Warm-up Listen to the theme song of Big Bang Theory. After listening a second time, list three terms that pop out at you. What is the big bang theory?

Learning Targets/Success Criteria Learning Target: Construct an explanation of the Big Bang Theory based on astronomical evidence of light spectra, motion of distant galaxies and composition of matter in the universe. Success Criteria: Explain how redshift of light from galaxies is an indication that the universe is currently expanding. Explain how cosmic microwave background is the remnant radiation from the Big Bang. Describe how the lighter elements (hydrogen and helium) were created within minutes of the big bang when the universe was hotter while heavier elements were created through the process of fusion as the universe cooled. Identify the composition of stars (hydrogen, helium and heavier elements) Identify the hydrogen-helium ratio of stars and interstellar gases (75% H: 25% He) Use reasoning to explain that an expanding universe must have been smaller in the past and can be extrapolated back in time to a tiny size from which it expanded.

Vocabulary Big Bang Theory: States the universe was created about 4 to 5 billion years ago as the result of explosions from expanding matter. Red shift: occurs when light seen coming from an object is proportionally shifted to appear more red Cosmic Microwave Background radiation: very low energy, very uniform radiation that we see filling the universe and is the strongest evidence for the validity of the Big Bang Theory.

Formation of the Universe Video Explanation by Stephen Hawking Watch the Hyperlink above for further explanation

The Big Bang Theory

Time begins The universe begins ~13.7 Billion years ago The universe begins as the size of a single atom The universe began as a violent expansion All matter and space were created from a single point of pure energy in an instant

~ 3 minutes after big bang The universe has grown from the size of an atom to larger than the size a grapefruit E=mc2 energy froze into matter according to Albert Einstein’s equation. This basically says that like snowflakes freezing, energy forms matter into clumps that today we call protons, neutrons and electrons. These parts later form into atoms

~ Several hundred thousand years after Big Bang ATOMS form (specifically Hydrogen and its isotopes with a small amount of Helium.) The early Universe was about 75% Hydrogen and 25% Helium. It is still almost the same today.

~200 to 400 million years after Big Bang 1st stars and galaxies form

~ 4.6 billion years ago Our Solar system forms

Explain how redshift of light from galaxies is an indication that the universe is currently expanding. Edwin Hubble's 1929 observation that galaxies were generally receding from us provided the first clue that the Big Bang theory might be right. Noticed that light from most galaxies was shifted to the red end of the electromagnetic spectrum.

Hubble’s Law The rate at which a galaxy is moving is directly proportional to its distance from us. In other words, the farther away a galaxy is from us, the faster it travels away from us. Thus the universe is expanding.

Hubble’s Law All Galaxies exhibit redshifts of spectral lines. More Distant Galaxies Recede Faster

The universe is expanding… Redshifts of light provide evidence

Activity One An Expanding Universe 3 MW 2 1

Doppler Effect and Using a Spectroscope Activity Two Doppler Effect and Using a Spectroscope http://www.pbslearningmedia.org/resource/phy03.sci.phys.energy.doppler/stellar-velocity-the-doppler-effect/

Explain how cosmic microwave background is the remnant radiation from the Big Bang. The presence of cosmic background microwave radiation is the leftover heat from the big bang. The universe was once very hot and is in a state of cooling. Cosmic Background Microwave Radiation provides this proof. It is currently about 3 Kelvin.

Cosmic Microwave Background Radiation Long-wavelength radiation that fills all space. Can be detected using special antenna. 1% of this can be detected in the static on your TV set. Let’s listen!!!

Steady State Theory As matter moves apart, new matter is created to fill the gaps. Cosmic Background Radiation in the universe ruled out the Steady State Theory.

Steady State Theory Opposes the Big Bang Theory Steady State Theory states that the universe has always been essentially the same as it is today and that it will continue that way forever.

Cosmic Background Radiation & History Connect Activity 3 Cosmic Background Radiation & History Connect

Describe how the lighter elements (hydrogen and helium) were created within minutes of the big bang when the universe was hotter while heavier elements were created through the process of fusion as the universe cooled. Identify the composition of stars (hydrogen, helium and heavier elements) Identify the hydrogen-helium ratio of stars and interstellar gases (75% H: 25% He)

Nucleosynthesis The universe was extremely hot and all matter was once in the form of free protons, electrons and neutrons that fused to form deuterium (an isotope of Hydrogen) Deuterium fused to form Helium…and so on and so on…. As nuclei fused, larger elements were formed.

If Hydrogen accounts for 91% of the sun’s elemental composition…how is hydrogen only 75% of the Sun’s mass? The Sun’s mass is about 75% H: 25% Helium