When did life arise on Earth?
a. Planet was born about 4.5 billion years ago. Life began about 3.85 billion years ago. It took a while for
life to begin because during firtst several hundred million years of Earths history was a period of
1. White Dwarf the exposed core of a star that has died and shed its outer layers in a planetary nebular.
a. hot at first but then slowly cools with time
b. Stellar in mass but small in size (radius). Quite dim compared to sun.
c. Starlike mass
1. The story of a stars life is a constant battle between gravity and pressure
a. Gravity overcomes pressure and a moleculr clouds forms protostars. Gravity continues to
have the upperhand until fusion begins in a stars core
b. Once hydrogen fu
1. Where do stars form?
a. Black patches within the Milky Way are interstellar gas clouds that appear dark because
they block our view of the stars and any glowing gas behind them.
i. These clouds are the birthplaces of stars
b. Interstellar me
1. How do we measure stellar luminosities?
a. Apparent brightness the brightness of a star as it appears to our eyes. The apparent
brightness of any star is the amount of power (energy per sec) reaching us per unit area.
Also know as flux.
1. How does your eye form an image?
a. Your eyes bring parallel rays of light to a focus on your retina. Glass lenses work similarly, so
distant objects form an image that is in focus on the focal plane.
b. A ray of light travels in waves in a s
Astronomy Chapter 5
1. How do we experience light?
a. Light is a form of energy: Radiation energy the energy that light carries
b. Energy and power
i. Joules unit of energy
ii. Power the rate of energy flow. Measured in watts
1. 1 watt = 1 joule per secon
Astronomy Chapter 4
1. How do we describe motion?
a. Three basic terms to describe how an object moves:
i. Speed speed of a car tells us how far it will go in a certain amount of time. Ex.
100 km/hr is a pseed and tells us that car will cover distance of
Astronomy Chapter 3
1. In what ways do all humans use scientific thinking?
a. Scientific thinking relies on the same type of trial and error thinking that we use in our
everyday lives, but in a carefully organized way.
b. How did astronomical observations
Astronomy Chapter 2.4
1. What was so mysterious about the movement of planets in our sky?
a. On any particular night, the planets move through the sky just like stars, rising in the east
and setting in the west.
i. But if you observe planetary motion amon
Astrology Chapter 2
1. What does the universe look like from Earth?
a. Constellation patterns of stars or a region of the sky with well-defined borders. Ex.
i. There are 88 constellations.
b. The celestial sphere a model that shows how the stars ap
Astrology Chapter 1
1. What is our place in the Universe?
a. Earth is aplnet orbiting the sun, Our sun is one of more than 100 billion stars int eh MWG.
Our galaxy is one of about 40 galaxies in the Local Group. The Local Group is one small part
of the Lo