- 2951 - ATOM - what happens on the inside? No one really knows what happens inside an atom. But two competing groups of scientists think they've figured it out. And both are racing to prove that their own vision is correct. Here's what we know for sure: Electrons whiz around "orbitals" in an atom's outer shell. Then there's a whole lot of empty space. Right in the center of that space, there's a tiny nucleus, a dense knot of protons and neutrons that give the atom most of its mass.
- But first you need to here the story of the nun who went to a Hooter’s Bar.
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- A nun, badly needing to use the restroom, walked into a local Hooters.
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- The place was hopping with music and loud conversation and every once in a while "the lights would turn off."
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- Each time the lights would go out, the place would erupt into cheers.
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- However, when the revelers saw the nun, the room went dead silent.
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- She walked up to the bartender, and asked, "May I please use the restroom?
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- The bartender replied, "OK, but I should warn you that there is a statue of a naked man in there wearing only a fig leaf."
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- "Well, in that case, I'll just look the other way," said the nun.
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- So the bartender showed the nun to the back of the restaurant.
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- After a few minutes, she came back out, and the whole place stopped just long enough to give the nun a loud round of applause. !
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- She went to the bartender and said, "Sir, I don't understand. Why did they applaud for me just because I went to the restroom?"
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- "Well, now they know you're one of us," said the bartender, "Would you like a drink?"
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- "No thank you, but, I still don't understand," said the puzzled nun.
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- "You see," laughed the bartender, "every time someone lifts the fig leaf on that statue, the lights go out.
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- Now, how about that drink?"
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----------------------------- 2951 - ATOM - what happens on the inside?
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- Those protons and neutrons at the center of the astom cluster together, bound by the “strong force“. The number of those protons and neutrons determine whether the atom is iron or oxygen or xenon, and whether it's radioactive or stable.
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- No one knows how those protons and neutrons (together known as nucleons) behave inside an atom. Outside an atom, protons and neutrons have definite sizes and shapes. Each of nucleons is made up of three smaller particles called “quarks“, and the interactions between those quarks are so intense that no external force should be able to deform them, not even the powerful forces between particles in a nucleus.
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- This theory is in some way wrong. Experiments have shown that, inside a nucleus, protons and neutrons appear much larger than they should be. Physicists have developed two competing theories that try to explain that weird mismatch, and the proponents of each are quite certain the other is incorrect. Both camps agree, however, that whatever the correct answer is, it must come from a field beyond their own.
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- Since the 1940s, physicists have known that nucleons move in tight little orbitals within the nucleus. The nucleons, confined in their movements, have very little energy. They don't bounce around much, since they are restrained by the strong force.
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- In 1983, physicists at the European Organization for Nuclear Research (CERN) noticed something strange: Beams of electrons bounced off iron in a way that was very different from how they bounced off free protons. That was unexpected. If the protons inside hydrogen were the same size as the protons inside iron, the electrons should have bounced off in much the same way.
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- Scientists came to believe it was a size issue. For some reason, protons and neutrons inside heavy nuclei act as if they are much larger than when they are outside the nuclei. Researchers call this phenomenon the “EMC effect“, after the “European Muon Collaboration”, the group that accidentally discovered it. It violates existing theories of nuclear physics.
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- While quarks, the subatomic particles that make up nucleons, strongly interact within a given proton or neutron, quarks in different protons and neutrons can't interact much with each other. The strong force inside a nucleon is so strong it eclipses the strong force holding nucleons to other nucleons.
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- At any given time, about 20% of the nucleons in a nucleus are outside their orbitals. Instead, they're paired off with other nucleons, interacting in "short range correlations." Under those circumstances, the interactions between the nucleons are much higher-energy than usual. That's because the quarks poke through the walls of their individual nucleons and start to directly interact, and those quark-quark interactions are much more powerful than nucleon-nucleon interactions.
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- These interactions break down the walls separating quarks inside individual protons or neutrons. The quarks making up one proton and the quarks making up another proton start to occupy the same space. This causes the protons (or neutrons) to stretch and blur. They grow a lot, albeit for very short periods of time. That skews the average size of the entire cohort in the nucleus thus producing the “EMC effect“.
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- Other scientists think the EMC effect is still unresolved. That's because the basic model of nuclear physics already accounts for a lot of the short-range pairing.
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- What is clear is that the traditional model of nuclear physics cannot explain this EMC effect. We now think that the explanation must be coming from QCD. Quantum Chromodynamics is the system of rules that govern the behavior of quarks.
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- Shifting from nuclear physics to QCD is a bit like looking at the same picture twice: once on a first-generation flip phone, that's nuclear physics, and then again on a high-resolution TV, that's quantum chromodynamics. The high-res TV offers a lot more detail, but it's a lot more complicated to build.
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- The problem is that the complete QCD equations describing all the quarks in a nucleus are too difficult to solve. Modern supercomputers are about 100 years away from being fast enough for the task. And even if supercomputers were fast enough today, the equations haven't advanced to the point where you could plug them into a computer.
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- That suggests we need a different model. We know that inside a nucleus are these very strong nuclear forces. These are a bit like electromagnetic fields, except they're strong force fields. The fields operate at such tiny distances that they're of negligible magnitude outside the nucleus, but they're powerful inside of it.
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- These force fields, which we call "mean fields" (for the combined strength they carry) actually deform the internal structure of protons, neutrons and pions (a type of strong force-carrying particle).
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- Just like if you take an atom and you put it inside a strong magnetic field, you will change the internal structure of that atom.
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- An experiment underway at Jefferson National Accelerator Facility in Virginia will move nucleons closer together, bit by bit, and allow researchers to watch them change.
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- A "polarized EMC experiment" that would break up the effect based on the spin (a quantum trait) of the protons involved. It might reveal unseen details of the effect that could aid calculations.
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- We still have a lot more to learn about atoms………….. Here are some more reviews:
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- 2913 - ATOM - can we see an atom? Well, that really depends on what we mean by “see.” We see something when light emitted or reflected from an object reaches our eyes and the signal is conducted to our brain.
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- 2867 - ATOM - and the electron cloud? The picture of the atom you were taught in high school is wrong, mainly because electrons aren’t point-like particles. Electrons are a‘fuzzy’ . They are tough to pin down due to their ‘Quantum Wave Function’, which is a complicated way of saying they exist as a field of “probability“, not as an individual particle.
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- 2709 - ATOMS - measuring how atoms work? - An atom can be viewed as a tiny electron orbiting a tiny nucleus at a certain radius. Let’s start with the hydrogen atom which is a single proton orbited by a single electron.
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- 2694 - ATOM - How can mathematics tell us how an atom works? It is 100 years of discovery. - It is how physicists were able to figure out the mathematics that defines the behavior of an atom. They are still figuring, but, we have come a long way.
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- 2685 - MOLECULE - how a molecule works? When there is more than one proton in the nucleus and more than one atom in orbit this classical physics math just becomes overwhelming. That is the reason the math of Quantum Mechanics was invented. When Quantum Mechanic’s math is used, the concept of the electron orbiting the proton completely disappears. The electron’s position around the nucleus becomes a probability distribution
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- 2452 - ATOMS -Michael Discovers Atoms. My grandson, Michael, was looking at pond water under his microscope. He could see small plants and animals moving around in the water. But, he also saw all the little pieces of dust jiggling, almost vibrating, in a zigzag manner. He asked me what causes everything to move like that?
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- 2377 - ATOM - defining the atom All the other elements in the periodic table above hydrogen and helium were created in the nuclear fusion of the stars The first stars formed with only hydrogen and helium. When they burned all their fuel and exploded as supernova they splattered the surrounding space with all the atoms in the higher level elements.
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- 2333 - Rainbows can tell us what the Universe is made of. Introduction to the science of spectroscopy.
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- 2318 - Brownian motion from atoms you can not see. My grandson, Michael, was 9 years old when he was looking at pond water under his microscope. He could see small plants and animals moving around in the water. But, he also saw all the little pieces of dust jiggling, almost vibrating, in a zigzag manner. He asked me what causes everything to move like that?
- 2315 - About how atoms were first discovered. How was the atom discovered, This review covers the first 100 years of discovery that started in 1808. John Dalton conclusively argued for the existence of the indivisible atom, and at the same time as Einstein was provided a way to directly measure those atoms, Thomson and Rutherford discovered that the atom wasn't indivisible at all. Instead, it was made of even tinier bits
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- 2307 - How small is the atom? An atom is very small. However, all atoms are about the same size, 10^-10 meters. Atoms of all the elements have different atomic weights but they still are about the same size in diameter.
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- 2255 - History of the atom.
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- 2256 - Atom’s stability and uncertainty?
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- 2147 - Rutherford’s atom. How the atom was discovered in 1911.
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December 25, 2020 ATOM - what happens on the inside? 2952
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