We all talk about the density of a scoop, or handful, or whatever, of concentrated nuclear matter, shorn of electrons so that atomic nuclei are adjacent.  My question is-if you really could obtain this (yes, I know the gravitational effects, but lets be sci-fi writers for a second), would this material maintain it's physical properties away from the extremely high gravity field of a neutron star?  Also, what would be the effect of such a large concentration of positive charges?  Thanks
201291
one of the properties of a neutron star (as far as i can tell) is that the electrons and the protons are so tightly packed that they form in to neutrons. But they are not bound together like they are in the nucleus of an atom.  \n\nThere is actualy a great statmech problem where you are suposed to calulate the radius of a neutron star using only the pauli exclution principle (basicly that fermions have the tendency to repell each other)\n\nat the moment there are two known things that are even denser... a black hole for one, and the neuclus of an atom. \n\nIf there was a free existing small part of a black hole, it would just explode in a matter of moments (~10^-14 sec i think).  as for a neutron star they would also fly appart because for the pauli exclution principle.  But if we have a huge mass of protons and neutron we would have a very very very very heavy atom.  It would attract electrons just like a normal atom.  But it would decay in just moments(problably very violently).   \n\nIt can be made, but it would exist in such small quantity and for so short of a time that it would seemingly have no properites
321858
One should not group antimatter particles all into the word element. It is possible to make any of the elements in the form of antimatter, and for any element the antimatter equivalent would be incredibly rare here on earth. Now to say the rarest is very hard because there could be at any given point in time a number of antimatter hydrogen atoms that might seem like a large number, to the human mind, here on earth. Anti hydrogen would be the most abundant anti element, although still inconcievably rare. However, some of the heaviest non-antimatter elements that have been created in the lab probably ocasionally briefly come into existence in nature here on earth. Some of these metals might be rarer than antihydrogen, the most abundent antielement here on earth. \nNote: positrons, anti electrons, are the most abundent easily observable antiparticle, but I have left them out because they are not an element.\n\nNow, as for the universe in general: It is a real curiousity that there does not seem to be an equal amount of antimatter as matter. We humans do not now how to create matter without also creating an equal amount of antimatter. Yet, it seems as though our universe is made up almost entirely of matter... What happened to all of the antimatter during the creation of the Universe??? I don't know, and as far as I am aware of there is not a solid leading theory to explain this enigma, but many ideas have been suggested with associated mathematics. Some of them propose that the antimatter went into another dimension. Others propose that there was a very slight inequality in the quantity of matter and antimatter with the difference being the matter that is currently in existence. Still others contend that the some total of matter and antimater within the Universe are still of equal quantities, but the areas where this antimatter is hiding is too far for light to have reached us from those locations. Although I have a preference between these ideas, I will not say what it is. So, lets just say that that might be a good topic for someone interested in the subject to do some real research.
7789
Correction: when stars "die", they either become a white dwarf (if they're light, where all elements are reduced to primarily iron, which has a lower energy state than anything lighter or heavier--hence, it becomes spent nuclear fuel that cannot react anymore), or a neutron star (as above, but with a mass so great that gravitational forces overwhelm nuclear forces making electron collapse into protons in a single mass), or they can become black holes (if their mass is so very great that all matter is compressed into a singlarity--ie, a point with infite density).  The mass of a black hole is guaged by the degree to which it curves the surrounding space-time continuum.\n\nA white dwarf glows as it is white-hot, but as it cools down, it becomes a brown dwarf, turning dark.\n\nThe debate in astronomy is whether the rate of the universe's expansion is sufficient to keep all black holes from collapsing.  On either end, a break prediction lies: in one scenario, everything forms one big singularity, while in the other, energy fluctations slowly even out until entropy is optimized throughout the universe, resulting in the "heat death" of the universe.
621870
All normal matter is composed of particles such as protons, neutrons and electrons, and all of these have the fundamental property of quantum mechanical spin. Spin gives each one of these particles an associated magnetic field. Because of this, and the fact that the average microscopic piece of matter contains huge numbers of these particles, it would be expected that all matter would be magnetic. Even antimatter would have magnetic characteristics. However, everyday experience shows that this is not the case.\n\nWithin each atom and molecule, the spin of each of these particles is highly ordered as a result of the Pauli Exclusion Principle. However, there is no long range ordering of these spins between atoms and molecules. Without long range ordering, there is no net magnetic field because the magnetic moment of each one of the particles is cancelled by the magnetic moment of other particles.\n\nPermanent magnets are special in that long range ordering does exist. The highest degree of ordering exists within magnetic domains. These domains can be likened to microscopic neighbourhoods in which there is a strong reinforcing interaction between particles, and as a result, a great deal of order. The greater the degree of ordering within and between domains, the greater the resulting field will be.\n\nLong range ordering (and the resulting strong net magnetic field) is one of the hallmarks of a ferromagnetic material.
81359
Gravity is only half of the picture.\n\nThe stars gravity does tend to pull the stars material towards the center of the star.\n\nHowever, there is also an expansive force - the force of the nuclear fusion reaction that is taking place inside the start.  This reaction creates light, heat, x-rays, cosmic rays and so on.. but it also pushes against the infalling star material, trying to push it back out.\n\nThe balance between gravity and fusion energy is why the star stays (about) the same size.\n\nSometimes gravity wins, and the star compresses all the way town to a neutron star or even a black hole.\n\nSometimes the nuclear reaction wins and the star explodes in a nova or supernova.\n\nMost stars are stable for a VERY long time (billions of years).
215918
All normal matter is composed of particles such as protons, neutrons and electrons, and all of these have the fundamental property of quantum mechanical spin. Spin gives each one of these particles an associated magnetic field. Because of this, and the fact that the average microscopic piece of matter contains huge numbers of these particles, it would be expected that all matter would be magnetic. Even antimatter would have magnetic characteristics. However, everyday experience shows that this is not the case.\n\nWithin each atom and molecule, the spin of each of these particles is highly ordered as a result of the Pauli Exclusion Principle. However, there is no long range ordering of these spins between atoms and molecules. Without long range ordering, there is no net magnetic field because the magnetic moment of each one of the particles is cancelled by the magnetic moment of other particles.\n\nPermanent magnets are special in that long range ordering does exist. The highest degree of ordering exists within magnetic domains. These domains can be likened to microscopic neighbourhoods in which there is a strong reinforcing interaction between particles, and as a result, a great deal of order. The greater the degree of ordering within and between domains, the greater the resulting field will be.
155450
look at column 7.  all of the densities appear there in grams/cm3.\n\nhttp://www.science.co.il/PTelements.asp
667583
Stars gain their energy through gravitational collapse. \n\nWhen the collapse raises core temperatures and pressures sufficiently, nuclear reactions begin. These reactions produce a lot of energy and a lot of photons. The photon pressure is sufficient to stop further collapse of the star.\n\nWhen the fusion materials are exhausted, collapse resumes. The core temperature and pressure then rise. When they are hot enough, further fusion of larger atoms occurs.\n\nThis continues up the periodic table until fusion is no longer possible. \n\nThe star then coninues to collapse to a very hot, degenerate ball. In some cases the temperature on the surface then gets high enough to cause a catastropic runaway fusion reaction of the helium on the surface, because the rate of fusion of helium is temperature dependent. \n\nThe start the explodes as a supernova. This throws off some matter (though not actually that much). The very high energy of the explosion is enough to produce heavier elements through nucleosynthesis.\n\nWhat is left is a tiny but very very hot star called a white dwarf. Because it is so tiny, it does not radiate much energy (it has a small surface area) so it is quite dim.
591931
Hmm interesting indeed. Well .. let me see what i think (cause i am not 100% sure yet).... Creation will be as a result of a super nova i agree. So all the particles that are produced will be radiating in an anourmous soup or particle matter. They will according to gravitational influences probably form some kind of motive arms of force that will be radial in form arcing away from the epicentre.. The super nova will create a pressure wave of force outwards. Also, in collapsing the black hole will create threads of gravitational pull around them. So it is likely that they will have pushed each other apart. We then have the period where the mass increases the force of gravity. The question now is does the gravity polarise.. i.e. Is there such thing as positive gravity and negative gravity. Well recent work on gravity fields seems to suggest that there are. So if there are two backholes are they polarised in the same way? Hmmm.. can two black holes form a single blackhole? What about the laws of equal and opposite forces? Would that allow two black holes to converge and eventually combine? Sense would suggest that they would stick together in some kind of orbit with each other. Or, would it be a survival of the fittest? OK i am ready to answer Qs 1,2 and 3 now. \n1. space between them would stay fixed in my opinion. But the concept of space and time would become distorted and stretched as they became closer to each other.\n2. They would change their gravitational polarisation in such a way as to make them co-linked but, they would not consume each other.\n3. The laws of matter and time would change for anything caught in the space between their struggle with each other.
547675
Are you just looking for nuclear scattering cross-sections?  If you want a mean free path, it's going to depend on the density.\n\nIf you have a better library than I do, you could pursue:\nhttp://cat.inist.fr/?aModele=afficheN&cpsidt=11017441\nwhich might have the cross section.  Searching the web for H(n,n') doesn't turn up as much promising as I had hoped.
21840
"What is charge?" is perhaps an impossible question to answer.  It is much easier to answer what does a charge do and physicists have covered that in detail through careful laboratory experiments.  For example, when a small dumbell is suspended at the center by a quartz filament, the unit will rotate one way when approached by a like charge and the opposite way for an opposite charge.  And the force can be determined by calibration.\n\nThat said, like charges repel and opposite charges attract.  Atoms consist of nuclei of positive protons and neutral neutrons and are surrounded by a field of orbiting negatively charged electrons.  It is almost impossible to push together two nuclei because their positive charges strongly repel (fusion energy is produced in the sun when hydrogen nuclei are in fact fused by overcoming the forces at great pressure and temperature).\n\nWhen you sit on a chair, you are being supported because the electrons of your skin atoms (or clothes?) are repelled by the electrons of the wood atoms.  Nothing can actually touch if examined under the power of an electron microscope.  We know that two objects can not occupy the same space and that goes for two electrons or two protons.  But two objects can be glued together if they attract.  Two bar magnets can be glued together if you match unlike poles.  An electron can be glued to a proton to make a hydrogen atom, the lightest atom; but even here the electron can not enter the nucleus because it is excluded. But I'd guess it takes a lot of electrons to repel you when seated, right?  hope this helps a little.
529240
Ancient Greek Mathematicians worked for years on trying to figure out how to square the circle.  It has been proved that the premise of the question was false (in Euclidean geometry); you can not square the circle (find the two integers whose ratio is pi).\n\nThe bottom line is that by asking an "impossible" question, you may spend quite a lot of time and energy searching for a non-existant answer.  So, define "isolated", define "very non-reactive" and define "hover".\nSo, let me rephrase your question: Can an atom of an element which interacts strongly with itself (to form the metallic state) be  isolated?  Answer:  it depends on what you mean by "isolated".\nWe certainly can separate it (using electrical or mechanical forces) from other atoms of its own kind. Q2: but will it interact with other atoms?A2 yes.Q3: hover? A3 "Hover"?  Doesn't that presume that the body you're talking about is 1) denser than air and 2) exerting a force to combat gravity??! A3a Or having a force exerted on it? Q3b yes, yes, the air molecules hit it around to keep it aloft!  Right? A3b So it DOES interact with the air molecules?  But forms no (by your assumptions) covalent bonds even though it was ripped out of a metallic bonding "home"...  I guess with a very inert gas atmosphere (helium), its possible.  But when it hits the wall of whatever its in it will probably stick, and being so much heavier than Helium it will most likely find its way to the bottom surface.  The problem is assuming that something that bonds (metallically) won't have a strong tendency to bond covalently.\nMercury, Hg, a toxic liquid metal at RT, has a very high vapor pressure (using special fluorescent lights you can "see" the mercury vaporizing from the surface of the liquid) and is fairly inert, but doesn't come off of a metal lattice so doesn't quite fit the bill.  Anyway, it will bounce around for quite a while before it reacts forming an amalgam or possibly being absorbed into your bloodstream and doing some neurological damage.  In general, metals are very reactive with oxygen, and I'm not sure there are any which won't (eventually) react with it unless the atoms find another way to stabilize themselves (say by forming a metal lattice).  Also, I'm not sure that Mercury vapor exists as isolated atoms, I seem to recall a paper on this recently...  Single atoms react to form a Octet in their valence shell, so outside of the nobel gasses, (not metals at normal pressures and temperatures) single atoms are not stable.  But for a while, an atom can and will bounce around.  Question:  If Xenon is heavier than air (check it!)  why isn't there more of it in the troposphere?\n\nKeep on asking the impossible questions!
209423
Some massive stars don't just fuse hydrogen into helium to burn. By the process of nuclear fusion the most massive stars will continue to fuse helium, lithium and even heavier elements in the periodic table as high as iron before they go super nova. When these stars go super nova even heavier elements such as Uranium can be formed.\nThe resulting nebula from the super nova will be rich some elements required to make rocky planets such as our own.\nPlanets are formed around stars in much the same way as stars . . . by gravity.\nNebula's can be quite lumpy. The more dense bits will, by the force of gravity, attract more matter, and become more dense, thus attract even more matter and so on.\nThis process will always end up with matter starting to spin. The Star that is forming in the middle will be surrounded by a spinning disc of gas and dust. This is called the accretion disc.\nThe accretion disc is also lumpy and the same process that forms the star also takes place, however as there is a lot less matter, these lumps rarely reach the pressures and temperatures required to start nuclear fusion and form stars, and so they condense into rocky planets, asteroid, or gas giants, depending on the composition of the matter that was there to start with.\nWhen there is enough matter in the accretion disc a binary star system is often formed.\nOne interesting fact is that if our solar systems Jupiter was four times more massive it would likely have been another smaller star.\nHope this helps!!!
388965
no, but i can tell you what we think it is:\n\nit is a star whose gravity is too great for the nuclear fusion in its core to negate.  it collapses in on itself and goes supernova.  then it is a neutron star.  if the gravity is still too great, it collapses some more and becomes a black hole.  its gravity is so strong that light itself cannot escape it (thus it is 'black').  they are suspected to be at the center of many galaxies, especially quasars and other active galaxies.  one is believed to be at the center of our own galaxy, the milky way.\n\nonce again, no one has really seen one, just the indirect evidence that one exists (strange star orbits, gas being sucked into nothing, strange bursts of some kind of rays (can't remember what kind) coming out of the poles, etc.\n\neverybody is pretty convinced that they exist.  its just kinda hard to prove.\n\nps the idiot down there who said black holes are dead galaxies has no clue what he is talking about. please ignore him.  and its not the size of an atom, its an infinitely small point, the swartzchild point.
271133
Not sure I buy that.  A neutron star is about 1.3-2.1 solar masses about 10 miles across. While that is much heavier than the earth, 10 miles across is pretty darn big compared to a test tube.  Doesn't work out to me.\n\nA teaspoon of it weighs about 10 million tons, assume 100 teaspoons or even 1,000 teaspoons and you don't have near the weight of the earth. It's mass is about 6 x 10^24 kg.\n\nA neutron star isnt exactly just bare neutrons, but I would need more evidence to beleive it.
14433
emilyrose gave a very thoughtful answer. \n\nReality on a small scale is quite a bit different than what we experience on our scale (the so-called "macroscopic scale"). I might make a few comments:\n\n1. Not only do the electrons in an atom have some wavelike properties, but the nucleus of an atom does as well. \n\n2. A "vacuum" is actually not really empty space, but a seething mass of virtual particles appearing and disappearing a very short time later (the Casimir effect is a strange force that is evidence for this mysterious force).
613555
mathematical dilemma. there is no answer to the question. Well at least none that are known. Just like the elements we know there out there but we have to figure them out first.  just like Einstein theory of fusion. its passable just not proved.