The book about the universe

I read a book about the universe at the KGU library. It was so interesting for me. Please let me tell about.
First of all, have you ever thought about the birth of the universe? I believed that the universe was born by the Big Bang. Big Bang is one of the large explosions that triggered the birth of the universe. However, according to the book, it is not true theory. The universe was filled vacuum energy the ancient times. The vacuum produced the repulsion. The universe has been expanding since then. And the age of universe is about 13.7billion year old now.
Second, have you ever thought about the size of the universe? It was not solved the correct size of the universe and it was not understood that the universe is limited or unlimited. However, this book taught me that it took over 13 billion light-years in the universe. Light can advance seven and a half laps around the earth. To explain plainly, it can advance thirty-thousand kilometers per second. Although this is the great high speed, it took thirteen hundred thousand light-years from our galaxy to the nearest galaxy. I understood how big the universe is!
Third, have you ever thought about the size of the stars and their properties? I’m interested in about that the best. A lot of stars have great energies. For example, the sun has high temperature. It is about 15 million degrees at the center of the sun. So, the sunlight is very dazzling. And, the sun is much bigger than the earth. However, there are so many stars that are larger than the sun. Some stars are two thousands time as large as the sun. In addition, there are a lot of stars that shined more brightly than the sun. When I had known the fact for the first time, I felt the earth is small star.(317words)