galaxies and super structures
DESCRIPTION
Galaxies and Super structures. Hubble Deep Field. What are galaxies?. Galaxies are systems made up of stars, gas, and dust. All galaxies have a center of mass that its stars orbit around. Galaxies can have from around ten million stars to a hundred trillion stars. - PowerPoint PPT PresentationTRANSCRIPT
GALAXIES AND SUPER STRUCTURES
Hubble Deep Field
What are galaxies? Galaxies are systems made up of stars,
gas, and dust. All galaxies have a center of mass that its
stars orbit around. Galaxies can have from around ten
million stars to a hundred trillion stars. In 1999 the Hubble telescope estimated
the total number of galaxies in the visible universe at 125 billion. http://imagine.gsfc.nasa.gov/docs/ask_astro/answers/021127a.html
Galaxy Shapes
Elliptical Galaxy M87
Elliptical Galaxy NGC 4649
http://chandra.harvard.edu/photo/category/galaxies.html
Galaxy ShapesElliptical (E0-E7)
Elliptical galaxies can range from nearly round to flatter, football-like shapes.
Elliptical galaxies are appear to be made up of older stars and have low rates of new star formation.
Whirlpool Galaxy
http://chandra.harvard.edu/photo/category/galaxies.html
Spiral Galaxy M101
http://chandra.harvard.edu/photo/category/galaxies.html
Galaxy ShapesSpiral (Sa, Sb, Sc)
• Spiral galaxies have the following characteristics:• A flat, rotating disc of (mostly newly created)
stars and interstellar matter• A central stellar bulge of mainly older stars,
which resembles an elliptical galaxy• A supermassive black hole at the very center
of the central bulge • Arms of stars radiating out from the central
bulge.
http://en.wikipedia.org/wiki/Spiral_galaxy
Barred Spiral Galaxy NGC 2903
http://en.wikipedia.org/wiki/File:NGC_2903_GALEX.jpg
Barred Spiral Galaxy NGC 1300
http://en.wikipedia.org/wiki/File:Hubble2005-01-barred-spiral-galaxy-NGC1300.jpg
Galaxy ShapesBarred Spiral (Sba, SBb, SBc)
Rather than a bulge, barred spirals have a bar shape in their centers.
The bar of barred spiral galaxies is thought to be the birthplace for new stars.
The Milky Way is a barred spiral.
Hoag’s Object (Ring Galaxy)
http://en.wikipedia.org/wiki/File:Hoag%27s_object.jpg
NGC 5866 (Lenticular Galaxy)
http://en.wikipedia.org/wiki/File:File-Ngc5866_hst_big.png
Colliding GalaxiesAntennae Galaxies
Galaxy ShapesIrregular
Although most galaxies in the universe are elliptical or spiral, some have irregular shapes.
Galaxies with irregular shapes are thought make up about ¼ of all galaxies.
These galaxies shapes are thought to be caused by gravitational forces of larger neighboring galaxies.
What are Super Structures?
Super structures are clusters and superclusters of galaxies.
Clusters and superclusters form large, orderly structures called filaments and walls.