Cosmic puzzle, reconstructing the shape of the universe

Welcome, young stargazers and cosmic explorers, to another mind-blowing adventure through the wonders of science! Today we embark on an intergalactic journey to answer one of the most profound questions in the cosmos: What is the shape of the Universe and where is it expanding to?

Let’s imagine the Universe as a colossal cosmic pizza, not just any pizza, but one that stretches infinitely in all directions, but wait, how can the Universe be a pizza if it lasts forever, right? Well, the pizza analogy is just a way to help us visualize its flatness, but it doesn’t mean that it is literally round like a pepperoni pie. In reality, the Universe appears to be flat according to observations of the cosmic microwave background radiation, meaning that if you were to leave in a rocket and travel far enough in a straight line, you would never return to the starting point. So, it is as if the Universe is an endless table where all the galaxies, stars and planets can hang out.

But hold on to your astronaut helmets! Some scientists believe that the Universe could be in the shape of a toroid, which is like a doughnut or a cosmic muffin. This idea comes from the concept of a “closed” Universe, where if you travel far enough in one direction, you will eventually return to your starting point, as if you were going around a doughnut hole. Just visualize boarding a spaceship, traveling in a straight line, and suddenly returning to the starting point. It’s as if the Universe has played a galactic magic trick on you! But don’t order donuts just yet, because there’s still more to the story.

Now, let’s talk about the expansion of the Universe, we know that it does not stand still; it gets bigger and bigger every second. Think of it like an inflated balloon, where the galaxies are the dots on the surface of the balloon, as the balloon expands, all those dots move away from each other, just as the galaxies do in our Universe. This concept of expansion was a real game changer in our understanding of the cosmos, was discovered by Edwin Hubble and is still expanding today, even as you read this blog. A fun way to think about this is with raisin bread, think of baking a loaf of raisin bread and as it bakes, the dough rises and the raisins (representing galaxies) separate. It’s like a cosmic breakfast with delicious science!

The expansion of the Universe also takes us back in time, you may have heard of the Big Bang theory. It is the idea that the Universe began as a singularity (a point of infinite density and temperature) about 13.8 billion years ago. Imagine the Universe as an infinite book, if you flip backwards through its pages, you will eventually reach the first page, and that is the Big Bang. The Universe, as we know it, started from that tiny, ultra-hot, dense point, and has been expanding ever since.

This is where things get even crazier. The expansion of the Universe is accelerating! This mysterious force called dark energy is pulling galaxies apart faster and faster, it’s like the cosmic equivalent of trying to run away from your shadow, but always one step ahead. Dark energy is a big cosmic puzzle, we still don’t understand it very well, but that’s the beauty of science. We are constantly exploring the unknown and making new discoveries.

So, what is the shape of the Universe? Is it a pizza, a bagel or something else entirely? The truth is that we are still putting this cosmic puzzle together, it’s trying to solve a puzzle with missing pieces, but that’s what makes it exciting. Science is an ongoing adventure and we are all in it together. As you gaze up at the night sky, remember that the Universe is vast, full of wonders and ripe for exploration. Until then, stay curious and keep stargazing!