The crossword clue possible answer is available in 7 letters. As of 1 September 2018, 3,823 known extrasolar planets in 2,860 planetary systems (including 632 multiple planetary systems), ranging in size from just above the size of the Moon to gas giants about twice as large as Jupiter have been discovered, out of which more than 100 planets are the same size as Earth, nine of which are at the same relative distance from t.This crossword clue Soviet satellite that launched the Space Age was discovered last seen in the Januat the Crosswords With Friends Crossword. * Several thousands of planets around other stars ('extrasolar planets' or 'exoplanets') have been discovered in the Milky Way. Six of the planets are orbited by one or more natural satellites. In order of increasing distance from the Sun, they are the four terrestrials, Mercury, Venus, Earth, and Mars, then the four giant planets, Jupiter, Saturn, Uranus, and Neptune. Under IAU definitions, there are eight planets in the Solar System. * Planets are generally divided into two main types: large low-density giant planets, and smaller rocky terrestrials. Since the dawn of the Space Age, close observation by space probes has found that Earth and the other planets share characteristics such as volcanism, hurricanes, tectonics, and even hydrology.

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.

At about the same time, by careful analysis of pre-telescopic observation data collected by Tycho Brahe, Johannes Kepler found the planets' orbits were not circular but elliptical. 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.

* The planets were thought by Ptolemy to orbit Earth in deferent and epicycle motions. Although eight of the planetary bodies discovered before 1950 remain 'planets' under the modern definition, some celestial bodies, such as Ceres, Pallas, Juno and Vesta (each an object in the solar asteroid belt), and Pluto (the first trans-Neptunian object discovered), that were once considered planets by the scientific community, are no longer viewed as such. This definition is controversial because it excludes many objects of planetary mass based on where or what they orbit. In 2006, the International Astronomical Union (IAU) officially adopted a resolution defining planets within the Solar System. As scientific knowledge advanced, human perception of the planets changed, incorporating a number of disparate objects. These were regarded by many early cultures as divine, or as emissaries of deities. Several planets in the Solar System can be seen with the naked eye. A planet is an astronomical body orbiting a star or stellar remnant that is massive enough to be rounded by its own gravity, is not massive enough to cause thermonuclear fusion, and has cleared its neighbouring region of planetesimals.The term planet is ancient, with ties to history, astrology, science, mythology, and religion.

Dawn of the space age crossword