The Big Bang Theory

What do you hear? Listen to the theme song of Big Bang Theory. After listening a second time, list three terms that pop out at you.

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 (longer wavelength) Cosmic Microwave Background Radiation (CMBR): 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.

This is the electromagnetic spectrum. Long wave, low energy Short wave, high energy

But First… The Electromagnetic Spectrum All objects produce 1 of 3 spectrums! Continuous: Contains all wavelengths Emission: Gives off specific wavelengths based on elements present Absorption: Absorbs specific wavelengths based on elements needed *Emission and Absorption are OPPOSITES!

The Visible Spectrum White light (sun) is actually a mixture of many different wavelengths. When separated, a rainbow or a continuous visible spectrum is revealed.

Gases that glow produce emission spectra. This is what you see when you point a spectroscope toward a neon light.

Emission spectra are like fingerprints…each element is different! Helium tube Argon tube

Introducing the Doppler Effect The train has a higher pitch whistle when approaching you. The train has a lower pitch when moving away from you. This Doppler Effect is caused by compression or stretching of sound waves. The same phenomenon occurs with light, only the object must be moving very fast to detect it.

Blue Shifts, Red Shifts Light waves moving away from an observer are stretched. They shift toward the red end of the spectrum. Those waves moving toward an observer are compressed. They shift toward the blue end of the spectrum. The larger the shift, the faster that object is moving.

Examples of Shifts from Moving Objects! Redshift Blueshift

Spectrum Shift and Speed Spectrum @ Rest Red shift The bigger the shift – the faster the object is moving either towards or way!

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

In the beginning… Our universe sprang into existence as "singularity" around 13.7 billion years ago. Singularities are zones which defy our current understanding of physics. They are thought to exist at the core of "black holes." These zones of infinite density are called "singularities." Our universe is thought to have begun as an infinitesimally small, infinitely hot, infinitely dense, something - a singularity.

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

Misconceptions about the Big Bang There was no explosion; there was (and continues to be) an expansion Rather than imagining a balloon popping and releasing its contents, imagine a balloon expanding: an infinitesimally small balloon expanding to the size of our current universe We tend to image the singularity as a little fireball appearing somewhere in space space began inside of the singularity. Prior to the singularity, nothing existed, not space, time, matter, or energy - nothing.

Big Bang evidence Universal expansion and Hubble’s Law 3 degree background radiation Quasars Radioactive decay Stellar formation and evolution Speed of light and stellar distances

1. Universal expansion and Hubble’s Law In 1929, Hubble observed the majority of galaxies are moving away from us and each other The farther, the faster they move Red Shift

Demo An Expanding Universe 3 MW 2 1

2. Back ground radiation Noise radiation (static) is evenly spread across space The amount of radiation matched predictions C.O.B.E satellite confirmed for the entire universe that noise radiation (static) is evenly spread Law of conservation of energy (energy can neither be created or destroyed) – energy remains constant over time

Explain how cosmic microwave background is the remnant radiation from the Big Bang. The presence of CMBR is the leftover heat from the big bang. (heat=infrared… stretched out become microwave waves) The universe was once very hot and is in a state of cooling. CBMR provides this proof. It is currently about 3 Kelvin.

Cosmic Microwave Background Radiation Can be detected using special antenna. 1% of this can be detected in the static on your TV set. Let’s listen!!!

3. Quasars - super large (solar system size) galactic cores that put out more light than whole galaxies Only found 10-15 billion light years away Found nowhere else Nothing exists past them

4. Radioactive decay Radiometric dating – gives us the age of items from the decay of radioactive materials found within the object Moon rocks have been dated and found to be older than Earth Gives us an estimated time that Earth and the Moon formed

5. Stellar formation and evolution We observe the life cycles of stars across the universe using tools such as satellites and telescopes we view stars form, burn and explode

6. Speed of light and stellar distances The speed of light is a universal constant of 300,000 km/s2 We observe stars millions/billions of light-years away A light-year is the distance that light travels in 1 year – the light we see today from a star 500 light years away is 500 years old The furthest stars away are 10-15 billion light years away We have telescopes that can see further, but there isn’t anything viewable

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 Cosmic Background Radiation & History Connect

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 ( up to Iron) were formed. Heavier elements produced from supernova explosions!

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

LASTLY – we are pretty sure everything has a beginning, right?