The SunThe Sun

Solar FactsSolar Facts

• Our Sun is a star, just like all the other stars in the night sky

• The name of our star is “The Sun”, but also “Sol”

• Latin for sun is “solis”, Greek for sun is “helios”

• Holds the entire Solar System together by its immense gravity

Solar FactsSolar Facts• Size: 1.4 million km. 110x Earth’s diameter. 1 million

Earths could fit inside the Sun.

• Temperature: Surface = 5,000° C (9,932° F), Inside = 15,000,000° C (27,000,000° F)

• Mass: 99.8% of entire Solar System’s mass, gravity = 28x Earth’s.

• Rotation (spinning): 25 days for equator to rotate, 27 days for poles to rotate

• Revolution: Sun revolves around center of our Milky Way galaxy.

Sun’s InteriorSun’s Interior1. Photosphere

2. Chromosphere

3. Core

4. Corona

5. Sunspots

6. Prominences & Solar FlaresWhere is the . . .

Convective Zone?

Radiation Zone?

Sun’s AtmosphereSun’s Atmosphere

• Corona (“Crown”)– Outer atmosphere, normally not visible (except during full solar

eclipse)– extends into space for millions of kilometers

• Photosphere (photo = “light”)– Middle atmosphere, is visible– Considered the surface layer of the sun

• Chromosphere (chromo = “color”)– Inner atmosphere, has a reddish color– Sometimes partially visible during a solar eclipse

Sun’s InteriorSun’s Interior• Convection Zone

– Outermost layer of interior– Gases move thru zone by convection currents (transfer of heat

by fluid movement)

• Radiation Zone– Middle layer of interior– Energy produced in core moves outward thru zone by radiation

(transfer of heat by energy waves)

• Core– Produces enormous amount of energy by nuclear fusion, fusing

hydrogen atoms (H) into helium atoms (He) under intense pressure and heat

Solar FeaturesSolar Features• Sunspots

– Dark spots on the sun’s surface– Areas of gas that are cooler than surrounding gases

• Prominences– Huge loops of gases linking sunspot regions

• Solar Flares– Prominences sometimes connect, causing the sun’s surface

gases to erupt far into space

• Solar Wind– Charged particles streaming from the sun, increased during

solar flares– Causes the planetary auroras, can interfere and damage

electronic equipment