The Hubble Space Telescope has provided us with some of the most incredible views of our Universe, capturing images of galaxies located up to 13.2 billion light-years away. But despite its impressive capabilities, Hubble has yet to answer one of the most fundamental questions in cosmology - can we see the Big Bang?
To understand why this is such a challenging task, we need to start by understanding what the Big Bang actually was. According to the prevailing theory, the Universe began as a single point of infinite density and temperature, known as a singularity, which rapidly expanded in the first fraction of a second. This rapid expansion is known as inflation, and it set the stage for the formation of stars, galaxies, and all the complex structures we see today.
The trouble is that we can’t see the Big Bang itself because it occurred over 13.8 billion years ago. We can’t look in any direction and see back to the moment of the Big Bang - at least, not with telescopes. Instead, scientists have to rely on other evidence to learn about the early Universe.
One of the ways we can study the early Universe is by looking at the cosmic microwave background (CMB). The CMB is a faint glow of radiation left over from the Big Bang, which permeates the entire Universe. It was first discovered by scientists working on the COBE satellite in the 1990s, and subsequent missions like the Planck satellite have mapped it in incredible detail.
By studying the patterns in the CMB, cosmologists can learn about the conditions of the Universe in its infancy. For example, they can measure the temperature and density of the Universe, and look for evidence of how it underwent inflation in the first moments after the Big Bang. This tells them a lot about the early Universe, but it doesn’t let them “see” the Big Bang as such.
So, why can’t we use a telescope like Hubble to look back to the moment of the Big Bang? The answer lies in the limitations of the Universe itself. As we look farther out into space, we are also looking further back in time. Light travels at a finite speed, so the farther away we look, the longer it takes for that light to reach us. This also means that the light we receive from distant objects has been stretched out and weakened by the expansion of the Universe.
At a certain point, we reach the “edge” of what we can see - a boundary known as the cosmic horizon. Beyond this horizon, the light is so weakened and stretched out that it is effectively impossible to detect. This means that even if we had a telescope powerful enough to see all the way to the cosmic horizon, we still wouldn’t be able to see the Big Bang itself.
So, what’s the answer? Will we ever be able to “see” the Big Bang? The short answer is no. Even with the most powerful telescopes imaginable, we simply can’t look back far enough in time to directly observe the moment of the Big Bang. However, this doesn’t mean that we can’t learn more about the early Universe. By continuing to study the CMB and other sources of information, we can continue to improve our understanding of the early Universe and the Big Bang itself. Who knows what mysteries we will uncover in the decades to come?