Honors Astronomy Unit 1

Rotation

Earth spinning on its axis

Revolution

Earth moving around the sun

Sidereal Month

Time for moon to orbit earth

Synodic Month

New moon to new moon

Brahe

Modified geocentric theory; all planets except earth go around the sun, but the sun goes around the earth.

Galileo

First to use telescope, phase cycle of Venus, first scientific method, the sun has spots

Copernicus

First accepted heliocentric theory ( what we know now)

Kepler

Laws of planetary motion

Ptolemy

Epicycles ( swirlies )

Aristarchus

Figured out relative sizes of sun, earth, moon, and relatives distances to Sun and moon

Aristotle

Earth is round ( shadow of earth during eclipse, stars changing, ship hull disappears before the sail)

Pythagoras

Earth is round

Keplers 1st law

Planets have elliptical orbits

Keplers 2nd Law

Speed changed while planets orbit the sun

Keplers 3rd Law

The further a planet is from the sun, the longer it takes to orbit. ( p2 = a3)

Inertia

The natural tendency of objects to stay in motion when in motion and at rest when in rest. Unless a force acts on it to change.

Newtons 1st law

Objects resist a change in motion ( like a rowboat putting force on water )

Newtons 2nd law

F=ma ( increase mass = decrease force, increase force = increase acceleration) like riding your bike

Newtons 3rd law

For every action there is an equal and opposite reaction force. Like when you jump, legs apply force to ground, ground applies reaction

Perihelion

When a planet is closest to the sun in orbit

Aphelion

When a planet is furthest away from sun in orbit

Mass

The total amount of matter or “stuff” in an object.

Weight

The force of gravity on an object

Escape velocity

The velocity of the object in which it can escape earth gravity

Surface gravity

Intensity of the force of gravity at the surface of the earth or a celestial body

Ecliptic

Orbital plane of the earth around the sun

Constellation

An area in the celestial sphere where certain groupings of stars are, named and formed into configurations.

How long does it take the moon to go through a cycle of phases?

29.5 days

When in retrograde motion, which way do planets move?

East to west

What causes retrograde motion?

Earth catches up to and passes another planet in orbit; looks like planet moved backwards

What, other than the sun, appears to move through the zodiac?

The moon and other planets in the solar system

Lunar eclipse

The earth passed between the sun and the moon ( Sun, Earth, Moon); moon turns a red color

Solar eclipse

The moon passed between the sun and earth ( Sun, Moon, Earth) ; sun gets covered up, to see it you need to travel; moon is smaller than sun

If a full moon is seen on earth, what order would the sun, moon, and earth be in?

A full moon is created when the moon is on the opposite side of the earth from the sun. Sun, Earth, Moon.

What is the order of the Sun, Moon, and Earth during a new moon?

Our moon moves between in earth and the sun. So, earth, moon, sun.

What are the seasons caused by?

The seasons are caused by the tilt of the earth while revolving, if the earths axis is pointing towards the sun it is summer for that hemisphere.

NOT THE DISTANCE BETWEEN THE EARTH AND SUN.

Example of changes due to ROTATION

Stars positions change on a daily basis

Example of changes due to earth’s REVOLUTION

The reason why different constellations are visible in different seasons