Earth, Sun, and MoonPgs. 23-28

What you need to know.

Tools of Astronomy

Radiation (or light) is a tool scientists use to study the objects in our solar system.

There are different types of radiation: radio, microwave, infrared, visible light, UV light, x-rays, and gamma rays.

Scientists use telescopes: Refracting and reflectingInterferometry is linking telescopes together so

they act as one.Because Earth’s atmosphere blocks infrared, UV, X

and gamma rays scientists have to send satellites and probes to space

The Moon

Soviet Union launched first satellite to the moon (Sputnik I)

Albedo is the amount of sunlight the moon reflectsNo erosion because no atmosphereHighlands-light, mountainous regionsMaria- dark, smooth plainsAll craters that have hit the moon are impact

cratersEjecta- material blasted out after an impact craterRilles- valley like structures in the Maria

History of the Moon

Age of moon between 3.8 and 4.6 billion years

Believe that Moon was heavily bombarded first 800 million years

Regolith- loose, ground up rock that built up after the multiple impacts

Moon has layered structure (Crust, mantle, and core) so it can have moonquakes

Formation Theories

First theory-rock got caught in Earth’s pull and formed into the moon (capture theory)◦Problem- compositions of earth and moon too

similarSecond Theory-simultaneous theory says

that earth and moon formed around same time

Third theory- impact theory says Earth hit a Mars sized object and the ejecta from that impact formed the moon

Sun-Earth-Moon System Annual Motions

Ecliptic-the plane in which Earth orbits about the Sun. Earth’s axis is tilted 23.5 degrees Sumer solstice-sun is directly ahead of the tropic of cancer

(June 21) Winter solstice- sun is directly over the tropic of Capricorn

(December 21) Equinoxes- autumnal and vernal. Days are of equal length

to nights

Phases of the Moon

You should have a chart that looks similar to the one below:

Motions of the Moon

Tides-bulges of ocean water on near and far sides of surface◦Neap tides-lower that normal tides; moon is at a

right angle to the sun◦Spring tides-Earth nearest the Sun and Moon is

nearest the EarthEclipses-alignment of Earth, Sun, and Moon

◦Solar eclipse-moon passes directly between the sun and earth

◦Lunar eclipse-Earth passes between Sun and Moon

Open Page

You need to have several illustrations in your notebook. The first is an illustration of the phases of the moon. You also need to have an illustration that depicts the solstices and equinoxes. The last is an illustration of each type of eclipse.

Our Solar SystemPg. 29

Early Ideas

Early astronomers assumed that the Sun, planets, and stars orbited a stationary Earth.

Called the geocentric modelMeans “Earth centered”

New Model

Scientists couldn’t account for why most planets moved to the east but one would move toward the west.

Called that phenomenon retrograde motion.Nicolaus Copernicus suggested the Sun was

in the middle of the solar systemHeliocentric modelExplained retrograde motion (inner planets

move faster than outer planets)

Kepler’s Laws

Said each planet orbits the Sun in a plane called an ellipse (first law).

Ellipse is centered on two points (called foci) instead of one like a circle.

The major axis passes through the foci of the ellipse.The semi-major axis is half the length of the major

axis.Semi-major axis is the average distance between

the sun and a planet. Average distance is measured in astronomical units

or AU (1.496 x 108 km)

Major Axis

Eccentricity

When a planet is closest to the sun, it is at perihelionWhen a planet is farthest away, it is at aphelion

Eccentricity is the ratio of the distance between the foci to the length of the major axis.

Eccentricity ranges between 0 and 1. 0 is a perfect circle, 1 is a very elongated oval.

Most planets have an orbit that aren’t very eccentric.

Mini Lab Pg. 777Put on pg. 30 in notebook

You will need a sheet of paper, push pins, cardboard, a ruler, and a pencil.