By Akshath Sivaprasad
Background Info • Discovered by Edwin Hubble in 1929 • Measured redshift (change in star’s spectrum, caused by star moving away from earth) from different galaxies • Concluded that wavelengths became red (stars were moving away), leaving one possible definition: the universe was expanding
The Big Bang Theory Background •
The Big Bang Theory answers the question: How did the universe begin?
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If the universe is expanding, then it must have in the past too. If we go back in time, the universe shrinks, and we eventually reach a period where the universe is a point.
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The point was infinitely dense, infinitely hot, and infinitely small. This point inflated, expanded, and cooled. is known as the Big Bang.
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From its original size, it expanded and cooled to the size of our current universe.
The Big Bang Theory Evidence 1. The universe must have had some beginning 2. Galaxies are moving away (Hubble’s Law as shown before) 3. Because the Big Bang was so hot, there must still be some remnant of heat. A radiation in 1965 was thought to be this remnant. 4. The hydrogen and helium elements are thought to be products of the Big Bang, which is why we those elements in abundance.
this diagram shows how the universe started of as a point (bottom) and became the universe as we know it today, complete with several galaxies (top)
Why the Universe is Expanding • the Big Bang Theory • universe was point current universe • shows universe was (and is) expanding • evidence from Edwin Hubble: • measured redshift from each close galaxy • redshift is when the wavelengths from distant galaxies lean towards the red spectrum, signifying that the galaxies were moving away • the galaxies moving away caused the green and blue colors to fall out of the wavelength leaving red (the only durable color) to reach us • found that galaxies were moving away • known as Hubble’s Law
Sources Information www.wikipedia.org/wiki www.big-bang-theory.com www.skyserver.sdss.org www.universe today.com Pictures
www.wikipedia.org/wiki www.delamangente.files.wordpress.com