Types of Galaxies Mr. Pfeffenberger Add Corporate Logo - - PowerPoint PPT Presentation

Types of Galaxies

• Mr. Pfeffenberger

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Elliptical Galaxies

Most common type of galaxy

– Shape – small/large, 3-dimensional ellipse

• r round

– Smooth,featureless appearance and appear basically the same from any angle. – Made up of old stars and containing a small amount of gas, and dust. – Most are yellow and red because they do not contain young stars. – Vary in size from small to extremely large

Elliptical Facts

• - do not have a disc or arms
• - smooth, baseball or football shaped
• - the smallest elliptical is called a

“dwarf” elliptical and appears to be the most common type of galaxy

• - the stars do not revolve around the

center in an organized way. Their movement is randomly oriented

Elliptical Galaxy

Spiral Galaxies

Spiral arms winding outward from inner regions

– Loose, lumpy spiral arms (two or more) are made

• f bright blue young stars in the cstar and yellow

stars throughout the disc, and dust. Most arms start close to the center of the galaxy; so it has a small central bulge. It is referred to as a pinwheel shape. – Made mainly of young stars and contains a large amount of gas.

Spiral galaxies II

– Example - Andromeda so far away that you can’t see its individual stars. It appears as a hazy spot in our sky. – It is about 2.2 million light years away

Spiral Galaxy with 3 main components: bulge, disk and halo

Barred Spiral Galaxy

• A pinwheel-shaped galaxy containing

many new stars and a large amount of gas.

• A “bar” of stars, dust and gas runs

across its center

Light year

• The distance that light travels in one

year.

• Light travels at 300,000 km/s, or about

9.5 trillion kilometers in one year.

• The nearest star to earth other than the

sun is Proxima Centauri.

• It is 4.2 light years away, or about 40

trillion kilometers.

Irregular Galaxies

– No definite structure – Smaller and less common than other galaxies – Tend to have a blue or white color because recent star formation makes galaxies appear blue. – Composed of both young and old stars, and it contains large amounts

• f gas and dust.

Irregular Galaxy

Milky Way

– Contains more than 400 billion stars and may contain up to 1 trillion – The visible disc of stars Is about 100,000 light years across – The sun is located about 30,000 light years out from its center

Milky Way

• The Sun orbits the center of the Milky

Way once every 240 million years

– Scientists do not know if it is a barred spiral galaxy or a normal spiral galaxy

Spiral Galaxy - Our Milky Way