Monday, July 27, 2009

1.1 Stars – Introduction


Stars are like our Sun, but there are many variations of them. One thing is true, they all begin there life by the spark of nuclear fusion at their cores.

Almost every dot in the night sky that we see are stars. All of those stars exist within our Milky Way Galaxy. Very rarely will a lone star actually exist in the spaces between galaxies, it is the norm for stars to only exist within galaxies.

There are two main groups of stars:

* Population II Stars - old, metal poor stars

* Population I stars - new, metal rich stars

In addition, there are two main endings of a stars life:

* Normal stars - like our Sun - end their life as a Planetary Nebula and White Dwarf

* Large stars end their life in a supernova and end up as a Neutron Star or Black Hole

Lifetime of a normal star:

* Dust cloud forms a Main Sequence star that burns for about 10 billion years

* Star ends Main Sequence life and swells to a Red Giant (about the size of Earth's orbit) and burns for 100 million years

* Star sheds is layers as a Planetary Nebula lasting 100,000 years

* Only the core of the star remains as a White Dwarf

1.0 Galaxy



The image above - a screen grab from The Sky version 6 - demonstrates what this strength look like. In ancient times, this was called a river of milk, spilled by the gods. The name of this feature would then be called the Milky Way - and the name stuck.

The Milky Way is actually a galaxy - a system of billions of stars gathered by mutual gravitation. Our knowledge of our galaxy (and many others) is still very new but much progress has been made. By using radio observations, we were able to determine the structure of our galaxy.

Tag

Assignment Lanka Tag Cloud
Computer Networks The History of Local Area Networks, LAN, The Topologies of a Networks, LANs describe different types of transmission Medias, Local Area Networks Access Methods, Carrier Sense Multiple Access with Collision Detect, Development of LAN Technologies. LAN -Token Ring, LAN Ethernet Digital, LAN - Ethernet Sun microsystems, LAN - Ethernet Mixed Environment, LAN - Token Ring was introduced by IBM LAN - IBM implementation of Token Ring, Token Ring Novell, LAN Token Ring - in a mixed environment, LAN - Fiber Distributed Data Interface, LAN - ATM, LAN Components, LAN Switching Methods, Virtual Local Area Network, Port based VLAN, Mac based VLAN, Protocol based VLAN, User Base VLAN, PC networks Components, PC networks Shared resources, PC Network operating systems, PC networks Novell Netware, PC networks Windows NT, PC networks IBM LAN Server Computer Programming Languages HTML Language, The Generations of Programming Languages, Different types of High Level Languages, Different types of High Level Languages Disadvantages
Computer Networks - IBM LAN Server, Windows NT Networks, Novell Netware, Network operating systems, Networks Shared, Networks Components, User Base, Protocol based, Mac based, Port based, VLAN, LAN Switching, LAN Components, ATM, Fiber Data, Token Ring, Token Ring Novell, IBM implementation, Ethernet, Sun microsystems, Ethernet Digital, Token passing, LAN Technologies, CSMA/CD, Access Methods, Transmission, Networks, The History of Local Area Networks, LAN