Unit 11- Astronomy

Big Bang Theory

A inconceivably large explosion that generated billions of galaxies and sent them flying apart.

Doppler Effect

When object approaches- higher than normal pitch

When object moves away- lower than normal pitch

Large Doppler Shift

Increased velocity

Small Doppler Shift

Decreased velocity

Geocentric

Concept that the Earth is the center of the universe

Ancient Greeks, Ptolemy, and Brahe believed in this theory

Ptolemy

Tried to explain retrograde motion 

orbits – planets were believed to have circular pads because it was a pure and perfect shape however couldn't fit observations with Theory 

Retrograde Motion

Apparent Westward drift of planets with respect to the Stars 

Brahe

Was the first to have the idea of the Stellar parallax the apparent shift in the position of a nearby star that occurs as we view the star from different positions in the Earth's orbit he believes in the geocentric system the sun can't be the center because there is no stellar parallax 

Stellar Parallax

The apparent shift in the position of a nearby star that occurs as we view the star from different positions in the Earth's orbit 

Heliocentric

The concept of a sun-centered solar system

who believed? Copernicus, Kepler, Galileo, and Newton 

Kepler

Laws of planetary motion

first law planets have elliptical path around the Sun 

second law Revolution covers equal areas in equal times there for the planet appears to move faster in some areas

Third Law the farther the planet is from the Sun the longer it's Revolution 

Galileo

Telescope observations 

observed four moons around Jupiter therefore not everything revolves around the Earth 

planets are circular disks not just points of light 

viewed an imperfect Moon and Sun 

four phases of Venus

Newton

Laws of Motion

inertia is what keeps objects moving gravity is an attractive force between 

two objects that increases with increasing Mass 

decreases with increasing distance 

inertia and gravity work together to keep objects revolving a long elliptical orbits

Stars

Large glowing balls of gas that generate heat and light through nuclear fusion in their core 

Nuclear Fusion

The process in which two or more smaller nuclei land together and make one larger nucleus while releasing energy 

Solar System

our star system

Galaxy

great island of stars in space containing from a few hundred million to a trillion or more stars

Nuclear fusion Equation

4H (yields) 1HE + energy

Supercluster

A gigantic region of space where many individual galaxies and many groups and clusters of galaxies are packed closer together than elsewhere in the universe 

Universe

the sum of all total matter and energy

Hottest Stars

blue, high mass, brighter, short life (8 million years)

Coolest Stars

red, smaller, dimmer, longer life (10 billion years)

Red giants

large, cool stars of high luminosity

Supergiants

very large and bright stars that appear at the top of the HR diagram

White dwarfs

how, compact corpse of low mass stars