DARK MATTER - to discover what it is?

 -  2790  -  DARK  MATTER  -  to discover what it is?  -  There is a race to discover “dark matter“. Dark matter is that elusive substance that has mystified science since the 1930s, when astronomers first realized galaxies needed some kind of invisible gravitational glue to hold them together. No one knew what it was, so it was named “dark matter“. 

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--------------------------  2790  -   DARK  MATTER  -  to discover what it is?

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-  The universe seems to hold more than five times as much “dark matter” as it does “normal” matter that we an see.   Scientists know very little about this universe’s dominant material. Dark matter could be made of one kind of particle or many different particles, we don’t know?

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-  Dark matter particles might be massively heavy or light. We think dark matter only interacts with other matter and itself via gravity, but dark matter could turn out to have interactions with any force of nature.  We just don’t know. 

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-  Addressing all these possibilities, physicists have conjured up quite a few dark matter candidates:

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-  The current candidates range from the grandest scales of the universe to the tiniest, from galaxies to subatomic particles.  Many of the experiments involve supercooling materials such as liquid xenon to subfreezing temperatures, which makes it easier for the materials’ atoms to bump into stray dark matter particles and thus find the elusive galactic particles existence.

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-  The odds-on favorite candidate is called a WIMP, the “weakly interacting massive particle“, but it has not been found despite intensive search efforts.

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-   Another candidate thehe “massive compact halo object“, or MACHO has fallen out of contention.

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-  Particle masses are measured in units called gigaelectron volts, or GeV. A  proton weighs about 1 GeV.   Electrons measure 0.0005 GeV and the heaviest known particle, the top quark, measures 172.9 GeV.

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-  Developed over many decades, the “standard model f elementary particles” is a stunning scientific success. With pinpoint precision, it describes three of nature’s four forces, electromagnetic, and the strong and weak nuclear forces. But the model also has gaps, including not being able to describe the fourth force, gravity, and failing to explain dark matter and its particles.

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-  A refinement of the standard model called “supersymmetry” smoothes over many of these flaws. It fills the gaps by proposing new, heavier partner particles for all known particles. Plug these new heavies into the mix, and their total mass strikingly matches the estimates for dark matter.

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-   Cosmologists had already been kicking around the idea of WIMPs without knowing what they might be, and suddenly they had a good match. Assuming supersymmetry’s heavier partners were WIMPs resolved everything so perfectly, researchers dubbed it the “WIMP miracle.” Conveniently, these WIMPs would interact with normal matter, albeit very weakly as their name implies; such interactions should render them discoverable.

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-  WIMPs also have failed to appear in other detection methods. Theories suggest the particles may occasionally destroy each other or decay, resulting in showers of gamma rays, but searches have found no convincing evidence detecting gamma rays.

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-  Many physicists expected that the Large Hadron Collider would produce heavy, novel particles, including WIMPs. But a decade of operations with no heavy partners to show for it has instead made some physicists question the whole notion of supersymmetry.

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-  Another particle called the “Axion” was  proposed in 1977.   Its mass is expected to be about 0.000,000,000,000,001 GeV.   Physicists originally came up with this particle to help fix a problem with the strong nuclear force, one of nature’s four fundamental forces. 

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-  Although the individual axion particles have a ridiculously low mass, the universe forming Big Bang could have churned out axions in abundance.  Enough axions could  constitute all the dark matter in the cosmos.

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-  To catch any fleeting axions, researchers at the “Axion Dark Matter eXperiment” at the University of Washington cool a cylinder to nearly absolute zero before it emits a strong magnetic field, which should transform the theoretical dark matter particles into radio waves. 

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-  The “Axion Dark Matter eXperiment (ADMX)” became the first device with the sensitivity necessary to detect axions. The experiment uses a 13-foot-long metal cylinder sunk into the floor, cooled to just above absolute zero to silence any signal-masking perturbations. 

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-  A magnet inside cranks out a powerful magnetic field that, according to theory, should convert any nearby axions into radio waves. To detect these infinitesimal signals which are a billionth of a billionth of a billionth of a watt each, ADMX has specially designed amplifiers.  With these amplifiers it is the most sensitive radio receiver ever built. 

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-  Researchers are presently “tuning” ADMX through millions of frequencies representing possible axion masses.  No detections so far.

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-  Another candidate is the “Sterile Neutrino” having a mass roughly 1 GeV.  It is a hypothesized new type, or flavor, of neutrino. Neutrinos are ubiquitous particles that come in three flavors and are all but oblivious to matter, passing clear through our bodies by the hundreds of trillions every second.

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-  The idea for sterile neutrinos gained traction when an experiment in the 1990s recorded a strange excess of one flavor, called the “electron neutrino“, over the other two known as muon and tau neutrinos. 

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-  The particles should have appeared in roughly equal numbers. Around that same time, though, experiments revealed that neutrinos transform from one flavor to another spontaneously as they fly about the universe. 

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-  Theorists postulated that the flavor skew arose because some neutrinos were temporarily morphing into a fourth, sterile flavor before “returning” as electron neutrinos. When other observations ended up contradicting the idea, physicists summarily dismissed that lone result as an experimental fluke.

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-  Yet in June 2018, a second experiment, MiniBooNE, found the same flavor excess based on a whopping 15 year’s worth of data. MiniBooNE experiment is housed at the Fermi National Accelerator Laboratory just outside Chicago.

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-   MiniBooNE is hardly mini. It is a sensor-studded sphere measuring nearly 40 feet across, filled with over 800 tons of pure mineral oil. The instrument registers the flashes of light emitted on the rare occasions when neutrinos bump into the oil’s constituent atoms. 

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-   Assuming sterile neutrinos are proved to exist, they are still likely neither sufficient in mass nor number to constitute the bulk of dark matter. But just as normal neutrinos come in three flavors, multiple kinds of sterile neutrinos, with different masses, may exist. 

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-  And going a step further, neutrinos may not be the only kind of particle with a sterile counterpart.  Their could be an entire “unstandard model,” full of particle types that invisibly interact with each other, all around us. 

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-  Dark photons, dark gluons, dark quarks and more could exist. All could be repositories of the extra stuff in the universe we perceive as dark matter. 

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-  Multiple new teams hope to further research out neutrinos’ weirdness with new projects.  A fresh experiment at Los Alamos, called “Coherent CAPTAIN-Mills” uses chilled vats of argon to capture any telltale oscillations between flavors of neutrinos. 

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-  A new particle called the “Strongly interacting massive particles” (SIMPs) was proposed in  2014.  Its mass expected to be about 0.1 GeV.   WIMPs, axions and sterile neutrinos are all postulated as indivisible, elementary particles.  SIMPs, on the other hand, are composite particles, made of other, smaller particles.  The most common examples of composite particles,  protons and neutrons, make up the normal matter around us.

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-  The smaller bits making up protons, neutrons and SIMPs are called “quarks“, but in the SIMP’s case, they would be individually composed of a quark paired with a hypothetical “antiquary“, which primarily goes about its business in the dark sector beyond the standard model.

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-  Still, the physics of composite particles is well understood, and that degree of familiarity could make SIMPs easier to detect and understand than the more exotic indivisible dark matter candidates. 

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-  SIMPs are strongly interacting with other SIMPs. That’s in contrast to WIMPs, which only weakly interact with each other and normal matter. As a result, instead of WIMPily flowing past their fellow particles, SIMPs would bounce off one another like billiard balls.

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-  Dark matter behaving in this boisterous manner would help explain two key astronomical observations that buck against WIMPs. The first concerns some colliding galaxies.  Astronomers inferred that a great amount of dark matter had detached from its host galaxies in a celestial smashup happening some 1.4 billion light-years away. This suggests the dark stuff pushes against itself and cannot readily flow together with the visible stars and gas as WIMPs should. 

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-  However, a second analysis using more accurate measurements now suggests perhaps the dark matter may not have separated from its galaxies after all.  The second puzzling observation involves the screwy distribution of dark matter within smaller galaxies. 

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-  Computer simulations show that due to gravity, WIMPs should stick together, forming dense clumps of dark matter in the centers of galaxies; they should also coalesce into chunks out in space. Yet observations clash with those predictions. 

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-   Galactically, dark matter seems too evenly spread out, and astronomers have never found the chunks the WIMP model predicts.  One more thing points to SIMPs instead. There should be enough of them to explain away all of the universe’s dark matter, unlike the more complicated theories other particles require. 

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-   In the late 1980s, scientists got their hopes up that MACHOs,  normal matter that were simply dim and tough to detect, could answer the dark matter question. These objects would range from planets to failed stars to black holes. Unfortunately, well-supported Big Bang models struggle to produce anywhere near enough regular matter for the MACHOs needed. 

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-   Observations have consistently ruled out any vast populations of  black holes, which should give themselves away when their gravity bends background starlight. An October 2018 study took out the last leg for MACHOs to stand on, putting serious constraints on the possibility of primordial black holes being the last plausible reservoir of significant unaccounted-for matter.

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-  WIMPs, SIMPs . . . and GIMPs?  The only force definitely felt by both matter and dark matter is gravity. Accordingly, some researchers have created gravity-only models  dubbed GIMPs, “gravitationally interacting massive particles“. 

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-  This concept is not new to physics.  It simply submits that black holes actually have all that missing dark matter bound up within them and act in essence like particles. 

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-   Alternatively, physicists have conjured GIMPs as elementary particles required by theories of our universe that include an extra fifth spatial dimension. 

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-  Perhaps the weirdest theory is “Planckian interacting dark matter” (PIDM). It consists of individual particles that each could weigh as much as 10 quadrillion protons. PIDM that spawned in the early universe should have left an indelible imprint on the Big Bang’s relic afterglow, called the cosmic microwave background, which researchers study for clues about the universe’s origins.

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-   Next-generation instruments could be sensitive enough to answer many of these this dark matter questions.  Stay tuned there is still more to learn.  

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-----------------------------  Other Reviews about Dark Matter:

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-  2768 -  DARK  MATTER  - What is the Universe Made of?  Since 1970 astronomers have believed Dark Matter existed because studying the orbits of galaxies and stars around galaxies could not be calculated based on the stars and matter they could see.  Either Kepler’s and Newton’s formulas for the laws of gravity and motion were incorrect, or there was matter there that they could not find. 

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-  2767 -  DARK  MATTER  - confirmed by new measurements? -   The first Fast Radio Burst detected came from a galaxy that is about 4 billion light-years away from Earth.   Using  dispersion measurements for these FRB’s, astronomers are able to make a rough calculation of how much dark matter the radio waves passed through before reaching earth.

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-  2718 -    DARK  MATTER  -  What is the Universe Made Of?  ?  We do not know?  95% of our knowledge is just “dark”.  We think 75% is energy and 25% is matter.  Remember matter and energy are the same thing,  simply separated by the speed of light squared, c^2. 

-  2631  -   DARK  MATTER  -  dark coffee would help?  Astronomer’s observations have determined the average density of matter in our universe to very high precision. But this density turns out to be much greater than can be accounted for with “ordinary atoms“.  Is there some other matter that we still don’t know about?

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- This Review 2631 lists 33 more Reviews about Dark Matter.  A real mystery in astronomy and all of science.

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-  August 13, 2020                                                                             2790                                                                                                                                                 

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

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 ---------------------   Sunday, August 16, 2020  -------------------------

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TELESCOPES - to do a 3D map of the Universe.

 -  2789  -  TELESCOPES  -  to do a 3D map of the Universe.   Since 2005, scientists have been scanning the night sky to create a three-dimensional map of our universe with the purpose of shedding light on one of the biggest mysteries in physics.  The quest is to learn the true nature and identity of dark energy and dark matter. 

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--------------------------  2789  -  TELESCOPES  -  to do a 3D map of the Universe. 

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-  This quest  is about to get a massive upgrade with the successful installation and testing of the Dark Energy Spectroscopic Instrument, or DESI.

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-  DESI features 5,000 optical fibers, each one designed to collect light from a single galaxy. DESI is to gather 20 times more data than previous surveys.  This telescope looks at infrared light.  This is light that has stretched out wavelengths because it has been traveling through an expanding Universe.

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-  A previous instrument on a different telescope, the Baryon Oscillation Spectroscopic Survey instrument, required collaborators to drill 1,000 holes into large metal plates that held fibers in a configuration that exactly matched the position of known galaxies in a small portion of the night sky. Each time scientists wanted to image new galaxies, a new plate had to be drilled and the fibers inserted by hand.

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-  With DESI, researchers have relegated the work of pinpointing galaxy locations to a hive of 5,000 robotic pencil-shaped tubes. These positioners have a precision of several micrometers, about one-10th the width of a human hair, and are capable of moving on their own to focus on distant galaxies.

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-  The images they take aren't ordinary photographs. Scientists are instead interested in the type of light the galaxies emit. All galaxies are in motion, mostly moving away from each other due to the expansion of the universe. And the light from those that move away from us is stretched into the low-frequency, red part of the spectrum, much the same way that sound waves from a siren are stretched when an ambulance moves past you.

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-  Scientists can use these redshifted signals to create a three-dimensional map of our universe stretching back 11 billion years into its past. By analyzing the distribution of galaxies through space and time, scientists can then make inferences about the nature of the unknown dark matter that pulls galaxies together and that of dark energy, which pushes them apart.

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-  Researchers completed the first round of testing on the robotic positioners last November.  A second milestone was achieved in January when the positioners were accurately pointed at over 2,000 stars simultaneously.

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-  The software is a key player in choreographing the movement of all 5,000 robotic positioners simultaneously.  The software guides the robotic positioners on a multistep process to locate galaxies.

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-   First, the focal plane, a large metallic structure that holds the positioners in place, must be pointed at just the right portion of sky. Just as old maritime navigators would use the position of the stars to guide their way, 10 high-resolution cameras embedded in the focal plane capture and analyze light from stars, which allows researchers to orient the telescope.

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-  These movements to position the focal plane have to be incredibly precise for each fiber to receive the most light that it can from its assigned galaxy. Nudged even a little off target, and the fiber will be only partially filled with its galaxy's light. But when positioned as designed, each fiber will be filled completely with the light of its galaxy, with minimal background.

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-  Once the telescope is pointed in the right direction, the robotic positioners begin an intricate mechanical waltz, peering deep into the sky to detect sources of light far too faint for human eyes to see.

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-  Their high degree of precision gets them most of the way to the desired galaxy, but the angle might still be slightly off for some. To get them the rest of the way, DESI has a CCD camera installed at the primary mirror of the telescope, which looks up at the focal plane.

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-   Researchers use a built-in light source to illuminate the fibers embedded in the robotic positioners. The fibers project the resulting small dots of light to the CCD camera, which then images them. The software compares the positions of the fibers in the images to where they should actually be pointed based on detailed star charts from previous surveys.

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The software then computes how far off each positioner is from the desired target, after which another system can move it the rest of the way toward its designated galaxy.

-  DESI is scheduled to operate for a total of five years, during which time it will measure the redshifts of over 30 million galaxies and quasars, i.e.: massive black holes. Scientists can then use this information to determine if and how the concentration of dark energy has changed throughout the history of our universe.

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-  We will have a 3D map of the Universe stretched out since the beginning.  This will be new eyes on the Universe.  What will we see with new eyes?

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-  August 12, 2020                                                                             2789                                                                                                                                                 

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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”  -----------

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 ---------------------   Thursday, August 13, 2020  -------------------------

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LIFE - how rare in the Universe?

 -  2788  -  LIFE  -  how rare in the Universe?  -  We learn about the history of the Universe just by looking at our own bodies. A fully grown adult human is an incredibly complex system, made up of trillions of cells and somewhere in the neighborhood of 1,028 atoms.  Atoms are the building blocks of all matter on Earth, and the Universe.

                      

--------------------------  2788  -  LIFE  -  how rare in the Universe?

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-  I am sure you do not realize how unusual it is that you are reading this.  It seems impossible that any life can really exist.  But here we are trying to figure it out in 5 pages.  

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-   The scientific story of what it takes to make a human teaches us an enormous amount about not only the evolution and history of life on Earth, but of the entire Universe as well.

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-  It wasn’t merely billions of years of life surviving, thriving, and filling every ecological niche possible on our planet that brought us into existence, it was the ecology of the entire Universe. 

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-  The story of how we came to be requires all sorts of cosmic predecessors, from previous generations of stars to the mergers of ancient galaxies to the Big Bang itself. Even “dark matter” plays an enormously important role in enabling human beings to exist in this Universe.

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-   It took 13,800,000,000 years for humans to come into being on Earth, and we’ve finally reconstructed the cosmic story of how we got here in just a few centuries..  On a very basic level, we can learn what a human being is simply by looking at the tiny components, the atoms, that make up our bodies. 

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-  Oxygen is the most abundant element in our body, followed by carbon, hydrogen, nitrogen and calcium. There are at least 56 different elements from the periodic table that make up at least 0.1 milligrams of a typical human, with both light and heavy elements playing important roles in the body's biological activities.

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-  For the past 200,000 years or so, human beings have walked upon this Earth, with each generation of modern humans descended from the prior one. This is how every living creature works.  All life is descended from its parent organism with the genetic material passed on from parent to child. There is an unbroken string of life going back more than four billion years on Earth. This is where every organism in existence today comes from.

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-  All the various forms of life that ever were, however, all rely on those same ingredients that humans do: those same atoms and those same elements. They all require a stable home where they can assemble into life forms that reproduce and sustain themselves for billions of years.  Like a rocky planet like Earth around a relatively stable star like our Sun. 

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-  There’s no guarantee that the evolution of something like human beings would be inevitable, but for every planet in the Universe with similar conditions to Earth, we have to recognize that it “might be possible“.

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-  What is needed to happen in the Universe for an Earth-like planet around a Sun-like star with the right raw ingredients for life to arise?  We need to  formulate hypotheses, perform experiments, make observations, and draw some conclusions.  Here goes:

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-  The first ingredient we need are the elements required for life: the various atoms that make up the periodic table. When we look at the Earth and the other bodies in our Solar System in detail,  including foreign meteorites which fall to Earth,  we can determine which elements are present in which ratios, and this includes all of the elements needed for life.

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-  By then studying the Universe, including:

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------------------------------------  large, massive stars,

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------------------------------------  supernova events,

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------------------------------------  small, Sun-like stars,

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------------------------------------  stellar remnants ,white dwarfs, neutron stars,

cosmic rays,  and even the Big Bang itself, 

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- We can determine where the majority of each element comes from. In order to make a Universe that allows for humans.  We can conclude what is required for you to be reading this.

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-  If our Universe begins with the hot Big Bang, the only elements that get created are hydrogen, helium, and a tiny bit of lithium ; nothing else. 

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-  The reason is simple.   In the earliest, hottest stages, you have plenty of protons and neutrons at high energies, but you also have enough photons that anytime the protons and neutrons bind together, the light photons come in and splits them apart.

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-  Only once the Universe expands and cools off sufficiently can protons and neutrons bind together to form heavier elements, and that takes time. By that time, things are so much less dense and energetic that the electric force repelling two helium atoms is so strong that the particles can’t overcome it.

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-   We can make the lightest elements in the Big Bang, but not the ones heavier than lithium.  For those, we have to wait a very, very long time: for stars to form.  It takes tens or even hundreds of millions of years for the Universe to cool enough and for gravitation to attract enough matter into individual locations to trigger the formation of stars for the first time.

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----------------------------  For that to happen, the Universe needs to:

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----------------------------  have been born with tiny imperfections in it, where some regions have more matter than others,

----------------------------  cool enough so that stable atoms can form from the ionized atomic nuclei and free electrons,  attract enough matter into one place so that gas clouds can collapse to form stars,

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----------------------------  and for that collapsing matter to radiate enough energy away so that nuclear fusion can start occurring in a star’s core.

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-  The first part is one of the key pieces of evidence for cosmic inflation; the second part is where the cosmic microwave background that we see comes from; the third is what takes all that time, tens to hundreds of millions of years, to occur; but the fourth part is a challenge.

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-  The way gas cools off to form stars involves radiating that energy away through their heavy elements. Without any of the heavy elements present, the only way to cool off is by hydrogen gas radiating, which is horribly inefficient. As a result, the very first stars in the Universe,  called Population III stars, were very different from the stars we form today.

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-  On average, the Universe forms a few large, heavy, massive, “blue stars” whenever new stars are formed, but the average new star is small: about 40% the Sun’s mass. Because of the lack of heavy elements, however, the average Population III star should be about 10 times as massive as the Sun, meaning they’re all short-lived and likely to die in a supernova explosion in a relatively short period of time.

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-  Supernovae not only create a large fraction of heavy elements, but they also lead to the formation of neutron stars, which themselves can then merge together to produce the heaviest elements of all: elements like iodine, gold, platinum and tungsten. These first stars are important, and the fact that they make supernovae is very important.

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-  These early star clusters only have a little bit of matter in them, while supernovae expel material at incredibly fierce speeds. If you run the math and add up how much material is there to form the first stars and compare it with how fast do supernovae eject material, you run into a puzzle.  The ejected material is too fast for the amount of mass that’s present, meaning that these heavy elements should overwhelmingly be ejected into the intergalactic medium.

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-  To solve this problem.  We need to hang onto that material so it can participate in future generations of star formation. We need it to help form subsequent generations of stars, so we can get low-mass stars,  rocky planets, so that we can have a terrestrial world like Earth rather than gas-dominated planets alone,  and life, because we need the chemistry that these heavy elements make possible.

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-  The normal, atom-based matter in the Universe alone isn’t enough to do this. All the gas, dust, and black holes that exist simply don’t provide us with enough gravitational force to hang onto this material. In a Universe made of atoms alone, the more massive structures that we see, structures like the one we inhabit, the Milky Way galaxy, would be impossible.

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-   In order to form the galaxies, we need an extra ingredient: “dark matter“.

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-  With dark matter, these early star clusters and proto-galaxies can have enough gravitation to hang onto the ejected material from supernovae and other cataclysms, all while drawing more and more matter into them. Over time, enough heavy elements are built up that more evolved stars, with substantial fractions of heavy elements, can begin to form. 

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-  These stars are lower in mass, and not only help produce many of the elements in our periodic table, but also white dwarfs, which merge and explode, leading to the formation of atoms like carbon, nitrogen, and calcium: vital elements for our bodies.

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-  Eventually, after billions of years have gone by, individual galaxies like the Milky Way will be rich enough in these heavy elements that when new stars form, they’ll also be capable of forming rocky, Earth-like planets around them. 

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-  It is thought that, some 9.2 billion years after the Big Bang, a star-forming region in our Milky Way created a wide variety of stars, one of which would grow into our Sun. Its proto-planetary disk would wind up forming four inner, rocky planets, as well as a system of outer, gas giant planets. The third planet from that Sun, Earth, would eventually form life and lead to human beings arising and allowing you to read this.

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-  None of this was a predestined conclusion. If we were to rewind the clock to the initial formation of our Solar System and run the clock forward again a billion times, it’s extraordinarily unlikely that human beings would arise even once.

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-   But if we were to rewind the clock back to the early stages of the hot Big Bang, a Universe filled with stars, galaxies, rocky planets, Sun-like stars, and trillions upon trillions of chances at life would be all but inevitable.

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-  The reason is simple: the laws and raw ingredients of the Universe are always the same:

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-------  A Universe born with normal matter will produce the light elements;

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------- a Universe with density imperfections will produce a first generation of stars;

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------- a Universe with dark matter will hang onto that ejected material and form stars with heavy elements;

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------- a Universe with a second generation of stars will form rocky planets and Sun-like stars;

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------- and a Universe with rocky, Earth-like planets will enable life to exist, survive, and thrive for billions of years.

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-   The rest might all be up to chance, but that’s what made our existence possible. I can’t believe we explained “everything” in only 5 pages.  I got it to where life could exist on this planet now you can take it the rest of the way.  After all, it is a miracle you are reading this.

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-  August 6, 2020                                                                             2788                                                                                                                                                

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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”  -----------

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 ---------------------   Friday, August 7, 2020  -------------------------

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MARS - Curiosity for 8 years.

-  2787  -  MARS  -  Curiosity for 8 years.  The NASA’s car-sized Curiosity rover celebrates eight (Earth) years on the Red Planet today (August 5, 2020), less than a week after its replacement the Perseverance rover took flight toward Mars. 

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--------------------------  2787 -  MARS  -  Curiosity for 8 years.  

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- See Review 2785 about “Perseverance” that is the rover to replace “Curiosity” in February 2021.  It s on it way since July, 2020. The hope is that Perseverance can match its predecessor's longevity.  

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-   Perseverance shares Curiosity's chassis and "sky crane" landing strategy, among other features. And the new rover will build upon the many discoveries that Curiosity has made over the years.

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-  Curiosity launched in November 2011 and touched down inside the 96-mile-wide Gale Crater on the night of Aug. 5, 2012, kicking off a surface mission designed to last at least one Martian year, which is equivalent to 687 Earth days.

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-  The main goal of Curiosity's $2.5 billion mission involves assessing whether the Gale Crater could ever have supported Earth-like life. The nuclear-powered robot has returned exciting news on that front, finding that the crater hosted a potentially habitable lake-and-stream system for long stretches in the ancient past, perhaps millions of years at a time.

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-  Curiosity has also detected complex organic chemicals, the building blocks of life as know it, in Gale Crater rocks. In addition, the rover has rolled through several plumes of methane and discovered a seasonal pattern in the concentration of this gas, which here on Earth is primarily produced by living organisms. Life’s abiotic processes can generate methane as well, however, and the source of the stuff within Gale is still unclear.

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-  In September 2014, Curiosity reached the base of Mount Sharp, which rises 3.4 miles into the sky from Gale's center. For the past six years, the rover has been climbing through the mountain's foothills, reading the rocks for clues about Gale's past habitable environments and how Mars transitioned into the cold, dry desert planet we know today.

-

-  During its eight years on Mars, Curiosity has drilled 27 rock samples, scooped up six soil samples and put more than 14 miles on its odometer.  The Mars surface-distance record is held by another rover, “Opportunity“, which covered 28.06 miles, or 45.16 between 2004 and 2018.

-

-  Perseverance's $2.7 billion mission aims to extend Curiosity's findings. The new rover will hunt for signs of ancient life in Mars' 28-mile-wide Jezero Crater, which was home to a lake and a river delta long ago. 

-

-  Perseverance will also collect and cache samples for future return to Earth and test out several new exploration technologies, including a tiny helicopter named Ingenuity and an instrument that generates oxygen from the thin, carbon dioxide-dominated Martian atmosphere.  See Review 2785 to learn more about this Perseverance Mars mission.  

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-  Perseverance is scheduled to touch down on Feb. 18, 2021. Maybe Curiosity will take a short break from its work in Gale Crater that day, look up at the Martian sky, and send well wishes to the new arrival.  We anxiously wait to see.  

-

-  See Review 2785 that also lists 10 more reviews about other Mars missions.   Over 40 missions have been sent there.  

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-  August 5, 2020                                                                             2787                                                                                                                                                 

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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”  -----------

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 ---------------------   Thursday, August 6, 2020  -------------------------

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UNIVERSE - measuring age with the oldest light?

-  2784  -  UNIVERSE -  measuring age with the oldest light?  Ancient light from the Big Bang, the start of the Universe,  has revealed a precise new estimate for the universe's age: 13.77 billion years, + or - 40 million years.  This new estimate is based on data from an array of telescopes in the Chilean Atacama Desert.   In addition to how old it is,  how fast is the universe expanding is another question? 

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-

--------------------------  2784 -  UNIVERSE -  measuring age with the oldest light        

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-  We need to understand the universe's expansion rate to make any sense of cosmology.  Cosmology is the science of our whole universe's past, present and future. Astronomers know that a mysterious substance called Dark Energy is causing the universe to expand at an ever-increasing rate in all directions.

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-   When astronomers point their telescopes into space to measure the Hubble constant rate of expansion (H0) they come up with numbers that disagree with each other, depending on the method they use.

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-  In our common terms the Universe is expanding 49,300 miles per hour for every million miles of distance of space.  The more space there is between us the faster the rate of recession away from us.

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-  One method, based on measurements of how fast nearby galaxies are moving away from the Milky Way, produces one number for H0. Another method, based on studying the oldest light in space, the Cosmic Microwave Background (CMB), produces another different H0. 

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-  The data from the Planck satellite, released in 2018, were the most important measurements of the CMB before now. With an unprecedented level of precision, they showed how sharply CMB measurements of H0 disagree with measurements based on the movement of nearby galaxies.

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-  Relying on data from the Atacama Cosmology Telescope (ACT) in Chile's Atacama Desert, the researchers tracked faint differences between different parts of the CMB , which appears to have different energy levels in different parts of the sky. 

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-  The CMB, which formed as the universe cooled after the Big Bang, is detectable in every direction in space as a microwave glow. It's more than 13 billion light-years in the distance, a relic of a time before stars and galaxies formed. 

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-  By combining  theories on how the CMB formed with precise measurements of its fluctuations, physicists can determine how fast the universe was expanding at that moment in time. That data can then be used to calculate H0.

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-  The Atacama methodically scanned half the sky between 2013 and 2016, looking particularly at microwave light. Then researchers spent years cleaning up and analyzing the data with the aid of supercomputers, removing other microwave sources that are not part of the CMB, to stitch together a full map of the CMB.

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-  The other approach to calculating H0 relies on pulsing stars known as cepheids, which reside in distant galaxies and pulse regularly. That timed pulsing allows researchers to perform precise calculations of their motion and distances from Earth.

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-  From a mountain high in Chile’s Atacama Desert, astronomers have taken a fresh look at the oldest light in the universe. Their new observations, plus a bit of cosmic geometry, suggest that the universe is 13.77 billion years old, give or take 40 million years.

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-  This estimate matches the one provided by the standard model of the universe and measurements of the same light made by the Planck a space-based observatory that ran from 2009-2013.

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- The trouble is that research teams measuring the movements of galaxies have calculated that the universe is hundreds of millions of years younger than the Planck team predicted. That discrepancy suggested that a new model for the universe might be needed, and sparked concerns that one of the sets of measurements might be incorrect.

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-  A portion of a new picture of the oldest light in the universe taken by the Atacama Cosmology Telescope. This part covers a section of the sky 50 times the moon’s width, representing a region of space 20 billion light-years across. 

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-That light, emitted just 380,000 years after the Big Bang, varies in polarization. Astrophysicists used the spacing between these variations to calculate a new estimate for the universe’s age. 

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-   The age of the universe also reveals how fast the cosmos is expanding, a number called the Hubble Constant, HO. The Atacama measurements suggest a Hubble constant of 67.6 kilometers per second per megaparsec. This result agrees almost exactly with the previous estimate of 67.4 by the Planck satellite team, but it’s slower than the 74 inferred from the other measurements of galaxies.

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-  Like the Planck satellite and its earthbound cousin the South Pole Telescope, the Atacama Telescope peers at the afterglow of the Big Bang.  CMB, marks a time 380,000 years after the universe’s birth, when protons and electrons joined to form the first atoms. Before that time, the cosmos was opaque to light.

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-  If scientists can estimate how far light from the CMB traveled to reach Earth, they can calculate the universe’s age. They measure the angle in the sky between two distant objects, with Earth and the two objects forming a cosmic triangle. If scientists also know the physical separation between those objects, they can use high school geometry to estimate the distance of the objects from Earth.

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-  Subtle variations in the CMB’s glow offer anchor points to form the two vertices of the triangle. Those variations in temperature and polarization resulted from quantum fluctuations in the early universe that got amplified by the expanding universe into regions of varying density. The denser patches would go on to form galaxy clusters.

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-   Scientists have a strong enough understanding of the universe’s early years to know that these variations in the CMB should typically be spaced out every billion light-years for temperature and half that for polarization. 

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-  This measurement was possible thanks to new technology.  From conception to deployment at the telescope to analysis, the process has spanned nearly 10 years.

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-  Astronomers still need more confidence in measurements of the universe’s oldest light.  For sure it is older than dirt.  More to come.

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-  August 1, 2020                                                                              2784                                                                                                                                                

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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”  -----------

-  https://plus.google.com/u/0/  -- www.facebook.com  -- www.twitter.com

 ---------------------   Tuesday, August 4, 2020  -------------------------

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BRAIN - how does it work?

-  2786  -  BRAIN  -  how does it work?   How the brain works remains a puzzle with only a few pieces in place. Remember the brain is trying to figure out itself.  Of these, one big piece is actually a conjecture: that there’s a relationship between the physical structure of the brain and how it functions.  I’ve been thinking about that and here is what I have come up with.

--------------------------  2786 -  BRAIN  -  how does it work?            

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-  The brain’s jobs is interpreting touch, visual and sound inputs, as well as speech, reasoning, emotions, learning, fine control of movement to name a few jobs. Science assumes that it’s the brain’s anatomy with its hundreds of billions of nerve fibers that make all of these functions possible. The brain’s “living wires” are connected in elaborate neurological networks that give rise to human beings’ amazing abilities.

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-  It would seem that if scientists can map the nerve fibers and their connections and record the timing of the impulses that flow through them for a higher function such as vision, they should be able to solve the question of how one sees. 

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-  Researchers are getting better at mapping the brain using “tractography” This is a technique that visually represents nerve fiber routes using 3D modeling. And scientists are getting better at recording how information moves through the brain by using enhanced functional magnetic resonance imaging to measure blood flow.

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-  But in spite of these tools, no one seems much closer to figuring out how we even “see“ with our eyes sending signals to the brain. Neuroscience has only a rudimentary understanding of how it all fits together.

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-   The overall goal of bioengineering research is to scientifically explain all these connections that activate different brain regions during cognitive tasks. 

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-  Electric near-field connections provide another level of communication within the brain.  Cognitive functions such as reasoning and learning use a number of distinct brain regions in a time-sequenced manner. Anatomy alone with the neurons and nerve fibers cannot explain the excitation of these regions in the brain by themselves.

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-  Some connections are actually “wireless.” These are electric near-field connections, and not the physical connections captured in ‘tract graphs“.  A very simple analogy of what is going on in the brain is how a wireless router works. The internet is delivered to a router via a wired connection. The router then sends the information to your laptop using wireless connections. The overall system of information transfer works because of both wired and wireless connections work together.

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-  Electric fields stem from charged particles flowing in and out of neurons at their uninsulated nodes.  In the case of the brain, nerve cells conduct electrical impulses down long threadlike arms called axons from the cell body to other neurons. 

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-  Along the way, wireless signals are naturally emitted from uninsulated portions of nerve cells. These spots that lack the protective insulation that wraps the rest of the axon are called nodes of “Ranvier“.

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-  The nodes of Ranvier allow charged ions to diffuse in and out of the neuron, propagating the electrical signal down the axon. As the ions flow in and out, electric fields are generated. The intensity and structure of these fields depends on the activity of each nerve cell.

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-  Investigations into how excited brain regions match up with cognitive functions make another mistake when they rely on assumptions that lead to overly simple models.  Researchers tend to model the relationship as linear with a single variable, measuring the average size of a single brain region’s response.

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-  Most living things do not have sensing systems that respond in a “linear“, one-to-one manner to stimuli.  Linear models assume that if the input to a system is doubled, the output of that system will also be doubled. This is not true of nonlinear models, where many output values can exist for single value of the input. And most scientists agree that neural computations are in fact nonlinear.

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-  A crucial question in understanding the link between brain and behavior is how the brain decides the best course of action among competing alternatives. For example, the frontal cortex of the brain makes optimal choices by computing many quantities, or variables, calculating the potential payoff, the probability of success and the cost in terms of time and effort. Since the system is nonlinear, doubling the potential payoff may make a final decision much more than twice as likely.

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-  The flow of information through the brain is much more complex and dynamic than a 2D model can adequately represent.  Linear models miss out on the rich variety of possibilities that can occur in brain function, especially those beyond what anatomical structure would suggest. It’s like the difference between a 2D and 3D representation of the world around us.

-

-  Current linear models just describe the average level of excitation in a brain region, or the flow across a brain surface. That’s much less information than nonlinear models from both enhanced functional magnetic resonance imaging and electric near-field bioimaging data. 

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-  Diagramming all the brain’s nonphysical links using recent advances in electric near-field mapping, and employing what we believe are biologically realistic many-variable nonlinear models, will get us one step closer to where we want to go. To learn how we learn.

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-  Better understanding of the brain will not only reduce the need for invasive operating procedures to correct malfunctions, it will also lead to better models for what the brain does best: computation, memory, networking and information distribution.

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-  Our brains obviously have a lot more to learn.

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--------------------------  Other Reviews available to learn how your brain works:

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-  2755  - BRAIN  -  be thankful for your brain?  It took 1.5 million years of evolution.  How did it get to be as good as it gets.  You may be surprised at the answer.

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-   2423  -  BRAIN  -  how the Brain Works?  Research on Huntington’s, Parkinson’s , Alzheimer’s and Epilepsy has shown that throughout life the brain does try to repair itself through the production of new brain cells.  If the brain cells stopped growing in adults,  you have what you got.  So truth be told the brain is trying to understand itself.  Here is a little more to learn about what your brain is doing.

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-  2355 - The Brain - it is what makes you you.  -  What was your memory just before you became conscious of it?  What is consciousness anyway?  Is consciousness something that resides at the molecular level, at the cellular level, at the neural circuit level, or at some higher organizational level in our brain?   It still remains unbelievable that consciousness can be created from mindless little neurons.

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-   2199   -  The human brain, is a challenge for physics to explain down to the level of quantum mechanics.  At the same time into meta physics and deep into philosophy.  (Metaphysics = abstract theory with no basis in reality.)  We are navigating the narrow path between solid ground and the edge of a swamp.

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-  1999 -  Success in life is a mindset.  So is raising or teaching kids.  .  The mindset is believing you can improve with practice and hard work rather than thinking that talent is something fixed.  The growth mindset is what makes a difference in a kid’s education.   Learn about the Pygmalion Effect.  Everyone is a teacher whether they realize it or not.

-

-  1998  -  Understanding Yourself - The Remarkable Brain. If the brain were simple enough to understand we would all be too simple to figure it out.  Serotonin is the brain’s “ don’t worry “, happy chemical. Noradrenalin is a biochemical providing the opposite effect of serotonin.  Moral lessons from Mom and Dad infuse morality into your brain. .  Regardless of our environment, or our situation, our human brain can always choose how to respond to it.    

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-  1403  -  How to become an athlete?   To become a good athlete use your brain.  First you better understand how your brain works.  The trick is to practice to where your brain is doing the thinking for you and you hit the ball without even realizing what you are doing.

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-  1405  -  How does the brain become a mind and create consciousness?   Human brains have figured out how the Sun shines, how life evolved from a single cell, why apples fall.  Our brains have built telescopes that see the galaxies as far back as the beginning of time.  We have built microscopes that see the contours of a single atom.  but, we have not figured our how the brain can possible do these things.  How are we even conscious that we are doing them

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-  1024 -   Brainology Mindset.   Dr. Carol Dweck is a psychologist who maintains that success in life is a mindset.  It is not luck.  It is not genius.  It is believing you can improve with practice and hard work rather than thinking that talent in something fixed.  The growth mindset is what makes a difference in a kid’s education

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-  922  -  Understanding yourself.   The Remarkable Brain.   If the brain were simple enough to understand we would all be too simple to figure it out.  The brain gets it complexity from having many parts, each having a specialized function.  It gets its complexity from the communications network that coordinates all of the parts through biochemical means.  It gets its complexity through evolving throughout a lifetime and over many lifetimes.  This review will help you understand not only yourself but your kids. 

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-  868  -  Seeing with ½ your brain.   You may think thinking is hard, but seeing is harder.  Visualization uses more than ½ your brain.  While you are sitting down reading this review your brain is using 33% of the oxygen that you breath.  When you are sitting and reading you are burning 33% of the calories your body has consumed.  A total of 1/6 of what you eat gets used by your brain.  And, if you worry a lot the ratio goes up.

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-  August 2, 2020                                                                             2786                                                                                                                           

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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”  -----------

-  https://plus.google.com/u/0/  -- www.facebook.com  -- www.twitter.com

 ---------------------   Monday, August 3, 2020  -------------------------

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MARS - Jezero Crator exploration?

-  2785  -  MARS  -  Jezero Crator exploration?  -  On July 30, 2020 NASA launched its most sophisticated and ambitious spacecraft to Mars in the search for signs of life beyond Earth.   The spacecraft is aptly named “Perseverance Rover“. 

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-

--------------------------  2785 -  MARS  -  Jezero Crator exploration?         

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-  This  2020 launchwill be the third launch to Mars this month, following the UAE’s “Hope” and China’s “Tianwen-1” spacecraft.

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-  NASA’s Perseverance will look for signatures of ancient life preserved in Mars rocks.  This rover will collect rock samples that will be brought back to Earth, where they can be scrutinized in laboratories for decades to come.

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-  Mars is one the few destinations in the Solar System that has had conditions suitable for life as we know it. There is a chance that Perseverance will collect the sample from Mars that answers the question: “Are we alone in the universe?” 

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-  This question is especially relevant right now. During the coronavirus pandemic, the mission has remarkably stayed on track for launch in spite of disruptions and delays, and we have been reminded that life on Earth is vulnerable and precious.

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-  On February 18, 2021, if all goes according to plan, Perseverance will enter the Martian atmosphere at 13,000 mph.  Seven nerve-racking minutes later, Perseverance will be lowered gently onto the surface by a jetpack. The rover will land in Jezero Crater, a site that will provide a window to a time when rain fell and rivers flowed on ancient Mars.

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-  Over the past 30 years, a fleet of rovers and orbiters have built a picture of an Earth-like ancient Mars. Between 3 and 4 billion years ago, Mars hosted vast river networks as long as the Mississippi, deep lakes that contained the building blocks of life, and hot springs that bubbled with potential for life. 

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-  These watery environments were able to exist because ancient Mars had a thick atmosphere. However, that atmosphere has been leaking away, leaving the surface today cold, dry and inhospitable.

-

- Jezero Crater was selected as the site on Mars that is most likely to preserve signs of life that might have inhabited Mars billions of years ago, when microbial life was first starting on Earth. 

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-  Satellite images of Jezero show a river leading into the crater and ending in a large delta, which must have formed in a long-lived ancient lake. A bathtub ring of carbonate minerals around the edge of the crater might have formed along ancient beaches, and may preserve rocks with microbial textures known as stromatolites. Stromatolites record some of the earliest signs of life on Earth, and Perseverance will search for similar signs of life on Mars.

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-  Perseverance will have many new capabilities that will transform how we explore Mars. The rover carries “Ingenuity“, a small helicopter that will be the first aircraft to fly on another planet. Because Mars’ atmosphere today is so thin, only 1% of the Earth’s, Ingenuity has to be extremely lightweight (4 lbs) with very large blades (4 feet tip-to-tip) to get off the ground.

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-   Ingenuity will take images of the distant landscape and help us scout the rover’s traverse.   Future Mars missions could adopt this model of rovers and aircraft working in tandem.

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-  Looking even further ahead, Perseverance will help prepare for future human missions to Mars. One of many challenges for astronauts will be the packing list for a two-year roundtrip journey, which includes air, water and rocket fuel to get home.

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-  If these resources could be harvested on Mars, human missions would be much more feasible. Perseverance will test a process for creating oxygen from Mars’ carbon dioxide atmosphere. In the future, similar instruments could be sent ahead of astronauts, so that breathable air and liquid oxygen rocket propellant are waiting when they arrive.

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-   Mars 2020 rover uses its drill to core a rock sample on Mars. The rover will collect and store rock and soil samples on the planet’s surface that future missions will retrieve and return to Earth. 

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-  The most immediate goal of the mission is to search for evidence of past life, and Perseverance’s science payload will allow the rover to search for organic materials and microbial textures at the scale of a grain of salt. 

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-  Finding definitive evidence of microbial life is extremely difficult. Ultimately, we will need to look at samples from Jezero with advanced instruments on Earth. This is why Perseverance will also collect pencil-sized rock cores that will be returned to Earth by a series of missions in the late 2020s.

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-  By laying the groundwork for sample return with Perseverance, NASA is taking the next giant leap in its exploration of Mars. The rocks collected by Perseverance may be our only shot in the foreseeable future to search for signs of life with samples from another planet. 

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-----------------------------------  More Reviews available:

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-  2783  - MARS  -  launch of Perseverance mission.  -  NASA's Mars 2020 Perseverance rover mission is on its way to the Red Planet to search for signs of ancient life and collect samples to send back to Earth.  Humanity's most sophisticated rover launched July, 2020.

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-  2776  -  MARS - 4th rock from the sun.   Mars is the forth rock from the Sun and is the easiest planet for us to get to.  Since 2007 we have 3 satellites orbiting Mars and 2 robots roving around the surface.  The robots take pictures and run tests on the soil sending the data up to the satellite overhead to be relayed back to Earth.  

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-   Review 2772  -  MARS  -  several steps to Perseverance.  The Mars Perseverance rover mission is part of NASA's Mars Exploration Program, a long-term effort of robotic exploration of the Red Planet. The Mars Perseverance mission addresses high-priority science goals for Mars exploration, including key questions about the potential for life on Mars.  

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-  Review 2760  -  MARS  -  Perseverance Rover in 2020 launch?  The mission is timed for a launch opportunity in July 2020 when Earth and Mars are in good positions relative to each other for landing on Mars. It takes less power to travel to Mars at this time, compared to other times when Earth and Mars are in different positions in their orbits.   

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-  2608  -  MARS  -  cosmic rays seen on Mars?   NASA is using the ‘InSight lander” to look for meteors on Mars.  From a glance at the images, the search seems straightforward.  But, the images show mostly ghosts, the invisible made visible and the visible drowned out amid the illusions.  Here is a summary of the data from sky watching on Mars.

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-  2276  -  Mars is our forth terrestrial planet from the Sun. See Review 2275 for the current information on the latest missions and what we learned.  This review is some of the earlier history and the math used to learn before our space ships could get there.

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-  2275  -  After 15 years, the mission of NASA's Opportunity rover has come to an end, but its successes on Mars have earned it a spot in the robot hall of fame.   The Mars Exploration Rovers mission featured two identical, golf-cart-sized, solar-powered rovers named Spirit and Opportunity. Spirit landed on Jan. 4, 2004. Opportunity landed on the opposite side of Mars on Jan. 24, 2004. 

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- 1905  -  Mars Explorations.  Over 40 missions have been sent to Mars.  20 were successful in studying the Red Planet.  This year the missions will get closer to the answer” “ Is there evidence of life on Mars? “

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- 1877  -  What can we earn from Oxygen?  Burn some in your brain and see if you can learn where oxygen came from.  Can we find some of this life giving oxygen on Mars?

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-  1860  -  Discoveries are coming fast in astronomy.  Space missions to Mars and Ceres collect enough data to keep astronomers working for decades.

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-  August 2, 2020                                                                            2785                                                                                                                                           

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

-----  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”  -----------

-  https://plus.google.com/u/0/  -- www.facebook.com  -- www.twitter.com

 ---------------------   Sunday, August 2, 2020  -------------------------

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