Hydrogen and Helium

      Using powerful telescopes, scientists have made extensive spectroscopic surveys of distant stars and galaxies. The data indicates that hydrogen and helium make up nearly all of the nuclear matter in the Universe. The most abundant element, hydrogen, accounts for 74% of the mass while helium contributes 25%. Heavier elements comprise less than 1% of the total.

      The observed 3:1 ratio of hydrogen to helium along with the relative scarcity of heavier elements yield critical clues

about the density, temperature, and expansion rate of the early Universe. The correlations between these observations and the predictions of the Big Bang model are striking pieces of evidence in support for the theory.  

Copyright 2005 by Lawrence Berkeley National Laboratory's Physics Division. Notice to Users.
.

. Fundamentals
..Evidence for the Big Bang
....The Expanding Universe
....Cosmic Microwave Background
....Elemental Abundancies

......Understanding Our History
......Composition of the Earth

......Composition of the Sun

......Hydrogen and Helium

......Nucleosynthesis

......Elemental Abundancies
......Formation of Light Elements
......Formation of Heavy Elements
......Quiz XV
......Quiz XVI
......Quiz XVII
....Evolution of Stars and Galaxies
....Consequences of the Big Bang

..Eras
..The Final Frontier
..Glossary









 >>

079