User:On the sky

The Universe is totality of including planets, stars, galaxies, the contents of Intergalactic space, and all matter and energy include the [[cosmos, the world and nature. The observable universe is about 46 billion light years in radius Scientific observation of the Universe has led to inferences of its earlier stages. These observations suggest that the Universe has been governed by the same physical laws and constants throughout most of its extent and history. The Big Bang theory is the prevailing cosmological model that describes the early development of the Universe, which is calculated to have begun 13.798 ± 0.037 billion years ago.  Observations have shown that the Universe appears to be expanding at an Accelerating rate. There are many competing theories about the ultimate fate of the universe. Physicists remain unsure about what, if anything, preceded the Big Bang. Many refuse to speculate, doubting that any information from any such prior state could ever be accessible.  There are various multiverse hypotheses, in which physicists have suggested that the Universe might be one among many universes that likewise

A galaxy is a massive, gravitationally bound system consisting of stars, Galaxies contain varying numbers of star systems, There are probably more than 170 billion  galaxies in the observable universe Our galaxy Name The  Milky Way  is a barred spiral galaxy some 100,000–120,000  light-years in diameter which contains approximately 100–400 billion stars. It may contain at least as many planets The oldest known star in the Galaxy is at least 13.6 billion years old and thus must have formed shortly after the Big Bang. Surrounded by several smaller satellite galaxies, the Milky Way is part of the Local Group of galaxies, which forms a subcomponent of the Virgo Supercluster.

A planet meaning wandering star is an astronomical object orbiting a star or stellar remnant that is massive enough to be rounded by its own gravity, The planets were thought by Ptolemy to orbit the Earth in deferent and epicycle motions. Although the idea that the planets orbited the Sun had been suggested many times, it was not until the 17th century that this view was supported by evidence from the first telescopic astronomical observations, performed by Galileo Galilei. By careful analysis of the observation data, Johannes Kepler found the planets' orbits were not circular but elliptical. As observational tools improved, astronomers saw that, like Earth, the planets rotated around tilted axes, and some shared such features as ice caps and seasons. Since the dawn of the Space Age, close observation by probes has found that Earth and the other planets share characteristics such as volcanism, hurricanes, tectonics, and even hydrology. Planets are generally divided into two main types: large, low-density gas giants and smaller, rocky terrestrials. Under IAU definitions, there are eight planets in the Solar System. In order of increasing distance from the Sun, they are the four terrestrials, Mercury, Venus, Earth, and Mars, then the four gas giants, Jupiter, Saturn, Uranus, and Neptune. Six of the planets are orbited by one or more natural satellites. Additionally, although not planets, the IAU accepts five dwarf planets]], Pluto with many others under consideration hundreds of thousands of  small Solar System bodies.