* Astronomy

Astrophysicist Alexander Kashlinsky of the NASA Goddard Space Flight Centre tackles this question.
The evolution of the universe is described by the physics of general relativity, which was discovered by Albert Einstein in the early 20th century. When compared to Newtonian physics, this theory provides a radically different framework for the physical description of the gravitational force.

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Title: Visualising spacetimes via embedding diagrams
Authors: Stanislav Hledik, Zdenek Stuchlik, Alois Cipko
(revised v2)

It is hard to imagine curved spacetimes of General Relativity. A simple but powerful way how to achieve this is visualising them via embedding diagrams of both ordinary geometry and optical reference geometry. They facilitate to gain an intuitive insight into the gravitational field rendered into a curved spacetime, and to assess the influence of parameters like electric charge and spin of a black hole, magnetic field or cosmological constant. Optical reference geometry and related inertial forces and their relationship to embedding diagrams are particularly useful for investigation of test particles motion. Embedding diagrams of static and spherically symmetric, or stationary and axially symmetric black-hole and naked-singularity spacetimes thus present a useful concept for intuitive understanding of these spacetimes' nature. We concentrate on general way of embedding into 3-dimensional Euclidean space, and give a set of illustrative examples.

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The power of what is known as the anthropic principle has been challenged by a claim that it cannot, after all, make useful predictions about the universe.
Supporters of the anthropic principle - the idea that the universe has to be the way it is for us to be around to observe it - say that it can explain many otherwise mysterious properties of the cosmos. They tend to focus on the so-called cosmological constant, or lambda, which determines the strength of the force that appears to be pushing the universe apart. String theory, combined with the theory of inflation, implies that there could be an infinity of universes, each with a different value of lambda ranging from zero up to a ludicrously high number about 10120 times what we observe.
Most of these universes would be sterile. A super-strong lambda, for example, would shred matter before it formed.

Source

Title: Spinor Theory of Gravity
Authors: M. Novello
Version 3

The proposal of this work is to provide an answer to the following question: is it possible to treat the metric of space-time - that in General Relativity (GR) describes the gravitational interaction - as an effective geometry? In other words, to obtain the dynamics of the metric tensor as a consequence of the dynamics of other fields. In this work we will use a slight modification of the non-linear equation of motion of a spinor field proposed some years ago by Heisenberg, although in a completely distinct context, to obtain a field theory that provides a framework equivalent to the way GR represents the gravitational interaction. In particular we exhibit a solution of the equations of motion that represents the gravitational field of a compact object and compare it with the corresponding Schwarzschild solution of General Relativity.

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