Nuclear Fusion
... inside a star approach 15,000,000 ◦ C, while the high pressure results in a density of approximately 160 g/cm3 which for comparison is 8x that of gold. Under these conditions the nuclei are free to move in a sea of electrons. Nuclear fusion takes place in the core of the sun where the density is at ...
... inside a star approach 15,000,000 ◦ C, while the high pressure results in a density of approximately 160 g/cm3 which for comparison is 8x that of gold. Under these conditions the nuclei are free to move in a sea of electrons. Nuclear fusion takes place in the core of the sun where the density is at ...
Review Guide - Cleveland ISD
... Chromosomes are found in the nucleus GENotype = GENes passed from each parent PHenotype = PHysical appearance of traits HOMOzygous = 2 of the same alleles for a trait HETEROzygous = 2 different alleles for a trait ...
... Chromosomes are found in the nucleus GENotype = GENes passed from each parent PHenotype = PHysical appearance of traits HOMOzygous = 2 of the same alleles for a trait HETEROzygous = 2 different alleles for a trait ...
exam1guide - Chemistry at Winthrop University
... There will be at three metric conversion questions, as well as questions about the metric system of measurement. Please see the sample test questions document for example questions. Scientific Methods: the definition and purpose of science, scientific accuracy, the natural world, “the” scientific me ...
... There will be at three metric conversion questions, as well as questions about the metric system of measurement. Please see the sample test questions document for example questions. Scientific Methods: the definition and purpose of science, scientific accuracy, the natural world, “the” scientific me ...
nuclear fusion
... nuclei falling in from outer shells stopped, partially disrupted made to bounce back as fragments release of p, n, high energy collisions ...
... nuclei falling in from outer shells stopped, partially disrupted made to bounce back as fragments release of p, n, high energy collisions ...
Evidence for the Big Bang
... The oldest stars (11 billion years) also have ~ 24% He so this He cannot have been made in stars! Big Bang - in early history the whole universe was the same temp as the inside of a star! Fusion in the first three minutes of history made the helium This shows that the universe was hot in earliest ...
... The oldest stars (11 billion years) also have ~ 24% He so this He cannot have been made in stars! Big Bang - in early history the whole universe was the same temp as the inside of a star! Fusion in the first three minutes of history made the helium This shows that the universe was hot in earliest ...
Stages in the Formation of Stars
... producing vast amounts of energy. _____________________________________________ 4. What two processes balance each other to make a star stable? ...
... producing vast amounts of energy. _____________________________________________ 4. What two processes balance each other to make a star stable? ...
Astronomy Homework - Life
... 13. Helium fusion lasts for a few (tens of millions/tens of billions) of years. 14. When there is no more helium to fuse in the core, the core will (expand/contract). 15. Surrounding the contracting carbon core of a star are, in order out from the core, fusion burning shells of (hydrogen then helium ...
... 13. Helium fusion lasts for a few (tens of millions/tens of billions) of years. 14. When there is no more helium to fuse in the core, the core will (expand/contract). 15. Surrounding the contracting carbon core of a star are, in order out from the core, fusion burning shells of (hydrogen then helium ...
Lecture 28 Formation of chemical elements
... that produces our sun’s energy and it is occurring in the vast majority of stars we can see. How much energy is released in hydrogen nuclear burning? We use E = Δmc2 to calculate nuclear mass of He 42He: rest mass of n: rest mass of p: C (speed of light): ...
... that produces our sun’s energy and it is occurring in the vast majority of stars we can see. How much energy is released in hydrogen nuclear burning? We use E = Δmc2 to calculate nuclear mass of He 42He: rest mass of n: rest mass of p: C (speed of light): ...
Stars: from Adolescence to Old Age
... Dying Process of Massive Stars At the end of the helium-fusion stage, a star with a mass greater than about 8 solar masses has not yet exhausted its inner resources Such a star is massive enough to cause more contraction that can trigger other kinds of fusion in its center Carbon can fuse into stil ...
... Dying Process of Massive Stars At the end of the helium-fusion stage, a star with a mass greater than about 8 solar masses has not yet exhausted its inner resources Such a star is massive enough to cause more contraction that can trigger other kinds of fusion in its center Carbon can fuse into stil ...
17 The Deaths of Stars
... 1. A small star that is the extremely dense core of the original star made of helium, carbon, oxygen, or neon depending on the original size of the star. Gravitational contraction quickly forces the material into electron degeneracy. It is called a white dwarf. 2. An envelope expanding away from the ...
... 1. A small star that is the extremely dense core of the original star made of helium, carbon, oxygen, or neon depending on the original size of the star. Gravitational contraction quickly forces the material into electron degeneracy. It is called a white dwarf. 2. An envelope expanding away from the ...
Time From the Perspective of a Particle Physicist
... • end up with core of Iron nuclei plus 26 unbound “free” electrons for every Fe • electrons are “degenerate” as so close together provide most of the pressure resisting gravity • enormous stress. electrons “give way” leaves “hole” size of Earth in center of star ...
... • end up with core of Iron nuclei plus 26 unbound “free” electrons for every Fe • electrons are “degenerate” as so close together provide most of the pressure resisting gravity • enormous stress. electrons “give way” leaves “hole” size of Earth in center of star ...
PowerPoint File
... • More massive stars have more fuel than less massive stars. • But they are using their fuel up at a fast rate, much faster than proportional to their mass. • So, massive stars run out of fuel sooner. The more massive, the shorter their Main Sequence lifetime ...
... • More massive stars have more fuel than less massive stars. • But they are using their fuel up at a fast rate, much faster than proportional to their mass. • So, massive stars run out of fuel sooner. The more massive, the shorter their Main Sequence lifetime ...
model
... Astronomy and Astrophysics, 29 (1991) 129-162 Francesca Matteucci, The Chemical Evolution of the Galaxy, Kluwer, Astrophysics and Space Science Library (2003) Francesca Matteucci, Chemical evolution of the Milky Way and its Satellites, 37th Saas-Fee Advanced Course, " The Origin of the Galaxy and th ...
... Astronomy and Astrophysics, 29 (1991) 129-162 Francesca Matteucci, The Chemical Evolution of the Galaxy, Kluwer, Astrophysics and Space Science Library (2003) Francesca Matteucci, Chemical evolution of the Milky Way and its Satellites, 37th Saas-Fee Advanced Course, " The Origin of the Galaxy and th ...
Element Brochure
... nearly everything. That makes it the most abundant element in the universe. ...
... nearly everything. That makes it the most abundant element in the universe. ...
12 C(α,γ) 16 O - Jefferson Lab
... • These gammas hit oxygen nuclei in laughing gas (N2O) inside of the bubble chamber ...
... • These gammas hit oxygen nuclei in laughing gas (N2O) inside of the bubble chamber ...
Big Bang and Beyond
... • Hoyle calculated the temperature inside a large star to be about 100 million degrees • and worked out how much kinetic energy this would give to the particles rushing around in the star's atmosphere. • Knowing the masses of both beryllium-8 and Helium, his hypothesis predicted that there must be a ...
... • Hoyle calculated the temperature inside a large star to be about 100 million degrees • and worked out how much kinetic energy this would give to the particles rushing around in the star's atmosphere. • Knowing the masses of both beryllium-8 and Helium, his hypothesis predicted that there must be a ...
Degeneracy pressure Normal/degeneracy pressure White dwarfs — Oct 10
... Making elements heavier than iron • Lighter elements (He, O, C, Ne, Mg, etc) are made by fusion with a release of energy ...
... Making elements heavier than iron • Lighter elements (He, O, C, Ne, Mg, etc) are made by fusion with a release of energy ...
Supernovae and supernova remnants
... that occurs at its own particular temperature. In general, the higher the temperature, the heavier the element created. Because the temperature increases as one goes deeper into the star and because the temperature in the core of a star is slowly increasing during this phase, an ‘onion-skin structur ...
... that occurs at its own particular temperature. In general, the higher the temperature, the heavier the element created. Because the temperature increases as one goes deeper into the star and because the temperature in the core of a star is slowly increasing during this phase, an ‘onion-skin structur ...
origin of the Solar System
... some elements condense into dust grains (presolar grains) and amorphous dust, either in stellar atmospheres or in interstellar space. Gas and dust collect into giant, cold molecular clouds. Dense cores collapse into stars, such as the Sun 4.56 Gy ago and planets, asteroids and comets form. Asteroids ...
... some elements condense into dust grains (presolar grains) and amorphous dust, either in stellar atmospheres or in interstellar space. Gas and dust collect into giant, cold molecular clouds. Dense cores collapse into stars, such as the Sun 4.56 Gy ago and planets, asteroids and comets form. Asteroids ...
Lecture 10 - Concord University
... neutronization occurs converting the electrons and protons into neutrons and releasing a blast of ...
... neutronization occurs converting the electrons and protons into neutrons and releasing a blast of ...
AS2001 - University of St Andrews
... Quark + antiquark annihilation photon/baryon ratio The quark soup heavy quark decay Quark-Hadron phase transition and neutron decay n/p ratio Big Bang nucleosynthesis primordial abundances Xp = 0.75 ...
... Quark + antiquark annihilation photon/baryon ratio The quark soup heavy quark decay Quark-Hadron phase transition and neutron decay n/p ratio Big Bang nucleosynthesis primordial abundances Xp = 0.75 ...
AY5 Announcements
... Which of the following is true of the White Dwarf the Sun will eventually become? A. It will be slightly more massive than the Sun as it will have converted the light-weight hydrogen into heavier helium B. It will have a slightly larger radius than the Sun because of its high temperature C. It w ...
... Which of the following is true of the White Dwarf the Sun will eventually become? A. It will be slightly more massive than the Sun as it will have converted the light-weight hydrogen into heavier helium B. It will have a slightly larger radius than the Sun because of its high temperature C. It w ...
File
... C. Iron is the most stable element 1. No natural fission or fusion 2. Photodisintegration of core 3. Quickly collapses D. e’s & protons fuse into neutrons E. Neutron degeneracy prevents total collapse F. Collapse rebounds in < 1 sec. ...
... C. Iron is the most stable element 1. No natural fission or fusion 2. Photodisintegration of core 3. Quickly collapses D. e’s & protons fuse into neutrons E. Neutron degeneracy prevents total collapse F. Collapse rebounds in < 1 sec. ...
Nucleosynthesis
Nucleosynthesis is the process that creates new atomic nuclei from pre-existing nucleons, primarily protons and neutrons. The first nuclei were formed about three minutes after the Big Bang, through the process called Big Bang nucleosynthesis. It was then that hydrogen and helium formed to become the content of the first stars, and this primeval process is responsible for the present hydrogen/helium ratio of the cosmos.With the formation of stars, heavier nuclei were created from hydrogen and helium by stellar nucleosynthesis, a process that continues today. Some of these elements, particularly those lighter than iron, continue to be delivered to the interstellar medium when low mass stars eject their outer envelope before they collapse to form white dwarfs. The remains of their ejected mass form the planetary nebulae observable throughout our galaxy.Supernova nucleosynthesis within exploding stars by fusing carbon and oxygen is responsible for the abundances of elements between magnesium (atomic number 12) and nickel (atomic number 28). Supernova nucleosynthesis is also thought to be responsible for the creation of rarer elements heavier than iron and nickel, in the last few seconds of a type II supernova event. The synthesis of these heavier elements absorbs energy (endothermic) as they are created, from the energy produced during the supernova explosion. Some of those elements are created from the absorption of multiple neutrons (the R process) in the period of a few seconds during the explosion. The elements formed in supernovas include the heaviest elements known, such as the long-lived elements uranium and thorium.Cosmic ray spallation, caused when cosmic rays impact the interstellar medium and fragment larger atomic species, is a significant source of the lighter nuclei, particularly 3He, 9Be and 10,11B, that are not created by stellar nucleosynthesis.In addition to the fusion processes responsible for the growing abundances of elements in the universe, a few minor natural processes continue to produce very small numbers of new nuclides on Earth. These nuclides contribute little to their abundances, but may account for the presence of specific new nuclei. These nuclides are produced via radiogenesis (decay) of long-lived, heavy, primordial radionuclides such as uranium and thorium. Cosmic ray bombardment of elements on Earth also contribute to the presence of rare, short-lived atomic species called cosmogenic nuclides.