When you look up at the night sky, what do you think about? Do you ever wonder about the twinkling lights and what they actually are? It is common knowledge that many of these lights are stars and planets.
If you have ever taken a long road trip, you might have a sense of the vastness of Earth. Even if you were to walk from one place to another for the rest of your life, you would only see a minuscule part of the entire Earth.
When we gaze into space, it is difficult to imagine that our large Earth is actually an insignificant speck compared to the enormity of the universe. The scale of the universe is truly mind-boggling.
For centuries, scientists have been fascinated by the origins of our universe. There is a part in all of us that wants to know what else is out there, and perhaps even who else is out there. Some people dream of traveling to the edge of the universe just to experience it.
Astronomers and astrophysicists use various modern tools, such as telescopes, supercomputers, advanced mathematics, and radiation detectors, to study the universe. With the help of these tools, they have been able to observe galaxies that are billions of light-years away.
But are these galaxies at the edge of the universe? No! Scientists understand that the size of the universe depends on its shape and how quickly it expands. Since they only have theories about these factors, they are unable to accurately measure the size of the universe.
Most astronomers estimate that the universe is approximately 13.8 billion years old. They make this estimation by measuring distances and the time it takes for light from the farthest galaxies to reach Earth.
Based on these findings, astronomers believe that from Earth, they can observe approximately 13.8 billion light-years in every direction. This means that Earth is at the center of an observable sphere with a radius of 13.8 billion light-years. In other words, the part of the universe that we can see from Earth is a sphere that is almost 28 billion light-years wide.
But is that the entire universe? No! It is much, much larger. The farthest visible galaxy has changed significantly during the time it takes for its light to reach Earth. Since the universe has been expanding since its beginning, a galaxy that was 13.8 billion light-years away from Earth at the birth of the universe would now be approximately 46 billion light-years away. This means that the universe would be 92 billion light-years wide.
In reality, the universe is even larger than that and it continues to expand. Based on data from modern probes and space telescopes, NASA scientists now believe that the universe has a flat shape, which means that it is infinite in size due to its constant expansion.
With an infinite universe, it is impossible to ever reach its edge. As humans, we can only hope to continue learning more about the universe as our technology improves and allows us to explore the outer reaches of the universe.
Traveling to the furthest point of the universe will only be possible in science fiction movies. This also applies to traveling to the farthest point of the observable universe. To give you an idea, think about how long it takes to travel to the Moon. Manned missions to the Moon have taken about three days, but the distance from Earth to the Moon is only 1.3 light-seconds. Now imagine how long it would take to travel 13.8 billion light-years!
Give it a try
Wasn’t today’s Wonder of the Day amazing? Keep exploring outer space by trying out the following activities with a friend or family member:
- You’re probably familiar with our solar system, but have you ever thought about how our solar system fits into the rest of the universe? You can learn more about the universe and our place in it by exploring An Atlas of the Universe online! Does the vastness of the universe blow your mind? Do you think it will ever be possible to travel to the ends of the universe? Why or why not? If you had the chance, would you go on a trip to the end of the universe?
- Interested in exploring the universe as an adult? Get a taste of what that might be like by visiting NASA’s Imagine the Universe website. There, you can learn more about astronomy, the scientific method, and the advanced mathematics involved by checking out You Be the Astrophysicist! Choose a problem and follow the steps to solve it like a real astrophysicist!
- Up for a challenge? Share with your friends and family what it’s like at the edge of the universe! Write a creative short story about your journey to the very edge of the universe. How did you get there? What do you see when you arrive? What surprises you? What happens if you attempt to go beyond the edge of the universe? Let your imagination run wild. If you want, you can even illustrate your story with your own drawings!
Sources of Wonder
- http://www.cfa.harvard.edu/seuforum/faq.htm
- http://www.windows2universe.org/kids_space/edge.html
- http://www.space.com/24073-how-big-is-the-universe.html
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