Source: The Universe: Hubble Deep Field,
Hubble Site

When asked the question "What is the universe?" what do you think of? Do you imagine the Earth? Or do you picture the Sun with planets orbiting around it? If so, you are only thinking of one small part of the vast structure that is our universe!

According the NASA’s StarChild Website, "The universe is a vast open space which contains all of the matter and energy in existence. The universe contains all of the galaxies, nebulae, stars, and planets. The exact size of the universe is unknown. Scientists believe the universe is still expanding outward. They believe this outward expansion is the result of a violent, powerful explosion that occurred about 13.7 billion years ago. This explosion is known as the Big Bang." The image to the right shows a portion of the universe as seen from the Hubble telescope. Almost every object in this image is a galaxy located anywhere from five to 10 billion light years away.

Watch this short video to learn more about the universe.