When we say that a particle "overcloses" the universe, we are referring to the concept of the critical density of the universe. This is the amount of matter and energy that is needed to keep the universe from collapsing in on itself. If a particle has too much mass or energy, it can contribute to an overabundance of matter and potentially cause the universe to collapse.
The critical density of the universe is calculated by using the Friedmann equations, which describe the evolution of the universe in terms of its density and expansion rate. This calculation takes into account the amount of visible matter, dark matter, and dark energy in the universe.
Particles, specifically dark matter and dark energy, play a major role in the expansion of the universe. Dark matter, which makes up about 27% of the universe's total mass, contributes to the gravitational pull that counteracts the expansion. On the other hand, dark energy, which makes up about 68% of the universe, has a repulsive effect and causes the expansion to accelerate.
If particles were to overclose the universe, it could lead to a collapse of the universe and potentially end all life as we know it. It is important for the critical density to be maintained in order for the universe to continue expanding and potentially support life.
In theory, yes, particles could potentially overclose the universe. However, current observations and calculations suggest that the amount of visible matter, dark matter, and dark energy in the universe is in line with the critical density, making it unlikely for particles to overclose the universe in the near future.