The Milky Way

When stars died, chemicals other than hydrogen and helium formed, which led to the next level of complexity—Heavier Chemical Element. Most stars spent about 90% of their life over billions of years on during protons and hydrogen nuclei into helium nuclei. When they run out of fuel, the furnace at the center of the star stopped supporting the star, and gravity took over. Small stars did not have much pressure at the center. They burned hydrogen slowly over billions of years at relatively low temperatures. When they died, they would slowly fade away. However, great stars had so much mass that they can create enormous pressures and temperature, and when the giant stars ran out of hydrogen, the temperature got cranked up even higher, which led the star to collapse. The high temperature that the collapse caused was able to make helium nuclei fuse into nuclei of carbon. When a star used up its helium, it collapsed again, and the cycle started over. The star heated up and began to fuse carbon to form

Stellar evolution stars exist because of gravity. The two opposing forces in a star are gravity (contracts) and thermal nuclear energy (expands). Stage 1 Birth is where gravity contracts the cloud and the temperature rises, becoming a protostar. Protostars are a hypothetical cloud of dust and atoms in space which are believed to develop into a star. Astronomers are fairly certain of their existence. Protostars are formed about a million years after a gas clump from an interstellar gas cloud has started

Stargazing is often thought to be something lovers would do on a date or something of a hobby. Astronomers and scientists of all kinds make their careers out of it every day.

The Low mass stars spend there main life as a fusion machine which turns hydrogen into helium and a very slow and methodical pace. When the energy released by this fusion reaches the surface it is released into space and this is the star luminosity. Over a long, long time sometimes billions of years a low mass star consumes the hydrogen in its core and converts it to helium, at which point the core starts to contract and shrink. Once all of the hydrogen inside the stars core begins to become totally exhausted, the core pressure gives way to the crush of gravity because it has no more fusion occurring in its core at that time. As the core shrinks rapidly and the outer layers start to expand the stars shape begins to grow in size and its luminosity becomes extraordinary brighter due to the outer shell starting to produce fusion more rapidly then the core did during the main sequence life of the star. As this situation grows more rapidly and extreme the core starts to rapidly burn again and fuse its core helium into carbon. Then just before its final death the star ejects its outer layers into space. This leaves only the degenerate carbon core and since this core is still very hot it emits intensely powerful ultraviolet radiation and glows brightly in what is known as a planetary nebula. The nebula fades and cools over around a million or so years and we are left with a white dwarf cooling indefinitely till

The life cycle of star is on an eternal cycle of birth, death and regeneration where the gases that form stars are ejected by the very stars when they die. This all starts with the helium gas and fusion of hydrogen. The life cycle of a star is formed from stellar nebula to high mass stars and low mass stars. Hertzsprung and Russell classified stars on the main sequence of the H-R diagram about 1910 that shows the relationship between luminosities and spectral types.

Gravity pulls dust and gas together until it forms a ball. After a bit of time, the temperature rises from all the gas and dust bumping into each other under the great pressure of the surrounding material reaches around 15 million degrees. This is called a protostar, and it reaches a temperature of about 10 million Kelvins. This is where nuclear fusion occurs, and a star is born.

Stars go through phases with each one altering the star. They start as a protostar then ignite to

The Nebula is the first stage which the star is born. The Nebula is actually a cloud of hydrogen gas and dust in space. There are a couple different types of

You are probably wondering where did these things come from and how are they formed? Well I am about to tell you, Low mass stars are formed when all the helium has fused into carbon, then the core collapses. As the star collapses, the outer layers of the star are expelled. A planetary nebula is formed by the outer layers a massive star that will undergo a supernova explosion. Then when the low mass star is done forming after billions of years they start to become giants.

The Milky Way is the galaxy that contains our Solar System. The descriptive "milky" is derived from the appearance from Earth of the galaxy a band of light seen in the night. From Earth, the Milky Way appears as a band because its disk shaped structure is viewed from within. Galileo Galilei first resolved the band of light into individual stars with his telescope in 1610. Until the early 1920s most astronomers thought that the Milky Way contained all the stars in the Universe. Following the 1920 Great Debate between the astronomers Harlow Shapley and Heber Curtis and an observation by Edwin Hubble showed that the Milky Way is just one of many galaxies.

Stars are born in a very complicated way. First the gravitational collapse of a cool, dense molecular cloud sends fragments into space. The fragments then contract and form stellar cores. The stellar cores then rotate and condense as they increase in temperature, to the point that a nuclear reaction occurs. The new born star burns hydrogen into helium for 90 percent of its life and is a sequence star. A star’s mass changes as it burns more hydrogen.Once there is no more hydrogen for the star to burn off of, energy generation will stop and the core will start contracting. As the internal temperature increases a shell of hydrogen gets ignited. The star begins to expand enormously and increases in luminosity. The star expands so large that if our star started to expand like this it would swallow Mercury and

The universe is cool. Just think about it, numerous items in this universe are cool. For example, Niagara Falls is so cool when the overflowing water comes rushing down. Also, the solar eclipse that happened this summer was cool. The eclipse occurred during the day and it became dark around 4:00 P.M. In a few states it was so dark the street lights came just like it was dusk. I didn’t even know the moon could cover the sun! The Milky Way galaxy is amazingly cool too. It contains over 200 billion stars. The Milky Way is a disk about 120,000 light years across with a central bulge that has a diameter of 12,000 light years. Most large galaxies have a supermassive black hole at the center, and the Milky Way is no exception. The universe has eight

A nebula is a star nursery where millions of new stars are created, nebulae vary is shape, size and temperature.Within the dark parts of a nebula are where the stars are usually born, within these dense, dark areas hydrogen-gas ,clouds and dust begin to spin as gravity crushes this matter into a super dense spherical shape, the beginning of a star.

For about another thirty million years, the star continues to contract and its central density, central temperature, and surface temperature increase; then it is a main sequence star where pressure and gravity are balanced and nuclear energy is being generated in the core. It takes forty to fifty million years for a star to reach this stage. The Sun is a main sequence star (McMillan, 2011).

Main sequence stars like our own sun enduring in a state of nuclear fusion during which they will produce energy for billions of years by replacing hydrogen to helium. Stars change over billions of years. When their main sequence phase ends they pass through other states of existence according to their size and other characteristics. The larger a star's mass, the shorter its lifespan is. As stars move toward the end of their lives, much of their hydrogen will be converted to helium. Helium sinks to the star's core and raises the star's temperature—causing its outer shell to expand. These large, puffy stars are known as Red Giants. The red giant phase is actually a prelude to a star shedding its outer layers and becoming a small, dense body called a White Dwarf. White dwarfs cool down for billions and billions of years, until they finally go dark and produce no energy at all. Once this happens, scientists have yet to observe, such stars become known as Black Dwarfs. A few stars avoid this evolutionary path and instead go out with a bang, exploding as Supernovae. These violent explosions leave behind a small core that will then turn into something called a Neutron Star or even, if the remainder is large enough, it is then turned into something called a Black Hole.