How did the big bang theory predict that only three kinds of neutrinos existed? And how did the theory of general relativiy predict that the universe is expanding? I keep reading about it but never get any of the details. Ok, this is off the subject. But I was wondering what the gravity of a baseball sized junk of a neutron star (300 trillion grams/cc) would do to you if you were standing close to it.
It would explode, as a piece of neutonium that big would be too small to be held together by it's own gravity. A neutronium bomb, probably much more than a megaton (but I don't know the exact yield). _________________ SF worldbuilding at http://www.orionsarm.com/main.html
Hum, That theory made no predictions on the number/types of neutrinos...( if i remember ). Check out this site for the history... http://www.ps.uci.edu/~superk/neutrino.html The theory <b>did</b> predict the amount of <i>neutrons though</i>... When the universe had cooled to a temperature of 6 × 109 K and the electron-positron production and annihilation process stopped. Also the number of neutrons stopped increasing by the proton-electron fusion process. The number of neutrons was fixed at a ratio of<i> 1 neutron for every 5 protons</i>. There was a very slight excess of ordinary matter over antimatter (by about 1 part in 10<sup>9</sup>). All of the protons, neutrons, and electrons in the universe today were created in the first few seconds after the Big Bang. The expanding universe had cooled to below about 10<sup>9</sup> K so that protons and neutrons could fuse to make stable deuterium nuclei (a hydrogen isotope with one proton and one neutron). Most of the helium in the universe was created from the primordial neutrons and protons (Although stars do produce some of the helium visible today), by the time the nucleosynthesis epoch ended. Stars to fuse hydrogen nuclei to make a helium nucleus use fusion. The fusion chain process in the early universe was slightly different than what occurs in stars because of the abundant free neutrons in the early universe. However, the general process is the same: protons react to produce deuterium (heavy hydrogen), deuterium nuclei react to make Helium-3 nuclei, and Helium-3 nuclei react to make the stable Helium-4 nucleus. The amount of the final Helium-4 product is not as sensitive to the density of the early universe The deuterium nucleus is the weak link of the chain process, so the fusion chain reactions could not take place until the universe had cooled enough. The exact temperature depends sensitively on the density at that time. Extremely small amounts of Lithium-7 were also produced during the early universe nucleosynthesis process. Lithium-7 and deuterium density depends sensitively upon the density of protons (2 up + 1 down quarks) and neutrons during this time. If the universe were too dense, then most of the deuterium would have fused into helium. The more neutrons that decay before combining with protons, the smaller the abundances of heavier elements. Only in a low-density universe can the deuterium survive. A denser universe would have had more deuterium fused to form helium, so the amount of the remaining deuterium seen today is used as a probe of the early density because of the sensitivity of its production to the density of the protons and neutrons and temperature in the early universe. . Comparing the observed densities of the primordial isotopes to those computed from models and translating the results into Omega, the density parameter, gives Omega = 0.015/h2 where h is the Hubble parameter divided by 100 km/sec/Mpc. The smaller Ho, the larger Omega; if Ho=50, Omega is approximately 0.06, whereas Ho=100 gives Omega of only 0.015. This range is still much less than Omega=1, but nucleosynthesis limits can indicate only the density of baryons, because only baryons participate in nuclear reactions. Hence we must conclude that the universe contains less than the critical density of baryons. After about 15 minutes Too cold for fusion. Free neutrons and protons were synthesised into the light elements: deuterium (D), helium-3, and helium-4. The universe consisted of 10% helium and 90% hydrogen, (25% helium and 75% hydrogen, by mass). There were also extremely small amounts of the Lithium-7 produced. The elements heavier than helium were produced in the cores of stars. The number of deuterium nuclei that do not later undergo fusion reaction to make Helium-3 nuclei also depends sensitively on the temperature and density of the protons and neutrons. A less dense universe would have had more deuterium remaining. Therefore, measurement of the primordial deuterium can show if there is enough matter to make the universe positively-curved and eventually stop the expansion. So the point is that deuterium was made in the Big Bang, but cannot be made inside stars. In fact, stellar processes destroy it. We know how much deuterium there is in stars and galaxies by measuring the light spectrum it leaves a characteristic fingerprint in the spectral lines. Because light from very distant galaxies takes a long time to reach us (sometimes, billions of years) they are seen as they were long ago. Spectroscopic measurements of the amount of deuterium in distant galaxies are the same as measuring the amount of deuterium around when the Universe was young. The standard calculations of what happened during the Big Bang, the amount of deuterium around is very closely tied to the total amount of atomic matter created. The more deuterium there is the less atomic matter there can be overall. The KamLAND neutrino experiment confirms that solar neutrinos have mass and change "flavor." The KamLAND (Kamioka Liquid-scintillator Anti-Neutrino Detector) detects antineutrinos, which are produced in nuclear reactions. Knowing how much nuclear energy the nearby nuclear reactors were producing, KamLAND physicists could calculate how many Antineutrinos would be created and how many should be detected during the experiment. Various ideas that the detectors themselves could only detect one type of neutrino was proposed. One type of detector relied on the flashed of light produced by a neutrino striking a hydrogen-peroxide molecule. This detector (deep underground) is vast, containing thousands of gallons of hair-bleach. And the walls of the container, houses thousands of electronic eyes, looking for one faint flash (Cherenkov Radiation) This experiment has shown that the neutrino can change flavour into another undetectable form by using mass. Neutrinos and antineutrinos come in three "flavours" — electron, muon, and tau — and each flavor has a different associated energy. The neutrinos oscillate. The sun does produce all three types of particle but they change on the way to the Earth.
Linkage This is all I've found on it. I understand how it would change things. But it didn't really say what exactly the prediction was. Ask The Space Scientist: How is the fact that 3 types of neutrinos exists, predicted by Big Bang Theory?
How much of the hydrogen in interstellar space is deuterium? Is their any other natural process that creates deuterium, even in really tiny amounts? Is their any traces of deuterium in the solar wind?
Good questions all. I wonder if Deuterium plays a role in powering brown dwarf stars or igniting the nucleur fires in ordinary stars?
Absolutely. A brown dwarf is defined as a body between 13 times and 80 times the mass of Jupiter- it has sufficient mass for the deuterium in the body of this kind of object to be compressed enough for deuterium fusion to take place. The smaller ones are not very hot - the compound Methane is present in large amounts, so they are sometimes called Methane brown dwarfs, while the hotter ones are characterised by the formation of the element Lithium, so are called Lithium dwarfs. _________________ SF worldbuilding at http://www.orionsarm.com/main.html
