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-------------------- 2562 - ANTIMATTER - mystery in physics?
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- When the Universe first formed it was a ball of energy. It expanded and cooled until some of the energy could condense into matter according to E=mc^2, or, m=E/c^2. This matter was the creation of the first elementary particles.
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- Paul Adrien Maurice Dirac was studying the elementary particle, the electron, in 1928. He was using Einstein’s relativistic equations. His equations always allowed two different energy states to exist. He speculated that one state was the electron and the other must be an equivalent particle with a positive charge. This was the first concept of the existence of antimatter.
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- In 1932 Carl David Anderson was investigating cosmic ray particles in a magnetically charged cloud chamber. Sure enough when cosmic rays hit a lead target elementary particles were emitted. Some particles had the equivalent mass of an electron but curved in the wrong direction. He discovered and named the positron. The positron is the antiparticle of the electron.
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- Today’s standard model of particle physics has an antiparticle for every elementary particle. For every matter there is an antimatter. In 1956 the antiproton was discovered by Segre and Owen Chamberlain.
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- It has 1836 times the mass of the electron. E=mc^2 requires 1.822*10^-27 grams, the mass of an electron, times 1836 times 90,000,000,000,000,000 meters^2 / second^2, the speed of light squared, to get the energy of 1,872,000,000 electron volts. It required the University of California proton synchrotron particle accelerator to create his amount of energy.
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- The other source of this amount of energy is cosmic rays which are actually atomic nuclei, mostly hydrogen nuclei, or protons that are accelerated to speeds near the velocity of light. Possibly it is the galaxy’s magnetic field that accelerates these charged particles like a giant cyclotron spiraling out from the center until they collide with the Earth’s atmosphere.
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- It is pretty hard to expect a cosmic ray proton to hit your lead target while you are watching so discovery of these higher energy particles and antiparticles had to wait for Earth based cyclotrons to be constructed.
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- Once a positron is created it cannot move more than a millionth of a second, or so, before it collides with an electron. The result is mutual annihilation of the mass of each. Mass is converted back into energy according to E=mc^2.
- 1.822*10^-27 grams * c^2 = 1,020,000 electron volts of energy.
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- This energy is in the form of gamma rays.
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- In addition to the conservation of energy the conservation of angular momentum must also be conserved. With the collision of the positron-electron three gamma ray photons each 340,000 electron volts are produced simultaneously and shoot off toward the corners of an equilateral triangle.
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- Or, if the electron and positron were spinning in the opposite directions the annihilation would result in two simultaneous gamma ray photons of 510,000 electron volts shooting off in the opposite directions.
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- So, when the Universe first formed and it began creating matter and antimatter in equal amounts there must have been self annihilation occurring all over the place. How did matter ever survive? This is a great mystery in physics today.
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- Some speculation is that because gravity was so weak in holding particles together. In fact it is so small that gravity has never been measured between individual particles.
The force of gravity is created by the particle called the graviton. Maybe there is an equivalent antiparticle called the anti-graviton.
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- If so, maybe some matter and antimatter got separated and anti-gravity accelerated their separation so that two independent Universes formed. Maybe there is a cosmos we live in and an anti-cosmos somewhere else. Of course the people in the anti-cosmos would think they were made of matter and we were the ones made of antimatter. Don’t ever shake hands with these guys. You would instantly become gamma rays going off in three directions.
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- A one ounce marble of anti matter rolled into a one ounce marble of matter would annihilate into energy equivalent to the electricity lighting every light bulb in the United States for 24 hours. Matter-antimatter energy conversion is 143 times more efficient than the fusion energy form a hydrogen bomb. Here is a table of comparisons:
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-------------------- Chemical reactions, 1 kilogram of gasoline = 42,000,000 Joules
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-------------------- Nuclear fusion, 1 kg of hydrogen = 2,600,000,000,000,000 Joules
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-------------------- Anti-matter, 1 kilogram = 180,000,000,000,000,000 Joules
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-------------------- A joule is one watt per second of energy.
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- A second speculation is the there is an inherent bias in the physical laws that favor matter over antimatter. This theory has symmetry breaking. For every 100,000,000 antiprotons, 100,000,001 protons are formed. The same with anti-electrons and electrons. This symmetry imbalance is enough to form the Universe of matter that we know.
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- Yet, antimatter is all around us. In 1956 scientists discovered the anti-neutron. In 1995 scientists were successful in producing anti-hydrogen and anti-deuterium atoms. But, they only lasted 40 nanoseconds. Hospitals today use positron emission topography, or PET, scans to see inside the human body. The positrons come from nuclides having a surplus positive charge created in a cyclotron.
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- If you could see gamma rays you would see a blinding light at the center of our Milky Way galaxy. There positrons and electrons are annihilating each other sending out gamma rays of 511,000 electron volts to 3,500 lightyears from the galaxy center. Some theories are that Dark Matter is generating this antimatter around the black hole at the center of our galaxy.
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- Yet production of antimatter on Earth is rare. Particle accelerators generate 1 to 10 nanograms per year. That is at a cost of $25,000,000 / gram. Positrons used in PET scans result from natural decay of radioactive isotopes.
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- Antimatter occurs naturally in Earth’s Van Allen belts of radiation. It occurs naturally in giant gas planets like Jupiter. Antimatter is generated in the Sun’s fusion process. If we could somehow harness antimatter it could transport a spaceship to Mars in one month. Today’s spaceships that put planetary probes on Mars took 11 months to reach their destination.
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- Antimatter is all around us. It is extremely powerful. We don’t understand it very well. Especially, we do not understand why their might be an inherent bias of matter over antimatter in our Universe.
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- Antimatter is not found naturally on Earth. Exceptions are, very briefly, during radioactive decay and when Cosmic Rays collide with atoms in the upper atmosphere. Also, very small amounts of antimatter, such as anti-hydrogen, can be produced in our particle accelerators. The small amount of antimatter produced by the largest particle accelerator, CERN in Geneva, Switzerland, would light a 100 watt bulb for only 3 seconds.
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- Anti-hydrogen produced at CERN has one positron and one antiproton in each atom. If the atoms remain suspended in a perfect vacuum they survive indefinitely. However, if the anti-hydrogen comes in contact with ordinary matter, such as the walls of a container, the atoms quickly annihilate each other and turn into energy in the form of gamma ray radiation and high energy particles called pions. The pions decay quickly into muons, neutrinos, positrons, and electrons. It all happens in a flash.
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- Antimatter is made of 12 fundamental anti-particles. Just as matter is made of 12 fundamental particles. The Standard Model for Particle Physics defines all matter being made of 6 varieties of quarks and 6 varieties of leptons. Quarks come in threes and make up protons and neutrons. Leptons come in three varieties of electrons and three varieties of neutrinos. So the 12 fundamental particles make up “ordinary matter”.
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- The Standard model also includes the anti-particles for each of these fundamental particles of matter. A total of 24 fundamental particles with mass. Particles and anti-particles have the same mass but opposite signs of charge. For example, the electron has a negative charge and the positron has the same mass but carries a positive charge. If an electron and a positron collide they vaporize in a flash of energy.
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- The Standard Model does include four “force carrying” particles, the photons, W-Z bosons, gluons, and gravitons but these are massless and only travel at the speed of light. Since they are massless they have no anti-particle counterpart.
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- In 1928 Paul Dirac predicted that anti-particles existed. He developed equations of motion for the waveforms of electrons using Einstein’s theory of relativity. His equations required that there be negative electrons as well as positive electrons. Therefore he predicted that a positive electron twin of the same mass must exist. It was in the math.
-
- In 1932 this particle was actually discovered in cloud chambers that were studying cosmic ray collisions in the upper atmosphere. The first anti-particle was called a positron. In 1955 the antiproton was discovered. In 1956 the anti-neutron was discovered. In 1995 the anti-hydrogen atom was created.
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- Today antiprotons are routinely produced in particle accelerators. Protons traveling at near light speed are smashed into a block of copper or iridium metal. ( Any material would work as a target. It is just that these are easy to cool and beefsteak would be too sloppy.)
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- The energetic protons are stopped so abruptly very high temperatures are created. Temperatures high enough to create matter-antimatter pairs. The anti-protons with their negative charge are pulled off from the collision using powerful magnets that direct the beam of anti-protons into their experiments.
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- Positrons are created by radioactive decay and are used in PET scans, or brain scans for medical diagnoses. PET scans are Positron Emission Topography. The positrons are injected into the body. They then annihilate electrons in nearby atoms in the brain.
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- The energy emerges as two gamma rays that shoot off in opposite directions at 510,000 electron volts. The angles of projection are precisely aligned to conserve the angular momentum. The gamma ray beams are detected in a ring of detectors very similar to a particle accelerator. The speed and angles are recorded in a computer and topography techniques are used to reconstruct an image of the brain and show the doctors if a tumor is there.
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- No one has ever observed the production of a particle or an anti-particle by themselves. They always come in pairs. To create a pair you need lots of energy. Your body is made of ordinary matter particles. These particles have been around for a long time. In fact, they were created 13,700,000,000 years ago. These particles were created from the energy of the Big Bang.
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- At time of the Big Bang they were created as pairs. An equal number of particles and anti-particles were produced. But, somehow, and we don’t know how, things got lopsided. When the annihilation of particle / antiparticle were over a small amount of matter was left over. That is what everything we know is made of, matter, but we do not know what happened to the anti-matter.
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- Maybe there was an anti-gravity and the anti-matter shot off to form some other anti-Universe. Of course aliens in an anti-Universe would think they were ordinary matter and we were made of anti-matter. If you ever meet, just don’t shake hands with these guys.
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- If there were not this lopsided result with the Big Bang all matter would not exist the and Universe would consist only of light radiation in empty space.
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- When electrons and positrons annihilate each other they change into photons. In other words fermions change into bosons. Or, in other words mass changes into energy. We know that because E=mc^2.
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------------------------------ Energy = mass * 90,000,000,000,000,000.
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------------------------------ Energy = kilograms * meters^2 /seconds^2.
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------------------------------ Force = mass * acceleration
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------------------------------ Force = kilograms * meters / second^2
------------------------------ Energy = Force * Distance
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- A particle thought to be moving faster than the speed of light, by another observer would be seen as a particle traveling backward in time and having the opposite charge. So, according to Richard Feynman, professor at Caltech, a positron can be viewed as an electron traveling backwards in time. Sorry, I can’t explain that one.
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- Physicists believe that other than having an opposite charge antimatter follows all the laws of physics the same as matter. But it is hard to prove. One piece of evidence comes from the Supernova explosion 1987A. Astronomers detecting neutrinos and anti-neutrinos from this explosion found them to be arriving Earth at the same time.
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- The Supernova is 164,000 lightyears away. If gravity was affecting matter differently than anti-matter then we would not expect both types of neutrinos to arrive simultaneously. Particle physicists are studying antimatter to learn if all the laws equally apply. We still don’t know for sure.
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- The starship Enterprise in Star Trek is powered by matter- antimatter fuel. It would be the ideal fuel. There is no better efficiency that creating matter into 100% energy. Especially with E=mc^2.
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- One kilogram would give you 90,000,000,000,000,000 kilogram*meter^2/second^2 of energy. One ounce would light every light bulb in the United States for 24 hours. A kilogram*meter^2/second^2 is a joule of energy and a joule is a watt of energy per second. We have just not figured how to mine antimatter yet.
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- Antimatter is not found naturally on Earth. Exceptions are, very briefly, during radioactive decay and when Cosmic Rays collide with atoms in the upper atmosphere. Also, very small amounts of antimatter, such as anti-hydrogen, can be produced in our particle accelerators. The small amount of antimatter produced by the largest particle accelerator, CERN in Geneva, Switzerland, would light a 100 watt bulb for only 3 seconds.
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- Anti-hydrogen produced at CERN has one positron and one antiproton in each atom. If the atoms remain suspended in a perfect vacuum they survive indefinitely. However, if the anti-hydrogen comes in contact with ordinary matter, such as the walls of a container, the atoms quickly annihilate each other and turn into energy in the form of gamma ray radiation and high energy particles called pions. The pions decay quickly into muons, neutrinos, positrons, and electrons. It all happens in a flash.
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- Antimatter is made of 12 fundamental anti-particles. Just as matter is made of 12 fundamental particles. The Standard Model for Particle Physics defines all matter being made of 6 varieties of quarks and 6 varieties of leptons. Quarks come in threes and make up protons and neutrons. Leptons come in three varieties of electrons and three varieties of neutrinos. So the 12 fundamental particles make up “ordinary matter”.
-
- The Standard model also includes the anti-particles for each of these fundamental particles of matter. A total of 24 fundamental particles with mass. Particles and anti-particles have the same mass but opposite signs of charge. For example, the electron has a negative charge and the positron has the same mass but carries a positive charge. If an electron and a positron collide they vaporize in a flash of energy.
-
- The Standard Model does include four “force carrying” particles, the photons, W-Z bosons, gluons, and gravitons but these are massless and only travel at the speed of light. Since they are massless they have no anti-particle counterpart.
-
- In 1928 Paul Dirac predicted that anti-particles existed. He developed equations of motion for the waveforms of electrons using Einstein’s theory of relativity. His equations required that there be negative electrons as well as positive electrons. Therefore he predicted that a positive electron twin of the same mass must exist. It was in the math.
-
In 1932 this particle was actually discovered in cloud chambers that were studying cosmic ray collisions in the upper atmosphere. The first anti-particle was called a positron. In 1955 the antiproton was discovered. In 1956 the anti-neutron was discovered. In 1995 the anti-hydrogen atom was created.
-
- Today antiprotons are routinely produced in particle accelerators. Protons traveling at near light speed are smashed into a block of copper or iridium metal. ( Any material would work as a target. It is just that these are easy to cool and beefsteak would be too sloppy.) The energetic protons are stopped so abruptly very high temperatures are created. Temperatures high enough to create matter-antimatter pairs. The anti-protons with their negative charge are pulled off from the collision using powerful magnets that direct the beam of anti-protons into their experiments.
-
- Positrons are created by radioactive decay and are used in PET scans, or brain scans for medical diagnoses. PET scans are Positron Emission Topography. The positrons are injected into the body. They then annihilate electrons in nearby atoms in the brain.
-
- The energy emerges as two gamma rays that shoot off in opposite directions at 510,000 electron volts. The angles of projection are precisely aligned to conserve the angular momentum. The gamma ray beams are detected in a ring of detectors very similar to a particle accelerator. The speed and angles are recorded in a computer and topography techniques are used to reconstruct an image of the brain and show the doctors if a tumor is there.
-
- No one has ever observed the production of a particle or an anti-particle by themselves. They always come in pairs. To create a pair you need lots of energy. Your body is made of ordinary matter particles. These particles have been around for a long time. In fact, they were created 13,700,000,000 years ago. These particles were created from the energy of the Big Bang.
-
- At that time they were created as pairs. An equal number of particles and anti-particles were produced. But, somehow, and we don’t know how, things got lopsided. When the annihilation of particle/antiparticle were over a small amount of matter was left over. That is what everything we know is made of, matter, but we do not know what happened to the anti-matter
-
- Maybe there was an anti-gravity and the anti-matter shot off to form some other anti-Universe. Of course aliens in an anti-Universe would think they were ordinary matter and we were made of anti-matter. If you ever meet, just don’t shake hands with these guys.
-
- If there were not this lopsided result with the Big Bang all matter would not exist the and Universe would consist only of light radiation in empty space.
-
- Physicists believe that other than having an opposite charge antimatter follows all the laws of physics the same as matter. But it is hard to prove. One piece of evidence comes from the Supernova explosion 1987A. Astronomers detecting neutrinos and anti-neutrinos from this explosion found them to be arriving Earth at the same time.
-
- The Supernova is 164,000 lightyears away. If gravity was affecting matter differently than anti-matter then we would not expect both types of neutrinos to arrive simultaneously. Particle physicists are studying antimatter to learn if all the laws equally apply. We still don’t know for sure.
-
- The starship Enterprise in Star Trek is powered by matter- antimatter fuel. It would be the ideal fuel. There is no better efficiency that creating matter into 100% energy. Especially with E=mc^2. One kilogram would give you 90,000,000,000,000,000 kilogram*meter^2 / second^2 of energy. One ounce would light every light bulb in the United States for 24 hours. A kilogram*meter^2 / second^2 is a joule of energy and a joule is a watt of energy per second.
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- We have just not figured how to mine antimatter yet. Now you know as much as I know about antimatter.
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- December 24, 2019 2562 730 607
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--------------------- Tuesday, December 24, 2019 --------------------
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