Modern science is made up of several fronts of study, many of them focused on solving urgent problems to ensure our survival. However, the quest to answer key questions, such as the principle of everything, has always been the greatest motivation to drive most scientific advances. Discoveries that provide technological leaps to improve our quality of life are almost always indirect consequences of much more ambitious studies.
By analyzing smaller and smaller elements of matter and the way they behave, Physics discovered the radiation and subatomic particles, which enabled studies capable of tracking and dating the origin of these particles. These surveys were essential to support theories about the origin of the Universe, such as the Big Bang, which is more accepted among scientists. However, they also point to its possible end.
the beginning of the end
As strong as the evidence supporting these ideas is, they remain only theories, not certainties, so studies in non-Newtonian physics continue to advance, finding even more primordial elements, such as dark matter.
Each discovery leads, consequently, to new lines of reasoning, opening paths to other fields of study. One of the most intriguing is about not where the cosmos was born, but when and how it will die..
Different ideas about the end of all existence have been gaining strength following the evolution of nuclear physics and quantum physics, but four of them stand out as the most possible:
Big Bounce or Big Rebote;Big Crunch or Big Collapse;Big Freeze or Great Freeze;Big Rip or Big Break.
The Great Collapse and the Great Rebound
A first idea, already discarded, is that of the Great Collapse (Big Crunch). For some time, the notion was believed that the gravitational forces between the elements of the cosmos would attract all the planets and stars that would eventually collapse into a single point, similar to the formation of black holes.
This point of singularity could then result in two possibilities, one in which the heat of this condensed mass would break the nuclei of atoms, which would cease to exist, and another in which this energy would trigger a new Big Bang.
The second hypothesis is known as the theory of big bounce (Big Bounce) and is based mainly on the notion that the Universe is a cyclical and non-linear natural phenomenon. According to this theoretical line, the great explosion of hyperconcentrated matter in a single point is an event that repeats itself every billion years.
After this event, the Universe would begin to grow to the point where the density itselfas a limiting constant, would begin to exert a counter force that would slowly decelerate the expansion process and initiate a contraction.
Despite raising questions, the Big Bang theory has long been the dominant idea for how the universe began. Could the revived Big Bounce theory offer a better way?https://t.co/QNwC96iCDB pic.twitter.com/zVK1ogaJB6
— Quanta Magazine (@QuantaMagazine) February 22, 2018
The propositions of Big Crunch It’s from Big Bounce, however, depend on concepts that the Universe is limited and that the gravitational attraction between its elements is sufficient to establish a “universal elastic memory”. In that case, the larger the universe became, the greater would be the opposing force to that movement. Consequently, despite the thunderous energy that propelled all existing elements out of the singularity, the expansion process would be constantly decelerating.
Expansion with positive acceleration
Both hypotheses have fallen into disbelief recently. Scientists still cannot determine exactly why this happens, but they can measure that the expansion speed of the Universe it is increasing, not decreasing.
With the discovery of dark matter, it was possible to determine that there is a positive acceleration in the distance of these particles, and consequently all others, from the center of the Big Bang. In the book Cosmic Queries: Startalk’s Guide to Who We Are, How We Got Here, and Where We’re Going (2021), Neil deGrasse Tyson devoted an entire chapter to the possible ends of the universe.
An essential point that the astrophysicist reinforces is that, despite being possible in theoretical models, the premise of the existence of an elastic memory was discarded, since the data measuring the speed of dark matter point only to a movement with positive acceleration. Thus, even without knowing exactly how this speed continues to increase, it empirically refutes the Big Crunch and Big Bounce theories.
The Great Freeze and the Great Disruption
TS Eliot published in 1925 The Hollow Men, perhaps one of his most famous poems. His conclusion is the maxim that defines the end of existence according to the very astrophysicists who have been looking for these answers: “This is how the world expires; not with an explosion, but with a sigh”.
As the results of studies on cosmic rays and particles have been confirming, the distance between all cosmic elements is getting bigger and faster. Assuming that the laws of conservation of energy and mass are true, the dimensions of the Universe are the result of the ratio between its average density and a critical density, limiting constant.
In case these densities are equal, the fast-paced growth process tends to stretch the Universe towards a limit, defining it as flat. Based on this, there is the formulation of the two most accepted theories for the end of everything. In both cases, as a result of this growth, the distance between planets and stars will increase indefinitely and there will come a point where the distance between molecular elements will also start to grow.
That will make the combustible gases from the fusion of stars begin to move away from the cores, encouraging these cosmic powerhouses of light and heat to burn less and less until they go out, resulting in the Great Freeze. Despite being a more widely accepted theory than Collapse and Rebound, the Big Freeze is losing traction to another less abstract assumption than a stretching of known space to a stagnation point.
Tearing up the matter
Still based on the premises of the Universe as a plane in accelerated growth, some astrophysicists, among them Neil deGrasse Tyson, believe more in the Big Rip theory. The concept behind this theory is essentially the same as that of Freezing.o, but predicts that the atomic deconstruction resulting from runaway growth still preserves the total energy of the system, as observed by Einstein in the postulation of the photoelectric effect.
The BIG RIP theory ??
Big RIP, Big Crunch, Big Freeze… How will the universe end ?
?? https://t.co/RjSNvjy48s?? : Gurumed#bigrip #bigcrunch #bigfreeze #universe #bigbang #galaxy #galaxies #cosmos #space #solarsystem #star pic.twitter.com/wXDoJ6oIs8
— From Space With Love (@FromSpaceWLove) February 26, 2019
Therefore, stretching the Universe to the defined limit would fatally break this plan. Contrary to the notion that the end of everything will be in a great new explosion similar to the Big Bang, it is possible that the Universe as we know it will end in a much calmer and simpler way, like a murmur or the tearing of a sheet of paper.
