Sonia M. Rompoti, MSc, Bsc

So, we are starting this series: when a toddler asks… and I’ll try to save time for all mothers out there: my baby asks me a million questions every day, and for some of them, she insists enough that I actually have to do proper research to answer (believe it or not, she is capable of going online and double checking my answers).

I have to hope that it is not just my little one; that all kids ask questions nonstop, and to save time: I’ll keep a log of the answers to save all of us time and energy.

What is the universe?

The universe refers to all of space, time, matter, and energy that exists. It encompasses everything we can observe, from the smallest particles to the largest galaxies and everything in between. It includes planets, stars, galaxies, black holes, nebulae, and other celestial objects.

The universe is believed to have originated from an event called the Big Bang, approximately 13.8 billion years ago. This event marked the beginning of space, time, and the expansion of the universe. Over billions of years, matter and energy have interacted to form galaxies, stars, and the diverse structures we observe today.

The universe is vast and continually expanding. It is composed of countless galaxies, each containing billions or even trillions of stars. Our own galaxy, the Milky Way, is just one of the billions of galaxies in the universe. Beyond what we can currently observe, the universe may extend even further, but its exact size and nature are still being explored by scientists.

Understanding the universe is a complex field of study that combines various scientific disciplines, including astronomy, cosmology, physics, and mathematics. Scientists use telescopes, space probes, particle accelerators, and other advanced tools to observe, measure, and analyze the universe, seeking to unravel its mysteries and understand its origins, evolution, and composition.

So, how big exactly is the Universe?

The size of the universe is a topic of ongoing scientific research and exploration, and our understanding of its vastness continues to evolve. However, based on current knowledge, the observable universe is estimated to have a diameter of about 93 billion light-years.

It’s important to note that the term “observable universe” refers to the portion of the universe that we can potentially observe from Earth, given the limitations imposed by the finite speed of light and the age of the universe. Beyond this observable region, the universe may extend even further, but we currently have no direct way of confirming its exact size or whether it is finite or infinite.

The universe is thought to have originated from the Big Bang approximately 13.8 billion years ago. Since then, it has been expanding, and the rate of this expansion is currently accelerating. The vastness of the universe is mind-boggling, and it contains billions of galaxies, each with billions of stars and countless other celestial objects.

It’s worth noting that our understanding of the universe is based on scientific observations, theories, and models. As technology advances and our knowledge expands, our understanding of the size and nature of the universe may continue to evolve.