# Understanding Our Universe : Current Status and Open Issues

@article{Padmanabhan2005UnderstandingOU, title={Understanding Our Universe : Current Status and Open Issues}, author={Thanu Padmanabhan}, journal={arXiv: General Relativity and Quantum Cosmology}, year={2005}, pages={175-204} }

1. Prologue: Universe as a physical system Attempts to understand the behaviour of our universe by applying the laws of physics lead to difficulties which have no parallel in the application of laws of physics to systems of more moderate scale — like atoms, solids or even galaxies. We have only one universe available for study, which itself is evolving in time; hence, different epochs in the past history of the universe are unique and have occurred only once. Standard rules of science, like…

## 28 Citations

### Quantum Versus Classical Nature of the Early Universe and Its Consequences (Entanglement

- Physics
- 2017

We look at early universe space-time which is characterized by a transition from Pre Planckian to Planckian space-time. In doing so we also invoke the geometry of Octonionic non commutative structure…

### Is Nature fundamentally continuous or discrete, and what violations of the Null Energy Condition tell us about information exchange between prior to present universes ?

- Physics
- 2011

Our contention, is that reality is actually analog, but that at a critical limit, as when the Octonian gravity condition kicks in, that for a time it is made to appear discrete. This due to an…

### Cosmic Initial Singularities in a Single Repeating Universe as Opposed to Their Behavior in a Multiverse

- Physics
- 2013

When the initial radius of the universe is set in four dimensions and if there is only ONE repeating universe, then the initial radii of the universe is R → 0 or gets very close to zero if we use the…

### The Friedmann Model

- Physics
- 2012

In early history of relativistic cosmology Alexander Friedmann (1923), in his book The world as space and time, modestly and wisely viewed cosmological models as “schematic and simplified, reminding…

### Is Temperature Quenching in the Early Universe Due to Particle Production, Or Quantum Occupation States, Or the Influence of Quantum Teleportation?

- Physics
- 2017

We examine the role of particle nucleation in the initial universe, and argue
that there is a small effect due to particle nucleation in terms of lowering initial
temperature, in tandem with energy…

### Accelerating universe in higher dimensional space time: an alternative approach

- PhysicsThe European Physical Journal Plus
- 2021

We have discussed here a higher dimensional cosmological model and explained the recent acceleration with a Chaplygin type of gas. Dimensional reduction is possible in this case. Our solutions are…

### Dark energy and gravity

- Physics
- 2008

I review the problem of dark energy focussing on cosmological constant as the candidate and discuss what it tells us regarding the nature of gravity. Section 1 briefly overviews the currently popular…

### Evidence for a Cosmological Phase Transition From the Dark Energy Scale

- Physics
- 2006

A finite vacuum energy density implies the existence of a UV scale for gravitational modes. This gives a phenomenological scale to the dynamical equations governing the cosmological expansion that…

### Quintessential Phenomena in Higher Dimensional Space Time

- Physics
- 2010

The higher dimensional cosmology provides a natural setting to treat, at a classical level, the cosmological effects of vacuum energy. Here we discuss two situations where starting with an ordinary…

### Quintessential phenomena in higher-dimensional space-time

- Physics
- 2011

Higher-dimensional cosmology provides a natural setting to treat, at a classical level, the cosmological effects of vacuum energy. Here we discuss two situations: in the first case we start with an…

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