1. The Creation of the Elements and the Relationship to Cosmic Events in the Universe

2. The Big Bang
The Big Bang Theory is the accepted scientific theory about the origin of the universe based upon multiple lines of evidence.
The “Big Bang” was a phenomenally energetic explosion that initiated the expansion of the universe.
All matter and energy were compressed at a single point (singularity) at the time of the explosion
We do not know what was before…..?
The age of the universe is calculated at 13.7 billion years (based on multiple methods of age dating based on empirical data).

3. The Big Bang vs. the Steady State Model
The Big Bang (1931) was first proposed by an Belgian cosmologist and priest named George LeMaitre based on theoretical calculations and astronomical measurements of distant galaxies (by Edwin Hubble) that demonstrated that the universe is expanding.
The competing theory was the Steady State Model (1948) which said that on the large scale the universe has always looked the same and that there was no beginning and is no end. To account for the observed expansion of the universe, it required that matter to be continuously created to fill gaps that would be created
by an expanding universe.

4. Scientific Evidence for the Big Bang Theory
The Red Shift of Distant Galaxies
(Hubble, 1927)
The Cosmic Elemental Abundances of Hydrogen and Helium and Big Bang Nucleosynthesis
(Alpher and Gamow, 1948)
The Cosmic Microwave Background (CMB) Radiation
(Penzias and Wilson, 1964)

5. Red Shift is Evident in Emission Spectra of Light from Stars and Galaxies

6. Hubble’s Law and Red Shift
Everything in the universe is moving away from everything else (Raisin bread analogy).
We are not at the center of the universe.
Edwin Hubble discovered that distant galaxies are moving away from us at rates faster than closer galaxies are moving away from us.

7. Cosmic Elemental Abuandances
Hydrogen (74%) and Helium (24%) are the most abundant elements in the universe.
Stellar nucleosynthesis alone cannot account for the large amount of Helium. (can only account for about 2%)
Big Bang nucleosynthesis calculations accurately predict the present cosmic abundances of hydrogen and helium.

8. Big Bang Nucleosynthesis
All Hydrogen and most Helium in the universe was produced during the Big Bang Event, starting ~100 seconds after the explosion. A small amount of Lithium was also produced.
Big Bang nucleosynthesis ceased within a few minutes because the universe had expanded sufficiently by then such that the temperatures and pressures were too low to support additional fusion reactions.

10. Cosmic Microwave Background Radiation
There is a background signal of microwave radiation emitted by the universe. It comes from the light energy given off during the “Big Bang” explosion.
It can be detected no matter which direction you point an antennae in the sky, at any time, day or night.
It was discovered by accident by two astronomers (Penzias and Wilson) working at Bell Labs in New Jersey in 1964.
Penzias and Wilson won the Nobel Prize in Physics in 1978 for their discovery.

11. Cosmic Microwave Background Radiation
Due to the cosmic background microwave radiation, the remnant radiation left over from the Big Bang, the universe has an ambient temperature of 3K.
The CMB radiation is remarkably uniform in its distribution. It has been mapped by the COBE (Cosmic Background Explorer) satellite.

12. Stellar Nucleosynthesis
Stars create elements by combining lighter nuclei into heavier nuclei via nuclear fusion reactions in their cores.
Enormous temperatures (15,000,000 K), pressures, and densities of matter are needed to initiate fusion (thermonuclear) reactions.
The basic nuclear reaction in the Sun converts hydrogen to helium and releases energy in the form of electromagnetic radiation. This is why stars shine!

13. Stellar Nucleosynthesis
Larger stars can fuse heavier elements.

14. Supernova Nucleosynthesis
Elements heavier than Iron are made primarly when giant stars explode in supernova events.

15. A summary… (you are made of stardust)

16. The Life Cycles of Stars

17. Nebulae
Nebulae are regions of gas and dust in interstellar space within galaxies.
Nebulae contain gas and dust from previously exploded stars.
Nebulae are the birthplaces of new stars. (recycling!)
When stars form, planets may form too (a solar system)

18. Nebulae (continued)
The image, roughly 3 light-years across, was taken May 29-30, 1999, with the Wide Field Planetary Camera 2. The colors in the image represent various gases. Red represents sulfur; green, hydrogen; and blue, oxygen.

19. Main Sequence Stars
The Hertzsprung-Russell (H-R) Diagram shows that there is some relationship between the temperature and luminosity (brightness) of a star. The clustering indicates something about how stars change over time. Young-middle age stars always plot on the main sequence.

20. Main Sequence Stars
Main sequence stars fuse hydrogen to helium.

21. Red Giants and White Dwarfs
NGC 6369 – Planetary Nebula with White Dwarf
V838 Monocerotis – Red Giant

22. Supernovae The Veil Nebula – 5000 to 10000 years old; in our galaxy
The Crab Nebula – Supernova Remnant
Observed 1000 years ago.

23. Neutron Stars and Black Holes