Unit 8: Astronomy

Celestial Sphere

A model of the sky; An imaginary sphere surrounding Earth on which celestial bodies are projected.

Polaris

The North Star

Revolution

Earth's yearly orbit around the Sun

Rotation

The act of rotating the earth on its axis

Foucault Pendulum

--proof the Earth rotates-- If a pendulum is suspended and allowed to swing back and forth you will see a gradual change in the direction of its swinging. (shifts clockwise in northern hemisphere and counter clockwise in southern hemisphere)

Coriolis Effect

The way Earth's rotation makes winds in the Northern Hemisphere curve to the right and winds in the Southern Hemisphere curve to the left.

Seasons

Peroids of time when the tilt of the earth determines where the sun rays hit the earth.

Perihelion

nearest point to the sun in the orbit of a planet or comet

Aphelion

the place in the orbit of a planet where the planet is farthest from the sun

Zenith

the highest point

Eqinox

either of the 2 times each year ( spring and fall) when the days and nights are equal lengths
On those days sun directly over Equator
Spring March 21 Fall September 23

Summer solstice

June 21, when the sun is at its northernmost point

Winter solsitce

When the Earth is tilted (in the Northern Hemisphere) the farthest from the sun.

Orbit

the path of an object as it revolves around another object in space

Focus

bring into focus or alignment

Eccentricity

oddity; idiosyncrasy

Inertia

(physics) the tendency of a body to maintain is state of rest or uniform motion unless acted upon by an external force

Spring Tides

tides that have the greastest tidal range due to the alignment of the earth-moon-sun system

Neap tides

tides with minimum daily tidal range that occur during the first and third quarters of the moon

Solar eclipse

occurs when the Moon passes directly between the Sun and Earth and casts a shadow over part of Earth

Solar system

sun, planets, and all the other objects that revolve around the sun

Geocentric Model

A representation of the universe in which starts and planets revolve around Earth. Ptolemy proposed the model.

Heliocentric Model

A representation of the relationship between the Sun and planets in which the planets revolve around the Sun. Copernicus proposed the model.

Terrestrial

on or relating to the earth

Jovian

The name given to the Gas Giants/Outer Plants

Universe

All of space and everything in it.

Milky Way Galaxy

the galaxy we live in

Doppler Shift

causes waves to bounce off moving object changing the frequency of wave

Red Shift

the change in the wavelength of light due to an object moving away from the observer.

Blue Shift

An increase in the measured frequency of light from an approaching source; called the blue shift because of the increase is towards the high, or blue, end of the color spectrum

Big Bang" theory

the theory that the universe originated 20 billion years ago from the cataclysmic explosion of a small mass of matter at extremely high density and temperature