Tides and Eclipses

Tides The tides are the rising and falling of the ocean surface as a result of the gravitational pull of the moon and the Sun on the earth. The Moon plays a bigger role than the Sun because it is closer.

Effect of the Moon on the Tides Water gets pulled towards the moon: High Tide in this location. Water bulges on opposite side from the moon also: High Tide in this location Low tide here, and on opposite side on the earth that you can’t see.

Role of the Sun The sun also has a gravitational pull on the earth. –When the sun is lined up with the moon and the earth, it “helps” the moon pull on the earth, and the tides become more extreme. –When the sun is not lined up with the moon and the earth, it partially cancels out the pull of the moon, and the tides are less extreme.

Spring Tides Sun, earth and moon are lined up. Higher high tide, Lower low tide. Regular Tide Level Tide Level during Spring Tides

Neap Tides High tide is lower than normal, and low tide is higher than normal. There is less difference between the level of the tides. Regular High tide level High Tide level during neap tides

Occurrence of Neap and Spring Tides Spring tides occur when sun, moon and earth are lined up: Full Moon and New Moon. Neap Tides occur when the sun and moon pull in opposite directions: First Quarter and Last Quarter.

Eclipses There are two types of eclipses: –Solar Eclipse- When the moon lines up exactly in between the sun and the earth. It blocks out the sun so we can’t see it. –Lunar Eclipse- When the earth lines up exactly in between the moon and the sun, and prevents sunlight from reaching the moon. Or, another way to say it is the moon moves into the shadow of the earth.

Solar Eclipse Occurs when the moon is a New Moon and lined up perfectly with the sun and earth. Places on earth in the Penumbra will see a Partial Solar Eclipse Places on earth in the Umbra see a Total Solar Eclipse

Solar Eclipse The only visible layers: Corona (halo) & sometimes Chromosphere (red ring)

Lunar Eclipse Occurs when the moon is a Full Moon and the earth, moon and sun are exactly lined up.

Lunar Eclipse

Sun and Moon

The Sun is…. A star In the Main Sequence stage 99% of the total mass in the solar system 109 times as big as the Earth It would take 1.3 million Earths to fill up the Sun.

Energy Production in the Sun Nuclear fusion occurs in the sun to give it its energy. Hydrogen is converted into Helium.

Structure of the Sun The sun does not have a solid surface. The visible surface is where its atmosphere becomes so thick that you can’t see through it. The sun is divided into 6 layers.

Layers of the sun

Layers of the Sun Corona - Outermost part of the sun’s atmosphere. Visible only during a solar eclipse Chromosphere - section of the sun’s atmosphere below the corona. Photosphere - the visible part of the sun’s atmosphere. The “surface” we see. Convective Zone- Section where convection currents carry energy to the outer atmosphere of the sun

Layers of the Sun Continued... Radiative Zone- Very dense section of the sun where energy is trapped. Core - inner part of the sun where the sun’s energy is produced by nuclear fusion. What Layer is shown here? Hint: Solar Eclipse

Solar Activity The circulation of energy causes gas in the photosphere to churn, causing magnetic fields that reach into space. –Sunspots - when the activity slows down in one spot, and the photosphere becomes cooler than other areas. Sunspots are cooler, dark spots on the sun. Sunspots change in a regular pattern. About every 11 years there is a peak in sunspots. They might affect our climate and cause lower temperatures on earth.

Sunspots

Solar Activity continued... Solar Flares- regions of extremely high temperatures and brightness that develop on the sun’s surface. When they erupt, they send streams of electrically charged particles into the solar system. –They can extend several thousand miles into space within minutes. –Particles from solar flares reach earth and interrupt radio and cell signals.

Solar Flare

Aurora Borealis Northern Lights When solar particles enter our atmosphere, they are attracted to the poles, and cause Aurora Borealis

Formation of the Moon Three explanations for how the moon could have formed: –Twin Theory –Meteor Impact Theory –Capture Theory

Twin Theory The moon formed at the same time as Earth. –Gravity pulled particles in the solar system together to make the earth and the moon out of a nebula

Meteor Impact Theory When Earth was first cooling, a meteor struck it and “splashed” a piece off which hardened to form the moon.

Capture Theory The Moon formed someplace else, it flew by Earth and gravity captured it into orbit.

Features of the Moon Maria - smooth dark plains on the moon Highlands- rugged mountains on the moon that appear as light places.

Features of the Moon Rilles - lines on the moon where the crust of the moon cracked when it cooled. Craters- round impacts from meteors

Why are there so many craters on the moon? The moon has no ATMOSPHERE, so it has no WEATHER, so there is no EROSION. Therefore, when the moon gets struck by a meteor, the crater stays there forever.

Label each section #1- #9