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  • richardmitnick 2:48 pm on April 17, 2017 Permalink | Reply
    Tags: Don Lincoln, The Five Forces, The Great Courses Daily,   

    From Don Lincoln of FNAL via The Great Courses Daily 

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    The Great Courses Daily

    A Search For the Theory of Everything

    FNAL Don Lincoln


    From a lecture series by Professor Don Lincoln, Ph.D. & Head Scientist at FermiLab

    The unifying theories of physics are among the greatest and most complex in all of science; their progression toward ever-grander insights will transform our understanding of the universe, and is nothing less than a search for the theory of everything.

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    No image caption. No image credit.

    “Dream no small dreams for they have no power to move the hearts of men.”

    This quote by Johann Wolfgang von Goethe is still powerful today, two centuries after he first wrote it down. It doesn’t matter whether you’re trying to broker an international peace treaty or cure a disease or change a society, it’s not the incremental improvements that stir the blood; it’s the big ideas.

    There is a class of scientists who who live by these words. They keep thinking big and asking “why,” with each answer resulting in yet another question. They do that over and over and over again, and the hope is that, one day, there will be no more questions, because we understand the reasons for everything. That is dreaming big!

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    Our mastery of the atom made chemistry possible and also allowed us to build electronics and computers that can calculate faster than human imagination. No image credit.

    In science, humanity has had great success over the centuries. Isaac Newton’s amazing ideas about gravity were the first major scientific steps toward a theory of everything, ideas that we still use to guide our space probes to distant targets, like when the New Horizons spacecraft buzzed by Pluto.

    NASA/New Horizons spacecraft

    Our mastery of the atom made chemistry possible and also allowed us to build electronics and computers that can calculate faster than human imagination.

    Each of these achievements is big in its own way, but they aren’t the biggest possible. While there’s no denying that these ideas originated from a grand dream, each represents merely a single facet of human knowledge. The ultimate goal of science is much bigger. The ultimate goal of science is nothing less than an understanding of the fundamental rules of the universe itself. That’s a pretty ambitious goal and it depends crucially on the idea, which seems to be a fact, that all of the phenomena we see around us are interconnected and arise from even deeper causes.

    The Standard Model

    While nobody claims that science is done in their search, you can regard the standard model as the current best guess of a grand unified theory.

    The Standard Model of elementary particles (more schematic depiction), with the three generations of matter, gauge bosons in the fourth column, and the Higgs boson in the fifth.

    That’s why it’s so important to understand it and what it signifies. For one thing, whatever the final theory of everything looks like, the standard model will be part of it.

    The key components of the standard model consist of:

    Quarks – found inside protons and neutrons in the center of atom;
    Leptons – the lightest of the subatomic particles, the most familiar one is the electron is found in the outskirts of every atom;
    Force-carrying particles, sometimes called gauge bosons – responsible for transmitting three of the four known forces;
    Higgs Boson – a particle whose existence was confirmed in 2012, the final missing piece to the standard model.

    Over the last few decades, science has unified forces that historically have seemed distinct. That’s incredibly exciting, but it also leads to a bit of confusion, so let’s clear that up a bit, by talking about the five forces — the third item in the components of the standard model.

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    Earth gravity. ThinkstockPhotos

    The Five Forces

    The five forces are as follows:

    Gravity, which keeps us firmly planted on the ground and guides the planets through their trajectories
    Electromagnetism, which includes electricity, magnetism, light and chemistry
    The strong nuclear force, which binds protons and neutrons together in the nucleus of atoms
    The weak force, which is responsible for forms of radioactivity
    The Higgs field, which gives mass to subatomic particles

    But why then, in some cases, does science refer to only three or four forces? Well, in the late 1960s, physicists showed that the weak force and electromagnetism were really two facets of a single thing, much in the same way that electricity and magnetism turned out to be two facets of something that we now call electromagnetism.

    Therefore, scientists often talk about an electroweak theory, so they might say that the forces are gravity, the electroweak force, the strong force, and the Higgs field. On the other hand, the Higgs field is inextricably tied with the electroweak force, so maybe it can get tucked under the electroweak umbrella. Under that way of thinking, there are but three: gravity, the strong force, and the electroweak complex.

    And how about the term forces? A better word for these would be interaction, because the word interaction means that some change is caused, like changing a particle’s identity without actually moving it. However, the word force is ingrained in the literature, so let’s stick with that word most of the time.

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    The Strong force is used to explain why the sun burns at such high temperatures. No image credit.

    The strong force is the strongest of the known forces. For example, it’s the force that explains why the sun burns so very hot. But it also has a weird behavior. It’s incredibly strong over very short ranges—say, the size of a proton. Once two particles are separated by a distance much larger than that, the strong force goes to zero. It’s a little like Velcro. If two pieces of Velcro are touching, they’re strongly bound together, but once they’re separated, they feel no attractive force at all. That particular facet plays a big role in understanding the large range observed in the mass of atoms. That’s the strong force.

    The next strongest force is electromagnetism, which unifies electricity and magnetism into a single force. It’s much weaker than the strong force, but it has a different behavior as far as distance is concerned. Two particles experiencing the electromagnetic force will, in principle, feel a force between one another even if they are located on opposite sides of the universe. Granted, that force will be very small, but it won’t be mathematically zero, because electromagnetism has an infinite range.

    Because of the difference in how the two forces change with distance, you have to be very careful to specify distances when you compare electromagnetism to the strong force, so you traditionally pick a separation distance of about the size of a proton, which is a femtometer, or 10−15 meters. At that separation distance, the strong force is about 100 times stronger than electromagnetism. Of course, given the short range of the strong force and the infinite range of electromagnetism, if two particles are separated by just a meter, or even a millimeter, electromagnetism is actually much stronger.

    The next weakest force is the weak force. The natural range of the weak force is about 1/1000 the size of a proton. However, if we ask how strong it is at the separation of a femtometer, it’s about 100,000 times weaker than the strong force. When we look at the weak force at its natural scale, we see that it’s actually similar to electromagnetism, and that was the beautiful insight that allowed for electroweak unification.

    Then there’s gravity. It has an infinite range like electromagnetism, but at the femtometer distance scale, gravity is approximately like 1040 times weaker than the strong force. That’s a one over a one followed by 40 zeros. “Approximately” because you get a different answer if you’re talking about the gravitational force between two protons, two electrons, or a proton and an electron, but the 1040 number gives you the right message: gravity is crazy weak. And, indeed, gravity is so weak that we’ve never figured out a way to study it on these super-small scales. If we tried, the measurements would just get swamped by the effects of the other forces. So gravity is not covered by the standard model.

    The Higgs field is a bit different — it actually gives mass to particles, so it’s not a force in the way that the others are. Therefore, it isn’t discussed in quite the same way because we don’t know how its strength compares to the others. This is one of the times where the word interaction is more apt. Because of its interaction, the Higgs field turns massless particles into massive particles.

    CERN CMS Higgs Event

    CERN ATLAS Higgs Event

    The standard model is amazing, and we’ve only bareley discussed one of it’s four components. With this standard model, science can explain basically everything we see, from why cells divide, to how stars burn, to why objects move in a particular manner, and on and on. The hope is that one day, we will be able to unify the electroweak and strong forces into a single force called a grand unified theory, which I’m certain we will discuss in a later article.

    See the full article here .

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  • richardmitnick 12:59 pm on April 17, 2017 Permalink | Reply
    Tags: Don Lincoln, , , Why is the Weak Force weak?   

    From Don Lincoln at FNAL: “Why is the Weak Force weak?” Video. 

    FNAL II photo

    FNAL Art Image
    FNAL Art Image by Angela Gonzales

    Apr 14, 2017

    FNAL Don Lincoln


    Don Lincoln

    The subatomic world is governed by three known forces, each with vastly different energy. In this video, Fermilab’s Dr. Don Lincoln takes on the weak nuclear force and shows why it is so much weaker than the other known forces.

    Watch, enjoy, learn.

    Fermilab is an enduring source of strength for the US contribution to scientific research world wide.

    See the full article here .

    Please help promote STEM in your local schools.

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    Fermilab Campus

    Fermi National Accelerator Laboratory (Fermilab), located just outside Batavia, Illinois, near Chicago, is a US Department of Energy national laboratory specializing in high-energy particle physics. Fermilab is America’s premier laboratory for particle physics and accelerator research, funded by the U.S. Department of Energy. Thousands of scientists from universities and laboratories around the world
    collaborate at Fermilab on experiments at the frontiers of discovery.

     
  • richardmitnick 9:23 am on March 12, 2017 Permalink | Reply
    Tags: , Don Lincoln, , , , The Weak Nuclear Force: Through the looking glass   

    From Don Lincoln: “The Weak Nuclear Force: Through the looking glass” Video 

    FNAL II photo

    FNAL Art Image
    FNAL Art Image by Angela Gonzales

    3.10.17

    Don Lincoln

    Fermilab is an enduring source of strength for the US contribution to scientific research world wide.

    Published on Mar 10, 2017

    Of all of the known subatomic forces, the weak force is in many ways unique. One particularly interesting facet is that the force differentiates between a particle that is rotating clockwise and counterclockwise. In this video, Fermilab’s Dr. Don Lincoln describes this unusual property and introduces some of the historical figures who played a role in working it all out.
    Access mp4 video https://www.youtube.com/watch?v=-gYeLHFr2LA .
    Watch, enjoy, learn.

    See the full article here .

    Please help promote STEM in your local schools.

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    Fermilab Campus

    Fermi National Accelerator Laboratory (Fermilab), located just outside Batavia, Illinois, near Chicago, is a US Department of Energy national laboratory specializing in high-energy particle physics. Fermilab is America’s premier laboratory for particle physics and accelerator research, funded by the U.S. Department of Energy. Thousands of scientists from universities and laboratories around the world
    collaborate at Fermilab on experiments at the frontiers of discovery.

     
  • richardmitnick 1:20 pm on January 17, 2017 Permalink | Reply
    Tags: Don Lincoln, Fermions and Bosons, , ,   

    From Don Lincoln at FNAL: “Fermions and Bosons” Video 

    FNAL II photo

    FNAL Art Image
    FNAL Art Image by Angela Gonzales

    Fermilab is an enduring source of strength for the US contribution to scientific research world wide.

    FNAL Don Lincoln
    From Don Lincoln

    In particle physics, there are many different types of particles, mostly ending with the phrase “-on.” In this video, Fermilab’s Dr. Don Lincoln talks about fermions and bosons and what is the key difference between these two particles.


    Access mp4 video here .

    See the full article here .

    Please help promote STEM in your local schools.

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    Fermilab Campus

    Fermi National Accelerator Laboratory (Fermilab), located just outside Batavia, Illinois, near Chicago, is a US Department of Energy national laboratory specializing in high-energy particle physics. Fermilab is America’s premier laboratory for particle physics and accelerator research, funded by the U.S. Department of Energy. Thousands of scientists from universities and laboratories around the world
    collaborate at Fermilab on experiments at the frontiers of discovery.

     
  • richardmitnick 12:37 pm on November 29, 2016 Permalink | Reply
    Tags: , Don Lincoln, , ,   

    From Don Lincoln at FNAL: Higgs Boson 2016 Video 

    FNAL II photo

    FNAL Art Image
    FNAL Art Image by Angela Gonzales

    Fermilab is an enduring source of strength for the US contribution to scientific research world wide.

    FNAL Don Lincoln
    From Don Lincoln of FNAL

    Published on Nov 16, 2016

    CERN CMS Higgs Event
    CERN CMS Higgs Event

    The Higgs boson burst into the public arena on July 4, 2012, when scientists working at the CERN laboratory announced the particle’s discovery. However the initial discovery was a bit tentative, with the need to verify that the discovered particle was, indeed, the Higgs boson. In this video, Fermilab’s Dr. Don Lincoln looks at the data from the perspective of 2016 and shows that more recent analyses further supports the idea that the Higgs boson is what was discovered.

    Watch, enjoy, learn.

    The data presented in this video can be seen in a technical form in this paper: http://cds.cern.ch/record/2158863/fil…. Figure 19 is a more accurate version.

    See the full article here .

    Please help promote STEM in your local schools.

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    Fermilab Campus

    Fermi National Accelerator Laboratory (Fermilab), located just outside Batavia, Illinois, near Chicago, is a US Department of Energy national laboratory specializing in high-energy particle physics. Fermilab is America’s premier laboratory for particle physics and accelerator research, funded by the U.S. Department of Energy. Thousands of scientists from universities and laboratories around the world
    collaborate at Fermilab on experiments at the frontiers of discovery.

     
  • richardmitnick 3:23 pm on November 12, 2016 Permalink | Reply
    Tags: , Accelerator Science: Circular vs. Linear, Don Lincoln,   

    From Don Lincoln at FNAL: “Accelerator Science: Circular vs. Linear “ 

    FNAL II photo

    FNAL Art Image
    FNAL Art Image by Angela Gonzales

    Fermilab is an enduring source of strength for the US contribution to scientific research world wide.
    Nov 10, 2016

    FNAL Don Lincoln
    Don Lincoln

    Particle accelerator are scientific instruments that allow scientists to collide particles together at incredible energies to study the secrets of the universe. However, there are many manners in which particle accelerators can be constructed. In this video, Fermilab’s Dr. Don Lincoln explains the pros and cons of circular and linear accelerators.

    See the full article here .

    Please help promote STEM in your local schools.

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    Fermilab Campus

    Fermi National Accelerator Laboratory (Fermilab), located just outside Batavia, Illinois, near Chicago, is a US Department of Energy national laboratory specializing in high-energy particle physics. Fermilab is America’s premier laboratory for particle physics and accelerator research, funded by the U.S. Department of Energy. Thousands of scientists from universities and laboratories around the world
    collaborate at Fermilab on experiments at the frontiers of discovery.

     
  • richardmitnick 8:00 am on October 8, 2016 Permalink | Reply
    Tags: , , Don Lincoln, , , ,   

    From Don Lincoln at FNAL: “Eight is enough” 

    FNAL II photo

    FNAL Art Image
    FNAL Art Image by Angela Gonzales

    Fermilab is an enduring source of strength for the US contribution to scientific research world wide.

    October 7, 2016

    FNAL Don Lincoln
    Don Lincoln

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    In the search for new physics, no stone can be left unturned. In this analysis, scientists looked for a new particle that underwent a cascade of decays, resulting in eight distinct particles. No image credit.

    While the LHC was built for many purposes, one of the key reasons it was created was to investigate the most energetic collisions possible. The basic idea is that high-energy collisions have the best chance of unveiling phenomena never before observed.

    In particle physics, low-energy things happen all the time, while high-energy things are extremely rare. To give a sense of scale, the lowest-energy collisions that we study occur about a billion times more often than the highest-energy collisions we can create.

    Now if you want to study very high-energy things, you want to use the strongest force available to you. That’s because a strong force makes many collisions, and if you make many collisions, you are more likely to see the rare and very high-energy type of event you are looking for. In particle physics terminology, that means that you need to use events that use the strong nuclear force.

    That works out as a good strategy at the LHC because the LHC collides protons together, and protons are full of quarks and gluons, both of which interact via the strong force. The basic idea is that a quark or gluon from one proton will interact with a quark or gluon from the other proton, merge into some new and undiscovered particle, and then decay and be observed in the detector. Now the CMS experiment has already looked into the case where this new particle decayed directly into two ordinary particles.

    CERN/CMS Detector
    CERN/CMS Detector

    It has also looked into the case where the new particle decayed into two new (but different) particles that then each decayed into two ordinary particles. In this scenario, there would be four ordinary particles hitting the detector. Neither of these analyses led to the discovery of new physics.

    However, there is no reason that these should be the only two possible scenarios. It could be that LHC collisions would make one new particle, which then decayed into two new but lower-mass particles, each of which subsequently decayed into two more new and even lighter particles, resulting in four, which each finally decayed into two ordinary particles, producing eight. Thus the CMS experiment went looking for events in which eight ordinary particles simultaneously hit the detector.

    CMS was searching for particles called “jets,” which are actually collections of even more particles, but we can use algorithms to reduce a jet to looking like a single particle. So they were looking for events that produced eight jets.

    So far so good. The problem with this analysis arises because, even without new physics, the strong nuclear force makes lots of events in which there are eight or more jets, so it is pretty hard to identify events with eight jets that are made by new physics. But there is one saving grace. The collisions in which eight jets are made by ordinary physics have the same basic distribution of total energy as the ones in which only two jets are made. So they use the well-understood two-jet data to make predictions of eight-jet data and then compare it to the measurements all eight-jet data. If too many eight-jet events are found, then maybe they’ve made a discovery.

    Sadly, no excess was found. But this was a clever technique and one that might well be worth pursuing in the future. The most recent paper was for data recorded at a collision energy of eight trillion electronvolts of energy (back in 2012), and we’ve recorded data with 13 trillion electronvolts. Maybe with the new data, this technique will lead to a different result.

    See the full article here .

    Please help promote STEM in your local schools.

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    Fermilab Campus

    Fermi National Accelerator Laboratory (Fermilab), located just outside Batavia, Illinois, near Chicago, is a US Department of Energy national laboratory specializing in high-energy particle physics. Fermilab is America’s premier laboratory for particle physics and accelerator research, funded by the U.S. Department of Energy. Thousands of scientists from universities and laboratories around the world
    collaborate at Fermilab on experiments at the frontiers of discovery.

     
  • richardmitnick 10:39 am on September 20, 2016 Permalink | Reply
    Tags: , Don Lincoln, , , Luminosity vs. Energy, ,   

    From Don Lincoln at FNAL- “Accelerator Science: Luminosity vs. Energy” 

    FNAL II photo

    FNAL Art Image
    FNAL Art Image by Angela Gonzales

    Sep 19, 2016

    FNAL Don Lincoln
    Don Lincoln

    Fermilab is an enduring source of strength for the US contribution to scientific research world wide.

    In the world of high energy physics there are several parameters that are important when one constructs a particle accelerator. Two crucial ones are the energy of the beam and the luminosity, which is another word for the number of particles in the beam. In this video, Fermilab’s Dr. Don Lincoln explains the differences and the pros and cons. He even works in an unexpected sporting event.

    Watch, enjoy, learn.

    See the full article here .

    Please help promote STEM in your local schools.

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    FNAL Icon
    Fermilab Campus

    Fermi National Accelerator Laboratory (Fermilab), located just outside Batavia, Illinois, near Chicago, is a US Department of Energy national laboratory specializing in high-energy particle physics. Fermilab is America’s premier laboratory for particle physics and accelerator research, funded by the U.S. Department of Energy. Thousands of scientists from universities and laboratories around the world
    collaborate at Fermilab on experiments at the frontiers of discovery.

     
  • richardmitnick 10:02 am on September 8, 2016 Permalink | Reply
    Tags: , , Don Lincoln, ,   

    From Don Lincoln for CNN: “Something is wrong with dark matter” 

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    CNN

    September 7, 2016

    FNAL Don Lincoln
    Don Lincoln

    Dr. Don Lincoln is a senior physicist at Fermilab and does research using the Large Hadron Collider. He has written numerous books and produces a series of science education videos. He is the author of The Large Hadron Collider: The Extraordinary Story of the Higgs Boson and Other Things That Will Blow Your Mind. Follow him on Facebook. The opinions expressed in this commentary are solely those of the author.

    Nearly a mile under the Black Hills of South Dakota sits a canister of the atomic element xenon, chilled cold enough to turn it to liquid. The canister is the Large Underground Xenon, or LUX, detector — the most sensitive dark matter detector in the world.

    SURF logo
    Sanford Underground levels
    Sanford Underground Research Facility
    LUX Dark matter Experiment at SURF
    LUX Dark matter Experiment at SURF

    But the results of a new analysis by the LUX Collaboration has left scientists perplexed about a substance that has guided the formation of the stars and galaxies since the cosmos began: dark matter.

    Since the 1930s, scientists have known that there was something unexplained about the heavens. Swiss astronomer Fritz Zwicky studied the Coma Cluster, a group of about a thousand galaxies, held together by their mutual gravitational interactions.

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    A map of the Coma cluster. http://www.atlasoftheuniverse.com

    There was only one problem: The galaxies were moving so fast that gravity shouldn’t have been able to hold them together. The cluster should have been ripped apart. In the 1970s, astronomers Vera Rubin and her collaborator Kenneth Ford studied the rotation rates of individual galaxies and came to the same conclusion. There appeared to be no way the observed matter contained in galaxies would generate enough gravity to keep the stars locked in their stately orbits.

    These observations, combined with many other independent lines of evidence, led scientists to consider several possible explanations. These explanations included the possibility that Newton’s familiar laws of motion might be wrong, or that our understanding of gravity needed to be modified. Both these proposals, though, have been largely ruled out.

    Another idea was that there was somehow invisible matter that was generating more gravity. Initial ideas centered on the possibility of black holes, brown dwarf stars or rogue planets roaming the cosmos, but those explanations have also been dismissed. Using a ruthless process of elimination worthy of Sherlock Holmes, astronomers have come to believe the explanation for all of the gravitational anomalies is that there must be some sort of new and undiscovered type of matter in the universe, which Zwicky in 1933 named “dunkle materie,” or dark matter.

    For decades, scientists have tried to work out the properties of dark matter and, while we don’t know everything, we know a lot. From astronomical observations, we know there is five times more dark matter in the universe than all the “billions and billions” of stars and galaxies mentioned in Carl Sagan’s oft-quoted phrase. We also know that dark matter cannot have electrical charge, otherwise it would interact with light and we would have seen it. In fact, by a process of elimination, we know that dark matter is not any known form of matter. It is something new. Of this, scientists are sure.

    However, scientists are less sure about the details.

    For decades now, the most popular theoretical idea was that dark matter was a WIMP, short for weakly interacting massive particle. A WIMP would have a mass in the range of 10 to perhaps 100 times heavier than the familiar proton. It was a particle like a heavy neutron (but definitely not a neutron), massive, electrically neutral, and stable on time scales long compared to the lifetime of the universe.
    The WIMP was popular for two main reasons.

    First, when cosmologists modeled the Big Bang and included WIMPs in the calculation, the WIMPs actively participated in the earliest phases of the birth of the universe but, as the universe expanded and cooled, the space between them grew large enough that they stopped interacting with one another. When scientists calculated how much mass should be tied up in the relic WIMPs, they found it was five times as much mass as ordinary matter, exactly the amount of dark matter seen by astronomers.

    The second reason for the popularity of the WIMP idea is that it explained a mystery in particle physics. The recently discovered Higgs boson has a mass of about 130 times that of the proton. Theoretical considerations predicted a much larger mass, but if a WIMP exists, it is easy to reconcile the prediction and measurement. These two reasons account for the popularity of the WIMP idea and are called “the WIMP miracle.”

    The LUX measurement is simply the most recent and most powerful of a long line of searches for dark matter. They found no evidence for the existence of dark matter and were able to rule out a significant range of possible WIMP properties and masses.

    Now this doesn’t mean the WIMP idea is dead or that dark matter has been disproven. There remain WIMP masses that haven’t been ruled out, and there exist other possible dark matter candidates, including objects called sterile neutrinos, which are possible cousins of the well-known neutrinos generated in nuclear reactors and in the sun. Another recurring proposed dark matter particle is the axion, suggested in the 1970s to explain mysteries in the asymmetry of subatomic processes. (Although neither sterile neutrinos, nor axions, have been observed).

    Nobody knows what the final answer will be. That’s why we do research. But there is no question that there is a mystery in the cosmos. Galaxies don’t act as we expect. The LUX measurement is a powerful new bit of information for astronomers to consider and has added to the general confusion, forcing scientists to take another look at ideas other than WIMPs.

    All this reminds me of the old Buffalo Springfield song: “There’s something happening here. What it is ain’t exactly clear …”

    See the full article here .

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  • richardmitnick 2:27 pm on August 25, 2016 Permalink | Reply
    Tags: , Don Lincoln, , , ,   

    From Don Lincoln via CNN: “A new planet in our neighborhood — how likely is life?” 

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    CNN

    August 24, 2016

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    Dr. Don Lincoln is a senior physicist at Fermilab and does research using the Large Hadron Collider. He has written numerous books and produces a series of science education videos. He is the author of Alien Universe: Extraterrestrial Life in Our Minds and in the Cosmos. Follow him on Facebook. The opinions expressed in this commentary are solely those of the author.

    Space. The final frontier.

    These words inspired many young people to enter science (including me), but I’ll bet that’s especially true for the team who announced Wednesday that they had found evidence of an Earth-like planet orbiting Proxima Centauri, our closest star. This planet is tentatively called Proxima b.

    Pale Red Dot
    Pale Red Dot project at ESO

    Scientists working at the European Southern Observatory (ESO), using the La Silla telescope, claim to have discovered the closest exoplanet to Earth.

    ESO 3.6m telescope & HARPS at LaSilla
    ESO 3.6m telescope & HARPS at LaSilla, Chile

    Exoplanet, of course, means planets orbiting stars other than the Sun. Over 3,000 exoplanets have been discovered by facilities like the ESO and the Kepler orbiting observatory. Most of them are huge planets orbiting very near their star — Jupiter-like planets heated to temperatures guaranteed to sterilize them of life as we know it.

    In recent years, instrumentation has improved to the point that not only can individual planets be found, but even complete solar systems, consisting of many planets. This has been a heady time for planet hunters.

    The goal of those inspired by Star Trek’s opening words has not been to find planets, but to find planets that are like Earth — meaning at a temperature on which liquid water could be present and which could theoretically support some form of life. This is what astronomers call “the habitable zone.” In addition, we’d like to find a planet that is nearby.

    After all, space is huge and human spacecraft using current technology would take tens of thousands of years to get to even this, our closest celestial neighbor. To give a sense of scale, that’s longer than human civilization has existed. There are plans under discussion that might reduce travel time to a more manageable duration, even less than a single human lifespan.

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    Related article: Proxima b: Closest rocky planet to our solar system found

    Centauris Alpha Beta Proxima 27, February 2012. Skatebiker
    Centauris Alpha Beta Proxima 27, February 2012. Skatebiker

    So what might this newly discovered planet look like? Well, even though its temperature is thought to be such that liquid water could exist, you shouldn’t imagine a lush and verdant world, with lovely blue waters, sandy beaches, lush and green plants, with an excited alien fish occasionally breaching the waters. There are lots of reasons why these are unreasonable expectations.

    Setting aside the possibility of life for a moment, Proxima Centauri is a red dwarf, which is the most common type of star in the galaxy. Red dwarfs are much smaller than our Sun. For instance, Proxima Centauri is only about 1.5 times larger than Jupiter. Red dwarfs are very dim. For instance, in the visible spectrum that we use to see, Proxima Centauri gives off 0.0056% as much as light as the Sun.

    Most of the light given off by Proxima Centauri is in the infrared region, but even if you compare all of the light emitted by Proxima Centauri in all wavelengths to the amount emitted by the Sun, Proxima Centauri still emits only 0.17% as much light as our own life-giving stellar companion. The star also emits as much x-rays as our own Sun, but Proxima b is much closer to its stellar parent, so the surface receives far more x-rays than Earth.

    In addition to being a very dim star, Proxima Centauri is known to be a “flare star,” which means the star periodically gives off far more light than usual. During these flares, the x-ray emission can go up tenfold.

    Because of the star’s small size, a planet in the habitable zone will have to be in a very small orbit, taking under two weeks to complete a single orbit. Any planet that close to a star will be “tidally locked,” which means that one face of the planet will constantly face the star. This is just like the Earth and Moon, where we see only one side of the Moon throughout the course of the Month. Proxima Centauri’s planetary companion will likely have one side in perpetual daylight, while the other is in perpetual night.

    So what about life? Are there any chances that an alien lizard might bask in Proxima Centauri’s light or try to find shade under an alien tree? Well, given the instability of the light emitted by the parent star, the answer is likely no, although the real answer to that question is obviously something for observations to answer.

    Given the very dim light output of the star, it is likely that any hypothetical plants would have to be black, as black is the most light-absorbent color. “Sunlight” would be precious and evolution would drive alien plants to find ways to collect every bit of energy that falls on them.

    Realistically, the prospect of life is improbable. This planet is unlikely to be a haven for people trying to escape the ecological issues of Earth, so we should not view this discovery as a way to ignore our own ecosystem.

    Still, the question of extraterrestrial life is a fascinating one, so astronomers are devising techniques to look at the planet’s atmosphere. Certain chemicals, like oxygen or methane, cannot exist long in a planet’s atmosphere without being constantly replenished by living organisms. Observing them would be strong evidence for life.

    So, what’s the bottom line? First, the discovery, if confirmed is extremely exciting. The existence of a nearby planet in the habitable zone will perhaps increase the interest in efforts like Project Starshot, which aims to send microprobes to Proxima Centauri with a transit time of about twenty years. It may well be that this discovery will excite an entirely new generation of the prospect “to boldly go where no one has gone before.”

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

     
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