Sun and Moon The Sun is A star

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

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 years there is a peak in sunspots. 11 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 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 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 • Highlandsrugged 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.

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