March 24, 2014

• Remember….• What is the smallest particle of matter that still retains

all of the properties of that matter?• What is in the center of the smallest particle of

matter?• What surrounds the center?• Do you remember that the atom is mostly empty

space?• What did we explore Friday that is mostly empty

space?

TEK 8.8B

• Recognize that the Sun is a medium-sized star near the edge of a disc-shaped galaxy of stars and that the Sun is many thousands of times closer to the earth than any other star.

• Star - a large ball of gas that generates its own energy by fusing hydrogen atoms to make helium. It is held together by its own gravity. This process emits a tremendous amount of energy, and some of the energy is in the form of light.

• Astronomical Unit (AU): The distance between the Earth and the sun (about 150 million kilometers, or 93 million miles).

Where’s The Sun? (where’s waldo?)

1. Where is our solar system located in the MilkyWay galaxy?

2. How does the Sun’s mass compare with other stars in the galactic neighborhood?

3. How does the distance of the Sun from Earthcompare to the distances of other stars from Earth?

4. How long does it take for light from the Sun toreach Earth’s surface?

Your Galactic Address

• North Ridge Middle School• 7332 Douglas Lane• North Richland Hills, Tx• USA, North America• Planet Earth• Solar System• Milky Way Galaxy• Virgo Supercluster• Universe

Artistic rendering of the possible shape of the known universe. http://scienceblogs.com/startswithabang/upload/2010/12/whats_in_the_uni verse/WMAP.jpeg

Virgo Supercluster

SUN’S MASS

• The Sun’s mass is 199 with 28 zeros after it in kg, and it’s a medium sized star.

• There are billions and billions of stars in the galaxy.

• To make writing the mass of these stars easier, the Sun is the frame of reference and the Sun is equal to one solar mass.

• Smaller stars < one solar mass• Larger stars> one solar mass

How Long Does it Take for the Light of our Sun to reach us?

http://www.universetoday.com/15021/how-long-does-it-take-sunlight-to-reach-the-earth/

The LIGHT-YEAR

• A light-year is a measure of distance. It is not a measure of time.

• A light-year is the distance that light travels in one year.

• It is equal to about 6 trillion miles.• 6,000,000,000,000 miles.

Science Journals – 3-25-14

• The light from Alpha Centauri A takes 4.3 years to reach Earth. The light from Ross 154 takes 9.7 years to reach Earth. The light from Luyten 726-8A takes 8.7 years to reach Earth. The light from Procyon A takes 11.4 years to reach Earth. The light from Sirius B takes 8.1 years to reach Earth.

1. What is the order of the following stars from the closest to Earth to the farthest from Earth?

Massive Stars

• OUR SUN IS JUST AN AVERAGE SIZED STAR!• There are stars out there much, much bigger…

Note down this definition -

Our Sun →