Astrophysics
Comet Neowise
More Comet Neowise
Lunar Eclipse May 15th. 2022
Jupiter and Saturn Conjunction December 18th. 2020. With Jupiter's four moons.
And these two were taken on December 21st. "Winter Solstice", 2020.
The Orion Nebula
A little known fact to many is that there are major storms that happen in Jupiter's atmosphere. These storms produce radio emissions that can be heard here on Earth. These storms can be heard on shortwave radios from 18Mhz. up to 21Mhz. Here is an example.
Cosmic Antimatter
Searches for Cosmic Antimatter Diego Casadei (
Submitted on 21 May 2004 (v1), last revised 13 Jun 2006 (this version, v3))
We know from experimental high energy physics that whenever matter is created, an equal amount of antimatter is also created. However, we live in a large region of the universe where the antimatter can not constitute more than a very small fraction of the total mass. The cosmic antimatter problem has been addressed since the beginning of modern cosmology, but no definite answer has been formulated despite of the several approaches that can be found in the literature. In this paper we will make a historical review and we will focus on the experimental techniques that has been proposed to reveal directly and indirectly the presence of cosmic antimatter in the universe. Indirect searches can be carried on with the measurements of the electromagnetic radiation in the microwave and gamma-ray range, and of the neutrino flavour, whereas direct searches lay on the measurement of the cosmic rays and probe shorter distances. Finally, the current limits on the cosmic antimatter to matter ratio are compared to the sensitivity of future experiments.
Submitted on 21 May 2004 (v1), last revised 13 Jun 2006 (this version, v3))
We know from experimental high energy physics that whenever matter is created, an equal amount of antimatter is also created. However, we live in a large region of the universe where the antimatter can not constitute more than a very small fraction of the total mass. The cosmic antimatter problem has been addressed since the beginning of modern cosmology, but no definite answer has been formulated despite of the several approaches that can be found in the literature. In this paper we will make a historical review and we will focus on the experimental techniques that has been proposed to reveal directly and indirectly the presence of cosmic antimatter in the universe. Indirect searches can be carried on with the measurements of the electromagnetic radiation in the microwave and gamma-ray range, and of the neutrino flavour, whereas direct searches lay on the measurement of the cosmic rays and probe shorter distances. Finally, the current limits on the cosmic antimatter to matter ratio are compared to the sensitivity of future experiments.
http://cosmos.phy.tufts.edu/~zirbel/ast21/sciam/AntiMatter.pdf
http://news.sciencemag.org/sciencenow/2011/11/cosmic-antimatter-excess-confirm.html
http://www.sciencedaily.com/releases/2013/04/130403115313.htm
Science News ... from universities, journals, and other research organizations
Search for Dark Matter: Experiment Measures Antimatter Excess in Cosmic Ray Flux Apr. 3, 2013 — The international team running the Alpha Magnetic Spectrometer (AMS1) today announced the first results in its search for dark matter. The results, presented by AMS spokesperson Professor Samuel Ting in a seminar at CERN2, are to be published in the journal Physical Review Letters. They report the observation of an excess of positrons in the cosmic ray flux.
The AMS results are based on some 25 billion recorded events, including 400,000 positrons with energies between 0.5 GeV and 350 GeV, recorded over a year and a half. This represents the largest collection of antimatter particles recorded in space. The positron fraction increases from 10 GeV to 250 GeV, with the data showing the slope of the increase reducing by an order of magnitude over the range 20-250 GeV. The data also show no significant variation over time, or any preferred incoming direction. These results are consistent with the positrons originating from the annihilation of dark matter particles in space, but not yet sufficiently conclusive to rule out other explanations.
"As the most precise measurement of the cosmic ray positron flux to date, these results show clearly the power and capabilities of the AMS detector," said AMS spokesperson, Samuel Ting. "Over the coming months, AMS will be able to tell us conclusively whether these positrons are a signal for dark matter, or whether they have some other origin."
Cosmic rays are charged high-energy particles that permeate space. The AMS experiment, installed on the International Space Station, is designed to study them before they have a chance to interact with the Earth's atmosphere. An excess of antimatter within the cosmic ray flux was first observed around two decades ago. The origin of the excess, however, remains unexplained. One possibility, predicted by a theory known as supersymmetry, is that positrons could be produced when two particles of dark matter collide and annihilate. Assuming an isotropic distribution of dark matter particles, these theories predict the observations made by AMS. However, the AMS measurement can not yet rule out the alternative explanation that the positrons originate from pulsars distributed around the galactic plane. Supersymmetry theories also predict a cut-off at higher energies above the mass range of dark matter particles, and this has not yet been observed. Over the coming years, AMS will further refine the measurement's precision, and clarify the behaviour of the positron fraction at energies above 250 GeV.
"When you take a new precision instrument into a new regime, you tend to see many new results, and we hope this this will be the first of many," said Ting. "AMS is the first experiment to measure to 1% accuracy in space. It is this level of precision that will allow us to tell whether our current positron observation has a Dark Matter or pulsar origin."
Dark matter is one of the most important mysteries of physics today. Accounting for over a quarter of the universe's mass-energy balance, it can be observed indirectly through its interaction with visible matter but has yet to be directly detected. Searches for dark matter are carried out in space-borne experiments such as AMS, as well as on the Earth at the Large Hadron Collider and a range of experiments installed in deep underground laboratories.
"The AMS result is a great example of the complementarity of experiments on Earth and in space," said CERN Director General Rolf Heuer. "Working in tandem, I think we can be confident of a resolution to the dark matter enigma sometime in the next few years."
Antiparticles Every elementary particle in the Universe appears to have a partner particle called its antiparticle that shares many of the same characteristics, but many other characteristics are the opposite of those for the particle. For example, the electron has as its antiparticle the antielectron. The electron and the antielectron have exactly the same masses, but they have exactly opposite electrical charges. The common stuff around us appears to be "matter", but we routinely produce antimatter in small quantities in high energy accelerator experiments. When a matter particle meets its antimatter particle they destroy each other completely (the technical term is "annihilation"), releasing the equivalent of their rest masses in the form of pure energy (according to the Einstein E=mc^2 relation). For example, when an electron meets an antielectron, the two annihilate and produce a burst of light having the energy corresponding to the masses of the two particles.
Because the properties of matter and antimatter parallel each other, we believe that the physics and chemistry of a galaxy made entirely from antimatter would closely parallel that of our our matter galaxy. Thus, is is conceivable that life built on antimatter could have evolved at other places in the Universe, just as life based on matter has evolved here. (But if your antimatter twin should show up some day, I would advise against shaking hands---remember that matter and antimatter annihilate each other!) However, we have no evidence thus far for large concentrations of antimatter anywhere in the Universe. Everything that we see so far seems to be matter. If true, this is something of a mystery, because naively there are reasons from fundamental physics to believe that the Universe should have produced about as much matter as antimatter.
Dark Matter Dark matter is the general term for matter that we cannot see to this point with our telescopes, but that we know must be there because we see its gravitational influence on the rest of the Universe. Many different experiments indicate that there is probably 10 times more matter in the Universe (because we see its gravitational influence) than the matter that we see. Thus, dark matter is basically what the Universe is made out of, but we don't yet know what it is! As one simple example of the evidence for dark matter, the velocity of rotation for spiral galaxies depends on the amount of mass contained in them. The outer parts of our own spiral galaxy, the Milky Way, are rotating much too fast to be consistent with the amount of matter that we can detect; in fact the data indicates that there must be about 10 times as much matter as we can see distributed in some diffuse halo of our galaxy to account for its rotation. The same is true for most other spiral galaxies where the velocities can be measured.
There are various candidates for the dark matter, ranging from ordinary matter that we just can't see because it isn't bright enough (for example, ordinary matter bound up in black holes, or very faint stars, or large planet-like objects like Jupiter) to more exotic particles that have yet to be discovered. There are some fairly strong arguments based on the production of the light elements in the Big Bang indicating that the majority of the dark matter cannot be ordinary matter or antimatter (which physicists call "baryonic matter"), and thus that the majority of the mass of the Universe is in a form very different from the matter that makes up us and the world around us (physicists call this "non-baryonic matter"). If that is true, then the matter that we are made of (baryonic matter) is but a small impurity compared to the dominant matter in the universe (non-baryonic matter). As someone has put it, "not only are we not the center of the Universe, we aren't even made of the right stuff!"
The nature of the dark matter is perhaps the most fundamental unsolved problem in modern astronomy.
Could the Dark Matter be Antimatter? It is conceivable that the dark matter (or at least part of it) could be antimatter, but there are very strong experimental reasons to doubt this. For example, if the dark matter out there were antimatter, we would expect it to annihilate with matter whenever it meets up with it, releasing bursts of energy primarily in the form of light. We see no evidence in careful observations for that, which leads most scientists to believe that whatever the dark matter is, it is not antimatter. http://csep10.phys.utk.edu/astr162/lect/cosmology/antimatter.html
Cosmic Rays Cosmic ray is the term given to high energy radiation which strikes the Earth from space. Some of them have ultrahigh energies in the range 100 - 1000 TeV. Such extreme energies come from only a few sources like Cygnus X-3. The peak of the energy distribution is at about 0.3 GeV.
The intensity of cosmic radiation increases with altitude, indicating that it comes from outer space. It changes with latitude, indicating that it consists at least partly of charged particles which are affected by the earth's magnetic field. The illustration at right shows that the detected cosmic ray flux peaks at about 15 km in altitude and then drops sharply (note the logarithmic scale on the altitude). This kind of variation was discovered by Pfotzer in 1936. It suggests that the detection method used was mainly detecting secondary particles rather than the primary particles reaching the Earth from space.
http://news.sciencemag.org/sciencenow/2011/11/cosmic-antimatter-excess-confirm.html
http://www.sciencedaily.com/releases/2013/04/130403115313.htm
Science News ... from universities, journals, and other research organizations
Search for Dark Matter: Experiment Measures Antimatter Excess in Cosmic Ray Flux Apr. 3, 2013 — The international team running the Alpha Magnetic Spectrometer (AMS1) today announced the first results in its search for dark matter. The results, presented by AMS spokesperson Professor Samuel Ting in a seminar at CERN2, are to be published in the journal Physical Review Letters. They report the observation of an excess of positrons in the cosmic ray flux.
The AMS results are based on some 25 billion recorded events, including 400,000 positrons with energies between 0.5 GeV and 350 GeV, recorded over a year and a half. This represents the largest collection of antimatter particles recorded in space. The positron fraction increases from 10 GeV to 250 GeV, with the data showing the slope of the increase reducing by an order of magnitude over the range 20-250 GeV. The data also show no significant variation over time, or any preferred incoming direction. These results are consistent with the positrons originating from the annihilation of dark matter particles in space, but not yet sufficiently conclusive to rule out other explanations.
"As the most precise measurement of the cosmic ray positron flux to date, these results show clearly the power and capabilities of the AMS detector," said AMS spokesperson, Samuel Ting. "Over the coming months, AMS will be able to tell us conclusively whether these positrons are a signal for dark matter, or whether they have some other origin."
Cosmic rays are charged high-energy particles that permeate space. The AMS experiment, installed on the International Space Station, is designed to study them before they have a chance to interact with the Earth's atmosphere. An excess of antimatter within the cosmic ray flux was first observed around two decades ago. The origin of the excess, however, remains unexplained. One possibility, predicted by a theory known as supersymmetry, is that positrons could be produced when two particles of dark matter collide and annihilate. Assuming an isotropic distribution of dark matter particles, these theories predict the observations made by AMS. However, the AMS measurement can not yet rule out the alternative explanation that the positrons originate from pulsars distributed around the galactic plane. Supersymmetry theories also predict a cut-off at higher energies above the mass range of dark matter particles, and this has not yet been observed. Over the coming years, AMS will further refine the measurement's precision, and clarify the behaviour of the positron fraction at energies above 250 GeV.
"When you take a new precision instrument into a new regime, you tend to see many new results, and we hope this this will be the first of many," said Ting. "AMS is the first experiment to measure to 1% accuracy in space. It is this level of precision that will allow us to tell whether our current positron observation has a Dark Matter or pulsar origin."
Dark matter is one of the most important mysteries of physics today. Accounting for over a quarter of the universe's mass-energy balance, it can be observed indirectly through its interaction with visible matter but has yet to be directly detected. Searches for dark matter are carried out in space-borne experiments such as AMS, as well as on the Earth at the Large Hadron Collider and a range of experiments installed in deep underground laboratories.
"The AMS result is a great example of the complementarity of experiments on Earth and in space," said CERN Director General Rolf Heuer. "Working in tandem, I think we can be confident of a resolution to the dark matter enigma sometime in the next few years."
Antiparticles Every elementary particle in the Universe appears to have a partner particle called its antiparticle that shares many of the same characteristics, but many other characteristics are the opposite of those for the particle. For example, the electron has as its antiparticle the antielectron. The electron and the antielectron have exactly the same masses, but they have exactly opposite electrical charges. The common stuff around us appears to be "matter", but we routinely produce antimatter in small quantities in high energy accelerator experiments. When a matter particle meets its antimatter particle they destroy each other completely (the technical term is "annihilation"), releasing the equivalent of their rest masses in the form of pure energy (according to the Einstein E=mc^2 relation). For example, when an electron meets an antielectron, the two annihilate and produce a burst of light having the energy corresponding to the masses of the two particles.
Because the properties of matter and antimatter parallel each other, we believe that the physics and chemistry of a galaxy made entirely from antimatter would closely parallel that of our our matter galaxy. Thus, is is conceivable that life built on antimatter could have evolved at other places in the Universe, just as life based on matter has evolved here. (But if your antimatter twin should show up some day, I would advise against shaking hands---remember that matter and antimatter annihilate each other!) However, we have no evidence thus far for large concentrations of antimatter anywhere in the Universe. Everything that we see so far seems to be matter. If true, this is something of a mystery, because naively there are reasons from fundamental physics to believe that the Universe should have produced about as much matter as antimatter.
Dark Matter Dark matter is the general term for matter that we cannot see to this point with our telescopes, but that we know must be there because we see its gravitational influence on the rest of the Universe. Many different experiments indicate that there is probably 10 times more matter in the Universe (because we see its gravitational influence) than the matter that we see. Thus, dark matter is basically what the Universe is made out of, but we don't yet know what it is! As one simple example of the evidence for dark matter, the velocity of rotation for spiral galaxies depends on the amount of mass contained in them. The outer parts of our own spiral galaxy, the Milky Way, are rotating much too fast to be consistent with the amount of matter that we can detect; in fact the data indicates that there must be about 10 times as much matter as we can see distributed in some diffuse halo of our galaxy to account for its rotation. The same is true for most other spiral galaxies where the velocities can be measured.
There are various candidates for the dark matter, ranging from ordinary matter that we just can't see because it isn't bright enough (for example, ordinary matter bound up in black holes, or very faint stars, or large planet-like objects like Jupiter) to more exotic particles that have yet to be discovered. There are some fairly strong arguments based on the production of the light elements in the Big Bang indicating that the majority of the dark matter cannot be ordinary matter or antimatter (which physicists call "baryonic matter"), and thus that the majority of the mass of the Universe is in a form very different from the matter that makes up us and the world around us (physicists call this "non-baryonic matter"). If that is true, then the matter that we are made of (baryonic matter) is but a small impurity compared to the dominant matter in the universe (non-baryonic matter). As someone has put it, "not only are we not the center of the Universe, we aren't even made of the right stuff!"
The nature of the dark matter is perhaps the most fundamental unsolved problem in modern astronomy.
Could the Dark Matter be Antimatter? It is conceivable that the dark matter (or at least part of it) could be antimatter, but there are very strong experimental reasons to doubt this. For example, if the dark matter out there were antimatter, we would expect it to annihilate with matter whenever it meets up with it, releasing bursts of energy primarily in the form of light. We see no evidence in careful observations for that, which leads most scientists to believe that whatever the dark matter is, it is not antimatter. http://csep10.phys.utk.edu/astr162/lect/cosmology/antimatter.html
Cosmic Rays Cosmic ray is the term given to high energy radiation which strikes the Earth from space. Some of them have ultrahigh energies in the range 100 - 1000 TeV. Such extreme energies come from only a few sources like Cygnus X-3. The peak of the energy distribution is at about 0.3 GeV.
The intensity of cosmic radiation increases with altitude, indicating that it comes from outer space. It changes with latitude, indicating that it consists at least partly of charged particles which are affected by the earth's magnetic field. The illustration at right shows that the detected cosmic ray flux peaks at about 15 km in altitude and then drops sharply (note the logarithmic scale on the altitude). This kind of variation was discovered by Pfotzer in 1936. It suggests that the detection method used was mainly detecting secondary particles rather than the primary particles reaching the Earth from space.
Cosmic Antimatter Rays! by Nicholas Mee on April 11, 2013
In 1912 the Austrian physicist Victor Hess conclusively demonstrated the existence of cosmic rays when he took an electrometer to an altitude of over 5000 metres in a hot-air balloon. At this altitude Hess detected four times as much radiation as at ground level.
We now know that the Earth is continually bombarded by high energy particles from the depths of space. On reaching the Earth’s atmosphere most of these cosmic rays collide with molecules of nitrogen or oxygen in the air, which is why only a small proportion of the rays reach the Earth’s surface. The atmosphere does a great job of protecting us from this harmful radiation, but it means that Earth-based detectors are unable to gain a clear picture of the incoming radiation. This is why the Alpha Magnetic Spectrometer (AMS) has been mounted on the International Space Station. It is designed to detect cosmic rays before they enter the atmosphere.
Since May 2011 AMS has been collecting data. It has already recorded the impact of far more cosmic ray particles than any previous space-based experiment. Cosmic rays do not all have the same identity. They are simply stable massive particles that are racing across the universe. These particles include protons, electrons and the nuclei of various types of atom.
Antimatter
The feature of cosmic rays that is getting physicists excited is the proportion of them that are antimatter particles.
It has been known since the 1930s that there is a mirror image particle, or antiparticle, for each matter particle. For instance, the antiparticle of the proton is known as the antiproton. It has exactly the same mass as the proton, but the opposite electric charge, so whereas the proton is positively charged, the antiproton is negatively charged. Similarly, the electron has an antiparticle, which is known as the positron. Whereas the electron is negatively charged, the positron is positively charged, as its name might suggest.
One of the mysteries that AMS is revealing is that there are far more cosmic ray positrons than expected.
Where do cosmic rays come from?
Most cosmic rays are produced in a supernova explosion in which a star has blasted itself apart in its death throes. All the elements in the Periodic Table are cooked up in these explosions and the shock waves send protons and atomic nuclei flying off into space with extremely high energies. These incredibly violent events might account for most of the particles that form cosmic rays, but the large quantities of cosmic ray positrons are thought to require a different explanation. There are two main ideas about their origin.
The Crab Nebula which was produced by a supernova explosion observed in 1054. (Copyright NASA)
Cosmic Lighthouses
Following a supernova explosion all that is left of the original star is an ultra-compact remnant known as a neutron star. The neutron star consists of a star’s worth of material compressed to the density of an atomic nucleus. This is the equivalent of the Sun being squeezed into a sphere the size of a major city such as London. The most famous example of a neutron star lies at the heart of the crab nebula, which was produced by a supernova explosion seen almost 1000 years ago in 1054.
Neutron stars spin extremely rapidly – the neutron star within the crab nebula is more massive than the Sun, but it rotates 30 times a second. This generates incredibly strong magnetic fields that produce two oppositely directed beams firing radiation into space like a cosmic lighthouse. When these beams point in our direction, once every rotation, a pulse of radiation may be detected. For this reason, these objects are known as pulsars. The pulsar beams are thought to act like gigantic particle accelerators, and they might be the source of the excess positrons detected by AMS.
Computer generated simulation of a pulsar. (Copyright Nicholas Mee)
Dark Matter
But there is another intriguing possibility. Many theorists think that the next big discovery at the Large Hadron Collider will be supersymmetry and that the lightest new particle predicted by the theory would be a stable particle that was produced in great profusion in the very early universe. If this is correct, the universe would still be full of these particles. In fact they would have all the characteristics of dark matter. Some theories of supersymmetry suggest that when two of these particles meet they will mutually annihilate to produce other particles that will then decay, the net result being the production of positrons. This might explain the surprisingly large quantity of cosmic ray positrons detected by AMS.
So the results from AMS could be the first signs of the existence of particles of dark matter.
Which Idea Is Correct?
Fortunately, there is a way to distinguish between these two possible solutions. If the hypothetical dark matter particle has a mass of say 175 GeV, which is perfectly possible and is about 200 times the mass of a proton, then when two such particle mutually annihilate a total of around 350 GeV would be released. This is the energy that is available to any new particles, such as positrons, that would be produced. This means that if dark matter particles are the origin of the positrons then there will be a maximum energy for such particles. Beyond this energy none will be detected.
If the positrons are being produced by pulsars, on the other hand, then there might be fewer with very high energies, but the numbers would be expected to tail off gradually with no abrupt limit to the energy of the positrons.
AMS has not yet collected sufficient data to distinguish between these two possibilities, but within the next few years it should be able to provide us with a definitive answer.
Further Information
My article Super Symmetry! includes more information about supersymmetry and how it might explain the origin of dark matter.
The latest results from the AMS detector were announced by Nobel laureate Sam Ting in a seminar at CERN on 3rd April. More details are given here: http://home.web.cern.ch/about/updates/2013/04/ams-experiment-measures-antimatter-excess-space
http://quantumwavepublishing.com/dark-matter/
For more detailed information, take a look at this paper: Viewpoint: Positrons Galore
In 1912 the Austrian physicist Victor Hess conclusively demonstrated the existence of cosmic rays when he took an electrometer to an altitude of over 5000 metres in a hot-air balloon. At this altitude Hess detected four times as much radiation as at ground level.
We now know that the Earth is continually bombarded by high energy particles from the depths of space. On reaching the Earth’s atmosphere most of these cosmic rays collide with molecules of nitrogen or oxygen in the air, which is why only a small proportion of the rays reach the Earth’s surface. The atmosphere does a great job of protecting us from this harmful radiation, but it means that Earth-based detectors are unable to gain a clear picture of the incoming radiation. This is why the Alpha Magnetic Spectrometer (AMS) has been mounted on the International Space Station. It is designed to detect cosmic rays before they enter the atmosphere.
Since May 2011 AMS has been collecting data. It has already recorded the impact of far more cosmic ray particles than any previous space-based experiment. Cosmic rays do not all have the same identity. They are simply stable massive particles that are racing across the universe. These particles include protons, electrons and the nuclei of various types of atom.
Antimatter
The feature of cosmic rays that is getting physicists excited is the proportion of them that are antimatter particles.
It has been known since the 1930s that there is a mirror image particle, or antiparticle, for each matter particle. For instance, the antiparticle of the proton is known as the antiproton. It has exactly the same mass as the proton, but the opposite electric charge, so whereas the proton is positively charged, the antiproton is negatively charged. Similarly, the electron has an antiparticle, which is known as the positron. Whereas the electron is negatively charged, the positron is positively charged, as its name might suggest.
One of the mysteries that AMS is revealing is that there are far more cosmic ray positrons than expected.
Where do cosmic rays come from?
Most cosmic rays are produced in a supernova explosion in which a star has blasted itself apart in its death throes. All the elements in the Periodic Table are cooked up in these explosions and the shock waves send protons and atomic nuclei flying off into space with extremely high energies. These incredibly violent events might account for most of the particles that form cosmic rays, but the large quantities of cosmic ray positrons are thought to require a different explanation. There are two main ideas about their origin.
The Crab Nebula which was produced by a supernova explosion observed in 1054. (Copyright NASA)
Cosmic Lighthouses
Following a supernova explosion all that is left of the original star is an ultra-compact remnant known as a neutron star. The neutron star consists of a star’s worth of material compressed to the density of an atomic nucleus. This is the equivalent of the Sun being squeezed into a sphere the size of a major city such as London. The most famous example of a neutron star lies at the heart of the crab nebula, which was produced by a supernova explosion seen almost 1000 years ago in 1054.
Neutron stars spin extremely rapidly – the neutron star within the crab nebula is more massive than the Sun, but it rotates 30 times a second. This generates incredibly strong magnetic fields that produce two oppositely directed beams firing radiation into space like a cosmic lighthouse. When these beams point in our direction, once every rotation, a pulse of radiation may be detected. For this reason, these objects are known as pulsars. The pulsar beams are thought to act like gigantic particle accelerators, and they might be the source of the excess positrons detected by AMS.
Computer generated simulation of a pulsar. (Copyright Nicholas Mee)
Dark Matter
But there is another intriguing possibility. Many theorists think that the next big discovery at the Large Hadron Collider will be supersymmetry and that the lightest new particle predicted by the theory would be a stable particle that was produced in great profusion in the very early universe. If this is correct, the universe would still be full of these particles. In fact they would have all the characteristics of dark matter. Some theories of supersymmetry suggest that when two of these particles meet they will mutually annihilate to produce other particles that will then decay, the net result being the production of positrons. This might explain the surprisingly large quantity of cosmic ray positrons detected by AMS.
So the results from AMS could be the first signs of the existence of particles of dark matter.
Which Idea Is Correct?
Fortunately, there is a way to distinguish between these two possible solutions. If the hypothetical dark matter particle has a mass of say 175 GeV, which is perfectly possible and is about 200 times the mass of a proton, then when two such particle mutually annihilate a total of around 350 GeV would be released. This is the energy that is available to any new particles, such as positrons, that would be produced. This means that if dark matter particles are the origin of the positrons then there will be a maximum energy for such particles. Beyond this energy none will be detected.
If the positrons are being produced by pulsars, on the other hand, then there might be fewer with very high energies, but the numbers would be expected to tail off gradually with no abrupt limit to the energy of the positrons.
AMS has not yet collected sufficient data to distinguish between these two possibilities, but within the next few years it should be able to provide us with a definitive answer.
Further Information
My article Super Symmetry! includes more information about supersymmetry and how it might explain the origin of dark matter.
The latest results from the AMS detector were announced by Nobel laureate Sam Ting in a seminar at CERN on 3rd April. More details are given here: http://home.web.cern.ch/about/updates/2013/04/ams-experiment-measures-antimatter-excess-space
http://quantumwavepublishing.com/dark-matter/
For more detailed information, take a look at this paper: Viewpoint: Positrons Galore
