Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Ch. 27.3 Star Groups
Document related concepts
Gamma-ray burst wikipedia , lookup
Fermi paradox wikipedia , lookup
International Ultraviolet Explorer wikipedia , lookup
Space Interferometry Mission wikipedia , lookup
Rare Earth hypothesis wikipedia , lookup
Shape of the universe wikipedia , lookup
Extraterrestrial life wikipedia , lookup
Modified Newtonian dynamics wikipedia , lookup
Aries (constellation) wikipedia , lookup
Aquarius (constellation) wikipedia , lookup
Fine-tuned Universe wikipedia , lookup
Cassiopeia (constellation) wikipedia , lookup
Stellar evolution wikipedia , lookup
Canis Major wikipedia , lookup
Cygnus (constellation) wikipedia , lookup
High-velocity cloud wikipedia , lookup
Flatness problem wikipedia , lookup
Perseus (constellation) wikipedia , lookup
Observational astronomy wikipedia , lookup
Lambda-CDM model wikipedia , lookup
Constellation wikipedia , lookup
Cosmic distance ladder wikipedia , lookup
Physical cosmology wikipedia , lookup
Non-standard cosmology wikipedia , lookup
Open cluster wikipedia , lookup
Hubble Deep Field wikipedia , lookup
Structure formation wikipedia , lookup
Corvus (constellation) wikipedia , lookup
Timeline of astronomy wikipedia , lookup
Transcript
Ch. 27.3 Star Groups Constellations Patterns of stars in the sky, in which the stars are not necessarily close together. 88 constellations recognized by astronomers. Most don’t look like the figures they are named after. Galaxies Typically contain about 100 billion stars. Also contain bright and dark nebulae. Our own Milky Way is part of the Local Group of galaxies. Up to a trillion galaxies in the known part of the universe. Types of Galaxies Spiral Barred spiral Elliptical---no young stars; little dust and gas Irregular The Milky Way A spiral galaxy. From Earth, seen as a faint cloud-like band of stars. 100,000 light-years in diameter. 2,000 light-years thick in the center. One complete rotation in 200 million years. Our sun is about 30,000 light-years from the center. Star Clusters Groups of stars, either open clusters (loosely shaped) or globular clusters (spherical shaped). Binary Stars Most stars in the galaxy are part of double, or even multiple-star systems. Important in determining stellar masses, by examining gravitational effects. Formation of the Universe Big Bang—the theory that the universe exploded from a singularity 12 to 15 billion years ago, and has been expanding ever since. Quasars are seen at the most distant parts of the observable universe; believed to have formed shortly after universe’s formation.
