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THE BIG BANG
HOW AND WHY DO INDIVIDUALS
CHANGE THEIR MINDS?
SY 2015-16
OVERVIEW
Key Disciplines:
Astrophysics and cosmology
Timespan:
Roughly 13.8 – 13.4 billion years ago
Driving Questions:
• How and why do individuals change their minds? (Religious narratives)
•
How and why did human understanding of the Universe change? (WH)
Threshold for the Day:
Threshold 1: The Big Bang
Objectives:
•
Students will recall how old the universe is.
•
Students will identify the Big Bang as the first among the eight thresholds of History.
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WHAT HAPPENED
DURING THE COSMOS?
Four main themes: Big History, Big Scale, Origin Story, and Thresholds appeared via the
Cosmic Calendar (Stars, Solar System, Earth, Life, and Humans).
• Big History tells the 13.8-billion-year story of the Universe.
• Big History is so big that in order to talk about it, we need to use measurements on an entirely
different scale from the ones we use everyday and in conventional History.
• All communities have created origin stories to answer important questions about life and the
Universe. Big History is a modern, scientific origin story told by a global community of scholars.
• Thresholds of complexity are the foundation of Big History: they’re fragile, diverse, precise, and
they led to entirely new things in the Universe.
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HOW DID OUR VIEW OF
THE UNIVERSE CHANGE?
Video / David Christian
• The ancient Greek thinker Ptolemy proposed a view of the Universe which was dominant in
Europe for more than 1,000 years.
• Ptolemy’s Universe consisted of six planets, the Moon, and the Sun that moved in circular
orbits around the Earth. What he knew, he observed with his naked eye.
• Over time, human observations of the planets and stars became more precise and led some
scientists to suggest alternative theories.
• Copernicus, Kepler, and Galileo contributed to a new view that put the Sun at the center of
the Universe, with the Earth moving around it in an elliptical (rather than a circular) orbit.
• These scientists used curved glass that allowed them to see these Celestial Bodies
through a new lens.
• In the 20th century, Edward Hubble measured the distance and speed of many galaxies and
found that most were moving away from Earth. He determined that the Universe was extremely
large and was still expanding. Reverse such expansion and the universe had to begin at one
common point.
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A BIG HISTORY OF
EVERYTHING
Video
• History begins with the Big Bang, a moment scientists are currently unable to describe with any
degree of certainty.
• The Universe appears to emerge from nothing, but scientists cannot describe the moments
before the Big Bang or the moment of the Big Bang itself. Major questions surround the origin of
the Universe.
• The Big Bang set the history of the Universe in motion.
Dark Matter: Radioactive Residue from the Big Bang
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Gravity
Article / Bob Bain
• While four fundamental forces were created by the Big Bang, gravity has played the most
influential role in the history of the Universe because it can operate over the largest scales.
• The nature of gravity helped define the future development of the Universe. If gravity had been
stronger, everything would have collapsed on itself. If gravity had been weaker, stars, planets,
and other complex combinations of matter could not have formed.
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ELECTROMAGNETISM
Video
• Another Ingredient
• Electromagnetism is one of the four forces created during the Big Bang.
• Electromagnetism plays an important role in atoms, binding electrons, which are negatively
charged, to the protons and neutrons in the nuclei, which is positively charged.
• Electromagnetism also plays an important role in the transmission of radio waves. Simple sound
waves, like those produced in human speech, can travel about 600 feet. The vibration of electric
and magnetic fields allows radio waves to travel over vast distances.
• Relevance: Electromagnetism allows humans to talk on cell phones.
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LOOKING INTO THE PAST
• Space and time are very closely related. Light travels incredibly fast, but over the vast distances
of space, it still takes large amounts of time for it to move from one place to another.
• When observing objects from Earth, you are seeing light that has been traveling for hundreds,
often thousands of years. This means that you are seeing objects as they appeared when that
light was emitted hundreds or even thousands of years ago.
• Edwin Hubble discovered evidence that light moving away from us redshifts, which led him to
conclude that the Universe is still expanding in all directions.
• Here on Earth, we are at the center of the “observable Universe.” From our vantage point, we
can theoretically see the same distance in every direction—46 billion light-years (also known as
our cosmic horizon).
• Telescope technology continues to reveal more and more about the early Universe.
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LOOKING AHEAD
WHAT’S NEXT?
In Unit 3, the first stars will appear. We will learn:
•
How stars formed
•
About the life (and death) of a star
•
About the origin of heavy chemical elements in aging and dying stars
•
How views of chemical elements changed over time
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