Search results
Results from the WOW.Com Content Network
No secondary characteristics have been observed around exoplanets. The sub-brown dwarf Cha 110913−773444, which has been described as a rogue planet, is believed to be orbited by a tiny protoplanetary disc, [150] and the sub-brown dwarf OTS 44 was shown to be surrounded by a substantial protoplanetary disk of at least 10 Earth masses. [151]
According to the IAU's explicit count, there are eight planets in the Solar System; four terrestrial planets (Mercury, Venus, Earth, and Mars) and four giant planets, which can be divided further into two gas giants (Jupiter and Saturn) and two ice giants (Uranus and Neptune). When excluding the Sun, the four giant planets account for more than ...
Three of the four inner planets (Venus, Earth, and Mars) have atmospheres substantial enough to generate weather; all have impact craters and tectonic surface features, such as rift valleys and volcanoes. [91] Mercury (0.31–0.59 AU from the Sun) [D 6] is the smallest planet in the Solar System.
Mercury, the smallest and innermost planet, has no moons, or at least none that can be detected to a diameter of 1.6 km (1.0 mi). [2] For a very short time in 1974, Mercury was thought to have a moon. Venus also has no moons, [3] though reports of a moon around Venus have circulated since the 17th century.
Venus is a primary feature of the night sky, and so has been of remarkable importance in mythology, astrology and fiction throughout history and in different cultures. The eight-pointed star a symbol used in some cultures for Venus, and sometimes combined into a star and crescent arrangement.
Venus rotates clockwise, and Uranus has been knocked on its side and rotates almost perpendicular to the rest of the Solar System. The ecliptic remains within 3° of the invariable plane over five million years, [ 2 ] but is now inclined about 23.44° to Earth's celestial equator used for the coordinates of poles.
The story appears to have been different on Mars, the fourth planet from the sun. Surface features on Mars indicate it had an ocean of liquid water billions of years ago. No such features have ...
The surface of Venus is comparatively flat. When 93% of the topography was mapped by Pioneer Venus Orbiter, scientists found that the total distance from the lowest point to the highest point on the entire surface was about 13 kilometres (8.1 mi), about the same as the vertical distance between the Earth's ocean floor and the higher summits of the Himalayas.