AY 101 – MIDTERM #1 STUDY GUIDE MAIN OBJECTIVES DISCUSSED IN CLASS

What is beyond the observable universe?

Geocentric- earth-centered model

Heliocentric- sun-centered model

Solar System- consists of the sun, planets and their moons, plus other smaller objects including asteroids  and comets

Galaxy- a great island of stars containing millions, billions, or trillions of stars

Galaxy Clusters- groups of galaxies with more than a few dozen large members

Superclusters- clusters of galaxy clusters

∙ The universe is 13.8 billion years old

∙ We can only see objects in our horizon, which is 13.8 billion light years in every direction ∙ The History of the Universe in 1 year:

January 1st– Big Bang

February – Milky Way formed

What is the copernican principle and what does it imply?

September 3rd– Earth formed

September 22nd– Early life on Earth

December 17th– Cambrian Explosion

December 26th– Rise of the dinosaurs

December 30th– Extinction

December 31st- 9pm – Hominids evolve

11:58pm – Modern humans evolve

25 seconds ago – Agriculture arises

11 seconds ago – Pyramids built

1 second ago – Kepler and Galileo show that earth orbits the sun

∙ Earth rotates from East to West

Astronomical Unit (AU) – Earth’s average distance from the sun, which is about 150 million km (93  million miles), usually used within solar systems

What is the law of conservation of angular momentum?

Light Year (LY) – the distance that light, which is about 10 trillion km (6 trillion miles), generally used for  distances between stars and galaxies If you want to learn more check out What are the 4 levels of measurement?

Observable Universe – the portion of the entire universe that we can potentially observe Solar Eclipse – moon blocks the sun (phase: new)

∙ Science is verifiable, repeatable, predictive, and self-correcting, whereas pseudoscience tries to  appear as science, but doesn’t use the scientific method

o Ex. Of Pseudoscience: astrology, psychokinesis, homeopathy, 2012 theory, ghost  hunting, crystal healing, crop circles, etc

∙ When we follow the scientific method, we try to prove theories wrong, not right ∙ We only see one face of the moon, meaning the earth rotates once a month

o NOTE: Look back over the phases of the moon

∙ Aristarchus was the first Greek to throw out the idea of a heliocentric model ∙ The Greek’s solution to retrograde motion was the idea of epicycles, but the theory required  epicycles on epicycles and become far too complex

Copernican Principle – we are not in a special place in the universe

Tycho Brahe – responsible for the most precise naked eye observations of planets, moon, supernova,  and comets

Kepler – created model that could explain Tycho’s observations using elliptical orbits

o First Law – planets orbit in elliptical orbits with Sun at the focus

o Second Law – planets move faster when closer to the sun

o Third Law – more distant planets orbit the sun at a slower pace Don't forget about the age old question of What is denoted by systems of law?
We also discuss several other topics like What is the history of horticulture?
We also discuss several other topics like What is absolute location?

∙ Most orbits are nearly circular but not perfect We also discuss several other topics like What is public trust doctrine?

∙ Galileo’s discoveries include

o We feel acceleration, not motion when it comes to the earth’s movement o Observations of all phases of Venus

o Moons of Jupiter

∙ Gravity is very weak and can only dominate very large objects If you want to learn more check out What are the components of a typical synapse?

∙ Motion consists of speed, velocity, and acceleration

Net force – total after balancing opposite forces

Force – a push/pull that modifies the motion of an object

∙ Electromagnetism is responsible for most daily activities and actions, NOT gravity Conservation of Angular Momentum - the tendency for an object to go around, orbit, or rotate