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Stars!!!
How stars are formed
Space is filled with thinly spread gas and dust. This is called interstellar medium. The gas atoms are mostly hydrogen and they are usually about a centimeter appart. The dust is mostly made of microscopic grains of carbon and silicon. When this mixture comes together it forms a dense cloud of gas and dust called a nebula. The stars gravity causes individual hydrogen atoms to fall to the center. The icrease of the energy makes the gas heat up. Millions of years later, the stars temperature reaches about 20 million degrees Fahrenheit. At this temperature, the hydrogen ignites and burns because of nuclear reactions. Nuclear reactions just keep on repeating, and a star is born.
Main sequence stars
Dwarf stars: Dwarf stars are relatively small stars. They can get up to 20 times the size of our sun and up to 20,000 times brighter
Yellow dwarf: Yellow dwarfs are small stars. Our sun is a yellowdwarf.
Red dwarf: A red dwarf is a small, cool, very faint star. Its surface temperature is under about 4,000 K.
Giant and super giant stars
Red Giant: A red giant is a relatively old star. Its diameter is about 100 times larger than the original star. The surface temperature is 6,500 K.
Blue Giant: A blue giant is a huge, very hot, blue star. It burns helium and is a post main sequence star.
Super Giant: A super giant is the largest known type of star. Some are almost as large as our entire solar system! These stars are very rare. When they die, they supernova and become a black hole.
Binary stars
Double star: A double star is two stars that appear close together in the sky. Some are true binaries which are two stars that revolve around one another. Others just appear next to each other because from Earth, they are in the same line of sight.
Binary star: A binary star is a system of two stars that rotate around a common center of mass known as the barycenter. About half of all stars are in a group of at least two stars.
Eclipsing binary star: An eclipsing binary star is two close stars that appear to be a single star varying in brightness because they are constantly increasing and decreasing the brightness of one another.
X- Ray binary star: An X- ray binary star is a special type of star. One of the two stars is collapsed. As matter is stripped from the normal star, it falls into the collapsed star, cretaing x- rays.
Star classification
Stars are classified by their spectra (the elements that they absorb) and thier temperature. There are seven main types of stars. In oder of decreasing temperature: O, B, A, F, G, K, and M. O and B are uncommon but very bright. M is common but dim.
Variable stars
Cepheid variable stars: These are stars that regularly pulsate in size and change in brightness. If the size increases, the brightness decreases. If the size decreases, the brightness increases. These stars may not permanently be variable stars. They could just be going through an unstable phase.
Maria variable stars: This is a stars whose brightness and size cycle over a long period of time. They are pulsating red giants that vary in magnitude. The name of this kind of star comes from the star Maria. Maria's variations were discovered in 1596.
Faint, virtualy dead stars
White dwarf: A white dwarf is a small, very dense, hot star. It is mostly made of carbon and is all that remains after a red giant has lost its outer layers. It's about the same size as the earth but much heavier! Eventualy, it will loose its heat and become a cold black dwarf.
Brown dwarf: A brown dwarf is a star whose mass is to small to have nuclear fusion occur at its core. It doesn't have a high enough temperature or pressure. It isn't very luminous either.
Neutron star: A neutron star is a small, super dense star. It has a diameter of around 5-10 miles! A neutron star is mostly made of tightly packed neutrons but it has a thin atmosphere of hydrogen.
Pulsar: A pulsar is a rapidly spinning neutron star that gives off energy in pulses.
Constellations
Many cultures told stories about hunters, warriors, kings and queens, birds, bears, horses, and other figures they saw in the sky. They used these myths to teach their history and how they saw their place in the universe. We use Greek and Roman names but other civilizations use different names and myths.
Constellations are now used to mark an area in the Celestial Sphere. The Big Dipper is an arterism that is part of Ursa Major. The Great Bear and large "w" constellations are part of Cassiopeia.
A planisphere tells you when each constellation can be seen each month. The reason that you can't always seen a certain constellation at night is because they are in the sky during the day and by the time its night, the Earth has rotated so you can't see them anymore. As the Earth orbits the sun, constellations become visible at different times and certain constellations are visible during different months. Star maps or charts are used to find constellations.
How stars die
When a stars life is beginning to end, the hydrogen supply begins to run out. The first visible sign of death is reddening and swelling of the outer regions. Once this happens, it is a red giant. When the star is all out of fuel, it can't generate pressure on the center of the star to balance the crushing force of gravity. The star collapses under the force of its own weight. A small star will collapse and become a white dwarf. A large star how ever will collapse and explode into a super nova! It is very bright and colorful because of all the gasses. These explosions create new stars over millions of years. After the large star explodes, it becomes either a neutron star or a blackhole...
Temperature Scale
-273K= 32 degrees Fahrenheit
K= Kelvin
The Sun
Size
The sun is the largest object in our solar system. It contains about 98% of our solar systems total mass. The sun has a diameter of 1,392,000 kilometers and its mass is 1.98892xx10 to the 30th power. It could hold over 1.3 million Earths!
Sun spots
Sun spots are brownish looking spots that are much cooler than the surrounding photosphere. They are only 7,000 degrees Fahrenheit! Bright, luminous, hydrogen clouds called faculae form right above regions where sun spots are about to form. Flares are bright filaments of hot gas shooting up from sun spots.
Layers
Corona: The corona is the outer atmosphere of the sun. It can only be seen during a solar eclipse. Large clouds of glowing gas called prominences appear here to.
Chromosphere: Solar energy passes through this region on its way out from the center of the sun.
Photosphere: The photosphere is 11,000 degrees Fahrenheit. It looks mottled because of energy eruptions on the surface.
Subsurface Flows
Convection Zone
Radiative Zone
Inner Core: The inner core hasa temperature of 27,000,000 degrees Fahrenheit. The pressure is 340 billion times Earths air pressure at sea level.
Solar energy
Solar energy is created at the sun's core. It takes about 1 million years for it to reach the surface. Every second 700 million tons of hydrogen are converted into helium ashes. In this process, 5 million tons of pure energy is released. So as time goes on, the sun is becoming lighter.
Predicted way of death
As the sun starts to die, it will begin to fuse helium in to heavier elements. This causes it to expand into a red giant. It will become so large it will swallow the Earth! After about 1 billion years as a red giant, the sun will suddenly collapse into a white dwarf. It may take a trillion years to cool off completely.
How stars are formed
Space is filled with thinly spread gas and dust. This is called interstellar medium. The gas atoms are mostly hydrogen and they are usually about a centimeter appart. The dust is mostly made of microscopic grains of carbon and silicon. When this mixture comes together it forms a dense cloud of gas and dust called a nebula. The stars gravity causes individual hydrogen atoms to fall to the center. The icrease of the energy makes the gas heat up. Millions of years later, the stars temperature reaches about 20 million degrees Fahrenheit. At this temperature, the hydrogen ignites and burns because of nuclear reactions. Nuclear reactions just keep on repeating, and a star is born.
Stars!!!
Variable stars
Cepheid variable stars: These are stars that regularly pulsate in size and change in brightness. If the size increases, the brightness decreases. If the size decreases, the brightness increases. These stars may not permanently be variable stars. They could just be going through an unstable phase.
Maria variable stars: This is a stars whose brightness and size cycle over a long period of time. They are pulsating red giants that vary in magnitude. The name of this kind of star comes from the star Maria. Maria's variations were discovered in 1596.
Main sequence stars
Dwarf stars: Dwarf stars are relatively small stars. They can get up to 20 times the size of our sun and up to 20,000 times brighter
Yellow dwarf: Yellow dwarfs are small stars. Our sun is a yellowdwarf.
Red dwarf: A red dwarf is a small, cool, very faint star. Its surface temperature is under about 4,000 K.
Red giant: A red giant is a relatively old star. It is usually an orange sort of color. the diameter is usauall 100 times larger than the original star. The surface temperature is under 6,500 K.
Blue giant: A blue giant is a large, very hot, blue star.It is a post main sequence star and it burns helium.
Super giant: A super giant is the largest known type of star. Some are almost as large as our entire solar system! These stars are very rare. When they die, they supernova and become black holes.
Faint, virtualy dead stars
White dwarf: A white dwarf is a small, very dense, hot star. It is mostly made of carbon and is all that remains after a red giant has lost its outer layers. It's about the same size as the earth but much heavier! Eventualy, it will loose its heat and become a cold black dwarf.
Brown dwarf: A brown dwarf is a star whose mass is to small to have nuclear fusion occur at its core. It doesn't have a high enough temperature or pressure. It isn't very luminous either.
Neutron star: A neutron star is a small, super dense star. It has a diameter of around 5-10 miles! A neutron star is mostly made of tightly packed neutrons but it has a thin atmosphere of hydrogen.
Pulsar: A pulsar is a rapidly spinning neutron star that gives off energy in pulses.
How stars die
When a stars life is beginning to end, the hydrogen supply begins to run out. The first visible sign of death is reddening and swelling of the outer regions. Once this happens, it is a red giant. When the star is all out of fuel, it can't generate pressure on the center of the star to balance the crushing force of gravity. The star collapses under the force of its own weight. A small star will collapse and become a white dwarf. A large star how ever will collapse and explode into a super nova! It is very bright and colorful because of all the gasses. These explosions create new stars over millions of years. After the large star explodes, it becomes either a neutron star or a blackhole...
Binary stars
Double star: A double star is two stars that appear close together in the sky. Some are true binaries which are two stars that revolve around one another. Others just appear next to each other because from Earth, they are in the same line of sight.
Binary star: A binary star is a system of two stars that rotate around a common center of mass known as the barycenter. About half of all stars are in a group of at least two stars.
Eclipsing binary star: An eclipsing binary star is two close stars that appear to be a single star varying in brightness because they are constantly increasing and decreasing the brightness of one another.
X- Ray binary star: An X- ray binary star is a special type of star. One of the two stars is collapsed. As matter is stripped from the normal star, it falls into the collapsed star,
Star classification
Stars are classified by their spectra (the elements that they absorb) and thier temperature. There are seven main types of stars. In oder of decreasing temperature: O, B, A, F, G, K, and M. O and B are uncommon but very bright. M is common but dim.
Constellations
Many cultures told stories about hunters, warriors, kings and queens, birds, bears, horses, and other figures they saw in the sky. They used these myths to teach their history and how they saw their place in the universe. We use Greek and Roman names but other civilizations use different names and myths.
Constellations are now used to mark an area in the Celestial Sphere. The Big Dipper is an arterism that is part of Ursa Major. The Great Bear and large "w" constellations are part of Cassiopeia.
A planisphere tells you when each constellation can be seen each month. The reason that you can't always seen a certain constellation at night is because they are in the sky during the day and by the time its night, the Earth has rotated so you can't see them anymore. As the Earth orbits the sun, constellations become visible at different times and certain constellations are visible during different months. Star maps or charts are used to find constellations.
The sun
Age
The sun is a middle aged star and is about 7 billion years old.
Size
The sun is the largest object in our solar system. It contains about 98% of our total solar system's mass. The sun has a diameter of 1,392,000 kilometers and its mass is 1.98892x10 to the 30th power. It can hold over 1.3 million Earths!
http://www.nasa.gov/images/content/171925main_heliolayers_label_516.jpg
Layers
Corona: The corona is the outer atmosphere of the sun. This is where prominences appear. Prominences are large clouds of glowing gas that erupt from the upper chromosphere.
Chromosphere: Solar energy passes through the chromosphere on its way out from the center of the sun.
Photosphere: The photoshere is 11,000 degrees Fahrenheit. It looks mottled because of energy eruptions on the surface.
Subsurface flows
Convection zone
Radiative zone
Inner core: The temperature of the inner core is 27,000,000 degrees Fahrenheit. The pressure is 340 billion times Earths air pressure at sea level.
Activeness
The sun has been active for about 4.6 billion years. It will continue to be active for at least another 5 billion years.
Solar energy
Solar energy is created at the suns core. It takes about 1 million years for it to reach the surface! Every second, 700 million tons of hydrogen is converted in to helium ashes. In this process, 5 million tons of pure energy is released, so as time goes on, the sun is becoming lighter and lighter.
Temperature scale
-273K=32 degrees Fahrenheit
K= Kelvin
Sun spots
Sun spots are brownish looking spots that are much cooler than the surrounding photosphere. They are only 7,000 degrees Fahrenheit! Bright, luminous, hydrogen clouds called faculae form right above regions where sun spots are about to form. Flares are bright filaments of hot gas shooting up from sun spots.
http://images.intellicast.com/App_Images/Article/130_0.jpg
Predicted way of death
When the sun begins to die, it will start to fuse helium into heavier elements causing it to expand. Soon it will have swollen up to a red giant. It will become so large that it will swallow the Earth! After about 1 billion years as a red giant, the sun will suddenly collapse into a white dwarf. It may take a trillion years to cool off.
http://www.youtube.com/watch?v=q9L7SMoT3RM&feature=player_embedded#at=84
http://www.singularsci.com/NiteSky14.JPG
http://www.youtube.com/watch?v=lFR5S_Fc-9w
http://apod.nasa.gov/apod/image/0603/bigdipper_carboni_c46.jpg
http://apod.nasa.gov/apod/image/0908/sn1006c_c800.jpg
http://www.youtube.com/watch?v=KCZfWwmaO6w&feature=related
http://ronhullauthor.com/poems/sun-spots.gif
http://www.nasa.gov/images/content/171925main_heliolayers_label_516.jpg
http://www.youtube.com/watch?v=q9L7SMoT3RM