Earth Science Notes The Earth, Moon, and Sun

Properties of the Earth Rotation refers to the spinning of earth on its axis When Earth spins on axis it causes day and night

Properties of the Earth Revolution refers to the orbiting of earth around the sun Earth’s orbit is an ellipse

Properties of the Earth Change in seasons are caused by the tilt of the earths axis as it revolves around the sun The hemisphere that is tilted toward the sun received more sunlight (has longer days)

The Seasons

Properties of the Earth Solstice is the day the sun reaches its greatest distance north or south of the equator Winter solstice and summer solstice

Properties of the Earth Equinoxes occur when the sun is directly above the Earth’s equator Sunlight hours are equal during this time Fall and Spring Equinox

Properties of the Earth The earth bulges slightly at the equator Gravity contracts earth into sphere Rotation cause Earth’s sphere to bulge Pull of moon creates tidal bulge

Properties of the Earth Earth has a magnetic poles Moving material inside the earth as well as Earth’s rotation may generate the magnetic field The poles change over time Recall magnetic reversals as evidence of seafloor spreading

The Moon Moon phases Different forms that the moon takes in appearance

The Moon Moon Phases - depend on the relative position of the Earth, Moon, and Sun. New Moon  Moon is between earth and the sun – no light is reflected Waxing Crescent  first thumbnail shaped portion of the moon seen First Quarter  one quarter of the moon is reflecting the sun light Waxing Gibbous  means more of the illuminated half can be seen each night

Moon Phases

Moon Phases (cont.) Full Moon  moon surface that faces earth reflects all light from sun Waning Gibbous  means less of the illuminated half can be seen each night Third Quarter  one quarter of the moon is reflecting the sun light Waning Crescent  last thumbnail shaped portion of the moon seen

Moon Phases

The Moon Solar eclipse occurs when the moon moves directly between the sun and the earth.

Solar Eclipse

The Moon Lunar eclipse occurs when the earth falls directly between the sun and the moon

The Moon Structure of the moon Models for moon’s interior derived from seismic activity (i.e. moonquakes) The moon is made up of crust, upper mantle, lower mantle, and core.

The Moon Origin of the Moon Various theories had been proposed for the formation of the Moon. Fission Theory – moon somehow separated from the earth Location – pacific basin Evidence – moon is made of materials similar to Earth’s mantle Problem – cast off of moon would be do to rapid spinning of Earth – no fossil evidence of this

The Moon Origin of the Moon Capture Theory: Moon was formed somewhere else in the solar system, and was later captured by the gravitational field of the Earth

The Moon Origin of the Moon The Condensation Theory: the Moon and the Earth condensed individually from the nebula that formed the solar system. Problem – if the Moon formed near Earth it should have nearly the same composition. Specifically, it should possess a significant iron core, and it does not.

The Moon Origin of the Moon The Giant Impactor Theory: proposes that a small planet the size of Mars struck the Earth just after the formation of the solar system, ejecting large volumes of heated material from the outer layers of both objects. A disk of orbiting material was formed, and this matter eventually stuck together to form the Moon in orbit around the Earth. This theory can explain why the Moon is made mostly of rock and how the rock was excessively heated. Furthermore, we see evidence in many places in the solar system that such collisions were common late in the formative stages of the solar system.

Giant Impactor Theory

Click the link to learn more about these missions Trips to the Moon Click the link to learn more about these missions http://www.lpi.usra.edu/expmoon/apollo_landings.html

The Sun Structure of the Sun

The Sun Structure of the Sun Corona – largest layer of the sun’s atmosphere, extends millions of km out into space Chromosphere – transition zone between the photosphere and the corona Photosphere – lowest layer of the sun’s atmosphere, where light is given off, 6000 K.

The Sun Convention layer – heat energy rises and falls in this layer as gases rise, cool, and then fall Radiation zone – energy from the suns core is transferred to the conduction zone Core – source of suns energy, where nuclear fusion takes place

The Sun Surface Features of Sun Sunspots – spots on the sun that are darker because they are cooler

The Sun Surface Features of Sun Prominences – arching columns of gas Maybe caused by Sun’s magnetic field

The Sun Auroras Created as a result of electrically charged particles from the sun’s corona hitting the earth’s atmosphere and ionizing gases there.

The Sun The sun is an average star. It emits average heat and light energy

Summary How does rotation and revolution differ? What are the effects of each? Explain why we have seasons. What are the phases of the moon? What is the difference between solar and lunar eclipses? Explain different theories regarding the origin of the moon. Describe the Sun’s structures and its features.