How do we place ourselves in the universe?

During our lifetimes, NASA has deployed exceptionally powerful astronomical instruments, such as the Hubble Space Telescope and the James Webb Space Telescope (JWST). These instruments are designed to examine extremely distant celestial objects. The Hubble telescope operates within the visible spectrum of light, whereas the JWST uses the infrared spectrum; sophisticated equipment is necessary to interpret the observations. Both telescopes have reported similar findings as discussed in this essay.

Light impulses in a vacuum travel at a constant speed, one of the immutable constants of nature. All observable galaxies, though moving somewhat randomly, generally appear to be separating from each other. This phenomenon was first observed by Edwin Hubble, after whom the Hubble Space Telescope is named. The most distant galaxies provide insights into the origin of the universe. They are moving away from us at increasing velocities, or equivalently, we are moving away from them at increasing velocities. Naturally, the light we observe from the most distant stars began its journey a significant time ago. The farther away a star, the longer it takes for its light to reach us. Therefore, when the Hubble and JWST telescopes observe the most distant stars, they are effectively looking into the distant past of the universe.

What do we know about the distant past? Galaxies are generally moving away from each other. Reversing this movement in time suggests that the universe originated from a small point of explosion over thirteen billion years ago—an event involving an unknown energy source.

After this event, the universe has continued to expand. The residual cosmic microwave background radiation from the creation event, discovered by Penzias and Wilson and reported in 1965, supports in quantitative detail the explosive model of the universe, now commonly referred to as the Big Bang. While this is significant, there are additional aspects to consider.

As previously mentioned, both the Hubble and Webb telescopes observe distant galaxies, which emitted their light during an earlier time in the universe’s history, thus providing insights into this period. These space telescopes enable us to view only a relatively narrow section of space through a long, thin observational field. When directed towards different areas of the sky, they present a similar depiction of the universe, showcasing far distant galaxies and stars emitting their light closer in time to the origin of the universe.

This observation raises the intriguing question: if the universe originated from a single explosive event, how is it possible that we see a consistent image of the origin regardless of the direction in which we look into the sky and into the distant space? Exactly, where is the origin to be found?

It may be necessary to reassess our understanding. We might ask today a seemingly straightforward question: “Is the origin of the universe an identifiable point, or is it located all around us as suggested by the Hubble and JWST observations? Is our local group of galaxies at the edge of the universe or at the center? And how does this view align with the concept of the universe being created by an explosive event nearly fourteen billion years ago? How can we be both at the universe’s center and at its edge?”

Many scientists propose that the universe is effectively infinite in time and space. However, the part of the universe we observe is not infinite. The observable universe contains a very large, yet countable, content. There remains the possibility that portions of the universe exist beyond our ability to observe.

Obviously, we are able to provide insights only on the observable universe, which is very large but finite. The question remains, though: how should we conceptualize the geometry of this universe, both the observable part and the potentially unobservable part, and how do we locate our position within it?

Based on current scientific understanding, a significant event occurred that led to the expansion of the universe as we experience it today, encompassing space, time, and matter.

If the universe and its contents were finite, it could be posited that beyond the universe there would exist a primordial “nothingness”, devoid of space and time. Given that our location appears to be centrally positioned within the observable universe, the concept of “beyond” may lose some significance. It may be more pragmatic to consider the possibility of an infinite universe which is somehow completely contained with parts not seen by us and with only our observable portion being finite. These limitations might reflect our current capabilities of observation or possibly the author’s limitations in comprehension.

Regardless of whether the observable universe is finite or infinite but partially unobservable, any point would be considered at its center, as the universe’s origin surrounds all locations. Yet, any position within the universe would also be at its edge, as each location receives cooled light from the cosmic microwave background radiation originating from the big bang. This light traveling through space and time is just now reaching us. From current scientific thought, the universe is thought to have begun with a significant event involving “everything, everywhere, all at once”.

Considerations about the granularity and uncertainty inherent in quantum mechanics also remain as puzzles. It is unclear if this represents the final understanding of physics…perhaps not, but it has remained remarkably steadfast until now without experimental contradiction. Furthermore, the recently observed connectedness of coupled photons or electron pairs positioned at large distances from one another, known as quantum entanglement, poses important questions. The hope is that our shortcomings will not prevail, allowing us to remain on Earth long enough to address these complex questions.