astronomy

=Astronomy= /
 * How does Density play a role in astronomical objects? (Stars, Planet formation, etc.)**
 * Astronomy:** Astronomy is the study of the universe.
 * Astronomy:** Astronomy is the study of the universe.

__**The Universe**__ :The universe is ever expanding.  Its is everything that Physically exsists.


 * __The Galaxies__** : There are billions of galaxies in the universe. A galaxy is a bunch of planets and stars brought together by the gravity from the center. There are three different types of galaxies: elliptical (which are young galaxies) spiral galaxies and barred spiral galaxies. Elliptical galaxies become either spiraled galaxies or barred spirals. astronomers believe that Earth is in a barred spiral galaxy.


 * __The Stars/Solar Systems__** : There are billions of stars in a galaxy. A star is a fusion of of energy and matter. Galaxies hold it all together and gravity eventually collapses and kills it. A star is a burning ball of gas and plasma, and it is always letting off energy. Stars have a strong gravitational pull and planets and other debris is found orbiting around them.

The Sun, an average-sized, middle-aged star, formed almost 5 billion years ago from a cloud of gas and dust.


 * __The Planets__** : A planet is a large object that orbits a star, is circular, and it dominates it's orbit. They can be made of mostly gas, and a little rock (outer planets), or mainly rock and little gas (inner planets).


 * __Inner Planets:__** The inner planets include Mercury, Venus, Earth (yay), and Mars. These planets are mainly rock, and a little gas.

Mercury- No moon or atmosphere.  It is .4 AU from the Sun

Venus- No moon, very thick atmosphere.  It is .7 AU from the Sun

Earth- One moon, (THE MOON) a pleasant atmosphere.  It is 1 AU from the Sun.

Mars- The closest planet to having life on ot, to our knowledge. It is 1.5 AU from the Sun


 * __Outer Planets:__** The outer planets include Jupiter, Saturn, Uranus, and Neptune. These planets are made of mainly gas, and a little rock.

 Jupiter Saturn Uranus Neptune Jupiter- Largest planet in the Solar System. 5.2 AU from the Sun.

Saturn- Made of Hydrogen, with small portions of Helium found on it. It is 9.2 AU from the Sun.

Uranus- Very similar to Neptune. It is 19.2 AU from the Sun.

Neptune- Has two major moons,Trintion and Neid. It is 30.1 AU from the Sun. NOTE: AU means Astronomical Unit. It is 150 million kilometers. (i got this info from wikipedia and my note book)


 * __Other Bodies__** : Most asteroids come from the asteroid belt, and most comets come from Oort's cloud. There is also the Kuiper belt where some comets and meteors come from.

Comets - Comets, thought to be leftovers of the early solar system, are made of dust, rocks, organic compounds, and ice.

Composition: Astronomer Fred Whipple created the term "dirty snowballs" as a description of comets. These bodies are made of dust, rocks, organic compounds, and ice. Ice, in the form of dry ice, water ice, and various frozen gases, makes up most of the comet. Comets have three parts: nucleus, coma, and tail.

Size: A comet nucleus can range in size from less than a mile (1 kilometer) to 15 miles (25 km) across. The longest comet tail, which measured over 354 million miles (570 million kilometers), belonged to Comet Hyakutake in May 1996.

Location: Thought to be leftovers of the early solar system, comets originate from the Oort Cloud — an area of cometary nuclei that surrounds the Sun at a distance of thousands of astronomical units. When a nucleus gets closer to the Sun, the ice melts and a tail is created.

Orbit: Orbit lengths vary among comets. Orbital periods can last from less than a century to over 100,000 years.

Number: Astronomers believe there could be as many as one trillion comets in the Oort Cloud.

Other information: Throughout history, comets were seen as good or bad omens. In 1066, Queen Matilda, wife of William the Conqueror, commissioned the famous Bayeux Tapestry after Comet Halley appeared in the sky for months before the Battle of Hastings.

The European Space Agency's Rosetta spacecraft will be the first to undertake the long-term exploration of a comet at close quarters. Currently on its way to Comet 67P/Churyumov-Gerasimenko, Rosetta will eventually reach its target in May 2014.

This is all from "Astronomy.com"

The vertical line (which stands straight up) shows the luminosity of the stars and the line that is horizontal (the line that lies down) shows the temperature of the stars. For instance in this picture it shows all of the stars in our Galaxy. On the upper right it has the Super Giants and those are not hot but they are luminous. And on the lower left it shows the white dwarfs and these are very hot but not very luminous. Our sun is located in the middle of the page known as the main sequence and it looks a little bit like a river.
 * __HR Diagram:__** This diagram serves two purpose one is to find its luminosity (its brightness) and also its temperature and this is what it looks like this-

Stars are like Celebraties:  In astronomy a star is a ball of matter whose gravity causes fusion. Fused matter makes larger atoms and releases lots of energy. The bigger the star is the faster it dies! The reason for that theory is because the more mass=more fusion rate, and the more fusion rate means it's getting bigger. When it gets like that, then it dies. That's the same as the celebrity star Marlin Man Row, she also did die as she became "bigger" or as we say more famous. So as you can see stars and celebraties are similar in some ways.

---Lauren Nosworthy(: ﻿ Star classification chart-Vincent Trekas

Mercury-

http://www.solarviews.com/eng/mercury.htm

Venus-

http://www.solarviews.com/eng/venus.htm

Earth- (You should know plenty about earth, but here's the link anyways) :)

http://www.solarviews.com/eng/earth.htm

Mars-

http://www.solarviews.com/eng/mars.htm

Jupiter-

http://www.solarviews.com/eng/jupiter.htm

Saturn-

http://www.solarviews.com/eng/saturn.htm

Uranus- heehee...

http://www.solarviews.com/eng/uranus.htm

Neptune-

http://www.solarviews.com/eng/neptune.htm

__Non-Planets__

Pluto- By the way, it says "dwarf planet' but that is incorrect, it's no longer a planet.

http://www.solarviews.com/eng/pluto.htm

Comets-

http://www.solarviews.com/eng/comet.htm

Asteroids-

http://www.solarviews.com/eng/asteroid.htm