Earth's surface, where temperatures rise to more than 2,000 degrees Fahrenheit. The carbon atoms within these diamonds are arranged in cubic shapes.

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-  The diamonds inside the Canyon Diablo meteorite are known as “lonsdaleite” and have a hexagonal crystal structure. These diamonds form only under extremely high pressures and temperatures. Scientists have successfully made lonsdaleite in a lab using gunpowder and compressed air to propel graphite disks 15,000 mph at a wall.  Lonsdaleite is otherwise formed only when asteroids strike Earth at enormously high speeds. 

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-   Instead of the pure hexagonal structures they were expecting, the researchers found growths of another carbon-based material called “graphene” interlocking with the diamond. These growths are known as “diaphites“, and inside the meteorite, they form in a particularly intriguing layered pattern. In between these layers are "stacking faults," which mean the layers don't line up perfectly.  

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-  Finding diaphites in the meteoritic lonsdaleite suggests that this material can be found in other carbonaceous material,.  Graphene is made of a one-atom-thick sheet of carbon, arranged in hexagons. 

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-   Because it is both as light as a feather and as strong as a diamond; both transparent and highly conductive; and 1 million times thinner than a human hair, it could one day be used for more targeted medicines, tinier electronics with lighting-fast charging speeds, or faster and bendier technology.

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-  Through the controlled layer growth of structures, it should be possible to design materials that are both ultra-hard and also ductile, as well as have adjustable electronic properties from a conductor to an insulator.  What we can learn from old meteors.  Amazing!

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-  Three other meteorites have been found that contain the molecular building blocks of DNA and its cousin RNA.  

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-  The new discovery supports the idea that, some four billion years ago, a barrage of meteorites may have delivered the molecular ingredients needed to jump-start the emergence of the earliest life on Earth. 

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-  However, not everyone is convinced that all of the newfound DNA components are extraterrestrial in origin; rather, some may have ended up in the meteorites after the rocks touched down on Earth.  Additional studies are needed to rule out this possibility.

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-  Assuming that all of the compounds did originate in space, one subset of building blocks, a class of compounds known as “pyrimidines“, appeared in extremely low concentrations in the meteorites. This finding hints that the world's first genetic molecules emerged not due to an influx of DNA components from space but rather as a result of the geochemical processes unfolding on early Earth.

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-   These nucleobases might be lurking, undetected, in the space rocks that slammed into Earth.   In lab settings, scientists have recreated the chemical conditions of interstellar space where immense clouds of gas and dust measure about 10 kelvins (minus 263.15 degrees Celsius) and the parent asteroids of meteorites can be found. 

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-   Researchers synthesized thymine, cytosine and the other primary nucleobases, suggesting that all of these compounds could theoretically be detectable in meteorites.

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-    Hydrocarbons and the building blocks of proteins (amino acids) have been identified in the three meteorites.   High-performance liquid chromatography is involved using pressurized water to separate the meteorite samples into their component parts. This extracted the nucleobases from each sample which was analyzed using mass spectrometry. 

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-    To check that the nucleobases were extraterrestrial in origin rather than the result of Earthly contamination, the team repeated the experimental procedures without any meteorite material in the test chambers. No nucleobases were detected during these blank experiments. 

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-  The team also had access to soil samples from the site where the Murchison meteorite first plummeted to Earth. They detected some nucleobases in the soil, but their distribution and concentrations are clearly different from those found in meteorites.

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-   Earth matter contains different ratios of carbon isotopes and nitrogen isotopes than matter from space,  analyses could help discriminate the terrestrial nucleobases from extraterrestrial ones.

-

-  If these results are representative of typical “pyramiding” concentrations in meteorites, then geochemical synthesis on early Earth would likely have been responsible for the emergence of genetic material, rather than inputs from extraterrestrial delivery.

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July 29, 2022      -     METEORITES  -    bringing the materials for life?         3638                                                                                                                                        

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--------------------- ---  Sunday, July 31, 2022  ---------------------------

3637 - JAMES WEBB - earliest discoveries?

  -  3637  -  JAMES  WEBB  -  earliest discoveries?  -  A new generation of astronomy is officially underway.  The best is yet to come, each new observation exposes a new portion of our shared cosmic story for the very first time. The Universe, to everyone studying it, will never be the same again.  Here is some of what we have already learned:

---------------------  3637  -    JAMES  WEBB  -  earliest discoveries?    

-  James Webb's very first deep-field image of the lensed galaxy cluster “SMACS 0723” and all the background objects it stretches and magnifies, we've seen deeper into the distant Universe than ever before. 

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-  There are new features revealed, new galaxies discovered, and new features about previously discovered objects that JWST's unique capabilities have enabled us to uncover.

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-  July 11, 2022, the very first science image of the James Webb Space Telescope (JWST) was unveiled to the world. Upon its release, it immediately broke the cosmic record for the deepest view ever taken of the Universe. 

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-  Prior to JWST’s first science release, the deepest view of our cosmos came from the Hubble eXtreme Deep Field: a region of space so small it takes up just 1/32,000,000 th of the sky. Within it, 5500 galaxies were found, spanning almost the entire history of the Universe: from just 400 million years after the Big Bang until today, or from when the Universe was merely 3% of its current age all the way to its present day.

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-  That image represented the deepest view of the Universe for a full decade. But by simply using its suite of instruments to observe a run-of-the-mill galaxy cluster the JWST has shown us the Universe as we’ve never seen it before. 

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-  Over the course of 50 days, with a total of over 2 million seconds of total observing time (the equivalent of 23 complete days), the Hubble eXtreme Deep Field (XDF) was constructed from a portion of the prior Hubble Ultra Deep Field image. Combining light from ultraviolet through visible light and out to Hubble’s near-infrared limit, this represents humanity’s deepest view of the universe.

-

-  There are a few keys to taking a “deep” view of the Universe. The first is to find an area of the sky that’s relatively pristine:

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-------------------  With no bright stars from within the Milky Way in its field of view,

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------------------- With no bright, extended, extremely nearby galaxies in the vicinity,

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------------------- Where there’s only a small, negligible amount of neutral, light-blocking matter due to the Milky Way’s foreground,

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------------------- Where even the brightest stars and galaxies remaining are faint enough so that they won’t be able to saturate the detectors and instruments under any settings.

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- Then, in as many relevant filters which probe a very specific wavelength range as possible, you take a series of images where you simply gather light, one photon at a time, from the same region of sky.

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-   Images that use the same filter, which view the region of the sky in the exact same wavelength range, then get “stacked” together.  The light from each individual frame gets added together, exposing the faintest objects perceptible in that wavelength range.

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-  Multiple different filters are combined to produce images.  Colors are assigned to each filter or set of filters, and then our eyes interpret the data the same way we’d interpret a full-color photograph.

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-  The Hubble Space Telescope was primarily designed as an “optical” observatory. It was  optimized to look at the same wavelengths of light that human eyes are sensitive to. Because it’s located in space, far above Earth’s atmosphere, it doesn’t have the same limitations that a ground-based telescope possesses: it can look at wavelengths that are otherwise blocked by Earth’s atmosphere. 

-

-  That means that it can see ultraviolet (shorter-wavelength) light as well, where the atmosphere is only partially transparent to it, and it can also see into the infrared (longer-wavelength) portion of the spectrum, where only a selection of wavelength ranges aren’t completely blocked by our atmosphere.

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-  Each different wavelength range will have its own unique resolution when it comes to the light that’s gathered.  The resolution is determined by the number of wavelengths of light that fit across the diameter of the telescope’s primary mirror. Although human vision extends from 400 to 700 nanometers, telescopes can assign filters to cover whatever wavelength range the operators desire.

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-  For Hubble, with its 2.4-meter diameter mirror, that means its “blue” filter of about 400 nanometers has about twice as good a resolution as its “red” filter of about 800 nanometers, and its infrared filters, which span from 1050 nanometers to 1600 nanometers, are again only half-as-sharp at the longest wavelengths.

-

-  For Hubble:

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-------------------   There are three optical filters, at 435, 606, and 814 nanometers, assigned to red, green and blue, respectively,

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----------------  There are four infrared filters, at 1050, 1250, 1400, and 1600 nanometers, all assigned-and-stacked to the same infrared channel,

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----------------   The overall composite combined all seven filters, assigning “blue” to the 435 nm channel, “green” to the 606 + 814 nanometer channel, and “red” to all four infrared channels combined.

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-  By looking at details in these channels separately, you can notice a slew of features. Cooler stars and diffuse starlight are brighter in the infrared. Features of a galaxy’s disk are sharpest in the shortest wavelengths, and become more smeared-out at longer and longer wavelengths.  

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-  A filter at 1600 nanometers isn’t only one-fourth as good as a filter at 400 nanometers; it’s actually only one-sixteenth as good. A galaxy that takes up 64 pixels (8-by-8) in Hubble’s blue filter would only take up 4 pixels (2-by-2) in Hubble’s farthest infrared filter.

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-   There are two factors at play that limit, at a fundamental level, what Hubble can see; these two factors are literally the difference-maker between Hubble and JWST.

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-   Hubble is warm; JWST is cold. If you want to detect anything and this goes for anything, ever, under any circumstances you need to be able to see a signal from what you’re measuring over and above the noise inherent to your instrument. Infrared radiation is simply a consequence of heat: objects at a certain temperature radiate heat, and that heat shows up as photons of a particular wavelength. The hotter you are, the more photons you’ll emit at higher and higher energies (and shorter and shorter wavelengths).

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-  In low-Earth orbit, Hubble, even wrapped in its highly reflective coating, still hovers somewhere around 200 K and up. This is what limits its wavelength capabilities: beyond 2,000 nanometers (2 microns), the observatory produces too much of its own internal radiation to do useful science. 

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-  JWST with its 5-layer sunshield is passively cooled down to below 40 K for all of its instruments, including NIRCam, the Near-Infrared camera, which can see all the way out to 5,000 nanometers (5 microns) without any active cooling.

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-   MIRI, the Mid-Infrared instrument, is actively cooled down to 6 K, enabling it to see light between 5,000 and 28,000 nanometers (5-28 microns) at its limits.

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-   You can’t see the most distant objects by looking in the same wavelengths as the ones where that light was initially emitted. The Universe isn’t static, it’s expanding: distant, gravitationally unbound galaxies all recede from one another against the backdrop of expanding space. When a distant object emits light even, very blue light, the expansion of the Universe stretches that light to longer and longer wavelengths.

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-  Hubble, even at the longest-wavelengths that it’s sensitive to, can’t really take us back to galaxies that emit light from the first 3% of the Universe’s history. But, NIRCam and MIRI capabilities means JWST can see much longer wavelengths, enabling it to reveal objects that are undetectable by warmer observatories.

-

-  There are objects out there so distant that their light takes 13,400,000,000  years to reach us, and that takes us beyond the limitations of Hubble.  That’s where the cosmic frontier is.  If we want to see the earliest galaxies, the first stars, and the youngest objects ever to form in the Universe, we simply have to go beyond the capabilities of current technology. That means longer wavelengths and cooler observatories, and that’s what JWST is delivering.

-

-  JWST, we can go out to a 14 times the maximum wavelength that the Hubble Space Telescope is sensitive to.

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-  Telescope size determines both resolution and light-gathering power. If you want to see farther into the distant Universe, and to see features you couldn’t see before, you have to increase the total amount of light you capture, and also observe the Universe at superior resolutions.

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-   With JWST, the NIRCam images, especially at the lowest wavelengths, will produce sharper images than Hubble ever could, owing to its large, 6.5-meter primary mirror that’s 270% the diameter of Hubble’s.

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-   At all wavelengths, JWST gathers more than 7 times the total amount of light as Hubble, meaning that it can not only expose fainter, more distant objects than Hubble ever could, but that it can do it with less observing time than Hubble would ever require. What Hubble requires a week for, JWST can do better in a day. What Hubble requires two months for, JWST can outperform in a week.

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-  The reason JWST can see what Hubble cannot is because of the difference in size, temperature, wavelength coverage, and the correspondingly-optimized instrument suite.

James Webb will have seven times the light-gathering power of Hubble, but will be able to see much farther into the infrared portion of the spectrum, revealing those galaxies existing even earlier than what Hubble could ever see.

-

-  The power of gravitational lensing, and strong gravitational lensing explicitly, reveals background sources that could never be practically seen otherwise. But this natural magnifying glass amplifies the light we receive, even at such long wavelengths, so JWST is able to reveal a number of objects never seen before because they were either too faint, too distant.  Their wavelength was stretched to too great a value to be seen previously.

-

-   Contained within the first JWST Deep Field are:

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------------------  A number of faint “blobs” that aren’t seen in the Hubble image, corresponding to galaxies that were too faint and/or too long in wavelength to be seen previously,

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-----------------  A number of objects that appeared only as faint smudges, previously, that now have obvious structure to them, such as spiral arms, resulting from JWST’s improved resolution, light-gathering power, and superior wavelength coverage,

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----------------  A brighter, wider glow from the central region: an example of what’s almost certainly intracluster light, inherent to most galaxy clusters that aren’t largely gas-depleted,

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-----------------  Numerous instances of “smudges” that were seen previously that are now seen to be multiple galaxies that appear to overlap, a tremendous demonstration of JWST’s superior resolution.

-

-  Although the official image release doesn’t include scientific data, a number of these objects are claimed to have their light come to us from as far back as 13.5 billion years ago: pushing our earliest cosmic views back by approximately 100 million years. 

-

-  This is just the first science result using this new JWST observatory .  Over the coming years an enormous number of cosmic records are going to be broken, most of them over and over again. We will have dozens of galaxies fainter, more distant, and with more pristine stellar populations that go beyond any of the cosmic record-holders lurking in the lensed field of this galaxy cluster. 

-

-  A new generation of astronomy is officially underway. Although the best is yet to come, each new observation, especially at this early stage, exposes a new portion of our shared cosmic story for the very first time. The Universe, to everyone studying it, will never be the same again.

- 

July 26, 2022           JAMES  WEBB  -  earliest discoveries?               3631                                                                                                                                        

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

-----  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”  -----------

--------------------- ---  Tuesday, July 26, 2022  ---------------------------

3636 - EARTH’S BIOLOGY - more life to be found?

  -  3636  - EARTH’S  BIOLOGY  -   more life to be found?   Scientists need to keep a wide-open mind about what could be lurking within the deep world.  We see only what we look for. If we don't look for something, we miss it.  How did life start anyway?

------------------  3636  -    EARTH’S  BIOLOGY  -   more life to be found? 

-  Octopus genes are more advanced than any other order of animals on Earth. One of the groups of genes that they exhibit codes for the development of their amazing distributed nervous system. “Octopods’ possess regenerative and camouflage capabilities, and are among the smartest animals on the planet.  

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There are species of single-celled organisms called “Archaea” that survive in environments so harsh they would melt the flesh from your bones in seconds. They live in super-alkaline lakes, in the ultra-high pressure of the Mariana trench, alongside nearly deep-fryer temperature hydrothermal vents, and can even survive high doses of gamma radiation. These are not bacteria, and may indeed be the earliest form of prokaryotic life on Earth.

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-  “Tardigrades“, called “water bears”, can survive in the harsh cold and pure vacuum of space, and can put themselves in a dormant state in which their metabolism reduces to 0.01% of normal, allowing them to live to nearly 30 years in more moderate conditions, essentially extending their expected lifespan of only a few months by 300 times.

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-  There are four species of “Hyena“, that powerful and hardy scavenger that lurks in the African savannah. Though they have physical and behavioral characteristics of both cats and dogs, they are neither. Hyenas belong to their own family, Hyenadae, and they evolved and thrived because they fit a particular niche in their ecosystem.

-

-  “Marsupials” were once the dominant mammalian order on the planet. Like other mammals, they give birth, but the young are undeveloped and spend most of their time outside of the mother’s body suckling and growing in a pouch.

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-   Marsupials boasted gigantic grazing species and terrifying predators the size of lions, but were eventually out competed by other mammals in those particular niches and now only exist in Australia and the Americas in more limited capacities.

-

-  “Turritopsis dohrnii” is a species of “medusae” jellyfish that, when reaching a point of being too old, injured or sick, reverts back into its “childlike” polyp state and then regrows, creating a cycle of near immortality.

-

-  These are a few creatures that live with us now, and they are nearly as different from us as much alien life will be.  But, despite how different these subjects are, the fact remains they evolved on Earth, with us. 

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-  We are all descendants of the very first living cells that appeared sometime between 3.8 and 4.3 billion years ago during the “Eoarchean Era“.  Since then, life has been branching out in innumerable different directions, constantly testing the boundaries of its environments to see what forms can thrive and what forms are insufficient. Darwin’s “survival of the fittest” has been at play for billions of years.

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-  Scientists estimate that there may be as many as 8,700,000 species currently alive on Earth today. We’re only sure of roughly 1.2 million of those, 13% which are catalogued. It’s taken the work of many generations of explorers and biologists to find and record them, but that’s where we are now. 

-

-  The work is never-ending.  We discover, on average, about 50 new species every day, based on the 18,000 found in 2016.  There’s a flipside to that number which is utterly horrifying:  150 species go extinct every day in our modern world, which may be 1,000 times the natural rate.

-

-  This means that we are losing species 3 times faster than we are finding them.  By this time next year, 36,000 types of living things will have gone extinct before we get a chance to witness their existence.

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-  What about all those species that lived, but we’ll never discover?  Based on the data scientists have currently, most species tend to exist for a period of 3 million years, at most, before they disappear. “Disappear”, in this instance, means went “extinct“.

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-  The fossil record as we know it comes almost entirely from evidence found in sedimentary rock, which generally is only found very near the surface of the planet. Over the huge expanse of geologic time, billions of years, via plate tectonics, volcanism and asteroid impacts, most of those deposits that have ever existed have been subsumed into much deeper layers of the planet. We will, likely, never have teams of paleontologists searching for fossils twenty miles below the surface.

-

-   When you consider the countless potential species of microscopic organisms, which multiply so quickly and have such short generations, there have likely existed many billions of species on Earth since the dawn of life.

-

-  All of life as we currently know it, everything we see living around us today, represents at most half a billion years of evolution. Every recognizable form of life, from flowers to insects to dinosaurs to deer, evolved in less than 1/8th of the time life has been on Earth.

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-  So much time is unaccounted for, so much evolution, that there may have been enough time for multiple entire other complete evolutionary trees to develop before being totally wiped clean from the face of the planet.  Think about that some more:

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-  Earth is not OUR Earth. It’s belonged to living things for so long that there may have been advanced, even intelligent, species to come along billions of years ago. It’s just been so long, with so many geologic changes along the way, that any evidence of their time here could never be uncovered.

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-  Where do we, humans, fit into this?  ”Neanderthals“, only existed for a few hundred thousand years before being put out of business by modern humans, “Homo sapiens“. All of the genus Homo has only been around for roughly 2.5 million years.

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-  Apes, as whole, have only existed for 15 million years, while modern sharks have managed to thrive for more than ten times that amount of time.

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-  Will modern humans still be around in a million years? 100,000 years? 1,000 years? There are ample reasons to assume we may not be here in 100 years.

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-  If we do manage to survive for millennia more, then we may have a chance to “disappear” like so many other species have.   Our species slowly transforming over time into NEW species, perhaps because we transport populations off-planet as Elon Musk and NASA plan to do.

-

-  “Homo sapiens” is the latest branch in a singular limb of the evolutionary tree. We have caused the extinction of many other of our fellow species, and continue to do so, at an alarming rate.

-

-   If we make it past our current two minutes to midnight setting on the Doomsday Clock, then we may be the ancestors to numerous other species that progress through oncoming millions, maybe even billions, of years remaining until the Earth is swallowed up when our dear Sun becomes a red giant.

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-  Something odd is stirring in the depths of “Canada's Kidd Mine“. The zinc and copper mine, 350 miles northwest of Toronto, is the deepest spot ever explored on land and the reservoir of the oldest known water. And yet 7,900 feet below the surface, in perpetual darkness and in waters that have remained undisturbed for up to two billion years, the mine is teeming with life.

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-  Many scientists had doubted that anything could live under such extreme conditions. But, the mine’s dark, deep water harbors a population of remarkable microbes.  The single-celled organisms don’t need oxygen because they breath sulfur compounds. Nor do they need sunlight. Instead, they live off chemicals in the surrounding rock, the glittery mineral pyrite, commonly known as fool’s gold.

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-   Scientists are starting to find similar microbes in other deep spots, including boreholes, volcanic vents on the bottom of the ocean and buried sediments far beneath the seafloor.

-

-  The deep microbial realm reveals a biosphere that’s more extensive, resilient, varied and strange than we had realized.  Cut off from light, air, and any connection to the surface, this shadowy realm seems more like an alien world than part of Earth.  

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-  Exploring it could help us understand how life might have begun on other planets as well as on our own. We might even find alien-like creatures living undetected right beneath our feet.

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-  Geobiologist estimated that some 5 x 10^29 cells live in the deep Earth.  That’s five-hundred-thousand-trillion-trillion cells. Collectively, they weigh 300 times as much as all living people combined. This hidden ecosystem as an “underground Galapagos.”

-

-  The denizens of the deep are an exotic bunch even beyond their appetite for solid rock. One species, the microbe “Geogemma barossii“, can live at temperatures of 250 degrees Fahrenheit.  This is well above the boiling point of water and close to the theoretical limit at which vital organic molecules start to disintegrate.

-

-  Studies of material drilled near the Mariana Trench in the Pacific Ocean hint that some organisms could be living six miles below the seafloor, limited only by the heat at such tremendous depths. Laboratory experiments show that some microbes can tolerate pressures 20,000 times higher than the air pressure at sea level, meaning that there are almost certainly more extreme ecosystems out there than the one in the Kidd Mine.

-

-  The pace of existence in the deep also seems radically different from that on the surface. In ancient environments like the trapped waters at the bottom of the Kidd Mine, food and energy are scarce. To compensate, cellular metabolism slows almost to a standstill.

-

-  Many of the microbes may survive for thousands of years or more without dividing, just replacing their broken parts.  There are so many deep microbes that, despite a seemingly lazy existence, they collectively exert a huge impact on their habitats. 

-

-  A community of cells on the ocean floor consume methane gas that bubbles up from ancient sediment.   Deep subsurface microbes eat massive amounts of methane that would otherwise be released, thus helping curb atmospheric levels of a potent greenhouse gas.

-

-   Fossils show that surface life has changed enormously over billions of years, but slow-motion deep life may retain much of its primitive characteristics. That’s especially true at the Kidd Mine, which is in one of the oldest, most stable portions of Earth’s crust.  The rock in and around the mine have lain undisturbed for 2.7 billion years, and have been cool enough to support life for at least 2 billion years.

-

-   Ancient water samples 4,300 feet deep within the Beatrix Gold Mine, South Africa to investigate the diversity and abundance of deep microbes.   Are they all still close relatives, or have they diversified and adapted significantly to their local environments? 

-

-  Such studies could offer hints about where life first arose on Earth. Charles Darwin imagined the beginning might have occurred in a warm little pond, but there's absolutely no reason why it could not have been a warm little rock fracture.  Sulfur-breathing microbes living beneath thick, protective layers of rock would have been well suited to the brutal conditions on our planet when it was young.

-

-  Another, even wilder possibility is that life originated more than once, with other forms still surviving somewhere on Earth.  We've literally only scratched the surface of the deep biosphere.  Might there be entire domains that are not dependent on the DNA, RNA and protein basis of life as we know it?  Perhaps we just haven’t found them yet.

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July 25, 2022          EARTH’S  BIOLOGY  -   more life to be found?         3636                                                                                                                                        

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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”  -----------

--------------------- ---  Tuesday, July 26, 2022  ---------------------------

3635 - WEBB - first galaxy?

  -  3635  -  WEBB  -  first galaxy?   -  During some of the James Webb Space Telescope’s first scientific observations astrophysicists  discovered the oldest galaxy ever observed.

---------------------  3635  -    WEBB  -  first galaxy?   

-   The galaxy, “GLASS-z13“, is 13.5 billion light years away. Webb saw light from the galaxy as it looked just 300 million years after the Big Bang, when the universe was still very young.  The Universe is thought to be 13.8 billion years old.  Earth is 4.5 billion years old.

-

-  The Hubble Space Telescope discovered a galaxy 13.4 billion light years away,

 “GN-Z11“.    GLASS-z13 observation smashes some assumptions about when galaxies started to form, how quickly they grew, and how many we can expect to find in the most distant reaches of the universe.

-

-  Most models for the birth of the Universe predicted that such ancient galaxies would be scarce, small, and dim. But GLASS-z13 is surprisingly bright.  It is a color image of a blurry orange-white galaxy in space.

-

-  Webb also discovered another surprisingly bright young galaxy, “GLASS-z11“, in the same relatively small patch of sky.  It is an area about 1.6 times wider than the full Moon viewed from Earth. 

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-  GLASS-z11 is about 13.4 billion light years away, roughly the same distance as GN-Z11. Where astronomers previously only knew of one galaxy dating back to the first few hundred million years of the universe, now they know about three. And they’ve only searched a very small area of the sky so far.

-

-  That seems to defy models that predict there shouldn’t be very many bright galaxies in the oldest parts of the universe.  Computer models based on the data from Webb’s NIRCam instrument suggest that by 300 to 400 million years after the Big Bang, each galaxy had formed a collection of stars with a total mass of around 1 billion times that of our Sun. Their surprising brightness at such an early moment in the universe’s evolution has implications for just how early these galaxies began forming.

-

-  The newly-discovered galaxies do match astrophysicists’ expectations by being both small compared to our own Milky Way, and to have relatively simple structures.

-

-  GLASS-z13 is about 1,600 light years wide, while the slightly closer GLASS-z11 is about 2,300 light years wide. Our Milky Way galaxy is about 100,000 light years wide.  GLASS-z11 appears to be a disc-shaped galaxy, without the fancy spiral arms of galaxies like our Milky Way .

-

-   That’s about what astrophysicists expected from the oldest galaxies in the universe.  How did small, simple galaxies like GLASS-z11 grow into large spiral galaxies like our Milky Way? 

-

-  Astrophysicists are fairly sure that it happened in a series of cosmic collisions. The first small galaxies merged to form larger ones, and that process repeated several times and is still happening. Earlier this year, 2022, astrophysicists even found physical evidence of an ancient merger in the Large Magellanic Cloud, a small galaxy adjacent to our own.

-

-  That process of galactic evolution is one of the major themes of Webb’s first year of science. Some of Webb’s first observations are focused on how the first galaxies formed and how they evolved. 

-

-  Technically, GLASS-z13 and GLASS-z11 are just candidates for the title of oldest known galaxies.   More data from Webb’s instruments will help confirm whether the two galaxies really are as old as they look.

-

-  Much more astronomy yet to come from the Webb telescope.

-

July 23, 2022                   WEBB  -  first galaxy                            3635                                                                                                                                        

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

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

--------------------- ---  Sunday, July 24, 2022  ---------------------------

3634 - JAMES WEBB - what can it see?

  -  3634  - JAMES  WEBB -  what can it see?  The $10 billion James Webb Space Telescope (JWST or Webb) is searching the cosmos to uncover the history of the universe's first galaxies and the formation of stars and planets.

---------------------  3634  -  JAMES  WEBB -  what can it see?  

-  The Near-Infrared Spectrograph (NIRSpec) on the Webb Telescope is used to study a region close to the center of our Milky Way galaxy.  It can pack more than 200 spectra in a single exposure. Each horizontal stripe represents a spectrum that scientists will be able to analyze to better understand the composition and properties of the gas found between the stars in this region.  

-

-    NIRSpec is designed to disperse infrared light from the distant universe into spectra, astronomical "rainbows" that measure how much light is present at which wavelengths. It reveals the physical properties of observed objects, including their temperature, mass and chemical composition.

-

-   In multi-object spectroscopy mode, NIRSpec can individually open and close about 250,000 small shutters, all just the width of a human hair, to view some portions of the sky while blocking others.  This allows observation of multiple specific targets while reducing interference from others. 

-

-  The missing piece of technology was infrared detectors that would be able to collect the faint light coming from those early stars and galaxies more than 13 billion light-years away.   Hubble was built to detect visible and ultraviolet light. These early galaxies do emit visible light, but because of their distance, the wavelength of this light gets stretched into the infrared part of the electromagnetic spectrum by the redshift. 

-

-   In the 1980s, infrared pictures were taken with one detector scanning the sky one pixel at a time.  The detectors on JWST have 2000 by 2000 pixels.   We have many more infrared pixels on JWST than Hubble had optical pixels when it was launched.

-

- The giant mirror will feed the light of stars and galaxies into four cutting edge instruments designed not only to take images, but also to analyze the chemical composition of the near and distant universe. 

-

-  “Spectroscopy” looks at how matter in the universe absorbs light. As different chemical elements absorb light at different wavelengths, astronomers will be able to reconstruct what stars, nebulas, galaxies and planets are made of. 

-

-    These improvements in the resolution of infrared imaging are critical for imaging the furthest reaches of the universe. Where the Hubble Space Telescope, or the recently retired infrared telescope Spitzer, could provide only a rough estimate of an ancient galaxy's age and chemical composition, Webb delivers with precision including the Wide Field Camera 3 installed during the final servicing mission in 2009. 

-

-   When it comes to these distant galaxies, the Wide Field Camera 3 runs out of wavelength.  Webb will be able to do that kind of thing, to say exactly that we see this particular galaxy 250 million years after the Big Bang.

-

-  If we are seeing that material some 500 million years after the Big Bang, it must have been made even earlier by stars we haven't yet seen.  Big stars form and die quickly, in only a few million years, so after 500 million years, you may have had lots of generations of massive stars.

-

-  The early universe had a very different chemical composition from what we see today. It consisted only of hydrogen, helium and a little bit of lithium. All the other chemical elements that we see now, including those that make life possible, were cooked up throughout eons inside those stars, then exploded as supernovae.

-

-  A lot of the chemical synthesis in the universe is around massive stars when they explode, or low mass stars in their final stages of evolution.   It's fascinating to me how we can go from having only three chemical elements to the vast array of diversity we see around us today.

-

-  The James Webb spectroscopes will be able to probe the chemical kitchens of those early galaxies, seeing what was cooking inside individual stars and what they fertilized the wider cosmos with when they exploded in powerful supernovas. 

-

-  Hubble's strength is imaging the visible universe, Webb's infrared superpowers will enable the telescope to see through dust right into the heart of nebulas, galaxies and star-forming regions that are hidden from Hubble's view. 

-

-  Previous infrared observatories with NASA's Spitzer Space Telescope, were much smaller than Webb and they couldn't see as far as Webb, and when they did, they only glimpsed those star-forming regions in a limited resolution. 

-

-   Previously, we could only see stars about 8 times the mass of the sun but now we should be able to see the formation of stars about as big as the sun and that process has never been observed before.

-

-  But,  it will not all be about far away places.    JWST can look at planets like Mars, Jupiter, Saturn, Uranus and Neptune but also into the Kuiper Belt.

-

-  The Kuiper Belt is a repository of comets, asteroids and other debris that encircles the outer solar system beyond the orbit of Neptune. It's a dark and cold region that is very difficult to explore because these objects reflect very little light. 

-

-   Exoplanets have atmospheres that have various molecules in them.  Like carbon dioxide, oxygen and nitrogen. 

-

-  The Near Infrared Camera (NIRCAM) is fitted with extra implements called coronographs, which block out the light of a star to see more clearly what is happening around it. That might involve alien systems of planets, some of which might be habitable, with water and atmosphere that could support life just like Earth.

-

-  The James Webb Space Telescope will change our view of the universe.  NIRCam will be crucial for accomplishing Webb's flagship goal: detecting the light from the earliest stars and galaxies. It's not just a simple infrared camera, but is fitted with some extra implements called coronographs. The coronographs will enable astronomers to block out the light of a star and look at what's happening around it, which makes it great for discovering orbiting exoplanets. 

-

-  NIRSpec is the main tool for cracking the chemistry of the universe. It will split the light coming from the distant universe into spectra, revealing the properties of the observed objects, including their temperature, mass and chemical composition. 

-

-  Because some of these objects are extremely distant and the light coming from them will be extremely faint, the James Webb Space Telescope, despite its giant mirror, will have to stare at them for hundreds of hours. To make those observations more efficient, NIRSPec will be able to observe 100 such distant galaxies at the same time.

-

-  It basically lets you open little doors and let the light through from one galaxy, but then block off all the light from everything else.   But you can open 100 doors at once.

-

-  The Mid-Infrared Instrument (MIRI)is a combination of a camera and a spectrograph, but unlike the previous two, it observes in the longer wavelengths of the mid-infrared part of the electromagnetic spectrum, which will make it a go-to instrument for everyone looking to study everything from comets and asteroids at the outskirts of the solar system to newly born stars and distant galaxies. 

- 

July 22, 2022        JAMES  WEBB -  what can it see?                   3634                                                                                                                                       

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

-----  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”  -----------

--------------------- ---  Sunday, July 24, 2022  ---------------------------

- 3633 - JAMES WEBB - lessons learned, so far?

  -  3633-   JAMES  WEBB -  lessons learned, so far?     On July, 2022, our understanding of the Universe changed forever as the first science images from the James Webb Space Telescope (JWST) were released to the world. 

---------------------  3633  -   JAMES  WEBB -  lessons learned, so far?    

-  The very first James Webb image that was unveiled was a deep-field image of galaxy cluster SMACS 0723. Across the variety of filters and instruments that were used to observe it aboard JWST, a total of 12.5 hours of time was spent observing this region of space. 

-

-  Although that might seem like an enormous amount of time, it’s just 2% of the time that was spent observing Hubble’s deepest view of the Universe  Hubble’s “eXtreme Deep Field” consisted of a cumulative 23 days of observing time.

-

-    JWST outperforms Hubble by more than we expected.  Hubble has a primary mirror that’s 2.4 meters across, JWST’s segmented mirror spans 6.5 meters.

-

-   This leads to a resolution that’s 270% as sharp for the same wavelength light and light-gathering power that’s 730% as great as Hubble’s  For the same amount of observing time, expect that JWST would collect 730% as much light as Hubble. 

-

-  Hubble time is divided up into “orbits,” as from its position in low-Earth orbit, it completes a revolution around our planet every 96 minutes. A total of 6 orbits, 4 in optical wavelengths and 2 in infrared wavelengths, were used to make the Hubble composite.   6 orbits multiplied by 96 minutes per orbit would equal 9.6 hours (576 minutes) of Hubble time.

-

-  During the first month after its launch, JWST’s priority was to reach and enter a stable orbit around the L2 Lagrange point. With the Sun, Earth, and Moon always behind it, there’s no chance of any of those sources ever obscuring its view.

-

-  Because it’s in orbit around Earth, spends more than 50% of its time with the Earth (and the Earth’s atmosphere) in the way of its desired target, and can only acquire useful data when its target is in full, unobstructed view of the telescope.

-

- Meanwhile, JWST is some 1.5 million km away at the L2 Lagrange point. It always faces away from the Sun, away from the Earth, and away from the Moon. It never has to contend with these obstacles to pristine observing, and so its observations of targets are 100% time-efficient, as opposed to less than 50% time-efficient like Hubble was. 

-

-   Areas of the sky that appeared to be cosmic voids aren’t always empty, after all. In theory, we knew this should be true, but with its very first deep-field images, JWST gave us the proof we needed. There are large regions of space that appear to have no stars or galaxies in them at all. Scientists have wondered, ever since these “voids” were discovered.

-

-  Galaxies come in many different morphologies, including spirals, ellipticals, rings, irregulars, and other various types and sub-types. With Hubble, the most distant galaxies were only visible as smudges that could not be resolved. With JWST, instead, their types and abundances can be tracked, measured, and classified across cosmic time and location. 

-

-   Having a 270% increase in resolution actually means a 700% increase in the number of pixels available for each source. A galaxy that’s just 3×3 pixels, to Hubble, will appear as 8×8 pixels to JWST. By seeing how the shapes and configurations of galaxies vary over cosmic time and location, we’ll learn how our Universe grew up throughout its history.

-

-   Spectroscopy involves breaking up the arriving light into its component wavelengths, and looking for either emission lines (spikes at particular wavelengths) or absorption lines (deficits at particular wavelengths) that correspond to quantum mechanical transitions of particular elements. If you can obtain multiple lines from the same element, you can determine how much that light has been shifted by from its emitted wavelengths due to the expansion of the Universe.

-

-    The most distant galaxy identified in JWST’s first deep-field image, this object’s light comes to us from 13.1 billion years ago.  With its extraordinary sensitivity to wavelengths beyond 2000 nanometers  any galaxy that’s a high-redshift candidate will now be subject to true spectroscopic confirmation, something neither one has been subjected to before.  JWST  can do this for each and every galaxy we want to measure, and will obtain:

-

----------------------  oxygen,

-

---------------------- hydrogen,

-

---------------------- neon lines,

-

---------------------- among potential others

-

-   The individual galaxies seen in this Hubble/JWST composite are much more clearly resolved in the JWST version. If spectroscopy can be performed on individual components of the same galaxy we can measure the rotational properties of the material inside, putting various dark matter models and modified gravity theories to the test. 

-

-  Astronomer are going to be able to rule out all sorts of versions of modified gravity. One of the most beautiful things about the idea of dark matter is that it explains so many observational phenomena on so many different scales with just that one addition. A Universe with dark matter can explain:

-

--------------------- how individual galaxies rotate and interact,

-

--------------------- how galaxies group and cluster together,

--------------------- how galaxies within a cluster move,

-

--------------------- how gravitational lensing distorts and magnifies background objects,

-

--------------------- how the large-scale structure of the Universe forms,

-

---------------------  how the imperfections imprinted in the Big Bang’s leftover glow should appear and be distributed.

-

-  Some versions of modified gravity predict that the behavior of rotating galaxies will evolve over cosmic time; other versions predict that young rotating galaxies and old rotating galaxies should have similar rotation curves. As we combine JWST’s resolution and spectroscopic capabilities, and apply them to rotating galaxies seen all across the Universe, we’ll be able to rule one class or the other of modified gravity theories out. We can also test our theories of dark matter as never before; whatever we learn, it will be because the Universe told us how it’s truly behaving.

-

-    The centers of galaxy clusters will be revealed in more detail than ever. 

-

--------------------- how much gas is present,

-

--------------------- what the stellar populations inside are like,

-

--------------------- how many globular clusters are inside of it,

-

---------------------  how many faint, satellite galaxies there are surrounding it,

for the closest galaxy clusters of all.

-

-   JWST, will be able to see what sorts of structures are present around these central galaxies; it will be able to resolve small, faint galaxies that would otherwise simply “smear” together with inferior resolution. 

-

-  We may even be able to use this to explain the distribution of sources that contribute to the intracluster light, and detect and determine the properties of satellite galaxies and globular clusters in the halos of galaxies like never before.

-

-   We have 20+ years of time with JWST to look forward to, and the new discoveries are only just starting. As Edwin Hubble so eloquently put it:  With increasing distance, our knowledge fades, and fades rapidly. Eventually, we reach the dim boundary, the utmost limits of our telescopes. There, we measure shadows, and we search among ghostly errors of measurement for landmarks that are scarcely more substantial. 

-

- The search will continue. Not until the empirical resources are exhausted, need we pass on to the dreamy realms of speculation.

-

-  With the new, unprecedented capabilities of JWST, we’re just beginning to see the Universe in, quite literally, a whole new light.

- 

July 21, 2022          JAMES  WEBB -  lessons learned, so far?             3633                                                                                                                                        

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

-----  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, July 21, 2022  ---------------------------

3632 - ASTRONOMY - viewed in the infrared.

  -  3632   -  ASTRONOMY  -  viewed in the infrared.  Herschel’s infrared observations are greatly helping astronomers in their ambitious endeavor of assembling the complex history of how stars and galaxies formed and evolved in the universe.  Now we have the James Webb infrared capability that will improve our vision by a factor of 100 times.

-

---------------------  3632  -      ASTRONOMY  -  viewed in the infrared.  

-  

-  Looking at the starry spectacle of the night sky, we might be tricked by its seemingly timeless beauty to think that the multitude of distant suns have been there since the beginning of time. But, if our eyes could peer back into cosmic history up to the first few seconds of our Universe, almost 14 billion years ago, they would be treated to a very different view.

-

-  Shortly after the Big Bang, the hot and dense phase the Universe was very different from what we can observe nowadays, and it took a few hundred million years for stars and galaxies to start to emerge from the primordial 'soup' that filled the early cosmos.

-

-  Piecing together how galaxies formed and evolved, giving birth to stars at different paces throughout the history of the Universe, is one of the most challenging topics in present day astronomy.

-

-  In their quest to investigate how galaxies differ at various cosmic epochs, astronomers have been collecting increasingly larger samples, searching for the light that was emitted by galaxies many billions of years ago and that has been traveling across the Universe ever since.

-

-   These studies greatly benefit from combining observations at different wavelengths of light, with the infrared band being crucial to pinpoint galaxies that are fiercely forming stars.

-

-  Star formation in galaxies takes place within dense clouds of gas that, for most of cosmic history, also contain small amounts of dust. Newborn stars shine brightly in ultraviolet and visible wavelengths, but only about half of this starlight leaves a galaxy unhindered; neighboring dust grains absorb the other half, radiating it again but, this time, at longer wavelengths.

-

-  As a result of the dust interspersed in the interstellar material, galaxies emit roughly 50 per cent of their total light at mid-infrared, far-infrared, and sub-millimeter wavelengths between 8 micron and 1 mm with a peak in the far-infrared, around 50-200 microns. For this reason, observations in this spectral range are fundamental for quantifying a galaxy's star formation activity.

-

-  The expansion of the Universe stretches the wavelengths of light emitted by distant objects. This effect, known as “redshift“, becomes increasingly more significant the farther a galaxy is from us.

-

-  This causes the peak of dust emission to move from the far-infrared to sub-millimeter wavelengths. Therefore observations that cover these two portions of the electromagnetic spectrum complement each other, capturing dusty emission from star formation in both nearby and distant galaxies.

-

-  Performing observations at infrared wavelengths with telescopes on the ground, however, is difficult, if not impossible,  because of the presence of Earth's atmosphere, so astronomers turned to space.

-

-  In the early 1980s, the US-Dutch-British Infrared Astronomical Satellite (IRAS) was the first space mission to map the sky in the far-infrared, followed by ESA's Infrared Space Observatory (ISO) in the late 1990s, NASA's Spitzer Space Telescope, launched in 2003, and JAXA's Akari, which operated between 2006 and 2011.  Now we have the James Webb Telescope in 2022.

-

-  With mid-infrared observations from ISO and Spitzer, astronomers started to perceive the glow of warm dust from individual star-forming galaxies sprinkled across the Universe's history.   With ESA's Herschel Space Observatory, launched in 2009 and operational until 2013 these investigations unleashed their full potential.  Cant wait to se what the James Webb brings us!

-

-  The Herschel observatory's broad spectral coverage, including the far-infrared and sub-millimeter range, extended to longer wavelengths than those probed by Spitzer, ISO, and Akari. As a result, astronomers could sense cooler dust than that which had been detected by its predecessors.

-

-  With its unprecedented angular resolution, Herschel could also spot galaxies that had been missed by these earlier observatories at the wavelengths they had in common.

-

-  Herschel’s particular spectral range made it possible to catch galaxies whose light had been redshifted to longer wavelengths than those probed by its predecessors, tracing out star formation to greater distances and thus earlier times in cosmic history.

-

-  With its 3.5-meter primary mirror, Herschel sported the largest infrared telescope flown to date, granting astronomers unprecedented sensitivity that was crucial to observe star-forming galaxies across the Universe.  Now James Webb gathers 100 times more light. 

-

-  Herschel's contribution was crucial to push the observations up to the time when the Universe was less than one billion years old, probing the full period when star formation peaked and even beyond.

-

-  This result, which has opened new avenues to study the evolution of galaxies, is somewhat suggestive of the revolutionary observations by Galileo who, just over four centuries before, had pointed the newly invented telescope at the diffuse white glow of the Milky Way, breaking it down into a myriad of individual stars.

-

-  With its deep surveys of several regions of the sky, Herschel revealed a Universe teeming with star-forming galaxies, their presence uncovered by the glow of dust heated by the stars in the making.

-

-  Measuring how bright a galaxy shines in the far-infrared can inform astronomers about how much dust is there and how cool it is, which can be used, in turn, to determine the pace of the galaxy's star formation activity.

-

-  In the present Universe, galaxies produce stars at a rather leisurely pace, with our Milky Way giving birth to only a few Sun-like stars every year. However, galaxies have been far more prolific in the past, and Herschel has been instrumental in estimating just how much.

-

-  Stars and galaxies have been bursting into life since the Universe was about half a billion years old, and astronomers now agree that this activity peaked a few billion years later. At that glorious epoch, Herschel confirmed that galaxies were forming stars roughly ten times faster, on average, than they are nowadays.

-

-  Shortly after, the average rate of star formation in galaxies began to decline, and it has been consistently doing so over the past ten billion years of cosmic history.  With such a marked difference in the star-forming activity of present and past galaxies we wonder whether the physical processes that regulate the stellar production also underwent any substantial change over the eons.

-

-  Most galaxies in today's Universe are making stars in a steady, gentle fashion, and only rarely do dynamical interactions of galaxies, or mergers, trigger the occasional, intense burst of stellar birth.

-

-  In spite of their higher production rates, most galaxies at earlier cosmic epochs seem to be quite 'ordinary': their greater productivity is likely an effect of cold gas, the raw material to make stars, being more plentiful at those times.

-

-  Earlier galaxies are not concealing any mysterious mechanism that boosts their star-making efficiency, but are most likely just scaled-up versions of the galaxies we observe at the present time.

-

-  This result relegates merger-triggered starbursts to a minor role in the total history of star formation; the decisive ingredient seems to be a steady supply of cold gas, which could well be provided by intergalactic streams.

-

-   The vast majority of star-forming galaxies seem to obey a very simple rule: the more massive a galaxy, the faster it is forming new stars. This relation, called the “Galaxy Main Sequence“, had already been identified using Spitzer observations of galaxies in more recent epochs, but Herschel confirmed that it applies also to earlier times.

-

-  Only a small fraction of extremely prolific starburst galaxies appear to break this rule, in the earlier and later Universe alike. Herschel did find that such behemoths were slightly more abundant at earlier times, but demonstrated that they were never the primary channel of star formation at any epoch.

-

-   The fierce activity of stellar production observed in starburst galaxies seems not to be sustainable over long periods of time, causing them to rapidly quench their star formation.

New analyses of Herschel observations have shown that the situation may not be so clear-cut after all. 

-

-  These studies indicate that the Galaxy Main Sequence might break down also in the case of very massive galaxies, suggesting that, as galaxies grow more massive by accreting cold gas, they could reach a point where they stop forming stars very efficiently. 

-

-  What caused the drop in star formation rate, ten billion years ago, and its overall declining trend ever since?  While it is evident that, in the past, galaxies had at their disposal a much larger supply of raw material from which to form stars than they do at present, the physical processes that drained them of their reservoirs of interstellar gas and dust are still not fully understood. 

-

-  Another open issue concerns a striking similarity observed between the long-term history of two apparently disparate processes that take place in galaxies: the formation of stars and the accretion of matter onto the supermassive black holes that are lurking at their cores.  Both processes appear to peak around ten billion years ago.

-

-   How can the evolution of black holes, which are relatively small-sized and confined at the center of their host galaxies, be linked to the star-forming activity that takes place on much larger scales?

-

-  The answer to some of these questions might lie in the 'feedback' effects exerted on the interstellar material that pervades a galaxy by stellar radiation and winds, supernova explosions, and outflows possibly triggered by the activity of its central black hole.

-

-  Astronomers have long been studying the role of feedback on galaxy evolution using a variety of observations across the spectrum. Looking at nearby galaxies that are forming stars more briskly than most of their neighbors.

-

-  Using Herschel data, astronomers discovered massive outflows of molecular gas streaming away from the cores of several star-forming galaxies in the local Universe. While outflowing gas in neutral and ionized form had been observed in earlier studies, this was the first detection of massive outflows of molecular gas being pushed away from a galaxy. The strongest outflows were seen in galaxies that host actively accreting supermassive black holes at their center, hinting at a role for black-hole feedback in draining a galaxy's reservoir of star-forming material.

-

-  Further clues were found in nearby radio galaxies, which exhibit symmetric jets of plasma flying out, at the speed of light, from the central black hole. These jets definitely have the power to affect the gas on much larger scales and perhaps even to impede the host galaxy's star formation.

-

-  Herschel observations were also key to proving a crucial aspect in these feedback matters, uncovering for the first time the causal link between the black hole activity at the center of a galaxy and the gas outflows seen on much larger scales. This was made possible by comparing a galactic-wide outflow of molecular gas, detected by Herschel, with X-ray data probing a powerful wind of ionized gas driven by the black hole at the core of the galaxy. 

-

-  As for Herschel's survey of over 12 billion years of star formation, a comparison with the simulated cosmos showed that some processes underlying galaxy evolution seem to be well understood, but many details remain unclear. 

-

-  Simulations are still far from reproducing the complex and diverse properties recorded by surveys of galaxies, especially concerning the link between feedback and star formation, and there is still much work to do before all pieces of this cosmic puzzle fall into place. 

-

-  Pushing the experimental boundaries farther than any of its predecessors, the Herschel mission has revealed a number of previously hidden gems, near and far, that have been crucial to piecing together this intriguing tale, while at the same time it also uncovered new mysteries that will keep astronomers busy for the foreseeable future.

-

-  Now in 2022 we have another infrared telescope observing our Universe.  The James Webb Telescope is collecting new and more data on the farthest reaches of our Universe.  We will some have more answers and more questions of how this universe of ours can about.   It is an amazing story to get to where you are reading this Review.

- 

July 18, 2022         ASTRONOMY  -  viewed in the infrared.           3632                                                                                                                                        

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

-----  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, July 21, 2022  ---------------------------