Space

Could the Big Rip Lead to Another Big Bang?

December 29, 2020December 29, 2020 by Manisha Mani

Our Universe being overpowered by dark energy has specifically caught many of our interest, as this was a element of the Universe that didn’t have to exist, much less dominate. Yet here we are, 13.8 billion years after the Big Bang, residing in a Universe where dark energy dominates the expansion of the Universe.

In physical cosmology, the Big Rip is a hypothetical model associated with the fate of the universe, in which the matter of the universe, from stars and galaxies to atoms and subatomic particles, is separated forcibly by the expansion of the universe at a certain time in the future, unless the distances between particles becomes infinite.

Hypothetical model

The truth of the hypothesis depends on the type of dark energy present in our universe. The type that could validate this hypothesis is a progressively increasing form of dark energy, also known as phantom energy. If the dark energy in the universe keeps on accelerating without limit, it could defeat all forces that hold the universe together. The important value is the equation of state parameter w, is the ratio between the dark energy pressure and its energy density. In case of 1 < w < 0, the expansion of the universe will increase, but the dark energy has a tendency to dissolve over time, and the Big Rip does not happen. Phantom energy has w < −1, that is, with the universe expands its density accelerates.

No wonder, a universe dominated by phantom energy is an accelerating universe, which is expanding at an ever-increasing rate. But this however signifies that the size of the observable universe and the particle horizon is continually contracting. In other words, the distance at which objects are moving away at the speed of light from an observer becomes ever closer, and the distance over which interactions can generate becomes ever shorter. When the size of the particle horizon becomes smaller than any particular structure, no interactivity by any of the fundamental forces can emerge between the most remote parts of the structure, and the structure is “ripped apart“. The model, thus, signifies that after a finite time there will be a final singularity, called the “Big Rip”, in which the observable universe eventually reaches zero size and all distances diverge to infinite values.

It could be something that diminishes with time, getting less and less dense, though slowly. It could be something that back-pedals the signs in the near future, causing the collapse of the Universe in a Big Crunch. Or it is believed to be something that gets stronger with time, causing the Universe to expand at a relatively faster rate as time passes by. And it’s this last possibility that leads assumptions to the Big Rip scenario.

Albeit there are few questions that can keep us up all night wondering the ultimate providence of the entire cosmos. According to the probabilities the stars will burn out or it can be replaced by new ones, which themselves will keep on burning out, until the Universe runs out of fuel. Galaxies will come together and release matter, while the space between bound galaxies and groups and clusters will lengthen forever. Dark energy would, this way, further lead to the expansion to not only be persistent, but also to accelerate.

It’s possible that dark energy could reprocess the Universe, if it causes the Big Rip. If dark energy escalates in strength, then this energy inherent to the fabric of space itself could be completely parallel with an early period in our Universe’s history where space lengthens at a remarkable rate also termed as cosmic inflation. Inflation removes all the pre-existing matter and energy from the Universe, leaving behind only the fabric of space. After a period of inflation, that energy somehow gets transferred into particles, antiparticles and radiation, and causes the hot Big Bang. This scenario has been discovered before, and is known as a regenerated Universe.

How the universe could tear itself to shreds?

It all began with the onset of Big Bang and it is assumed to end with a Big Rip.

Recently a mathematical model has been revealed which encourages the idea that the universe could tear itself apart in 22 billion years, during which everything from galaxies to stars, planets, individual atoms and even time itself are torn to shreds. This theory takes the rapid and accelerating expansion of the universe as its starting point, claims it will increase constantly, eventually reaching infinity with catastrophic results.

The new model to support that Big Rip theory was developed by Marcelo Disconzi, an assistant professor of mathematics at University of Vanderbilt in Tennessee. He and two other physics professors Thomas Kephart and Robert Scherrer were struggling with the problem of cosmic viscosity and raised questions such as how sticky the universe really is or when they realised their work encouraged the Big Rip.

The hypothesis of Disconzi is based on some of the existing theories about dark energy, which a largely theoretical substance is thought to make up 70 percent of the universes mass. For a Big Rip to come into force, dark energy must procure in its battle with gravity to such a point where it can rip apart individual atoms. He further began by noticing the mugginess of the universe or how resistant it is to expansion and contraction. So-called cosmological thickness is different to the thickness of something like maple syrup, which is measured by how rapidly a liquid can move through a small opening. He linked his theory of cosmological viscosity to the Big Rip, which was first hypothesised in the year 2003, by observing that what happens to the motion of fluids in supernovae and neutron stars. His breakthrough was in coming up with a theory that elaborated what happened when sticky fluids progressed at near light speed. Previous models did not give much clarity in results, with one even suggesting that fluids would travel faster than the speed of light.

The new evidence suggests that the extension of the universe will at final become infinite. The supposition relies on two big leaps about the behaviour of dark energy in the present scenario and in the faraway future. Previous models did not majorly focus on viscosity, but according to the hypothesis given by Disconzi, it is the viscosity of the universe which powers its violent catastrophe. His theory is based on proposals made by French mathematician André Lichnerowicz in the year 1950s. This isn’t the only model of our demise. Theories in contrast involve the Big Freeze where the universe progresses so vast that supplies of gas are spread so thin that no new stars can be formed. According to this model, time becomes an endless void in which nothing ever happens as there is little to no energy left in the universe. On the other hand, we could be moving towards the Big Crunch, when the extension of the universe slows to a crawl and the Big Bang happens in reverse as everything collapses back into a singularity.

Perhaps it’s not the most joyful thought, however, people have engrossed with the thoughts with how the world around them could end for millennia. As per the scientific age is concerned, one such serious possibility comes from maths and physics. The theory of the Big Rip, thus, explains that at some point in the far-fetched future, the universe could rip itself apart, with everything in existence from animals to atoms becoming shredded. The cosmological model of the Big Rip is predicated on the notion that if the universe continues to grow in its expansion, it will eventually be overpowered by the forces of the dark energy. Dark energy is the rather mysterious force that is predicted to make up 68% of the energy of the observable universe. If it overwhelms gravitational, electromagnetic and weak nuclear forces, the universe would literally fall apart.

Conclusion

If the Big Rip is real, then not only is the Universe expanding (which happens irrespective of dark energy), and not only will distant objects appear to grow away from us at relatively faster rates as time goes on (which happens due to the forces of dark energy), but objects which are bound to stay together with the help of any of the fundamental forces will eventually be ripped apart by the ever-accelerating power of dark energy.

After billions of years in the future, our local group will see the stars at the outskirts get tossing into space, as they become unbound from the gravity of our far future galaxy, that is, Milkdromeda. As time progresses to go on, more number of stars will be seen tossing outward, eliminating the structure we know as the galaxy and transferring us into a collection of billions of unbound stars and stellar corpses eventually.