Add to table of Contents: Big Bang Lab Pg. 4 Big Bang Theory Pg. 5

What is a scientific theory? As humans, we form theories all of the time. What is a theory? What is a scientific theory?

A scientific theory A scientific theory is when scientists have tested a hypothesis many times and the hypothesis is supported by data. Scientific ideas are not considered theories until they are generally accepted principles that explain a vast number of observations and experimental data. Examples of scientific theories include: the Atomic Theory, the Theory of Natural Selection, the Theory of Plate Tectonics as well as many other widely supported and accepted scientific principles.

1927 Georges Henri Lemaitre first came up with the “Big Bang” on a mathematical basis, though he called it 'hypothesis of the primeval atom'. It utilized Einstein’s theory of relativity (E=mc2 ) Edwin Hubble was the first person to provide observational evidence for it, and Fred Hoyle later named it the Big Bang theory, though he did so as a sarcastic joke.

Big Bang Theory The universe was created between 10 - 20 billion years ago from a cosmic explosion. The original matter was small and dense, but we don’t know what it was.

Big Bang, con’t It explains why distant galaxies are traveling away from us at great speeds=expanding. It also predicted the existence of cosmic background radiation-the glow left over from the explosion itself.(discovered in 1964)

March 24, 2014

Background radiation Polarized light Big Bang Big Bang Gravity waves 2014 – allowed us to see polarized light from the Big Bang

What does the Big Bang Theory explain What does the Big Bang Theory explain? What are 2 pieces of evidence supporting the Big Bang Theory?

The Expanding Universe Breaking down the light from celestial objects into its colors has helped us understand the universe. A spectrum can tell astronomers what an object is made of, how hot it is, and its direction and speed. Spectroscopy has revealed the great abundance of hydrogen and helium in the universe.

Red-shifted Stars Spectroscopy revealed the expansion of the universe. When an object moves away from us, the lines in its spectrum get displaced toward longer wavelengths, with the amount of this so-called redshift proportional to the object’s velocity. Edwin Hubble first showed that the spectrum of almost every galaxy is shifted to the red, and that the farther away the galaxy, the greater the redshift. From these observations, cosmologists correctly deduced that the universe is expanding. What would show that galaxies are moving away from us?? How would it be possible to be staying the same distance away if the Big Bang Theory was true?

Edwin Hubble first showed that the spectrum of almost every galaxy is shifted to the red, and that the farther away the galaxy, the greater the redshift. Red-shift shows that the universe is expanding(objects moving away). What would show that galaxies are getting closer to us? Blue-shift would show objects moving toward us.

Big Bang Balloon Read the direction sheet Big Bang Balloon Read the direction sheet. Follow the steps and complete the data sheet.