FORMATION OF THE LIGHT ELEMENTS IN THE BIG BANG THEORY EXPLANATION AND EVIDENCES

 Big Bang Theory The big bang theory is a cosmological model stating that the universe started its expansion about 13.8 billion years ago.

The origin of all the naturally occurring elements fall into two phases:  Big Bang or Primordial Nucleosynthesis —the origin of the “light” elements; and  Stellar Nucleosynthesis— the origin and production of the “heavy” elements.

 Nucleosynthesis is the process that creates new atomic nucleus from preexisting nucleons, which is proton neutrons.  Primordial or Big Bang Nucleosynthesis refers to the process of producing the “light elements” shortly after the Big Bang.  The energy and temperature of the universe are extremely high to cause the neutrons and protons to combine and form certain species of atomic nuclei in a process called nuclear fusion.

Formation of Light Elements  Big bang nucleosynthesis is the process of producing the light elements during the big bang expansion.

In the beginning, the universe was very hot that matter was fully ionized and dissociated. Few seconds after the start of the big bang, the universe was filled with protons, neutrons, electrons, neutrinos, and positrons. After the first three minutes, the universe cooled down to a point where atomic nuclei can form. Protons and neutrons combined to form atomic nuclei such as deuterium. However, the temperature of the universe was still much greater than the binding energy of deuterium.  Binding energy is the energy required to break down a nucleus into its components. Therefore, deuterium easily decayed upon formation.

The lifetime of a free neutron to decay is about ten minutes. However most neutrons do not have time to decay. After only about three minutes have elapsed, something else occurs. Neutrons interact with protons to form nuclei of deuterium, or heavy hydrog en. The deuterium soon gains another neutron to form tritium, which in turn rapidly absorbs a proton to form a helium nucleus of mass 4, consisting of two protons and two neutrons.

The (hydrogen, helium, deuterium, lithium) were produced in the Big Bang nucleosynthesis. The lightest elements (hydrogen, helium, deuterium, lithium) were produced in the Big Bang nucleosynthesis. According to the Big Bang theory, the temperatures in the early universe were so high that fusion reactions could take place. This resulted in the formation of light elements: hydrogen, deuterium, helium (two isotopes), lithium and trace amounts of beryllium.

Through Nuclear Fusion, the light elements- Hydrogen (H), Helium (He), and small amounts of lithium (Li) and beryllium (Be) were formed. The isotopes produced during the big bang nucleosynthesis were H-1, H-2, H-3, H-4, L-7.  An Isotope is a form of an element that has the same atomic number of the original element but with different atomic mass or mass number.

During the formation of the universe in the so-called big bang, only the lightest elements were formed : hydrogen, helium, lithium, and beryllium. Hydrogen and helium dominated; the lithium and beryllium were only made in trace quantities. The other 88 elements found in nature were created in nuclear reactions in the stars and in huge stellar explosions known as supernovas. Stars like the Sun and planets like Earth containing elements other than hydrogen and helium could only form after the first generation of massive stars exploded as supernovas, and scattered the atoms of heavy elements throughout the galaxy to be recycled.

Light elements, including hydrogen, helium, deuterium, and lithium, were formed in the Big Bang because of the weak nuclear interaction, which is responsible for radioactive decays of unstable isotopes. Moreover, processes such as nucleosynthesis and thermonuclear fusion.

Helium is synthesized inside stars by thermonuclear fusion. However, most stars, like the sun, are still burning hydrogen and so have made little helium, and certainly dispersed none of it. This confirms that helium has mostly not been synthesized along with the heavier elements, such as the metals, but was made prior to the formation of the first stars. The coincidence between observation and prediction of the helium abundance in the universe provides one of the major pieces of evidence for the Big Bang theory.

Physical Science Group 1 PRESENTED BY: ANGEL ANN SANTIAGO JERICHO GONZALES