Unit 1: Introduction to Earth Sciencepart 2

Origins of Planet Earth

Scientific Knowledge

Law Theory

ParadigmHYPOTHESIS

Evidence, Theories, ParadigmsScientific Knowledge

• Evidence – facts collected by observation and measurement which serve as a springboard for development of theories

ex. Seismic energy recorded by a seismogram

Hypothesis

• Is a tentative or untested explanation to explain how or why things happen in an observed manner.

• Usually one than one is developed to explain a set of observations.

Ex. Phytoplankton blooms in early winter due to convection currents in the ocean. (evidence comes from satellite imagery)

Ex. Phytoplankton blooms occur in summer due to warmer water. (old hypothesis)

Theory

• A well tested and widely accepted view that explains certain observable facts.

• Develops from a hypothesis that has survived extensive scrutiny and competing hypotheses have been eliminated.

• Can change if new observations are made that cannot be explained by the current theory

Examples of Theories

• Theory of Evolution• Atomic Theory of Matter• Cell Theory• Particle Theory of Matter• Theory of continental Drift• Theory of Plate Tectonics

Paradigm

• Is a theory that that is held with a high degree of confidence with a lot of evidence.

• Explains a large aspect of the natural world.

• Provides the framework for research and practice in a subject area.

Ex. Theory of Plate Tectonics

Paradigm Shift

• is where a current paradigm becomes replaced by a new paradigm

• Is rare and very slow since people must abandon original beliefs and practices

Ex. Spontaneous Generation BiogenesisEx. Geocentric Solar System HeliocentricEx. Rigid Earth Theory Continental Drift Plate

Tectonics

Law

• A formal statement summarizing observations of natural phenomena occurs under given conditions.

• Is supported mathematically.• Is always true and never changes. ***(usually)

Ex. Newton’s Laws of MotionEx. Mendel’s Laws of GeneticsEx. Law of Conservation of Mass

Formation of the Universe

Formation of the Universe

How Could This Be?

Earth In A Big Universe

• Many people, cultures and religions have tried to describe where and how the universe and earth came into being

Formation of the Universe

• Creationism (considered a Non-Scientific View):

• Belief in the bible, other holy texts or spoken word that led to the idea that Earth was created by a creator with purpose

Big Bang Theory

• Explains the origin of the Universe:– all galaxies, – solar systems, – stars, – Planets –Moons, asteroids, comets etc.

• Explanation is still ongoing (collecting evidence)

Big Bang Theory

• Proposes that universe originated as a single mass that exploded around 15 billion years ago. (best estimate is 13.7 bya)

• After a few billion years material cooled and condensed into stars and galaxies.

• The explosion caused continuous expansion so galaxies moved away from one another.

• About 5 bya our solar system formed within the Milky Way galaxy

• Expansion and cooling continues.

Big Bang Theory Evidence

• Edwin Hubble (1929) discovered the “cosmological red shift” of galaxies which shows continuous expansion

• Arno Penzias & Robert Wilson (1963) cosmic background radiation left behind from Big Bang

• 1989 – 2001 Nasa Satellites measured and mapped CBR (cosmic background radiation)

• Thousands of Scientists worldwide are trying to reproduce the Big Bang using computer animation

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Doppler Effect

Song

• “The Big Bang Theory Theme Song” - YouTube

• Listen to the song and reflect on how the first verse describes the things we discussed in this lesson.

A

Solar Nebular Hypothesis pg.19,628

• Explains the formation of the solar system which began about 5 bya (at least 10 by after the Big Bang occurred)

4 stages of Solar Nebular Hypothesis

1. NebulaHuge rotating cloud of dust and gas contracts due to gravity to form a “nebula”

4 stages of Solar Nebular Hypothesis

2. Protosun• Most material is gravitationally swept

toward the centre and rotates to form a flattened disk

• Material is concentrated at the center to form the protosun (presun)

• Gravitational energy was converted to heat raising the temperature at the center.

4 stages of Solar Nebular Hypothesis

3. Protplanets• As temperatures dropped, substances with rock

forming minerals (iron and nickel) joined together while orbiting the sun.

• Repeated collisions over millions of years formed the planets.

• Close to the sun Terrestrial (rocky) planets formed.• Further from the sun Jovian ( large, gaseous, low

density) planets formed.

4 stages of Solar Nebular Hypothesis

4. Solar Systems• Remaining debris was either collected into the

planets and moons or swept into space by solar wind.

Stage 2Stage 1

Stage 3 Stage 4

C

STSE

“The Search for Other Solar Systems”

• This STSE proves the importance of advancements in scientific methods and technology. We can now observe other solar systems. Also, we humans are being forced to re-examine our theories of solar system formation (e.g. “Solar Nebula Hypothesis”).

• Read and Answer Questions 1-4 (In Portfolio)

STSE

• Remember:

• Universe Vs. Solar System• The Universe: incorporates several solar systems.• A solar system: is represented by planets orbiting stars.

• Habitable Zone (Goldilocks zone)• This zone in a solar system is where liquid water can exist on

the surface and not too far from the star it is orbiting (too cold) or too close to the start it is orbiting (too hot). Just right!

STSE• If you can find planets orbiting stars (other than the sun), then

you have found a solar system.• There have been 1500 solar systems found to date.

• Five Methods for Finding Solar Systems1. Radial Velocity Method2. Transit Photometry Method3. Astrometry Method4. Microlensing Method5. Direct Imaging

STSE• Transit: The passage of a planet between a star and the Earth.

• Extrasolar planets: Planets that exist in other solar systems (as opposed to the solar system where Earth exists). These are called exoplanets.

• Gemini North• The Gemini Observatory Program has been in operation by Canada and its

purpose is to find extrasolar planets. The powerful telescopes remove the effect of twinkling stars, allowing clearer views into space. They also minimize star light, thereby allowing for more focus on light being given off by the extrasolar planets.

• Kepler Mission• Designed to survey a part of our region of the Milky Way Galaxy to

discover Earth-sized planets in or near the habitable zone.1500 found to date!

STSE• The Solar Nebula Hypothesis infers that a solar system should

have rocky inner planets and larger gaseous planets much further out.

• Many solar systems found do not fit the pattern described above.

• Maybe gravity and friction has caused the larger planets to move.

• Alone, the “Solar Nebula Hypothesis” seems too simplistic. Maybe it just represents the formation and configuration of early planets.

STSE

• The light an extrasolar planet emits is very significant. This is because the atmosphere surrounding each planet influences the light that gets emitted.

• ***Water, methane, and ozone are required in atmospheres in order for them to be able to support life. Detailed spectrometry could tell scientists if life (as we know it) exists on planets.