Milky Way GalaxyCierra Yoshikawa

Tomohiro Hoshino

What is the Milky Way Galaxy?

Spiral galaxy Containing 400 billion stars

including our solar system Plus gas and dust x750 solar mass

What is the Milky Way Galaxy?

100000 light year in diameter Formed by the collapse of a

large region of gas and dust Part of group of galaxies called

the Local Group Group of 30 galaxies that are

about 5 million light years across

Other Info

Milky Way Arms

Perseus Arm

Saittarius Arm

Cygnu Arm

Orion Arm (our solar system)

Norma Arm

Sctum-Crux Arm

3 General Components

The halo Nuclear bulge The disk

The Halo

Consists of the oldest stars and dark matter, absence of gas or dust 146 Globular Clusters

Spherical shape Believed to be formed 10-15 billion

yrs ago Produces hot gas called gamma-ray

halo

The Disk

Contains the sun and other intermediate-to young stars (million –ten billion years old), gas and dust

Approximately 300pc (1,000 light years) thick and 30kpc (100,000 light years) in diameter

The Disk Cont.

Sun sits about 2/3 of the way from the center to the edge of the disk.

Sun revolves around the center every 250 years

Nuclear Bulge

The center of the Galaxy Dimension 1kpc by 6kpc Shaped like a football

Crowded with stars which are 10 billions years old or older (population II)

Nuclear Bulge Cont.

The most brightest region is called Sgr A ~ 2 x 106 M of Sun within 1 pc Stars are only 1000 AU apart A collision every 106 years

Types of Stars

Population I: Younger, metal-rich stars Found in disk

Population II: Older, metal- poor stars Found in halo

View from Earth

Can only be seen on a clear night

Looks like a band of stars splashed on the sky

Can’t see spiral structure from Earth, images of structure created from computer modeling based on information from stars as they orbit the galaxy

Most of it in invisible from Earth due to being in the disk

5,000-8,000 stars visible from Earth

View from Earth

Works Cited “Our Solar System in the Milky Way Galaxy.” N.p.

N.d. Web. 16 April 2011. <http://www.enchantedlearning.com/subjects/astronomy/solarsystem/where.shtml>.

“Our own Galaxy-The Milky Way.” Cambridge Cosmology: Galaxies, N.d. Web. 16 April 2011. <http://www.damtp.cam.ac.uk/research/gr/public/gal_milky.html>.

“The Milky Way Galaxy.” N.p. 25 Aug. 2005. Web. 16 April 2011. <http://seds.org/messier/more/mw.html>.

“The Milky Way Galaxy.” University of California, San Diego Center for Astrophysics & Space Sciences, N.d. Web. 16 April 2011. <http://casswww.ucsd.edu/public/tutorial/MW.html>.