Is the Universe Infinite?
It is quite normal to wonder about the universe. Its vastness and majesty trigger awe. But its nature is still a lingering mystery. Is the universe finite or infinite?
Most deliberations on this topic seem like word games. But, one thing is certain. The history — and knowledge — of the universe carved by humans, based on the information we received, is a small part of the big picture: a universe of our own creation, one that is plagued by dark forces and our ignorance.
When we talk about the universe, we mean everything. In fact there is much beyond what we, or even our most advanced telescopes, can see. Researchers can trace the history of the universe to any point since the first light penetrated the fabric of the cosmos and reached us. However, there is a fundamental limit to this conundrum. We do not and will not have any idea about any of the regions in the universe from where the light, carrying valuable information that helps us to carve the history, hasn’t reached us.
Our most acceptable model of the universe says it has a finite origin, but is expanding. Though it has enormous volume that we can perceive, it remains finite now, and that volume will increase, so only in the infinite future will it actually be infinite. It opens up the question about the geometric shape of our universe. Is it flat like a sheet of paper or closed like a football or an open entity without any limits? Actually, there are conflicting answers to this question even as cosmologists scan through the huge data they have been collecting to nail down this perplexing issue.
In an infinite universe, a photon (light) will never find its way back unless it is forced to do so. But in a finite universe, it must end up in the same location from where it started. The density of matter in the universe would play a critical role in deciding which of them is correct. Even now astronomers are not completely confident about either of these possibilities.
Yet, it is completely within the limits of scientific inquiry to think about the unknown. So what lies beyond the known borders of the known universe? Even if light began its voyage immediately after the big bang, it could have so far traveled only about 13.7 billion light years of distance. To make matters worse, the same light has to encounter an expanding universe during its trip, making it unable to reach us. Are there any structures and patterns out there like or unlike what we have in our observable universe?
Though we can’t ever see such patterns, there is a way that we could feel the effect of such entities if they exist. That’s exactly what astrophysicist Alexander Kashlinsky of NASA’s Goddard Space Flight Center suggests. By studying the giant clusters of galaxies and their scattering, he and his team noticed a peculiar phenomenon. They concluded that something from way beyond the edge seems to be pulling powerfully on galaxies in our universe, yanking them along in a motion he calls “dark flow.” This has nothing to do with the known effects of dark energy that causes the galaxies to expand from each other. These researchers say, there’s evidence that galaxy clusters are being pulled along by a force outside the visible universe.
As if dark matter and dark energy are not enough to complicate the mystery surrounding the universe, the new phenomenon of dark flow, though many scientists disagree, has added another dimension to the already incomprehensible picture of the cosmos. However, Kashlinsky estimates the effects that dark flow extends all across the universe. In other words, our galaxies are pulled by matter that is beyond our known universe. Some even suggest that this could be from other universes that float like bubbles in the cosmic ocean along with our own, unknown to us. At this point, such thoughts do not merit any serious consideration as an observational science.
Not surprisingly, Sir Arthur Eddington, the English astronomer whose experiments verified Einstein’s Theory of Relativity, once said : “Not only is the universe stranger than we imagine, it is stranger than we can imagine.”
Is there anything special about our location in the universe? According to the Copernican principle, which is the foundation of modern astronomy, it must not be so. Whatever we experience in this part of space-time must be more or less the same everywhere even if we can’t observe it. This must be true for any observer anywhere in the universe. The inability to discern the parts of the universe gives rise to the impression that the universe must be infinite in every direction we look.
The universe may be infinite, but its origin, as we understand, demands it has a finite age. All we can say is there is much more than what we see out there.
The concept of infinity is vividly described in Vedic cosmology. In Sanskrit ananta means infinity and the universe, though cyclic in nature, is anaadi and anant, which implies something without beginning and end. Hinduism subscribes to the theory that the universe is beginning-less and endless. It also maintains that there are many more worlds and universes than there are drops of water in the ocean. These universes are made by Lord Brahma, the Creator, maintained by Lord Vishnu, the Preserver, and destroyed by Lord Shiva.
After the destruction of each universe, there will be a vast ocean left. Lord Vishnu, resting on the great snake Ananta, floats on this ocean. Some scriptures suggest that a lotus flower springs from his navel and from this emerges Lord Brahma. And it is from Lord Brahma that all manifest, to be destroyed eventually.
Any discussion about the nature of the universe underscores the human limitations and ignorance. As Einstein once remarked, “Only two things are infinite, the universe and human stupidity, and I’m not sure about the former.”