Our Universe is BIG. But exactly how big?

Our Universe is BIG. But exactly how big?

The size of our Universe is one of the fundamental questions of astronomy. What we can observe gives us an answer, but it’s likely much bigger than that.

Physicists usually refer to the observable universe as the portion that has light that can reach us. It is a spherical region around the Earth, since the region is centered around the observer.

A simulated view of the entire observable universe”, approximately 93 billion light years (or 28.5 billion parsecs) in diameter. The scale is such that the fine grains represent collections of large numbers of superclusters. The Virgo Supercluster—home of Milky Way—is marked at the center, but is too small to be seen in the image. (Credit: Andrew Z. Colvin).

The observable universe is believed to be a mind-boggling 93 billion light-years wide. Take into account that a single light-year is approximately 9 trillion kilometers long and you will see just how massive this is.

Scientists use different techniques to measure this, including studying cosmic background radiation, a leftover from the Big Bang. In fact, the new James Webb space telescope will enable us to look even better into this.

The Cosmic Microwave Background as seen from the Planck satellite. (Credit: ESA).

The observable universe is estimated to host at least 100 billion galaxies. Beyond its limits, the universe goes on, so those 93 billion light-years wide may just be the beginning…

If you need a moment to take a breath, that’s ok. It can be hard (and even scary) to grasp just how huge the universe is, but also inspiring to know our place in it.

If you want to make more sense of this Universe, come see the world-renowned string theorist Brian Greene live in conversation!

Brian Greene Live

Brian Greene is touring across Australia and New Zealand to explore the fascinating story of our universe, and along the way remind us of how unique, fragile and meaningful our circumstances are.

Part philosopher and part physicist, don’t expect him to get bogged down in equations – Brian’s passion spills over into discussions of free will, art, religion and ethics, which he examines through the lens of not only a scientist with 40 years experience, but also as a kid whose curiosity knows no bounds.

This event will be your reminder that the vastness of our universe cares little for human beings, so it’s up to us to take charge of our destiny.

Grab your tickets to see one of our generation’s greatest minds in full force.

The Story of our Universe

The Story of Our Universe: An Introduction to Cosmology is a four-week course covering 13.8 billion years of history.

The universe is old. Really old. If its entire history were crammed into one 24-hour day, the first humans wouldn’t arrive until 23:59!

Together we’ll explore this fascinating history. You’ll learn what the early universe was like, how stars and galaxies formed, and how black holes and dark matter work.

You’ll also learn how this story ends—a big freeze where the universe accelerates into a cold and lonely infinitude of nothingness, a big rip where the fabric of spacetime is torn apart at the seams, or something else entirely.

The course is filled with sublime photographs and vivid explanations which are guaranteed to inspire awe, even in the deepest cynic.

With instruction from one of Australia’s leading cosmologists, as well as a community of like-minded peers, you’ll finish this course with a deeper appreciation of our universe’s grandiosity.

Join us as we venture deep into spacetime.