The universe

The universe is the totality of space and time, all forms of matter, energy and momentum, and the laws and physical constants that govern them. However, the term is also used in a few different contextual senses and refers to concepts such as cosmos, the world or nature.1 The study, on larger scales, is the subject of cosmology based on astronomy and physical discipline, which describes all The aspects of this universe, with its phenomena.

Science modeled the universe as a closed system containing energy and matter bound to space-time and governed primarily by causal principles. Based on observations of the observable universe, physicists try to describe the space-time in which, along with all matter and energy in it.

Experiments suggest that the universe is governed by the same physical laws, which are constant throughout its length and history. It is homogeneous and isotropic. The dominant force at cosmological distances is gravity and general relativity is currently the most accurate way to describe the theory. The other three fundamental forces and the particles in which they operate are described by the standard model.

The universe has at least three dimensions of space and one of time, although it is not experimentally to be discarded additional dimensions. Space-time seems to be connected easily, and space has a very small or even null mean curvature, so that Euclidean geometry is, as a general rule, are throughout the universe.

The most accepted moment on the formation of the universe theory was theorized by the Belgian Lemaître canon, from the equations of Albert Einstein. Lemaitre concluded (contrary to what Einstein thought) that the universe was not stationary, that the universe had an origin. It is the Big Bang model, which describes the space-time expansion of a space-time singularity. The universe went through a rapid period of cosmic inflation that swept away all initial irregularities. Since then, the universe has expanded and become stable, cooler and less dense. Small variations in mass distribution resulted in fractal segregation in portions, which are in the present universe as clusters of galaxies.

Astronomical observations indicate that the universe has an age of 13,730 ± 120 million years (between 13,610 and 13,850 million years) and at least 93,000 million light-years extension.2

Because, according to special relativity, matter can not move at a speed greater than the speed of light, it may seem paradoxical that two objects in the universe may have separated 93 billion light years only 13 billion years ago; However, this separation does not conflict with the theory of general relativity, since it only affects movement in space, but not space itself, which can be extended at a higher rate, not limited by the speed of light. Therefore, two galaxies can be separated from each other more quickly than the speed of light, if the space between them, that it dilates.

Recent observations have shown that this expansion is accelerating, and that most matter and energy in the universe are called dark matter, and dark energy, the common (baryonic) matter, accounts for just over 5% of the total.

Measures on the spatial distribution and redshift of distant galaxies, cosmic background radiation, and the relative percentages of the lighter chemical elements, support the theory of space expansion, and more generally, the theory of Big Bang, which proposes that the universe itself was created at a specific time in the past.

As for their ultimate fate, the current evidence seems to support the theory of permanent expansion of the universe (Big Freeze or Big Rip), which indicates that the same space expansion, because there will come a point where atoms will be separated In subatomic particles. Other possible futures that were considered speculated that dark matter could exert enough gravity force to halt the expansion and make all matter is compressed again; Something that scientists call Big Crunch or the big implosion, but recent observations go in the direction of great wear.