The Sun

Stars & Galaxies

The Sun

IV. The SunA. All life on Earth depends on the energy that comes from the star in the center of our solar system.B. Energy produced by the Sun is due to hydrogen atoms fusing together to produce helium atoms. C. The Sun is composed of 3 layers:1. Photosphere innermost not as hot2. Chromosphere transition zone3. Corona largest & hottest layerV. Sun Surface FeaturesA. The sun appears to be a smooth layer but has many surface features including:1. Sun spots cooler areas2. Prominences arching columns of gas3. Flares gases shooting straight upward4. CMEs (coronal mass ejections) auroras All due to magnetic field & reactions across the Sun.

Solar Eclipse

Occurs when the Sun, Moon, and Earth line upCan only happen during a New MoonGenerally, they occur every 2-5 yearsLunar EcipseOccurs during a Full MoonOccurs when Moon, Earth, and Sun are directly aligned. Next one is October 8, 2014

Auroras

Solar FlaresThe sun unleased a powerful solar flare late Monday (Oct. 22), releasing waves of radiation into space that have already caused a short radio blackout onSolar flares are caused when magnetic activity ramps up in certain patches, called sunspots, on the surface of our sun

I. ConstellationsA. Constellations are patterns of stars that are named as a group. (88 exist in our sky)

B. All the constellations we see in the sky are part of our galaxy (large collection of stars, gas, & dust held together by gravity), the Milky Way Galaxy

II. Absolute & Apparent Magnitude A. The actual brightness of the star refers to the stars absolute magnitude.

B. How bright the star actually is to the viewer on Earth is called the apparent magnitudeApparent Magnitude does not equal absolute magnitutde

III. Measuring in SpaceA. Distance in space is measure in light years or the distance light travels in one year (9.5 trillion km)Used to estimate the distance of stars from EarthThe distance shifts depending on the motion/position of Earth as it orbits (parallax)

VI. Properties of StarsA. Basic properties of stars include:1. Diameter 2. Mass 3. Brightness 4. Energy Output (luminosity) 5. Composition 73% hydrogen, 25% helium6. Surface Temperature appears different due to very slight composition differencescan range from 0.1 times our suns diameter to 100 times larger15VII. Classifying Stars A. Hertzsprung & Russell Diagram shows the relationship of temperature & brightness among stars

B. Main Sequence(90%) vs. Dwarfs & Giants (bright)

IIX. Life of a StarScientists theorize that a star goes through a few steps (as hydrogen depletes)1. Nebula ball of gas & dust 2. Main sequence pieces of nebula are pulled together due to gravity, force increases energy/temperature3. Red Giant vs. Red Super Giant when hydrogen begins to deplete outer layer cools & expands, (if large sequence is more quick & violent)4. White Dwarf vs. Neutron Star or Black hole outer layers cool & escape to space leaving hot dense core

IX. GalaxiesA. Galaxies are groups into clusters.B. Types of galaxies:1. Spiral Galaxies 2. Elliptical Galaxies football 3. Irregular Galaxies small irregular

X. Gravitational PullA. Every 2 bodies in the universe attract each other with a force that is proportional to the product of their masses.

In other words gravitational force depends on their masses & the distance between the 2 bodiesGravity increase with larger mass & closer proximityThink about 2 magnets