The Universe is all of time and space and its contents. It includes planets, stars, galaxies, the contents of intergalactic space, the smallest subatomic particles, and all matter and energy.
Currently, the observable universe is about 28 billion parsecs or 91 billion light-years in diameter. The size of the whole Universe isn’t known to humankind and may be either finite or infinite.
Observations and the development of physical theories have led to inferences about the composition and evolution of the Universe.
In this interesting documentary, we’ll learn more about the universe we’re living in, the science of Cosmology and the theories which helped us in understanding some info about the place we’re living in which we call the Cosmos.
Observations of the distribution of these galaxies and their spectral lines have led to many of the theories of modern physical cosmology.
Recent observations in the late 1990s indicated the rate of the expansion of the Universe is increasing indicating that the majority of energy is most likely in an unknown form called dark energy. The majority of mass in the universe also appears to exist in an unknown form, called dark matter.
The Big Bang theory is the prevailing cosmological model describing the development of the Universe. Space and time were created in the Big Bang, and these were imbued with a fixed amount of energy and matter; as space expands, the density of that matter and energy decreases.
After the initial expansion, the Universe cooled sufficiently to allow the formation first of subatomic particles and later of simple atoms.
Giant clouds of these primordial elements later coalesced through gravity to form stars. Assuming that the prevailing model is correct, the age of the Universe is measured to be 13.799±0.021 billion years.
There are many competing hypotheses about the ultimate fate of the Universe. Science remains unsure about what, if anything, preceded the Big Bang.
This article is from Science’s archive, originally published on an earlier date.