These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute. Announcements - N/A Outline of Last Lecture I. Definition of Science II. What exactly is the planet’s Crisis? a. Earth’s History of Crises, Back to Prehistoric Times III. Introduction to Earthquakes Outline of Today’s Lecture I. The Big Bang Theory and its Proofs II. The Creation of the Universe a. Our Solar System, Earth and the Moon III. Life on Earth: The Goldilocks Zone and Darwin’s Dilemma IV. A brief intro to Volcanoes Today’s Lecture Origin and Structure of the Earth The Big Bang Theory Melvin Slipher came up with what is now known as the Big Bang Theory in 1913. The discovery of 12 galaxies beyond the Milky Way all showed the “red shift”, a doppler effect indicating all were speeding away at high speeds. The theory states that everything began in a small part of space before blowing up and expanding - this formed the Milky Way, Our Galaxy, the Solar System, and then Earth. Doppler Effect: Wave phenomena ex. light/sound wave. If it’s moving towards a subject the wave gets squished, and if it moves away from a subject, the wave stretches out. A peculiar example of this is the sound created by an ambulance siren (higher in pitch when moving towards you, lower when moving away) 1927: Edwin Hubble confirms Slipher’s observation. The most distant object moved at the largest velocity, meaning that the universe is expanding. A pressing question still looming over the observation remains: will the universe’s expansion continue on forever, or will it eventually collapse? 1964: Arno Penzias and Robert Wilson Find Evidence in Support of the Big Bang: At Bell Labs in NJ whilst conducting experiments regarding radio astronomy but could not get rid of a bothersome noise signal. They discovered that a constant noise source existed, and that the earth is bathed in a cosmic background radiation that comes from the Big Bang. GEOL 108Lg Becker, Thorsten 2012 Fall Week 1 Lecture 1 August 30A Closer Look at the Big Bang 14 billion years ago, there was a singularity. This is where everything began, and into the void, something went wrong. This caused Quantum Fluctuations, and an initial stage of inflation and expansion. This caused a dramatic change - atoms formed, first proton formed - this led to the development of elements, e.g. P+E=Hydrogen, P+P=Helium). More complex elements were formed by the fusion of lighter elements, e.g. 4He=1 Oxygen. The building up of atoms via nucleosynthesis led to the formation of stars, than galaxies, then planets. Strangely, the galaxies are not distributed evenly, for everything in the universe began a non-linear evolution. At around 400 Million years ago, the first stars were formed after what were known as the Dark Ages. The Solar System Almost all planets orbit the sun on a common plane, in the same direction. Planetary orbits are almost perfectly circular. The sun has the most mass in the solar system. The Inner Planets are rocky, metallic and solid with iron cores. The outer are mostly made up of gas and ice. HOW IT ALL BEGAN: roughly spherical, slowly rotating nebula began to contract, concentrating mass/containing energy associated with spin - conservation of angular momentum let to them speeding up, contracting and rotating like ice skaters. A flat, rapidly rotating disc form, which then spawned chunks of planetary matter, produce what then became planetesimals. The planetesimals attracted particles, and thus the planets were formed. The giant outer planets grew by gas accretion, and are all low density. A protostar was formed, which we now know as our Sun. Planetary configuration: The strong thermal and pressure gradient developed by the early sun evaporated the volatile elements in the inner terrestrial planets and condensed them in the outer gaseous planets. The chemistry of the planets is related to their distance from the Sun. Earth’s Composition--->The Creation of Earth’s moon The commonly accepted scientific theory about the Moon’s origins describes that when the Earth was quite young, a planet the sized crashed into it. The planet crashed with such speed that it was destroyed, nearly destroying planet Earth. The force of the Mars-sized planet, causing the two planetary materials to essentially become one. The collision sent large amounts of debris from the crashing planet and earth into space. These debris fragments eventually came together to form the Moon. Earth’s Composition The Goldilocks Zone What scientists aptly coin the Goldilocks Zone is also known as the Habitable Zone - this term refers to the region surrounding a star, in this case the sun, within which it is possible for a planet to maintain liquid water on the surface. Being that liquid water is a vital source for all known lifeforms, a planet that has sufficient atmospheric pressure to maintain water on the planet’s surface - thus requiring it to have a sufficient mass and gravity. It must be far enough away from the sun for the water to condense, and far enough away so it doesn’t freeze (most of the time, anyway). Early on, there was no oxygen in the universe. A rise in oxygen after 2.5 billion years has to do with rocks that can incorporate the element. Oxygen is then saturated, leading to a rise in oxygen atoms which then causes an explosion of life. DARWIN’S DILEMMA: When did life appear? Phanerozoic - complex animals suddenly appear, but not in any rocks older than that period - Cambrian Explosion. There are a range of observations of life going back to 4.0 Ga (Billion years ago). 3.5 million years ago is thbe earliest evidence we have of life on earth. While in the beginning there was no oxygen, pre-Cambrian times led to the abundance of oxygen which then, in turn, led to a range of complexity allthe way up until 120,000 years ago when Homosapiens began to spread across the earth. Volcanoes A volcano is essentially any place on where material from the inside of the planet makes its way through to the planet's surface. Some of elemental compounds emitted from a volcano, such as hydrogen, nitrogen and carbon dioxide , are absorbed by the atmosphere, while the water produced goes to the oceans. Tohoku, Japan Earthquake This earthquake occurred offshore of Japan, caused by the pacific plate moving into the Eurasian plate - one goes underneath the