Chapter 1 Quiz: Olivia Ward

1. What is our place in the universe?

We live on Earth which is a planet in the solar system that is located in the Milky Way Galaxy. The Milky Way is a part of the Local Group which is a part of the Local Supercluster. Everything is thus a part of the universe.

2. How did we come to be?

The Big Bang, which took place 14 billion years ago, started the universe through expansion. New elements, beside the universe’s original hydrogen and helium, were created through the life cycles of the stars and were released into space when the star died. As humans, we are made up of those new elements, therefore we are star dust.

3. How can we know what the universe was like in the past?

One light-year is equivalent to 10 trillion kilometers. The farther away we look at something, the father back in time we can see it. We can see the universe from formation and onward based on distance.

4. Can we see the entire universe?

No, because if we tried looking farther than 14 billion light-years, we couldn’t see anything. 14 billion light years is the boundary of our observable universe.

5. How big is Earth compared to our solar system?

If the sun equaled the size of a large grapefruit, Jupiter would then equal the size of a marble and Earth would be the size of the tip of a ball point pen. Earth would orbit 15 meters away from the sun.

6. How far away are the stars?

According to a 1 to 10 billon scale, 1 light-year (10 trillion kilometers) is equal to 1000 kilometers. The closest star system, Alpha Centauri, is 4.4 light-years away. On that 1 to 10 billion scale, they are 4400 kilometers away, which is the distance across the United States.

7. How big is the Milky Way Galaxy?

On a 1 to 10^19 scale, each light-year becomes 1 mm and the diameter of the Milky Way becomes 100 meters, which is the length of a football field. The Milky Way has about 100 billion stars. If you counted 1 star per second, it would take more than 3000 years to count all of them.

8. How big is the universe?
   
   The Milky Way is one of 100 billion galaxies in the observable universe. It would take one thousand years to count all of the galaxies and there are 100 billion stars per galaxy. All of the grains of sand on every beach on Earth is comparable to the number of stars in the universe.
   
   
9. How do our lifetimes compare to the age of the universe?

Our lifetime can be put into a 1 year perspective with the Cosmic Calendar. On January 1^st, the Big Bang occurred. On September 22^nd, early life on Earth began. At 11:58 pm on December 31^st, modern humans evolved. The pyramids were built 11 seconds ago.

10. How is Earth moving in our solar system?

The Earth rotates daily around its axis and the speed of the rotation is depends on the location. Earth orbits the sun in about 365 days.