"Air showers"
Observatory element (West Desert UT)
fun equipment, strange science.
Posted on 11/26/2017 8:31:20 PM PST by ETL
The finding keeps open the possibility that the particles come from dark matter
New observations of the whirling cores of dead stars have deepened the mystery behind a glut of antimatter particles raining down on Earth from space.
The particles are antielectrons, also known as positrons, and could be a sign of dark matter — the exotic and unidentified culprit that makes up the bulk of the universe’s mass. But more mundane explanations are also plausible: Positrons might be spewed from nearby pulsars, the spinning remnants of exploded stars, for example. But researchers with the High-Altitude Water Cherenkov Observatory, or HAWC, now have called the pulsar hypothesis into question in a paper published in the Nov. 17 Science.
Although the new observations don’t directly support the dark matter explanation, “if you have a few alternatives and cast doubt on one of them, then the other becomes more likely," says HAWC scientist Jordan Goodman of the University of Maryland in College Park.
Earth is constantly bathed in cosmic rays, particles from space that include protons, atomic nuclei, electrons and positrons. Several experiments designed to detect the showers of spacefaring particles have found more high-energy positrons than expected (SN: 5/4/13, p. 14), and astrophysicists have debated the excess positrons’ source ever since. Dark matter particles annihilating one another could theoretically produce pairs of electrons and positrons, but so can other sources, such as pulsars.
It was uncertain, though, whether pulsars’ positrons would make it to Earth in numbers significant enough to explain the excess. HAWC researchers tested how positrons travel through space by measuring gamma rays, or high-energy light, from two nearby pulsars — Geminga and Monogem — around 900 light-years away. Those gamma rays are produced when energetic positrons and electrons slam into low-energy light particles, producing higher-energy radiation.
(Excerpt) Read more at sciencenews.org ...
The particles are antielectrons, also known as positrons, and could be a sign of dark matter — the exotic and unidentified culprit that makes up the bulk of the universe’s mass. But more mundane explanations are also plausible: Positrons might be spewed from nearby pulsars, the spinning remnants of exploded stars, for example. But researchers with the High-Altitude Water Cherenkov Observatory, or HAWC, now have called the pulsar hypothesis into question in a paper published in the Nov. 17 Science.
Although the new observations don’t directly support the dark matter explanation, “if you have a few alternatives and cast doubt on one of them, then the other becomes more likely," says HAWC scientist Jordan Goodman of the University of Maryland in College Park.
Earth is constantly bathed in cosmic rays, particles from space that include protons, atomic nuclei, electrons and positrons. Several experiments designed to detect the showers of spacefaring particles have found more high-energy positrons than expected (SN: 5/4/13, p. 14), and astrophysicists have debated the excess positrons’ source ever since. Dark matter particles annihilating one another could theoretically produce pairs of electrons and positrons, but so can other sources, such as pulsars.
It was uncertain, though, whether pulsars’ positrons would make it to Earth in numbers significant enough to explain the excess. HAWC researchers tested how positrons travel through space by measuring gamma rays, or high-energy light, from two nearby pulsars — Geminga and Monogem — around 900 light-years away. Those gamma rays are produced when energetic positrons and electrons slam into low-energy light particles, producing higher-energy radiation.
The positron or antielectron is the antiparticle or the antimatter counterpart of the electron. The positron has an electric charge of +1 e, a spin of 1/2 (same as electron), and has the same mass as an electron.
When a positron collides with an electron, annihilation occurs. If this collision occurs at low energies, it results in the production of two or more gamma ray photons (see electron–positron annihilation).
Positrons may be generated by positron emission radioactive decay (through weak interactions), or by pair production from a sufficiently energetic photon which is interacting with an atom in a material.
https://en.wikipedia.org/wiki/Positron
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Antimatter
In modern physics, antimatter is defined as a material composed of the antiparticle (or “partners”) to the corresponding particles of ordinary matter.
In theory, a particle and its anti-particle have the same mass as one another, but opposite electric charge, and other differences in quantum numbers. For example, a proton has positive charge while an antiproton has negative charge.
A collision between any particle and its anti-particle partner is known to lead to their mutual annihilation, giving rise to various proportions of intense photons (gamma rays), neutrinos, and sometimes less-massive particle–antiparticle pairs.
Annihilation usually results in a release of energy that becomes available for heat or work. The amount of the released energy is usually proportional to the total mass of the collided matter and antimatter, in accord with the mass–energy equivalence equation, E = mc2.[1]
Antimatter particles bind with one another to form antimatter, just as ordinary particles bind to form normal matter.
For example, a positron (the antiparticle of the electron) and an antiproton (the antiparticle of the proton) can form an antihydrogen atom. Physical principles indicate that complex antimatter atomic nuclei are possible, as well as anti-atoms corresponding to the known chemical elements.
There is considerable speculation as to why the observable universe is composed almost entirely of ordinary matter, as opposed to an equal mixture of matter and antimatter. This asymmetry of matter and antimatter in the visible universe is one of the great unsolved problems in physics.[2]
The process by which this inequality between matter and antimatter particles developed is called baryogenesis.
Antimatter in the form of anti-atoms is one of the most difficult materials to produce.
Individual antimatter particles, however, are commonly produced by particle accelerators and in some types of radioactive decay.
The nuclei of antihelium have been artificially produced with difficulty. These are the most complex anti-nuclei so far observed.[3]
https://en.wikipedia.org/wiki/Antimatter
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Composition of dark matter: baryonic vs. nonbaryonic
Baryonic matter
Baryons (protons and neutrons) make up ordinary stars and planets. However, baryonic matter also encompasses less common black holes, neutron stars, faint old white dwarfs and brown dwarfs, collectively known as massive compact halo objects (MACHOs).[74] This ordinary, but hard to see, matter could explain dark matter.
However multiple lines of evidence suggest the majority of dark matter is not made of baryons:
Sufficient diffuse, baryonic gas or dust would be visible when backlit by stars.
The theory of Big Bang nucleosynthesis predicts the observed abundance of the chemical elements.
If there are more baryons, then there should also be more helium, lithium and heavier elements synthesized during the Big Bang.[75][76]
Agreement with observed abundances requires that baryonic matter makes up between 4–5% of the universe’s critical density. In contrast, large-scale structure and other observations indicate that the total matter density is about 30% of the critical density.[69]
Astronomical searches for gravitational microlensing in the Milky Way found that at most a small fraction of the dark matter may be in dark, compact, conventional objects (MACHOs, etc.); the excluded range of object masses is from half the Earth’s mass up to 30 solar masses, which covers nearly all the plausible candidates.[77][78][79][80][81][82]
Detailed analysis of the small irregularities (anisotropies) in the cosmic microwave background.[83] Observations by WMAP and Planck indicate that around five-sixths of the total matter is in a form that interacts significantly with ordinary matter or photons only through gravitational effects.
Non-baryonic matter
Candidates for nonbaryonic dark matter are hypothetical particles such as axions, sterile neutrinos or WIMPs (e.g. supersymmetric particles).
The three neutrino types already observed are indeed abundant, and “dark”, and matter, but because their individual masses – however uncertain they may be – are almost certainly tiny, they can only supply a small fraction of dark matter, due to limits derived from large-scale structure and high-redshift galaxies.[84]
Unlike baryonic matter, nonbaryonic matter did not contribute to the formation of the elements in the early universe (”Big Bang nucleosynthesis”)[14] and so its presence is revealed only via its gravitational effects.
In addition, if the particles of which it is composed are supersymmetric, they can undergo annihilation interactions with themselves, possibly resulting in observable by-products such as gamma rays and neutrinos (”indirect detection”).[84]
https://en.wikipedia.org/wiki/Dark_matter#Composition_of_dark_matter:_baryonic_vs._nonbaryonic
Sorry for the repeat of the excerpt in the first comment section. Just about falling asleep as I’m typing. Not sure how I did that.
My money says it’s the Russians.
“There is considerable speculation as to why the observable universe is composed almost entirely of ordinary matter, as opposed to an equal mixture of matter and antimatter.
This asymmetry of matter and antimatter in the visible universe is one of the great unsolved problems in physics.[2]”
"Air showers"
Observatory element (West Desert UT)
fun equipment, strange science.
An air shower is an extensive (many kilometres wide) cascade of ionized particles and electromagnetic radiation produced in the atmosphere when a primary cosmic ray (i.e. one of extraterrestrial origin) enters the atmosphere.
The term cascade means that the incident particle, which could be a proton, a nucleus, an electron, a photon, or (rarely) a positron, strikes an atom’s nucleus in the air so as to produce many energetic hadrons.
The unstable hadrons decay in the air speedily into other particles and electromagnetic radiation, which are part of the shower components.
The secondary radiation rains down, including x-rays, muons, protons, antiprotons, alpha particles, pions, electrons, positrons, and neutrons.
The dose from cosmic radiation is largely from muons, neutrons, and electrons, with a dose rate that varies in different parts of the world and based largely on the geomagnetic field, altitude, and solar cycle.
Airline crews receive more cosmic rays if they routinely work flight routes that take them close to the North or South pole at high altitudes, where this type of radiation is maximal.
The air shower was discovered by Bruno Rossi in 1934. By observing the cosmic ray with the detectors placed apart from each other, Rossi recognized that many particles arrive simultaneously at the detectors.[1] This phenomenon is now called an air shower.
https://en.wikipedia.org/wiki/Air_shower_(physics)
Interesting
Related Electric Universe Material -
https://www.thunderbolts.info/wp/2013/01/06/the-powers-of-darkness/
https://www.thunderbolts.info/wp/2013/07/07/the-powers-of-darkness-2/
https://www.thunderbolts.info/wp/2013/12/12/the-powers-of-darkness-3/
Above is a series of three separate but interconnected articles on Dark Matter from the Electric Universe Perspective.
How do we know distant galaxies *aren’t* made of anti-matter?
Assuming there is an attraction to do so............
Steve Naftilan of the Joint Science Department at The Claremont Colleges answers:
“When matter and antimatter meet, they annihilate each other and the mass is converted into energy—specifically, into gamma-rays. If a distant galaxy were made of antimatter, it would constantly be producing gamma-rays as it encountered the matter in the intergalactic gas clouds that exist throughout galaxy clusters.
“We do not see any steady stream of gamma-rays coming from any source in the sky. Therefore, astronomers conclude that there are not occasional ‘rogue’ galaxies made of antimatter.
If there is any large amount of antimatter in the universe, it must encompass at least an entire galaxy cluster, and probably a supercluster. One might postulate the existence of such antimatter superclusters, but then one would be faced with the problem of coming up with a mechanism that, shortly after the big bang, would have separated these now-gigantic clumps of antimatter from the neighboring clumps of mater. No such mechanism has yet been envisioned.”
>Scott Dodelson is a scientist in the Theoretical Astrophysics Group at Fermi National Accelerator Laboratory. He offers a more detailed reply:
“The question of whether or not there is anti-matter in the universe has been around ever since the prediction of the existence of the anti-proton early this century. For reasons that I’ll explain, most physicists don’t believe there is much anti-matter around. But the fact that the question is still being asked (by many scientists) indicates that it has not been definitively answered. We may all be in for a big surprise!
“With that background, here is an overview of our present thinking. A simple way to test and see if there is anti-matter around is to send out a ‘detector.’ In this case, it is completely trivial to make a detector: it simply has to be made of matter! Any time matter collides with anti-matter, the two annihilate and produce lots of gamma rays. We have sent spacecraft to Jupiter and other planets. These objects didn’t annihilate, so we know that our solar system does not contain much anti-matter.
“In fact, we can make a much stronger statement about the abundance of anti-matter by searching for gamma rays from other galaxies and clusters of galaxies. A typical cluster does not emit many gamma rays, so all the galaxies in it must be made solely of matter. It is possible that all the galaxies in a given cluster are made of matter while all those in another are made solely of anti-matter.
If this were true, then there would be immense gamma radiation coming from the boundary regions between clusters of different types. At present, such radiation is not observed, a fact that again argues against this separation. Matter and anti-matter therefore must be separated on scales larger than cluster sizes (roughly ten million light years).
“There is a strong argument against the possibility that matter and anti-matter exist in equal numbers in our universe but are for some reason separated. This argument goes back to the early universe and asks, When must the matter and anti-matter have been separated? It must have been very early, when the temperature of the universe was roughly 500 billion Kelvins. If they hadn’t separated by then, matter and anti-matter would have mutually annihilated, because the universe was very dense.
Is it possible to think of a mechanism that separated matter from anti-matter when the universe was very hot and dense? Apparently not, for any way of separating them has to obey causality. Early in the history of the universe, when annihilation between matter and anti-matter was occurring, the farthest possible distances that were in causal contact with each other were about 100 kilometers. This size is a billion times smaller than the regions that would grow to be clusters. So it seems impossible that matter was separated from anti-matter on scales the size of clusters today.
The most natural explanation is that the universe is made up only of matter and contains no large reservoir of anti-matter. In fact, there are theories which explain how such an asymmetry could have occurred.
“Having said all this, I want to reiterate that this is not the final word. The arguments I have presented are suggestive but not compelling. For this reason, some physicists are excited about the Alpha Magnetic Spectrometer, a device that the National Aeronautics and Space Administration wants to fly in the Earth’s orbit that will look directly for anti-matter.”
https://www.scientificamerican.com/article/how-do-we-know-that-dista/
Thanks, ETL.
If you mean when the positron/anti-electron encounters an ordinary electron in the atmosphere, I don't know.
Yeah. I was working with the guys on Mt Hopkins (AZ) back in 71 when they first started building “fly eye’ detectors using milsurp searchlight mirrors & photomultiplier tubes..
Last I was in Delta Ut, I got the tour at the Lon and Mary Watson Cosmic Ray Center. Pretty fun stuff, but as a “worker bee” (vs a starving post doc) I made the choice long ago to skip “grant-funded” projects.
Still, *Coherent* Cherenkov radiation is what makes the air shower phenomenon so...cool.
Still, pretty cool stuff.
BTW - Cherenkov radiation - the glow seen in air showers is the same glow seen in atomic reactors where the neutrons strike a water moderator.
https://arxiv.org/abs/1107.0665
I’m still convinced that if a functional lightsaber is possible, it’ll use an arc of positrons coming out of the hilt as it’s blade.
You’re welcome.
Here’s another one...
Are there antimatter galaxies?
by Fraser Cain, Universe Today
https://phys.org/news/2016-06-antimatter-galaxies.html
Just had the impression from a somewhat layman's viewpoint that there was an "annihilation" event when they merged, with E=MC^2 being about 100% efficiency.
Yeah, electron mass is small, but if enough is going on.............
Good read, to be read again in the morning.
"Assuming there is an attraction to do so"
That is a great question. I imagine they should attract. Then you have to get into what the fundamental nature of what 'positive' and 'negative' actually is. I know it's related to spin. Also, for what it's worth, protons are in a different category of subatomic particles than electrons. Electrons are in the lepton family. Protons, some other family/category.
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