JOURNEY TO ASTRONOMY

JOURNEY TO ASTRONOMY


Astronomy is the study of stars, planets, and space. As you study astronomy, you will learn about yourself.
Astronomy tells you:



• Where are We?
• When is Now?
• What are We?




WHERE ARE WE? 

Knowledge of Earth's location in the Universe has been shaped by 400 years of telescopic observations and has expanded radically in the last century. What we know right now is that we live on Earth which is a planet.

*Earth: Home Planet

*The orbit of Moon: 768,210 km. The average diameter of the 
    orbit of the Moon relative to the Earth.

*Earth’s orbit: 299.2 million km. The average diameter of the orbit 
  of the Earth relative to the Sun. Encompasses the Sun, Mercury, 
  and Venus.

*Inner Solar System: Encompasses the Sun, the inner planets 
  (Mercury, Venus, Earth, Mars) and the asteroid belt.

*Outer Solar System: Includes the outer planets (Jupiter, Saturn, 
  Uranus, Neptune).

*Kuiper belt: Belt of icy objects surrounding the outer Solar 
  System. Encompasses the dwarf planets

*Oort cloud: Spherical shell of over a trillion comets.

*Local Interstellar cloud: Interstellar cloud of gas through which 
  the Sun and a number of other stars are currently traveling.

*Milky Way galaxy: Our home galaxy, composed of 200 billion to 
  400 billion stars and filled with the interstellar medium.

*Local group:  Group of at least 47 galaxies of which the Milky 
  Way is a part. Dominated by Andromeda (the largest), the Milky 
  Way and Triangulum; the remainders are dwarf galaxies.

*Virgo supercluster: It comprises roughly 100 galaxy groups and 
  clusters, centered on the Virgo Cluster. The Local Group is     
   located on the outer edge of the Virgo Supercluster.

*Observable Universe: More than 100 billion galaxies, arranged in 
  millions of superclusters, and voids creating a foam-like 
  superstructure.

*Universe: Minimum Beyond the observable universe lie the 
  unobservable regions from which no light has reached the Earth 
  yet. No information is available, as light is the fastest traveling 
  medium of information. The Universe is likely to contain more 
  galaxies in the same foamlike superstructure.

WHEN IS NOW?

Now that you have an idea where you are in space, you need to know where you are in time. The stars shone for billions of years before the first human looked up and wondered what they were.

Imagine beginning is BIG BANG and replaying the entire history of the universe till TODAY. Observations tell astronomers that the big bang filled the entire universe with hot, glowing gas, but as the gas cooled and dimmed, the universe went dark.
There was no light for the next 400 million years until gravity was able to pull some of the gas together to form the first stars. Galaxies formed in large numbers. Our home galaxy would be one of those taking shape.
By the time universe is full of galaxies, but the sun and Earth have not formed yet.4.6 billion years ago, about 9 billion years after the big bang, marks the formation of the sun and planets of our solar system

About 3.4 billion years ago, to mark the earliest firm evidence for life on Earth microscopic creatures in the oceans and the emergence of life on land only 0.4 billion (400 million) years ago.

Dinosaurs go extinct 65 million years ago.
What about people? 4 million years from TODAY.
Civilization, the building of cities, began about 10,000 years ago.

Compare the history of human civilization with the history of the universe. Every war you have ever heard of, every person whose name is recorded, every structure ever built from Stonehenge to the building you are in right now shows that Humanity is very new to the universe. Our civilization on Earth has existed for only a flicker of an eye-blink in the history of the universe. Only in the last hundred years or so have astronomers begun to understand where we are in space and in time.

WHAT ARE WE?


Astronomy is important to you because it will tell you what you are. Notice that the question is not “Who are we?” As you study astronomy, you will learn how you fit into the history of the universe. You will learn that the atoms in your body had their birth in the big bang when the universe began. Those atoms have been cooked and remade inside generations of stars, and now, after billions of years, they are inside you. Where will they be in another billion years? This is a story everyone should know, and astronomy is the only course on campus that can tell you that story.

Buy cool Astronomy Stuff and start you journey.




Stay tuned for more interesting facts about astronomy!

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