Hi, I am Abbi as my G-ma calls me. I am going to take you on a little adventure through space. We are going to learn some interesting facts about the Milky Way, the Solar System, the Asteriod Belt, and about Quasars. Space travel has always been one of the things on my bucket list. So now that I have someone to share this experience with I am going to do it. So buckle up and let go!

We will start our adventure by leaving the planet we call home. Just in case you didn't know boys and girls, we live on the planet called Earth. Earth is the only planet that has life on it. Our atmosphere is made up of mostly Nitrogen, oxygen, with small amounts of argon and carbon dioxide. Earth's atomsphere is divided up into five layers. The exosphere is the highest level of the five, and this is where the atmosphere merges into outer space. The Thermosphere is where the International Space Shuttle Station orbits Earth. The Aurora Borealis and Aurora Australis are in this layer. The Mesosphere is where the Mesopause is, which is the coldest part of atmosphere.  This is the layer where meteors burn up. The Stratosphere is where earth's ozone layer is.  This layer also absorbs harmful radiation from the sun. Its air is thin so this is where the weather ballons, and jet aircraft fly.  The Troposphere is closet to Earth's surface. This layer contains half of Earth's atmosphere. Almost all of the water vapor and dust in the atmosphere are in this layer, and this is where clouds form. Scientist say that the Earth's atmosphere is getting warmer because of the greenhouse effect, which traps heat in Earh's atmosphere.

Our first stop is the Milky Way! The Milky Way is a barred spiral galaxy with a diameter of 100,00 light years across. The Milky Way is where our solar system is, in the Orion Arm (just in case you didn't know, the Milky Way has arms). The Milky Way never stops rotating, it's actually moving through space constantly at a  velocity of speed  of about 600 km per second.  In the center of the Milky Way there is a huge black hole that is a massive source of radio waves, scientist believe that it is because it doesn't give off any electromagnetic radiation. There is always accretion (accumulations of layers of matter) trying to get into the black hole. There are over 100 billon planets in the Milky Way. New stars  are formed here. There are over 200 billion stars, but stars are always being destroyed because of supernova.  There are 10 extrasolar comet systems that have been identified as of 2013 using the absorption spectrum here in the Milky Way. There are 30 constellations in the Milky Way.  It is really gassy and dusty in here, but its matter makes up part of the luminous (light) matter in the galaxy.  The Milky Way is not the only galaxy in space. There are over 100 billion other galaxies out here in space.  Did you know that scientist say that the Milky Way will have a head on collision with The Andromeda Galaxy in about 4 billion years.

Next stop will be the solar system. The solar system is made up of a whole lot of planets, stars, asteriods, comets, moons, dust, gas, and a lot of other interesting things that we are going to explore during our adventure through space. The solar sytem is 4.5 billon years old. Scientist (a person who is studying or has expert knowledge of one or more of the natural or physical sciences) believe that it evolved from the collasping of a giant cloud of dust and gas, because of its own gravity. Then it formed a giant circle, and a small star started to form, which got bigger and bigger. On the other side of this giant circle there was more gases and dust forming smaller planets, and other space stuff.  After the star grew more dust and gas started to collapse, and the star exploded forming the sun. This is what we call the Big Bang Theory.  This is the scientific explanation of how the whole universe began.  The sun is in the center of the solar system. Everything in our solar system orbits around the sun. The sun's gravitational field pulls everything in space towards it. The sun is known as the parent star. (I think it's called the parent because it tells everyone what to do).  It has the largest mass in the solar system.

In the 1500s' scientist thought that the earth was the center of the universe. It was Ptolemy, an Egyptian scientist who developed this theory of an earth centered universe, and that the planets spun in circles around the Earht. It wasn't until Copernicus challenged his theory that we found out the truth.  He stated that the earth traveled around the sun. He had just a theory based on logical reasoning, and step by step thinking ,and geometry. When he told his theory to people they didn't believe him. It wasn't  until Kepler proved that the a planet did not orbit in a circle, but in an ellipse,  which is the shape of an egg, , and they orbited around the sun. 

The planets orbital  patterns are counter clockwise around the sun. The planets closet to the sun are Mercury (is the planet closest to the sun. It is also the smallest of the rocky planets), Venus (is the 2nd largest terrestrial planet, and it is called earth's sister. It rotates in the opposite direction of the other planets. It's the hottest planet. It is the second brightest object in the sky), Earth (is the only planet that can sustain life, it has a powerful magnetic field caused by the nickel-iron core, and it has one natural satellite, the moon), and Mars (known as the red planet, its atmosphere is made up of mostly carbon dioxide. It has the same landmass as earth. Pieces of mars have fallen to earth). These are called "Rocky" planets because they are made up of rock and metal. They are heavy planets, and move slower than the other planets. They don't have rings or a lot of moons.  These are the planets that are farther away from the sun : Jupiter (its stripes and swirls are cold windy clouds of ammonia and water. It has a red spot  is a massive storm that is bigger than earth. It is surrounded by more than 50 moons, and it is also called a "wandering star"), Saturn (Saturn is so big until it can fit 760 Earth's in it!) , Uranus, (this planet is tipped on its side with an axial tilt of 98 degrees, and it is the coldest planet), and Neptune (it is the smallest of the gas giants. It has large wind storms. Neptune also has 14 moons). These planets are known as gas giants, or Jovian planets. They are made up of mostly helium or hydrogen. These planets are light and move quicker than the other planets, and they also rings and  moons.