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  • richardmitnick 1:19 pm on July 31, 2019 Permalink | Reply
    Tags: , , , , Cosmic Rays, , ,   

    From Ethan Siegel: “How To Prove Einstein’s Relativity In The Palm Of Your Hand” 

    From Ethan Siegel
    July 31, 2019

    1
    Cosmic rays, which are ultra-high energy particles originating from all over the Universe, strike protons in the upper atmosphere and produce showers of new particles. The fast-moving charged particles also emit light due to Cherenkov radiation as they move faster than the speed of light in Earth’s atmosphere, and produce secondary particles that can be detected here on Earth. (SIMON SWORDY (U. CHICAGO), NASA)

    Supernova remnant Crab nebula. NASA/ESA Hubble


    Supernova remnant Crab nebula. NASA/ESA Hubble

    3
    The Tibet ABγ experiment is located at an altitude of 4300 m in Yangbajing, China. With an array of scintillation detectors and underwater water-Cherenkov detectors covering 65,700 m2, the experiment measures the secondary particles that are produced when a high-energy photon strikes the upper atmosphere. An artist’s depiction of such an air shower is shown in the image. Tibet ASγ Collaboration.

    Particle physics is everywhere, even in the palm of your hand.

    When you hold out your palm and point it towards the sky, what is it that’s interacting with your hand? You might correctly surmise that there are ions, electrons and molecules all colliding with your hand, as the atmosphere is simply unavoidable here on Earth. You might also remember that photons, or particles of light, must be striking you, too.

    But there’s something more striking your hand that, without relativity, simply wouldn’t be possible. Every second, approximately one muon — the unstable, heavy cousin of the electron — passes through your outstretched palm. These muons are made in the upper atmosphere, created by cosmic rays. With a mean lifetime of 2.2 microseconds, you might think the ~100+ km journey to your hand would be impossible. Yet relativity makes it so, and the palm of your hand can prove it. Here’s how.

    3
    While cosmic ray showers are common from high-energy particles, it’s mostly the muons which make it down to Earth’s surface, where they are detectable with the right setup. (ALBERTO IZQUIERDO; COURTESY OF FRANCISCO BARRADAS SOLAS)

    Individual, subatomic particles are almost always invisible to human eyes, as the wavelengths of light we can see are unaffected by particles passing through our bodies. But if you create a pure vapor made out of 100% alcohol, a charged particle passing through it will leave a trail that can be visually detected by even as primitive an instrument as the human eye.

    As a charged particle moves through the alcohol vapor, it ionizes a path of alcohol particles, which act as centers for the condensation of alcohol droplets. The trail that results is both long enough and long-lasting enough that human eyes can see it, and the speed and curvature of the trail (if you apply a magnetic field) can even tell you what type of particle it was.

    This principle was first applied in particle physics in the form of a cloud chamber.

    4
    A completed cloud chamber can be built in a day out of readily-available materials and for less than $100. You can use it to prove the validity of Einstein’s relativity, if you know what you’re doing! (INSTRUCTABLES USER EXPERIENCINGPHYSICS)

    Today, a cloud chamber can be built, by anyone with commonly available parts, for a day’s worth of labor and less than $100 in parts. (I’ve published a guide here.) If you put the mantle from a smoke detector inside the cloud chamber, you’ll see particles emanate from it in all directions and leave tracks in your cloud chamber.

    That’s because a smoke detector’s mantle contains radioactive elements such as Americium, which decays by emitting α-particles. In physics, α-particles are made up of two protons and two neutrons: they’re the same as a helium nucleus. With the low energies of the decay and the high mass of the α-particles, these particles make slow, curved tracks and can even be occasionally seen bouncing off of the cloud chamber’s bottom. It’s an easy test to see if your cloud chamber is working properly.

    5
    For an extra bonus of radioactive tracks, add the mantle of a smoke detector to the bottom of your cloud chamber, and watch the slow-moving particles emanating outward from it. Some will even bounce off the bottom! (NASA/GRC/BILL BOWLES)

    If you build a cloud chamber like this, however, those α-particle tracks aren’t the only things you’ll see. In fact, even if you leave the chamber completely evacuated (i.e., you don’t put a source of any type inside or nearby), you’ll still see tracks: they’ll be mostly vertical and appear to be perfectly straight.

    This is because of cosmic rays: high-energy particles that strike the top of Earth’s atmosphere, producing cascading particle showers. Most of the cosmic rays are made up of protons, but move with a wide variety of speeds and energies. The higher-energy particles will collide with particles in the upper atmosphere, producing particles like protons, electrons, and photons, but also unstable, short-lived particles like pions. These particle showers are a hallmark of fixed-target particle physics experiments, and they occur naturally from cosmic rays, too.

    6
    Although there are four major types of particles that can be detected in a cloud chamber, the long and straight tracks are the cosmic ray muons, which can be used to prove that special relativity is correct. (WIKIMEDIA COMMONS USER CLOUDYLABS)

    The thing about pions is that they come in three varieties: positively charged, neutral, and negatively charged. When you make a neutral pion, it just decays into two photons on very short (~10–16 s) timescales. But charged pions live longer (for around 10–8 s) and when they decay, they primarily decay into muons, which are point particles like electrons but have 206 times the mass.

    Muons also are unstable, but they’re the longest-lived unstable fundamental particle as far as we know. Owing to their relatively small mass, they live for an astoundingly long 2.2 microseconds, on average. If you were to ask how far a muon could travel once created, you might think to multiply its lifetime (2.2 microseconds) by the speed of light (300,000 km/s), getting an answer of 660 meters. But that leads to a puzzle.

    7
    Cosmic ray shower and some of the possible interactions. Note that if a charged pion (left) strikes a nucleus before it decays, it produces a shower, but if it decays first (right), it produces a muon that will reach the surface. (KONRAD BERNLÖHR OF THE MAX-PLANCK-INSTITUTE AT HEIDELBERG)

    I told you earlier that if you hold out the palm of your hand, roughly one muon per second passes through it. But if they can only live for 2.2 microseconds, they’re limited by the speed of light, and they’re created in the upper atmosphere (around 100 km up), how is it possible for those muons to reach us?

    You might start to think of excuses. You might imagine that some of the cosmic rays have enough energy to continue cascading and producing particle showers during their entire journey to the ground, but that’s not the story the muons tell when we measure their energies: the lowest ones are still created some 30 km up. You might imagine that the 2.2 microseconds is just an average, and maybe the rare muons that live for 3 or 4 times that long will make it down. But when you do the math, only 1-in-1050 muons would survive down to Earth; in reality, nearly 100% of the created muons arrive.

    8
    A light-clock, formed by a photon bouncing between two mirrors, will define time for any observer. Although the two observers may not agree with one another on how much time is passing, they will agree on the laws of physics and on the constants of the Universe, such as the speed of light. When relativity is applied correctly, their measurements will be found to be equivalent to one another, as the correct relativistic transformation will allow one observer to understand the observations of the other. (JOHN D. NORTON)

    How can we explain such a discrepancy? Sure, the muons are moving close to the speed of light, but we’re observing them from a reference frame where we’re stationary. We can measure the distance the muons travel, we can measure the time they live for, and even if we give them the benefit of the doubt and say that they’re moving at (rather than near) the speed of light, they shouldn’t even make it for 1 kilometer before decaying.

    But this misses one of the key points of relativity! Unstable particles don’t experience time as you, an external observer, measures it. They experience time according to their own onboard clocks, which will run slower the closer they move to the speed of light. Time dilates for them, which means that we will observe them living longer than 2.2 microseconds from our reference frame. The faster they move, the farther we’ll see them travel.

    9
    One revolutionary aspect of relativistic motion, put forth by Einstein but previously built up by Lorentz, Fitzgerald, and others, that rapidly moving objects appeared to contract in space and dilate in time. The faster you move relative to someone at rest, the greater your lengths appear to be contracted, while the more time appears to dilate for the outside world. This picture, of relativistic mechanics, replaced the old Newtonian view of classical mechanics, and can explain the lifetime of a cosmic ray muon. (CURT RENSHAW)

    How does this work out for the muon? From its reference frame, time passes normally, so it will only live for 2.2 microseconds according to its own clocks. But it will experience reality as though it hurtles towards Earth’s surface extremely close to the speed of light, causing lengths to contract in its direction of motion.

    If a muon moves at 99.999% the speed of light, every 660 meters outside of its reference frame will appear as though it’s just 3 meters in length. A journey of 100 km down to the surface would appear to be a journey of 450 meters in the muon’s reference frame, taking up just 1.5 microseconds of time according to the muon’s clock.

    10
    At high enough energies and velocities, relativity becomes important, allowing many more muons to survive than would without the effects of time dilation. (FRISCH/SMITH, AM. J. OF PHYS. 31 (5): 342–355 (1963) / WIKIMEDIA COMMONS USER D.H)

    This teaches us how to reconcile things for the muon: from our reference frame here on Earth, we see the muon travel 100 km in a timespan of about 4.5 milliseconds. This is just fine, because time is dilated for the muon and lengths are contracted for it: it sees itself as traveling 450 meters in 1.5 microseconds, and hence it can remain alive all the way down to its destination of Earth’s surface.

    Without the laws of relativity, this cannot be explained! But at high velocities, which correspond to high particle energies, the effects of time dilation and length contraction enable not just a few but mostof the created muons to survive. This is why, even all the way down here at the surface of the Earth, one muon per second still appears to pass through your upturned, outstretched hand.

    If you ever doubted relativity, it’s hard to fault you: the theory itself seems so counterintuitive, and its effects are thoroughly outside the realm of our everyday experience. But there is an experimental test you can perform right at home, cheaply and with just a single day’s efforts, that allow you see the effects for yourself.

    You can build a cloud chamber, and if you do, you will see those muons. If you installed a magnetic field, you’d see those muon tracks curve according to their charge-to-mass ratio: you’d immediately know they weren’t electrons. On rare occasion, you’d even see a muon decaying in mid-air. And, finally, if you measured their energies, you’d find that they were moving ultra-relativistically, at 99.999%+ the speed of light. If not for relativity, you wouldn’t see a single muon at all.

    Time dilation and length contraction are real, and the fact that muons survive, from cosmic ray showers all the way down to Earth, prove it beyond a shadow of a doubt.

    See the full article here .

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    “Starts With A Bang! is a blog/video blog about cosmology, physics, astronomy, and anything else I find interesting enough to write about. I am a firm believer that the highest good in life is learning, and the greatest evil is willful ignorance. The goal of everything on this site is to help inform you about our world, how we came to be here, and to understand how it all works. As I write these pages for you, I hope to not only explain to you what we know, think, and believe, but how we know it, and why we draw the conclusions we do. It is my hope that you find this interesting, informative, and accessible,” says Ethan

     
  • richardmitnick 4:01 pm on February 18, 2019 Permalink | Reply
    Tags: A new technique dubbed STeVE for “starting TeV events, A second technique called LESE for low-energy starting events, , , , Both of these techniques introduce a new online event selection filter that selects starting events based on an initial fast reconstruction, Cosmic Rays, , Gamma-ray emission, However gamma rays can also be produced in environments where neutrino emission would be disfavored, , Searches combining both techniques result in an effective area comparable to ANTARES which thanks to its location in the Mediterranean Sea has a priori a better neutrino view of our galaxy, STeVE and LESE where tested with 3 and 4 years of IceCube data respectively, The gamma-ray galactic sky shows a large concentration of sources in the Southern Hemisphere, The highest energy gamma rays could be produced in the same mechanisms that produce the highest energy neutrinos,   

    From U Wisconsin IceCube Collaboration: “Improving searches for galactic sources of high-energy neutrinos” 

    U Wisconsin ICECUBE neutrino detector at the South Pole

    18 Feb 2019
    Sílvia Bravo

    The search for sources of high-energy neutrinos and cosmic rays has revealed neutrinos from distant galaxies and from all over the sky traveling through the Antarctic ice. Closer sources, though, those that could produce neutrino emission in the Milky Way, have been more elusive.

    In IceCube, the signature of sources such as galactic supernova remnants peaks at low energies, well below 100 TeV, where the large background of atmospheric muons is difficult to filter out. The bulk of galactic neutrino emission is expected in the southern sky, where the Earth cannot serve as a natural filter to remove the million-to-one muon-neutrino signal. In a recent paper by the IceCube Collaboration, two new techniques improve searches at energies from 100 TeV down to 100 GeV. When tested with a few years of IceCube data, these new selections improve the sensitivity and discovery potential, allowing for the first time the search for galactic point-like sources using track events created by muon neutrinos that in many cases are indistinguishable from atmospheric muon tracks. These results have just been submitted to the journal Astroparticle Physics.

    1
    The differential discovery potential at −60° declination for LESE (light blue), STeVE (dark blue), the combined selection (LESE +STeVE) (red), a cascade point-source search (gray), a starting tracks search targeting higher energies (MESE) (gray dashed), throughgoing (light gray dashed), all with the IceCube detector, and of the ANTARES point-like source search (black). In this plot, all results are calculated for an equal three-year exposure. Image: IceCube Collaboration

    Scientists have speculated that at high energies neutrino emission should be associated with gamma-ray emission, since the highest energy gamma rays could be produced in the same mechanisms that produce the highest energy neutrinos. However, gamma rays can also be produced in environments where neutrino emission would be disfavored.

    The gamma-ray galactic sky shows a large concentration of sources in the Southern Hemisphere, where both the galactic center and the majority of the galactic plane are seen from Earth. This is, thus, a region worth exploring with IceCube to look for potential neutrino emission from the same sources that produce the gamma rays.

    However, the most successful searches for high-energy neutrinos select particle interactions that start in the detector—both cascade- and track-like events—or track-like events that come from the northern sky. Track-like events are those that provide a good pointing resolution, which on average is well below 1 degree.

    In previous searches for astrophysical neutrinos using events with the interaction vertex within the detector, a fairly high energy cut was also applied to obtain an efficient selection. The concern is that the majority of galactic neutrino emission could happen at lower energies and, thus, might be removed with this cut. To lower this energy threshold and still preserve a good pointing resolution in the southern sky, researchers have looked closer at track events in IceCube.

    In a new technique dubbed STeVE, for “starting TeV events,” the selection focuses on neutrino events between 10 and 100 TeV and uses techniques developed in a previous IceCube analysis (link to MESE news 414) to remove the background of multiple parallel atmospheric muon events, which has proved to be a resistant background at low energies. In addition, this event selection strategy exploits the difference in the observed photon pattern of bundles of low-energy atmospheric muons compared to individual high-energy muons.

    In a second technique, called LESE, for low-energy starting events, the selection was optimized for neutrinos below 10 TeV. At low energies and due to the small granularity of the IceCube detector, with strings of sensors deployed at horizontal distances of 125 meters, it’s easier for muon tracks to enter the detector without significant energy deposition detected by the outer layers of sensors, which mimics a muon neutrino interacting within the detector volume. LESE aims at selecting track-like events with energies as low as 100 GeV, leveraging the experience gained with veto-based selection techniques in searches for dark matter.

    Both of these techniques introduce a new online event selection filter that selects starting events based on an initial fast reconstruction. This new filter is the first to accept starting events from the entire southern sky while maintaining as large as possible active detector volume.

    STeVE and LESE where tested with 3 and 4 years of IceCube data, respectively, in a search for sources of astrophysical neutrinos anywhere in the southern sky and for neutrino emission from the direction of 96 known gamma-ray sources. No significant excess of neutrino emission was found, but the techniques have proven to be sensitive to strong galactic sources of low-energy astrophysical neutrinos.

    “Studying starting events from the southern sky at these energies poses many new challenges,” explains Rickard Ström, a main analyzer who worked on this study as a PhD candidate at Uppsala University. “We leveraged expertise from previous searches for point sources and exotic signatures such as dark matter. This was the first time IceCube was able to study point sources in the southern sky at these energies and using tracks with degree precision,” adds Ström.

    Searches combining both techniques result in an effective area comparable to ANTARES, which thanks to its location in the Mediterranean Sea has a priori a better neutrino view of our galaxy. STeVE and LESE selections reduce the muon background to a few thousand events per year and significantly improve IceCube’s sensitive and discovery potential of point-like sources in the southern sky with neutrinos with energies below 100 TeV.

    From From U Wisconsin IceCube Collaboration

    See the full article here .

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    IceCube is a particle detector at the South Pole that records the interactions of a nearly massless sub-atomic particle called the neutrino. IceCube searches for neutrinos from the most violent astrophysical sources: events like exploding stars, gamma ray bursts, and cataclysmic phenomena involving black holes and neutron stars. The IceCube telescope is a powerful tool to search for dark matter, and could reveal the new physical processes associated with the enigmatic origin of the highest energy particles in nature. In addition, exploring the background of neutrinos produced in the atmosphere, IceCube studies the neutrinos themselves; their energies far exceed those produced by accelerator beams. IceCube is the world’s largest neutrino detector, encompassing a cubic kilometer of ice.

    IceCube employs more than 5000 detectors lowered on 86 strings into almost 100 holes in the Antarctic ice NSF B. Gudbjartsson, IceCube Collaboration

    Lunar Icecube

    IceCube DeepCore annotated

    IceCube PINGU annotated


    DM-Ice II at IceCube annotated

     
  • richardmitnick 6:03 pm on December 17, 2018 Permalink | Reply
    Tags: Cosmic Rays, , ,   

    From U Wisconsin IceCube Collaboration: “IceCube and HAWC unite efforts to dissect the cosmic-ray anisotropy” 

    U Wisconsin ICECUBE neutrino detector at the South Pole

    IceCube employs more than 5000 detectors lowered on 86 strings into almost 100 holes in the Antarctic ice NSF B. Gudbjartsson, IceCube Collaboration

    Lunar Icecube

    IceCube DeepCore annotated

    IceCube PINGU annotated


    DM-Ice II at IceCube annotated

    From From U Wisconsin IceCube Collaboration

    17 Dec 2018
    Sílvia Bravo

    HAWC High Altitude Cherenkov Experiment, located on the flanks of the Sierra Negra volcano in the Mexican state of Puebla at an altitude of 4100 meters(13,500ft), at WikiMiniAtlas 18°59′41″N 97°18′30.6″W. searches for cosmic rays

    It was only a few years ago that IceCube provided the first view of the arrival direction distribution of cosmic rays in the Southern Hemisphere. Observations in the Northern Hemisphere, including those from the HAWC gamma-ray observatory earlier this year, had already shown that the number of cosmic rays hitting the atmosphere varied depending on their direction and energy. The anisotropy patterns found in the Southern Hemisphere supported models that pointed to the local interstellar magnetic field as the origin of the dominant effects of this observation.

    In an attempt to better understand the anisotropy, the IceCube Neutrino Observatory and HAWC have united their efforts to study cosmic-ray arrival directions in both hemispheres at the same primary energy. The goal of this combined observation was to get a nearly full-sky coverage to study the propagation of cosmic rays with median energy of 10 TeV through our local interstellar medium as well as the interactions between interstellar and heliospheric magnetic fields. Results have just been accepted for publication in The Astrophysical Journal and include measurements on how the anisotropy modulations are distributed over different angular scales.

    1
    he all-sky distribution in relative intensity of 10 TeV cosmic rays (CR) obtained with the HAWC and IceCube observation. Blue means deficit with respect to the mean CR flux and red excess. On the left, the white arrow indicates the direction of motion of the solar system through the local interstellar medium; the black lines indicate the local interstellar magnetic field lines outside of the heliosphere. On the right, the view of the opposite side of the sky.

    Cosmic rays swirling through space constantly bombard Earth from every direction. Out of every 1,000 cosmic rays there is at most one cosmic ray with a preferred (nonrandom) arrival direction. We refer to this as anisotropy, and this tiny 0.1% effect is what scientists would like to decipher.

    The variations are small but significant and show two different amplitude scales, a large-scale anisotropy with variations of one per mille and a small-scale anisotropy with variations of one per ten thousand.

    The cosmic-ray anisotropy is associated with the distribution of the cosmic ray sources and with the properties of the magnetic fields through which the cosmic rays propagate. However, the limited field of view of any ground-based experiment prevents us from capturing the anisotropy features that are wider than the observable sky.

    The angular variations of this anisotropy support the contribution of two different mechanisms: the mean propagation along the turbulent interstellar magnetic field, which is expected to isotropically diffuse cosmic rays, and the deflection in nearby magnetic fields—the local interstellar magnetic field (LIMF) and the heliosphere—whose relative contribution depends on energy.

    Ground-based experiments typically require averaging the number of cosmic rays along each declination band, to estimate its response to a perfectly isotropic flux. This has the effect of washing out the vertical (north-south) component of the anisotropy. On the other hand, the heliospheric deflections induced on the cosmic-ray particle distribution by the long interstellar propagation are partially aligned along the LIMF and not significantly affected by the north-south blindness.

    In this study, IceCube and HAWC joined efforts to get a full-sky coverage that captures for the first time a full, unbiased picture of the cosmic-ray anisotropy. The work used five years of IceCube data, from May 2011 to May 2016, and two years of HAWC data, from May 2015 and May 2017.

    The fit of the IceCube-HAWC observed anisotropy at 10 TeV shows the expected alignment with the LIMF. Researchers then used this deviation to derive the north-south component of the dipole anisotropy.

    Previous studies of the anisotropy have shown that the dominant dipole variation starts to decrease around 10 TeV and then to abruptly increase again at energies around 100 TeV. This had been explained as a possible effect of the heliosphere, which has a much larger impact for lower energy cosmic rays.

    Deviations of the anisotropy from the LIMF could be due to the motion of the observer and/or to the effects of the heliosphere on the LIMF. However, only a full-sky study of the cosmic-ray anisotropy at different energies will make it possible to distinguish between these or other possible effects, thus enabling a deeper understanding of the properties of the LIMF and the heliosphere.

    See the full article here .

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    Please help promote STEM in your local schools.

    Stem Education Coalition
    IceCube is a particle detector at the South Pole that records the interactions of a nearly massless sub-atomic particle called the neutrino. IceCube searches for neutrinos from the most violent astrophysical sources: events like exploding stars, gamma ray bursts, and cataclysmic phenomena involving black holes and neutron stars. The IceCube telescope is a powerful tool to search for dark matter, and could reveal the new physical processes associated with the enigmatic origin of the highest energy particles in nature. In addition, exploring the background of neutrinos produced in the atmosphere, IceCube studies the neutrinos themselves; their energies far exceed those produced by accelerator beams. IceCube is the world’s largest neutrino detector, encompassing a cubic kilometer of ice.

     
  • richardmitnick 10:29 am on October 25, 2018 Permalink | Reply
    Tags: , , Cosmic Rays, , NASA ANITA balloon, Similar to the light blue glow of Chernekov light emitted in water surrounding nuclear reactors, Something energetic has travelled through the planet – a phenomenon that is just not allowed within the Standard Model of particle physics, The Askaryan effect, UHECRs- ultra-high energy cosmogenic neutrinos   

    From University of Hawaii via COSMOS: ““Upside down” cosmic rays may be new particle” 

    U Hawaii

    From University of Hawaii

    COSMOS

    25 October 2018
    Alan Duffy

    1
    In the vastness of Antarctica, two subatomic particles are challenging the standard model. Credit: Joseph Van Os/Getty Images

    A handful of particles erupting from the ice of Antarctica may well be the first indication of a new particle of nature.

    Each and every second your body is struck by hundreds of cosmic rays, particles that are created from some of the most energetic events in the known universe, such as exploding stars or accreting blackholes.

    Cosmic rays, as the name suggests, are of cosmic origin and tend to strike the ground from space. Yet NASA’s Antarctic Impulsive Transient Antenna (ANITA) – an array of radio antennas dangling from a balloon 37 metres above the ground – has spotted particles emanating from the ground. This suggests that something energetic has travelled through the planet – a phenomenon that is just not allowed within the Standard Model of particle physics.

    NASA ANITA balloon to detect cosmic ray showers and will monitor 32 potential gaseous contaminants, including formaldehyde, ammonia and carbon monoxide,

    NASA ANITA balloon team

    NASA ANITA balloon carrries scientific instruments above will detect cosmic ray showers


    The intriguing findings are reported in the journal Physical Review Letters, by a team led by Peter Gorham from the University of Hawaii, in the US.

    ANITA’s a balloon circumnavigates Antarctica, detecting cosmic ray showers, in particular ultra-high energy cosmogenic neutrinos (UHECRs), as they collide with ice below.

    The system detects these collisions by the emission of radio waves from the burst of secondary particles generated as the neutrinos move in the ice more quickly than light.

    This process is known as the Askaryan effect, and is similar to the light blue glow of Chernekov light emitted in water surrounding nuclear reactors.

    In its first flight ANITA detected 16 such events, showing the power of this technique to detect the otherwise ghost-like neutrinos. The radio waves reflected back towards the balloon became horizontally polarised – in much the same way that light becomes horizontally polarised when it reflects off a puddle.

    Surprisingly, hidden in the first run of data, a single UHECR was detected from below the horizon from the ice, but without any polarisation from reflection. This was noted at the time, but the evidence wasn’t strong enough to rule out the particle being produced in the ice itself.

    In the third flight of ANITA another 20 UHECRs were detected – and again a single event was detected from the ice without the reflected polarisation.

    The two events now suggest that high energy particles have travelled all the way through the earth, creating a burst of Askaryan radio waves in the ice, like upside-down cosmic rays.

    While standard neutrinos are famously non-interacting, capable of flying through light years of solid lead, their high energy counterparts have a much greater cross-section, or chance, of collision. In fact, the UHECRs spotted by ANITA can’t possibly have travelled through the earth without collision, at least according to the Standard Model of particle physics.

    Possible solutions include interactions beyond the Standard Model, or even an entirely new particle, such as a sterile neutrino. More such detections are required to confirm any such claims but for now these tentative signals are exciting hints of a new era of physics.

    See the full article here .

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    System Overview

    The University of Hawai‘i System includes 10 campuses and dozens of educational, training and research centers across the Hawaiian Islands. As the public system of higher education in Hawai‘i, UH offers opportunities as unique and diverse as our Island home.

    The 10 UH campuses and educational centers on six Hawaiian Islands provide unique opportunities for both learning and recreation.

    UH is the State’s leading engine for economic growth and diversification, stimulating the local economy with jobs, research and skilled workers.

     
  • richardmitnick 8:23 am on October 17, 2018 Permalink | Reply
    Tags: , , , Cosmic Rays, , , Speed of Light, The CMB: the cosmic microwave background, The CNB: the cosmic neutrino background, The Universe Has A Speed Limit And It Isn’t The Speed Of Light, The WHIM: the warm-hot intergalactic medium   

    From Ethan Siegel: “The Universe Has A Speed Limit, And It Isn’t The Speed Of Light” 

    From Ethan Siegel

    Oct 16, 2018

    1
    All massless particles travel at the speed of light, including the photon, gluon and gravitational waves, which carry the electromagnetic, strong nuclear and gravitational interactions, respectively. Particles with mass must always travel at speeds below the speed of light, and there’s an even more restrictive cutoff in our Universe. (NASA/Sonoma State University/Aurore Simonnet)

    Nothing can go faster than the speed of light in a vacuum. But particles in our Universe can’t even go that fast.

    When it comes to speed limits, the ultimate one set by the laws of physics themselves is the speed of light. As Albert Einstein first realized, everyone looking at a light ray sees that it appears to move at the same speed, regardless of whether it’s moving towards you or away from you. No matter how fast you travel or in what direction, all light always moves at the same speed, and this is true for all observers at all times. Moreover, anything that’s made of matter can only approach, but never reach, the speed of light. If you don’t have mass, you must move at the speed of light; if you do have mass, you can never reach it.

    But practically, in our Universe, there’s an even more restrictive speed limit for matter, and it’s lower than the speed of light. Here’s the scientific story of the real cosmic speed limit.

    When scientists talk about the speed of light — 299,792,458 m/s — we implicitly mean “the speed of light in a vacuum.” Only in the absence of particles, fields, or a medium to travel through can we achieve this ultimate cosmic speed. Even at that, it’s only the truly massless particles and waves that can achieve this speed. This includes photons, gluons, and gravitational waves, but not anything else we know of.

    Quarks, leptons, neutrinos, and even the hypothesized dark matter all have masses as a property inherent to them. Objects made out of these particles, like protons, atoms, and human beings all have mass, too. As a result, they can approach, but never reach, the speed of light in a vacuum. No matter how much energy you put into them, the speed of light, even in a vacuum, will forever be unattainable.

    But there’s no such thing, practically, as a perfect vacuum. Even in the deepest abyss of intergalactic space, there are three things you absolutely cannot get rid of.

    The WHIM: the warm-hot intergalactic medium. This tenuous, sparse plasma are the leftovers from the cosmic web. While matter clumps into stars, galaxies, and larger groupings, a fraction of that matter remains in the great voids of the Universe. Starlight ionizes it, creating a plasma that may make up about 50% of the total normal matter in the Universe.

    WHIM-Warm-Hot Intergalactic Medium Trevor Ponman U Birmingham


    The CMB: the cosmic microwave background. This leftover bath of photons originates from the Big Bang, where it was at extremely high energies. Even today, at temperatures just 2.7 degrees above absolute zero, there are over 400 CMB photons per cubic centimeter of space.

    CMB per ESA/Planck


    ESA/Planck 2009 to 2013

    The CNB: the cosmic neutrino background. The Big Bang, in addition to photons, creates a bath of neutrinos. Outnumbering protons by perhaps a billion to one, many of these now-slow-moving particles fall into galaxies and clusters, but many remain in intergalactic space as well.

    CNB- the cosmic neutrino background-Amand Faessler U Tuebingen

    3
    A multiwavelength view of the galactic center shows stars, gas, radiation and black holes, among other sources. But the light coming from all of these sources, from gamma rays to visible to radio light, can only indicate what our instruments are sensitive enough to detect from 25,000+ light years away. (NASA/ESA/SSC/CXC/STScI)

    Any particle traveling through the Universe will encounter particles from the WHIM, neutrinos from the CNB, and photons from the CMB. Even though they’re the lowest-energy things, the CMB photons are the most numerous and evenly-distributed particles of all. No matter how you’re generated or how much energy you have, it’s not really possible to avoid interacting with this 13.8 billion year old radiation.

    When we think about the highest-energy particles in the Universe — i.e., the ones that will be moving the fastest — we fully expect they’ll be generated under the most extreme conditions the Universe has to offer. That means we think we’ll find them where energies are highest and fields are strongest: in the vicinity of collapsed objects like neutron stars and black holes.

    4
    In this artistic rendering, a blazar is accelerating protons that produce pions, which produce neutrinos and gamma rays. (IceCube/NASA)

    U Wisconsin IceCube experiment at the South Pole



    Neutron stars and black hole are where you can not only find the strongest gravitational fields in the Universe, but — in theory — the strongest electromagnetic fields, too. The extremely strong fields are generated by charged particles, either on the surface of a neutron star or in the accretion disk around a black hole, that move close to the speed of light. Moving charged particles generate magnetic fields, and as particles move through these fields, they accelerate.

    This acceleration causes not only the emission of light of a myriad of wavelengths, from X-rays down to radio waves, but also the fastest, highest-energy particles ever seen: cosmic rays.

    Cosmic rays produced by high-energy astrophysics sources (ASPERA collaboration – AStroParticle ERAnet)

    Artist’s impression of the active galactic nucleus (DESY, Science Communication Lab)

    Whereas the Large Hadron Collider accelerates particles here on Earth up to a maximum velocity of 299,792,455 m/s, or 99.999999% the speed of light, cosmic rays can smash that barrier. The highest-energy cosmic rays have approximately 36 million times the energy of the fastest protons ever created at the Large Hadron Collider. Assuming that these cosmic rays are also made of protons gives a speed of 299,792,457.99999999999992 m/s, which is extremely close to, but still below, the speed of light in a vacuum.

    There’s a very good reason that, by time we receive them, these cosmic rays aren’t more energetic than this.

    The problem is that space isn’t a vacuum. In particular, the CMB will have its photons collide and interact with these particles as they travel through the Universe. No matter how high the energy is of the particle you made, it has to pass through the radiation bath that’s left over from the Big Bang in order to reach you.

    Even though this radiation is incredibly cold, at an average temperature of some 2.725 Kelvin, the mean energy of each photon in there isn’t negligible; it’s around 0.00023 electron-Volts. Even though that’s a tiny number, the cosmic rays hitting it can be incredibly energetic. Every time a high-energy charged particle interacts with a photon, it has the same possibility that all interacting particles have: if it’s energetically allowed, by E=mc², then there’s a chance it can create a new particle!

    5
    Whenever two particles collide at high enough energies, they have the opportunity to produce additional particle-antiparticle pairs, or new particles as the laws of quantum physics allow. Einstein’s E = mc² is indiscriminate this way. (E. Siegel / Beyond The Galaxy)

    If you ever create a particle with energies in excess of 5 × 10¹⁹ eV, they can only travel a few million light years — max — before one of these photons, left over from the Big Bang, interacts with it. When that interaction occurs, there will be enough energy to produce a neutral pion, which steals energy away from the original cosmic ray.

    The more energetic your particle is, the more likely you are to produce pions, which you’ll continue to do until you fall below this theoretical cosmic energy limit, known as the GZK cutoff. (Named for three physicists: Greisen, Zatsepin, and Kuzmin.) There’s even more braking (Bremsstrahlung) radiation that arises from interactions with any particles in the interstellar/intergalactic medium. Even lower-energy particles are subject to it, and radiate energy away in droves as electron/positron pairs (and other particles) are produced.

    We believe that every charged particle in the cosmos — every cosmic ray, every proton, every atomic nucleus — should limited by this speed. Not just the speed of light, but a little bit lower, thanks to the leftover glow from the Big Bang and the particles in the intergalactic medium. If we see anything that’s at a higher energy, then it either means:

    1.particles at high energies might be playing by different rules than the ones we presently think they do,
    2.they are being produced much closer than we think they are: within our own Local Group or Milky Way, rather than these distant, extragalactic black holes,
    3.or they’re not protons at all, but composite nuclei.

    The few particles we’ve seen that break the GZK barrier are indeed in excess of 5 × 10¹⁹ eV, in terms of energy, but do not exceed 3 × 10²¹ eV, which would be the corresponding energy value for an iron nucleus. Since many of the highest-energy cosmic rays have been confirmed to be heavy nuclei, rather than individual protons, this reigns as the most likely explanation for the extreme ultra-high-energy cosmic rays.

    6
    The spectrum of cosmic rays. As we go to higher and higher energies, we find fewer and fewer cosmic rays. We expected a complete cutoff at 5 x 10¹⁹ eV, but see particles coming in with up to 10 times that energy. (Hillas 2006 / University of Hamburg)

    There is a speed limit to the particles that travel through the Universe, and it isn’t the speed of light. Instead, it’s a value that’s very slightly lower, dictated by the amount of energy in the leftover glow from the Big Bang. As the Universe continues to expand and cool, that speed limit will slowly rise over cosmic timescales, getting ever-closer to the speed of light. But remember, as you travel through the Universe, if you go too fast, even the radiation left over from the Big Bang can fry you. So long as you’re made of matter, there’s a cosmic speed limit that you simply cannot overcome.

    See the full article here .

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    Please help promote STEM in your local schools.

    Stem Education Coalition

    “Starts With A Bang! is a blog/video blog about cosmology, physics, astronomy, and anything else I find interesting enough to write about. I am a firm believer that the highest good in life is learning, and the greatest evil is willful ignorance. The goal of everything on this site is to help inform you about our world, how we came to be here, and to understand how it all works. As I write these pages for you, I hope to not only explain to you what we know, think, and believe, but how we know it, and why we draw the conclusions we do. It is my hope that you find this interesting, informative, and accessible,” says Ethan

     
  • richardmitnick 10:42 pm on October 2, 2018 Permalink | Reply
    Tags: , Cosmic Rays, , , , , ,   

    From SLAC National Accelerator Lab: “Peering into 36-million-degree plasma with SLAC’s X-ray laser” 

    From SLAC National Accelerator Lab

    October 2, 2018
    Ali Sundermier
    For commnication
    communications@slac.stanford.edu

    1
    At the Matter in Extreme Conditions (MEC) instrument at LCLS, the researchers zapped knuckle-shaped samples with a laser to create plasma, then used an X-ray scattering technique to watch it expand and collide. (Matt Beardsley/SLAC National Accelerator Laboratory)

    When you hit a piece of metal with a strong enough laser pulse you get a plasma – a hot, ionized gas found in everything from lightning to the sun. Studying it helps scientists understand what’s going on inside stars and could enable new types of particle accelerators for cancer treatment.

    Now a team of researchers has used an X-ray laser to measure, for the first time, how a plasma created by a laser blast expands in the hundreds of femtoseconds (quadrillionths of a second) after it’s created. Their technique could eventually reveal tiny instabilities in the plasma that swirl like cream in a cup of coffee.

    The experiments at the Department of Energy’s SLAC National Accelerator Laboratory involved scientists from SLAC, German research center Helmholtz-Zentrum Dresden-Rossendorf (HZDR) and other institutions, and was reported in Physical Review X in September.

    Blasting cancer cells

    Led by scientist Thomas Kluge at HZDR, the researchers have been working to harness the behavior of plasma to create a new type of particle accelerator for proton therapy, an existing cancer treatment that involves blasting tumors with charged particles rather than X-rays. This approach is gentler on the surrounding healthy tissue than traditional radiation therapy.

    When solid matter is zapped with a laser the interaction forms a plasma, causing a steady stream of protons to burst out of the back side of the sample. The researchers hope to use the proton streams to storm tumors and obliterate cancer cells. But producing these fast protons in a reliable way requires a better understanding of how plasma changes as it expands.

    “Instabilities can arise from the complex streams of electrons and ions moving back and forth in the plasma,” Kluge says. “You probably know one of these instabilities from the mushroom-shaped clouds that form when you drip milk into your morning coffee.”

    Hotter than ever

    Until now, it was difficult to probe plasma changes directly because they’re so tiny and happen on extremely fast time scales. This work, says Josefine Metzkes-Ng, co-author and junior group leader at HZDR, could only be done at SLAC where the researchers used a high-power, short-pulse optical laser beam to create the plasma and the Linac Coherent Light Source X-ray free-electron laser to probe it.

    SLAC/LCLS

    At the Matter in Extreme Conditions (MEC) instrument at LCLS, researchers create incredibly hot and dense matter that mimics the extreme conditions in the hearts of stars and planets. Simulations show that the researchers achieved a new temperature record for matter studied with a free-electron laser: 36 million degrees Fahrenheit, almost 10 million degrees hotter than the sun’s core.

    The researchers fabricated solid samples that consisted of raised silicon bars, like knuckles sticking out from a fist. They found that in the quadrillionths of seconds after they zapped the sample with intense, short pulses from the optical laser, tiny amounts of plasma stacked up between the knuckles. A special form of scattering that uses X-ray pulses from LCLS allowed them to peer inside the plasma to follow its evolution.

    This technique will pave the way for better understanding plasma instabilities, allowing researchers to create proton sources for cancer therapy with relatively small footprints that, unlike conventional accelerators, can be operated within a hospital. It will also be useful in research relevant to fusion energy, other types of novel particle accelerators and laboratory astrophysics.

    Speedy cosmic particles

    Siegfried Glenzer, director of the High Energy Density Division at SLAC, who helped with the paper, is especially excited about the prospect of using this technique to better understand the astrophysical processes that give cosmic rays – subatomic space particles that plunge into Earth’s atmosphere at almost the speed of light – their extreme energies.

    The highest-energy cosmic rays can pack a force comparable to that of a major league fastball hurtling toward a batter at 100 mph, condensed into a single subatomic particle. To accelerate a proton to the same energies as these cosmic rays, scientists would have to build an accelerator that sends particles traveling from Earth to Saturn and back.

    Using LCLS, scientists are able to recreate some of the astrophysical processes that may produce these high-energy cosmic rays, such as energetic jets that shoot out from the turbulent hearts of active galaxies. Now the new technique will allow them to directly observe the plasma instabilities that might be responsible for accelerating cosmic rays.

    “Cosmic rays are the largest particle accelerators known to mankind,” Glenzer says. “They have a million times higher energy than particles accelerated in the Large Hadron Collider. Recently, astronomers traced a cosmic ray particle to an active galactic nucleus jet. Our goal is to produce these types of jets in the laboratory so we can study the formation of these instabilities and show whether they can accelerate particles to such high energies and, if so, how it happens.”

    Flipping the light switch

    According to Kluge, “This research has opened the black box of how short-pulse lasers interact with solids, allowing us to directly see a little of what’s going on, which previously could only be simulated with largely unverified atomic models.

    “It’s a little like switching on a light,” he says. “Although we have some ideas, we don’t know what we will find, but surely it will help us develop the next generation of laser-based ion accelerators and could shape new applications in astrophysics, medicine and plasma physics. For me as a theorist and simulation guy, the most exciting thing about this project is that I can now lay my simulations aside and look at the real thing.”

    The research team also included scientists from Technical University Dresden, European XFEL, University of Siegen, Friedrich Schiller University Jena and Leibniz Institute of Photonic Technology, all in Germany.

    LCLS is a DOE Office of Science user facility. Funding was provided by the DOE Office of Science.

    See the full article here .


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    SLAC Campus
    SLAC is a multi-program laboratory exploring frontier questions in photon science, astrophysics, particle physics and accelerator research. Located in Menlo Park, California, SLAC is operated by Stanford University for the DOE’s Office of Science.

     
  • richardmitnick 8:21 am on August 26, 2018 Permalink | Reply
    Tags: Cosmic Rays, , , One photon emitted during the solar minimum had an energy as high as 467.7 GeV, , , Strange gamma rays from the sun may help decipher its magnetic fields, The high-energy light is more plentiful and weirder than anyone expected   

    From Science News: “Strange gamma rays from the sun may help decipher its magnetic fields” 

    From Science News

    August 24, 2018
    Lisa Grossman

    The high-energy light is more plentiful and weirder than anyone expected.

    1
    A TANGLED SKEIN The sun’s knotted magnetic fields, visualized here as white lines, scramble cosmic rays and may cause them to shoot energetic light called high-energy gamma rays toward Earth. Solar Dynamics Observatory/GSFC/NASA

    NASA/SDO

    The sleepy sun turns out to be a factory of extremely energetic light.

    Scientists have discovered that the sun puts out more of this light, called high-energy gamma rays, overall than predicted. But what’s really weird is that the rays with the highest energies appear when the star is supposed to be at its most sluggish, researchers report in an upcoming study in Physical Review Letters. The research is the first to examine these gamma rays over most of the solar cycle, a roughly 11-year period of waxing and waning solar activity.

    That newfound oddity is probably connected to the activity of the sun’s magnetic fields, the researchers say, and could lead to new insights about the mysterious environment.

    “The almost certain thing that’s going on here is the magnetic fields are much more powerful, much more variable, and much more weirdly shaped than we expect,” says astrophysicist John Beacom of the Ohio State University in Columbus.

    The sun’s high-energy gamma rays aren’t produced directly by the star. Instead, the light is triggered by cosmic rays — protons that zip through space with some of the highest energies known in nature — that smack into solar protons and produce high-energy gamma rays in the process (SN: 10/14/27, p. 7).

    All of those gamma rays would get lost inside the sun, if not for magnetic fields. Magnetic fields are known to take charged particles like cosmic rays and spin them around like a house in a tornado. Theorists have predicted that cosmic rays whose paths have been scrambled by the tangled mass of magnetic fields at the solar surface should send high-energy gamma rays shooting back out of the sun, where astronomers can see them.

    Beacom and colleagues, led by astrophysicist Tim Linden of Ohio State, sifted through data from NASA’s Fermi Gamma-ray Space Telescope from August 2008 to November 2017.

    NASA/Fermi LAT


    NASA/Fermi Gamma Ray Space Telescope

    The observations spanned a period of low solar activity in 2008 and 2009, a period of higher activity in 2013 and a decline in activity to the minimum of the next cycle, which started in 2018 (SN: 11/2/13, p. 22). The team tracked the number of solar gamma rays emitted per second, as well as their energies and where on the sun they came from.

    There were more high-energy gamma rays, above 50 billion electron volts, or GeV, than anyone predicted, the team reports. Weirder still, rays with energies above 100 GeV appeared only during the solar minimum, when the sun’s activity level was low. One photon emitted during the solar minimum had an energy as high as 467.7 GeV.

    Strangest of all, the sun seems to emit gamma rays from different parts of its surface at different times in its cycle. Because cosmic rays that hit the sun come in from all directions, you would expect the entire sun to light up in gamma rays uniformly. But Beacom’s team found that during the solar minimum, gamma rays came mainly from near the equator, and during the solar maximum, when the sun’s activity level was high, they clustered near the poles.

    “All of these things are way more weird than anyone had predicted,” Beacom says. “And that means the magnetic fields must be way more weird than anyone had thought.”
    ____________________________________________________
    The missing middle

    These plots show that the sun shot light called high-energy gamma rays from its middle during a period of low solar activity (from about August 2008 to the end of 2009, left), but not during a period of high activity (from 2010 until 2017, right). The gamma rays seem to migrate from the equator to the poles after 2010. Rays with less than 100 billion electron volts, or GeV, of energy are depicted as circles; those with 100 GeV or more are triangles. The bar graphs represent the number of gamma rays that came from different latitudes.

    3
    T. Linden et al/Physical Review Letters 2018
    ____________________________________________________

    Beacom and colleagues tried to connect the excess gamma rays to other solar behaviors that change with magnetic activity, like solar flares or sunspots (SN: 9/30/17, p. 6). “So far nothing has really held up to any sort of scrutiny,” says astrophysicist Annika Peter, also at Ohio State.

    High-energy gamma rays may offer a new way to probe the magnetic fields in the uppermost layer of the solar surface, called the photosphere. “You can’t see [the fields] with a telescope,” Beacom says. “But these [cosmic rays] are journeying there, and the gamma rays they send back are messengers of the terrible conditions there.”

    More observations are coming soon. NASA’s Parker Solar Probe, which launched on August 12, will take the first direct measurements of the magnetic field in the sun’s outer atmosphere, or corona (SN: 7/21/18, p. 12).

    154f8-sol_parkersolarprobe2_nasa


    NASA Parker Solar Probe Plus

    And as the sun enters the next solar minimum, the highest-energy gamma rays are starting to return. In February, Fermi caught its first gamma ray with an energy above 100 GeV since 2009.

    “There really is something strange afoot,” says solar physicist Craig DeForest of the Southwest Research Institute, who is based in Boulder, Colo., and was not involved in the work. “When there’s some new discovery, scientists don’t shout ‘Eureka!’ They go, ‘Hm, that’s funny. That can’t be right.’ This is a classic case of that.”

    See the full article here .


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    Please help promote STEM in your local schools.

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  • richardmitnick 1:13 pm on July 14, 2018 Permalink | Reply
    Tags: , Cosmic Rays, , ,   

    From U Hawaii via Eureka Alert: Late to the Party, but “Hawaii telescopes help unravel long-standing cosmic mystery” 

    U Hawaii

    From University of Hawaii Manoa

    via

    EurekAlert!

    12-Jul-2018

    Astronomers and physicists around the world, including in Hawaii, have begun to unravel a long-standing cosmic mystery. Using a vast array of telescopes in space and on Earth, they have identified a source of cosmic rays.

    Artist’s impression of a blazar emitting neutrinos and gamma rays via IceCube and NASA

    Blazar. NASA Fermi Gamma ray Space Telescope. Credits M. Weiss/ CfA

    NASA/Fermi LAT

    NASA/Fermi Gamma Ray Space Telescope

    Astronomers and physicists around the world, including in Hawaii, have begun to unravel a long-standing cosmic mystery. Using a vast array of telescopes in space and on Earth, they have identified a source of cosmic rays–highly energetic particles that continuously rain down on Earth from space.

    In a paper published this week in the journal Science, scientists have, for the first time, provided evidence for a known blazar, designated TXS 0506+056, as a source of high-energy neutrinos. At 8:54 p.m. on September 22, 2017, the National Science Foundation-supported IceCube neutrino observatory at the South Pole detected a high energy neutrino from a direction near the constellation Orion. Just 44 seconds later an alert went out to the entire astronomical community.

    U Wisconsin ICECUBE neutrino detector at the South Pole

    IceCube employs more than 5000 detectors lowered on 86 strings into almost 100 holes in the Antarctic ice NSF B. Gudbjartsson, IceCube Collaboration

    Lunar Icecube

    IceCube DeepCore annotated

    IceCube PINGU annotated


    DM-Ice II at IceCube annotated

    The All Sky Automated Survey for SuperNovae team (ASAS-SN), an international collaboration headquartered at Ohio State University, immediately jumped into action. ASAS-SN uses a network of 20 small, 14-centimeter telescopes in Hawaii, Texas, Chile and South Africa to scan the visible sky every 20 hours looking for very bright supernovae. It is the only all-sky, real-time variability survey in existence.

    ASAS-SN Brutus at lcogt site Hawaii

    LCOGT Las Cumbres Observatory Global Telescope Network, Haleakala Hawaii, USA, Elevation 10,023 ft (3,055 m)

    “When ASAS-SN receives an alert from IceCube, we automatically find the first available ASAS-SN telescope that can see that area of the sky and observe it as quickly as possible,” said Benjamin Shappee, an astronomer at the University of Hawaii’s Institute for Astronomy and an ASAS-SN core member.

    On September 23, only 13 hours after the initial alert, the recently commissioned ASAS-SN unit at McDonald Observatory in Texas [image of exas unit N/A] mapped the sky in the area of the neutrino detection. Those observations and the more than 800 images of the same part of the sky taken since October 2012 by the first ASAS-SN unit, located on Maui’s Haleakala, showed that TXS 0506+056 had entered its highest state since 2012.

    “The IceCube detection and the ASAS-SN detection combined with gamma-ray detections from NASA’s Fermi gamma-ray space telescope and the MAGIC telescopes that show TXS 0506+056 was undergoing the strongest gamma-ray flare in a decade, indicate that this could be the first identified source of high-energy neutrinos, and thus a cosmic-ray source,” said Anna Franckowiak, ASAS-SN and IceCube team member, Helmholtz Young Investigator, and staff scientist at DESY in Germany.

    MAGIC Cherenkov telescope array at the Roque de los Muchachos Observatory on the island of La Palma, in the Canaries, Spain, sited on a volcanic peak 2,267 metres (7,438 ft) above sea level

    Since they were first detected more than one hundred years ago, cosmic rays have posed an enduring mystery: What creates and launches these particles across such vast distances? Where do they come from?

    One of the best suspects have been quasars, supermassive black holes at the centers of galaxies that are actively consuming gas and dust.

    Quasar. ESO/M. Kornmesser

    Quasars are among the most energetic phenomena in the universe and can form relativistic jets where elementary particles are accelerate and launched at nearly the speed of light. If that jet happens to be pointed toward Earth, the light from the jet outshines all other emission from the host galaxy and the highly accelerated particles are launched toward the Milky Way. This specific type of quasar is called a blazar [above].

    However, because cosmic rays are charged particles, their paths cannot be traced directly back to their places of origin. Due to the powerful magnetic fields that fill space, they don’t travel along a straight path. Luckily, the powerful cosmic accelerators that produce them also emit neutrinos, which are uncharged and unaffected by even the most powerful magnetic fields. Because they rarely interact with matter and have almost no mass, these “ghost particles” travel nearly undisturbed from their cosmic accelerators, giving scientists an almost direct pointer to their source.

    “Crucially, the presence of neutrinos also differentiates between two types of gamma-ray sources: those that accelerate only cosmic-ray electrons, which do not produce neutrinos, and those that accelerate cosmic-ray protons, which do,” said John Beacom, an astrophysicist at the Ohio State University and an ASAS-SN member.

    Detecting the highest energy neutrinos requires a massive particle detector, and the National Science Foundation-supported IceCube observatory [above] is the world’s largest. The detector is composed of more than 5,000 light sensors arranged in a grid, buried in a cubic kilometer of deep, pristine ice a mile beneath the surface at the South Pole. When a neutrino interacts with an atomic nucleus, it creates a secondary charged particle, which, in turn, produces a characteristic cone of blue light that is detected by IceCube’s grid of photomultiplier tubes. Because the charged particle and the light it creates stay essentially true to the neutrino’s original direction, they give scientists a path to follow back to the source.

    About 20 observatories on Earth and in space have also participated in this discovery. This includes the 8.4-meter Subaru Telescope on Maunakea, which was used to observe the host galaxy of TXS 0506+056 in an attempt to measure its distance, and thus determine the intrinsic luminosity, or energy output, of the blazar.


    NAOJ/Subaru Telescope at Mauna Kea Hawaii, USA,4,207 m (13,802 ft) above sea level

    These observations are difficult, because the blazar jet is much brighter than the host galaxy. Disentangling the jet and the host requires the largest telescopes in the world, like those on Maunakea.

    “This discovery demonstrates how the many different telescopes and detectors around and above the world can come together to tell us something amazing about our Universe. This also emphasizes the critical role that telescopes in Hawaii play in that community,” said Shappee.

    See the full article here .


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    Please help promote STEM in your local schools.

    Stem Education Coalition

    System Overview

    The University of Hawai‘i System includes 10 campuses and dozens of educational, training and research centers across the Hawaiian Islands. As the public system of higher education in Hawai‘i, UH offers opportunities as unique and diverse as our Island home.

    The 10 UH campuses and educational centers on six Hawaiian Islands provide unique opportunities for both learning and recreation.

    UH is the State’s leading engine for economic growth and diversification, stimulating the local economy with jobs, research and skilled workers.

     
  • richardmitnick 5:34 pm on December 10, 2017 Permalink | Reply
    Tags: , , , Cosmic Rays, , , , , NASA's SuperTIGER Balloon Flies Again to Study Heavy Cosmic Particles, ,   

    From Goddard: “NASA’s SuperTIGER Balloon Flies Again to Study Heavy Cosmic Particles” 

    NASA Goddard Banner
    NASA Goddard Space Flight Center

    Dec. 6, 2017
    Francis Reddy
    francis.j.reddy@nasa.gov
    NASA’s Goddard Space Flight Center, Greenbelt, Md.

    A science team in Antarctica is preparing to loft a balloon-borne instrument to collect information on cosmic rays, high-energy particles from beyond the solar system that enter Earth’s atmosphere every moment of every day. The instrument, called the Super Trans-Iron Galactic Element Recorder (SuperTIGER), is designed to study rare heavy nuclei, which hold clues about where and how cosmic rays attain speeds up to nearly the speed of light.

    1
    NASA’s Super-TIGER balloon

    The launch is expected by Dec. 10, weather permitting.

    1
    Explore this infographic [on the full article] to learn more about SuperTIGER, cosmic rays and scientific ballooning.
    Credits: NASA’s Goddard Space Flight Center

    Download infographic as PDF

    “The previous flight of SuperTIGER lasted 55 days, setting a record for the longest flight of any heavy-lift scientific balloon,” said Robert Binns, the principal investigator at Washington University in St. Louis, which leads the mission. “The time aloft translated into a long exposure, which is important because the particles we’re after make up only a tiny fraction of cosmic rays.”

    The most common cosmic ray particles are protons or hydrogen nuclei, making up roughly 90 percent, followed by helium nuclei (8 percent) and electrons (1 percent). The remainder contains the nuclei of other elements, with dwindling numbers of heavy nuclei as their mass rises. With SuperTIGER, researchers are looking for the rarest of the rare — so-called ultra-heavy cosmic ray nuclei beyond iron, from cobalt to barium.

    “Heavy elements, like the gold in your jewelry, are produced through special processes in stars, and SuperTIGER aims to help us understand how and where this happens,” said lead co-investigator John Mitchell at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “We’re all stardust, but figuring out where and how this stardust is made helps us better understand our galaxy and our place in it.”

    When a cosmic ray strikes the nucleus of a molecule of atmospheric gas, both explode in a shower of subatomic shrapnel that triggers a cascade of particle collisions. Some of these secondary particles reach detectors on the ground, providing information scientists can use to infer the properties of the original cosmic ray. But they also produce an interfering background that is greatly reduced by flying instruments on scientific balloons, which reach altitudes of nearly 130,000 feet (40,000 meters) and float above 99.5 percent of the atmosphere.

    The most massive stars forge elements up to iron in their cores and then explode as supernovas, dispersing the material into space. The explosions also create conditions that result in a brief, intense flood of subatomic particles called neutrons. Many of these neutrons can “stick” to iron nuclei. Some of them subsequently decay into protons, producing new elements heavier than iron.

    Supernova blast waves provide the boost that turns these particles into high-energy cosmic rays.

    4
    NASA’s Fermi Proves Supernova Remnants Produce Cosmic Rays. February 14, 2013.

    NASA/Fermi Telescope


    NASA/Fermi LAT


    As a shock wave expands into space, it entraps and accelerates particles until they reach energies so extreme they can no longer be contained.

    4
    On Dec. 1, SuperTIGER was brought onto the deck of Payload Building 2 at McMurdo Station, Antarctica, to test communications in preparation for its second flight. Mount Erebus, the southernmost active volcano on Earth, appears in the background.
    Credits: NASA/Jason Link

    Over the past two decades, evidence accumulated from detectors on NASA’s Advanced Composition Explorer satellite and SuperTIGER’s predecessor, the balloon-borne TIGER instrument, has allowed scientists to work out a general picture of cosmic ray sources. Roughly 20 percent of cosmic rays were thought to arise from massive stars and supernova debris, while 80 percent came from interstellar dust and gas with chemical quantities similar to what’s found in the solar system.

    “Within the last few years, it has become apparent that some or all of the very neutron-rich elements heavier than iron may be produced by neutron star mergers instead of supernovas,” said co-investigator Jason Link at Goddard.

    Neutron stars are the densest objects scientists can study directly, the crushed cores of massive stars that exploded as supernovas. Neutron stars orbiting each other in binary systems emit gravitational waves, which are ripples in space-time predicted by Einstein’s general theory of relativity. These waves remove orbital energy, causing the stars to draw ever closer until they eventually crash together and merge.

    Theorists calculated that these events would be so thick with neutrons they could be responsible for most of the very neutron-rich cosmic rays heavier than nickel. On Aug. 17, NASA’s Fermi Gamma-ray Space Telescope and the National Science Foundation’s Laser Interferometer Gravitational-wave Observatory detected the first light and gravitational waves from crashing neutron stars. Later observations by the Hubble and Spitzer space telescopes indicate that large amounts of heavy elements were formed in the event.

    “It’s possible neutron star mergers are the dominant source of heavy, neutron-rich cosmic rays, but different theoretical models produce different quantities of elements and their isotopes,” Binns said. “The only way to choose between them is to measure what’s really out there, and that’s what we’ll be doing with SuperTIGER.”

    SuperTIGER is funded by the NASA Headquarters Science Mission Directorate Astrophysics Division.

    The National Science Foundation (NSF) Office of Polar Programs manages the U.S. Antarctic Program and provides logistic support for all U.S. scientific operations in Antarctica. NSF’s Antarctic support contractor supports the launch and recovery operations for NASA’s Balloon Program in Antarctica. Mission data were downloaded using NASA’s Tracking and Data Relay Satellite System.

    For more information about NASA’s Balloon Program, visit:

    http://www.nasa.gov/balloons

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    NASA’s Goddard Space Flight Center is home to the nation’s largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe.

    Named for American rocketry pioneer Dr. Robert H. Goddard, the center was established in 1959 as NASA’s first space flight complex. Goddard and its several facilities are critical in carrying out NASA’s missions of space exploration and scientific discovery.


    NASA/Goddard Campus

     
  • richardmitnick 11:55 am on November 3, 2017 Permalink | Reply
    Tags: , , Because it is inaccessible it probably isn’t a burial chamber, Cosmic Rays, Cosmic rays reveal unknown void in the Great Pyramid of Giza, Every minute tens of thousands of muons pass through each square meter of Earth, Great Pyramid of Giza, he particles are much like electrons but 207 times as massive, he scientists have “seen” the void using three different muon detectors in three independent experiments, , Such a big void can’t be an accident   

    From Science: “Cosmic rays reveal unknown void in the Great Pyramid of Giza” 

    ScienceMag
    Science Magazine

    Nov. 2, 2017 [I kept ignoring this story because I had only found it in lesser providers. Science Mag is a trustworthy source.]
    Giorgia Guglielmi

    1
    Artist’s rendering of a cross-section of the Great Pyramid showing the newly discovered void (represented as a white area) above the large inclined corridor known as grand gallery. ScanPyramids mission

    Some 4500 years ago, the ancient Egyptians built the Great Pyramid of Giza as a tomb for the pharaoh Khufu, also known as Cheops, one that would ferry him to the afterlife. Now, using subatomic particles raining down from the heavens, a team of physicists has found a previously unknown cavity within Khufu’s great monument.

    “Such a big void can’t be an accident,” says Mehdi Tayoubi, president of the non-profit Heritage Innovation Preservation Institute in Paris, who led the research. The discovery has already stirred the interest of archaeologists and particle physicists alike.

    Made of an estimated 2.3 million stone blocks and standing 140 meters tall and 230 meters wide, the Great Pyramid is an engineering mystery, much like its two smaller sister pyramids, Khafre’s and Menkaure’s. Archaeologists know that it was built for Khufu, who died in 2566 B.C.E. But they have long wondered exactly how the pyramid was constructed and structured.

    Now, archaeologists are getting help from an unlikely source: cosmic rays, subatomic particles that rain down from space. In fact, a team of physicists has found a previously unknown void within the pyramid by imaging it with muons, high-energy byproducts of cosmic rays that are created when protons and other atomic nuclei strike the atmosphere.

    Every minute, tens of thousands of muons pass through each square meter of Earth. The particles are much like electrons but 207 times as massive. Because they’re so heavy, the negatively charged particles can travel through hundreds of meters of stone before being absorbed—whereas electrons make it only a few centimeters. So just as doctors use x-rays to look into our bodies, physicists can use muons to peek into thick structures—from volcanoes to disabled nuclear power plants. To do that, all researchers need to do is to place a muon detector, such as tile-sized special photographic films, underneath, within, or near an object and count the number of muons coming through the thing in different directions.

    One of the first times scientists used muon imaging was to search for hidden chambers in Khafre’s pyramid at Giza in the late 1960s. None was discovered. This time around, after a 2016 experiment revealed anomalies that could indicate something behind its walls, scientists set out to image Khufu’s pyramid. To do that they placed various direction-sensitive muon detectors in the queen’s chamber and in an adjacent corridor within the pyramid and at its base on the north side, and analyzed the collected data every 2 to 5 months. As proof of principle, they confirmed the presence of three known large cavities: the queen’s and king’s chambers, and a long corridor that connects them, known as the grand gallery.

    But, just above the grand gallery the researchers also spotted a new void area, they report today in Nature. The new cavity is nearly 8 meters high, 2 meters wide, and at least 30 meters long—like a cathedral, but much narrower—and it rises 20 meters above the ground in the pyramid’s core.

    The scientists have “seen” the void using three different muon detectors in three independent experiments, which makes their finding very robust, says Lee Thompson, an expert in particle physics at the University of Sheffield in the United Kingdom who was not involved in the work. But the cavity’s detailed structure remains unclear: It might be one or many adjacent compartments, and could be horizontal or slanted.

    At this stage, the cavity’s function can only be guessed. Because it is inaccessible, it probably isn’t a burial chamber, says archaeologist Mark Lehner, director of Ancient Egypt Research Associates in Boston, who was not involved in the research. “It’s not the ideal place to contain a body,” he says. It could have purely symbolic meaning, as a passage for the pharaoh’s soul, Tayoubi says.

    Zahi Hawass, an Egyptologist based in Cairo who chairs the committee that reviewed the research project, cautions against calling the cavity a “secret room,” as pyramid builders often left large gaps between stone blocks, a construction strategy that makes the pyramid’s core look like Swiss cheese. The void might simply have served to relieve the weight of the stone blocks above the grand gallery to preserve it from collapse, like the five compartments, stacked on top of each other, that protect the king’s chamber in the same pyramid, Lehner says.

    To answer questions about the cavity’s structure and function, the researchers hope to do more muon imaging experiments with finer resolution. This means placing more detectors inside and near the pyramid that collect data for longer—up to several years, Tayoubi says. Understanding the detailed structure of the cavity could also help determine how the Great Pyramid was built in the first place, whether using external ramps or internal passages through which stone blocks were carried to the higher levels of the structure.

    Until then, the new finding, although “impressive,” doesn’t dramatically change the way we think about pyramids, Lehner says. But other scientists, such as particle physicist Guido Saracino of the University of Naples Federico II in Italy, are thrilled. According to Saracino, this work confirms that particle physics can have important practical applications, including archaeological surveys. And one day it may help scientists figure out how the ancient pyramids were built.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

     
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