93 billion light years to the end of the universe: what's next?

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This question about the limits of the universe is one of the questions that humans will undoubtedly continue to ask themselves until the end of time.

We're not sure, but we can try to imagine what the limit of the universe might be, if there is one.

Go back in time

Before we begin, we need to go back in time. The night sky seemed to have always looked the same throughout human history. It has been so stable that humans around the world took inspiration from the patterns they saw in the stars to orient themselves and explore.

To our eyes, the sky seems infinite. With the invention of telescopes about 400 years ago, we were able to see further than our eyes ever could. We continued to discover new things in the sky and found more stars, then started to notice that there were a lot of strange looking cosmic clouds.

Astronomers gave them the name “nebula”, from the Latin words meaning “mist” or “cloud”. Less than 100 years ago, we first confirmed that these cosmic clouds or nebulae were in fact galaxies. They resemble the Milky Way, the galaxy in which our planet is located, but they are very far away.

The amazing thing is that in every direction we look in the universe, we see more and more galaxies. In this image from the James Webb Space Telescope, which observes a part of the sky equivalent to the area covered by a grain of sand when held at arm's length, we can see thousands of galaxies.

It's hard to imagine that there is a limit where all this stops.

The edge of the universe

However, there is technically a limit to our universe. We call it the “observable” universe. Indeed, we do not know if our universe is infinite, that is to say if it continues to infinity.

Unfortunately, we may never know because of one hindering factor: the speed of light.

We can only see light that has had time to travel to us. Light travels at the exact speed of 299,792,458 meters per second. Even at this speed, it takes a long time to cross our universe. Scientists estimate that the size of the universe is at least 93 billion light years, and probably even larger.

What would we see if there was an edge?

If we traveled to the very edge of the universe we think exists, what would there actually be?

Many other scientists (including myself) think that there would simply be… more universes!

As I said, there is a theory that our universe has no limit and could continue indefinitely.

But there are other theories as well. If our universe has a limit and you cross it, you might find yourself in a completely different universe. (For now, this is best kept for science fiction).

Although there is no direct answer to this question, it is precisely questions like these that help us continue to explore and discover the universe, and that allow us to understand our place in it. let's occupy.

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