Gourt > Science > Astronomy > Galaxies (2)
A galaxy is a huge gravitationally bound system of stars, interstellar gas and dust, plasma, and (possibly) unseen dark matter. Typical galaxies contain 10 million to one trillion (107 to 1012) stars, all orbiting a common center of gravity. In addition to single stars and a tenuous interstellar medium, most galaxies contain a large number of multiple star systems and star clusters as well as various types of nebulae. Most galaxies are several thousand to several hundred thousand light years in diameter and are usually separated from one another by distances on the order of millions of light years.
Although so-called dark matter appears to account for around 90% of the mass of most galaxies, the nature of these unseen components is not well understood. There is some evidence that supermassive black holes may exist at the center of many, if not all, galaxies.
Intergalactic space, the space between galaxies, is filled with a tenuous plasma with an average density less than one atom per cubic meter. There are probably more than a hundred billion (1011) galaxies in the observable universe.
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Deep Sky Observing :: Amateur
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Millionaire Follows Dad's Footsteps — Into Space
Thu, 09 Oct 2008 08:41:00 -0400
Richard Garriott, a famous video game developer, is paying millions of dollars for a ride on a Russian rocket to the International Space Station. He has wanted to go to space since he was a kid. His father and all of his neighbors were NASA astronauts. It's the first time the child of an American astronaut will blast off into space.
Young Galaxy's Magnetic Field Is Surprisingly Strong
Fri, 03 Oct 2008 13:53:00 -0400
Current models indicate that the magnetic fields that enclose galaxies grow slowly over billions of years. But scientists have used a telescope to peer back millions of years in time and discovered a distant galaxy with a magnetic field at least 10 times the average strength.
SpaceX Celebrates First Successful Rocket Launch
Fri, 03 Oct 2008 13:53:00 -0400
SpaceX's flagship Falcon1 rocket has successfully launched from an island in the central Pacific, becoming the first privately-developed rocket to orbit the planet. NASA has already contracted SpaceX to begin private space flight missions to the International Space Station beginning in 2010.
Computer Malfunction Delays Hubble Mission
Fri, 03 Oct 2008 13:31:00 -0400
NASA has postponed a planned repair mission to the Hubble Space Telescope after a new problem developed with the orbiting observatory. Ed Weiler, associate administrator of the Science Mission Directorate at NASA, explains why repairs won't take place until Feb. 2009 — at the earliest.
For Young Chinese, Spacewalk An Indicator Of Might
Sat, 27 Sep 2008 17:05:00 -0400
China on Saturday will become only the third nation — after Russia and the United States — to carry out a spacewalk. The event will be broadcast live nationwide. This milestone underscores China's technological achievements and is boosting national pride.
Solar Winds, Crucial To Life On Earth, Decreasing
Fri, 26 Sep 2008 12:45:00 -0400
Solar winds — invisible gas plasma emitted by the Sun — protect the solar system from cosmic rays that are hostile to terrestrial life. But new data from the Ulysses NASA probe indicate solar wind output is lower than has ever been previously documented.
Andromeda Galaxy - Information about the Andromeda Galaxy with descriptions and pictures.
Arp's Catalog of Peculiar Galaxies - Summarizes the catalog of 338 peculiar galaxy views gathered by Dr. Halton C. Arp.
Meta Description: [ Comprehensive exploration of the galaxies involved in Halton C. Arp's Atlas of Peculiar Galaxies, to support the astronomical observer. ]
Atlas of the Andromeda Galaxy - Contains information and tables about the Andromeda Galaxy.
Classifying Galaxies - Includes pictures and a lesson for learning Hubble's system of classification.
Complete Spiral Galaxy Pictures Gallery - Contains over 600 pictures of all spiral galaxies larger than 3 minutes of arc for all constellations in the Northern and Southern celestial hemispheres.
DIRECT Project Homepage - Determining the distances to nearby galaxies.
Dust in Spiral Galaxies - HST and ISO Results.
European Network: The Formation and Evolution of Galaxies - Purpose is to understand the creation of galaxies and the universe has evolved. Plans to study distant galaxies at optical, infrared, and radio frequencies.
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Extragalactic bookmarks - List of resources dedicaced to extragalactic astronomy: Databases, projects, education ...
Meta Description: [ Collection of links to other sites of
interest for extragalactic astronomy. Includes: Extragalactic databases,
Catalogues and Data, Groups and teams active in extragalactic,
Educational astronomy, Abstract/preprint services..
Gathered by CRAL-galaxies at observatoire de Lyon ]
Faulkes Telescope Educational Guide - Galaxies - Some useful information about the formation of galaxies.
Meta Description: [ This is the Faulkes Telescope Educational Guide ]
Galaxies - NASA Windows to the Universe. Includes illustrations and introductory information about a variety of galaxies.
Galaxies - Some useful information about kinds of galaxies, content of galaxies, clusters of galaxies, galaxies and cosmology.
Galaxies - Astronomy Photos from the Hubble Space Telescope, Hubble, NASA, ESO, Chandra, Gemini and Apollo mission archives. Images of space, earth, planets, stars, galaxies, nebula.
Meta Description: [ Astronomy Photos from the Hubble Space Telescope, Hubble, NASA, ESO, Chandra, Gemini and Apollo mission archives. Images of space, earth, planets, stars, galaxies, nebula. High resolution digital lab for astro imagers and astro photographers. ]
Galaxies - List of galaxies with photos.
Galaxies - Galaxies with their descriptions.
Galaxies - Contains a set of notes by Nick Strobel. Topics include the structure of the Milky Way, the characteristics of other galaxies, and finding distances to other galaxies.
Galaxies - Many selected links to websites dedicated to galaxies.
Meta Description: [ Portal to selected sites about galaxies and their evolution ]
Galaxy classification - Wikipedia, the free encyclopedia - An article about the Galaxy classification.
Galaxy Collisions - A review article for non-specialists.
Galaxy Evolution Explorer - Contains information about the growth of various galaxies. Also includes images, news, and a glossary.
Meta Description: [ Caltech's Galaxy Evolution Explorer public homepage. GALEX will measure the history of star formation in the Universe, 80% of the way back to the Big Bang. ]
Galaxy Pair Picture Gallery - Images of interacting galaxy pairs
Galaxy Photography - Contains various images of a selection of galaxies.
Meta Description: [ Galaxy, Photography, Images by Jason Ware ]
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Globular Clusters in the Andromeda Galaxy - Data, observation notes, and more about globular clusters within the galaxy.
Meta Description: [ Angelfire on Lycos, established in 1995, is one of the leading personal publishing communities on the Web. Angelfire makes it easy for members to create their own blogs, web sites, get a web address (domain) and start publishing online. ]
High Redshift Supernova Search - Project at Lawrence Berkeley National Lab to search for supernovas in very remote galaxies. This provides an accurate means of measuring the distances to remote galaxies and thereby determining the age of the universe.
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Lecture 28: Types of Galaxies - This site is about Spiral, Elliptical, Irregular Galaxies with their important characteristiŃs.
M31 - the Andromeda Galaxy - Includes a catalog of globular clusters, photos, and brief description.
Phil Marshall - Explains gravitational lensing by clusters. Includes pictures of MS1054.
Spiral Galaxies - Spiral galaxies with short descriptions and photos.
The Electronic Sky - Large list of galaxies with detailed descriptions.
The Galaxy Catalog - Zsolt Frei - This site contains a collection of digital images of 113 nearby galaxies.
The Small Magellanic Cloud, SMC - Gives mathematical measurements relating this galaxy that orbits the Milky Way. Includes history about first known discoveries and links to photo galleries.
UMass High Energy Astrophysics Group - Research group primarily interested in high energy activities in galaxies, particularly the interplay between massive stars and the interstellar medium.
Meta Description: [ Homepage of the UMass High Energy Astrophysics Group ]
Carl Sagan Origins Of The Universe Part1 |
