Evidence for the Big Bang Theory The evolution

Evidence for the Big Bang Theory The evolution of the Universe can be compared to a display of fireworks that has just ended: some few wisps, ashes and smoke. Standing on a cooled cinder, we see the slow fading of the suns, and we try to recall the vanished brilliance of the origin of the worlds. ~ Abbe George-Henri Lemaıtre

1. Universal expansion and Hubble’s Law • In 1929, Edwin Hubble found evidence to support Lemaître's theory. – He observed that other galaxies were moving away from us and each other. – And, farthest galaxies were moving faster than the ones close to us Hubble’s Law: v = H 0 x d

Red Shift • Evidence of expansion: Red Shift • Which is an example of the Doppler Effect

• If an object is moving toward Earth, its wavelengths of light are compressed. – causes the object to look more blue • If an object is moving away from Earth, its wavelengths of light are stretched. – Causes the object to look more red

• Because all galaxies beyond the Local Group show a red shift, they must be moving away from Earth. • If all galaxies outside the Local Group are moving away from Earth, then the entire universe must be expanding.

2. Cosmic Background radiation • Discovered 1965 by Arno Penzias and Robert Wilson • came from the first photons that streamed through the universe – which are now so stretched out (due to the universe’s expansion) that they are in the form of microwave energy. • Tune your TV between the stations and about 1% of the static on the screen is the afterglow of the big bang.

• C. O. B. E satellite confirmed temperature variations in the Universe & that noise radiation (static) is evenly spread – Stephen Hawkings described this as "the most important discovery of the century, if not of all time. " • Amount of radiation discovered matched predictions

3. Abundance of Light Elements • In 1948, George Gamow proposed that during the first few minutes of the Big Bang, it could have been hot enough for nuclear fusion to occur.

• Ralph Alpher and Robert Herman worked out the details & found that nuclear processes would produce just the right abundance of helium to match that seen in stars today.

4. Growth of Structure • explains how the large-scale structures (stars, galaxies, gigantic super clusters of galaxies, & the voids between them) formed • ~ 10, 000 years after the Big Bang, the Universe cooled to the point that the gravitational energy was able to collect together matter. • Observations made using tools such as satellites, telescopes, and computer modeling

References • https: //pseudoastro. wordpress. com/2009/03/ 18/defending-the-big-bang-the-four-pillars-ofthe-modern-big-bang-theory/ • https: //www. youtube. com/watch? v=xtr. YF_hx x. UM • http: //www. rialto. k 12. ca. us/eisenhower/