Evidence for the Big Bang?

1920’s – Edwin Hubble At time of Big Bang, matter was SO dense & hot (billion degrees) that the universe acted like a GIANT nuclear reactor

Hydrogen (H) atoms fused (nuclear fusion) to make light elements (helium (He), lithium (Li) creating billions of stars (in millions of galaxies)

Discovered Andromeda Galaxy: galaxies exist outside our Milky Way

Galaxies are moving apart & away from other galaxies

• TODAY’S AGENDA:

• Notes: Evidence for the Big Bang• EM Spectrum and Visible Light

MONDAY 12/8/2014

Homework: 1. Wavestown Worksheet due Tuesday

12/9/2014 for 20 Points

Evidence for the Big Bang Theory

• Light & Electromagnetic Radiation

• Doppler Effect (Doppler Shift)

Evidence for the Big Bang? The Electromagnetic Spectrum

1665: Isaac Newton observed sunlight (white light) passing through a glass prism produced a rainbow of colors = visible light spectrum

The Electromagnetic Spectrum

• WAVELENGTH: Distance from the top of one wave to the top of the next wave

Each form of radiation has a different wavelengthWhat does a radiation’s wavelength tell us?

How powerful (how much energy) the radiation isWhat kind of radiation it is

Evidence for the Big Bang?

The Electromagnetic Spectrum

Visible Iight travels in the form of electromagnetic (EM) wavesROYGBIV (red, orange, yellow, green, blue, indigo, violet) & white

Visible light is SMALL portion of electromagnetic (EM) spectrumRadio wavesMicrowavesInfraredUltraviolet raysX-raysGamma rays

Brain Pop: EM Spectrum http://www.brainpop.com/science/ energy/electromagneticspectrum/

The Electromagnetic Spectrum

Visible light:Red light = looooooooooooooongest,

Violet light = shortest

On the entire EM Spectrum, Radio waves: longest wavelength

Visible light: middle

Gamma rays: shortest wavelength

Evidence for the Big Bang?

The Doppler EffectOccurs with starlight (visible light & other forms of EM radiation) in galaxies too!!!

Scientists have observed galaxies moving away & apart from each other at high speeds (Rubberband Lab?)

Light moving toward observer wavelengths of light appear shorter = “Blue Shift”

Light moving away from observerwavelengths of light appear longer = “Red Shift”

The Doppler Effect…sound waves

In order to understand the Doppler Effect better, think about standing next to a train track.

What does the train’s horn sound like when it is approaching toward you quickly?

What does the train’s horn sound like when it is moving away from you quickly?

http://paws.kettering.edu/~drussell/Demos/doppler/carhorn.wav

Evidence for the Big Bang?

The Doppler EffectShift in wavelengths of energy (radiation or sound) moving toward or away from an observer = “Doppler Effect (Doppler Shift)”

The spectra of most galaxies is moving toward the Red end = moving away from us (our galaxy)

Degree of Red Shift = speed at which galaxies are traveling