Exploring Astronomy Photography Of Outer Space Universe

The universe appears to have a smooth spacetime continuum consisting of three spatial dimensions and one temporal (time) dimension. On the average, space is observed to be very nearly flat (close to zero curvature), meaning that Euclidean geometry is experimentally true with high accuracy throughout most of the Universe. Spacetime also appears to have a simply connected topology, at least on the lengthscale of the observable universe. However, present observations cannot exclude the possibilities that the universe has more dimensions and that its spacetime may have a multiply connected global topology, in analogy with the cylindrical or toroidal topologies of twodimensional spaces.
The universe appears to behave in a manner that regularly follows a set of physical laws and physical constants. According to the prevailing Standard Model of physics, all matter is composed of three generations of leptons and quarks, both of which are fermions. These elementary particles interact via at most three fundamental interactions: the electroweak interaction which includes electromagnetism and the weak nuclear force; the strong nuclear force described by quantum chromodynamics; and gravity, which is best described at present by general relativity. The first two interactions can be described by renormalized quantum field theory, and are mediated by gauge bosons that correspond to a particular type of gauge symmetry. A renormalized quantum field theory of general relativity has not yet been achieved, although various forms of string theory seem promising. The theory of special relativity is believed to hold throughout the universe, provided that the spatial and temporal length scales are sufficiently short; otherwise, the more general theory of general relativity must be applied. There is no explanation for the particular values that physical constants appear to have throughout our universe, such as Planck's constant h or the gravitational constant G. Several conservation laws have been identified, such as the conservation of charge, momentum, angular momentum and energy; in many cases, these conservation laws can be related to symmetries or mathematical identities.
• Fine tuning
It appears that many of the properties of the universe have special values in the sense that a universe where these properties only differ slightly would not be able to support intelligent life. Not all scientists agree that this finetuning exists. In particular, it is not known under what conditions intelligent life could form and what form or shape that would take. A relevant observation in this discussion is that for an observer to exist to observe finetuning, the universe must be able to support intelligent life. As such the conditional probability of observing a universe that is finetuned to support intelligent life is 1. This observation is known as the anthropic principle and is particularly relevant if the creation of the universe was probabilistic or if multiple universes with a variety of properties exist .

