Venus is the second-closest planet to the Sun, orbiting it every 224.7 Earth days. After Earth's Moon, it is the brightest object in the night sky, reaching an apparent magnitude of −4.6. As an inferior planet from Earth it never appears to venture far from the Sun, and its elongation reaches a maximum of 47.8°. Venus reaches its maximum brightness shortly before sunrise or shortly after sunset, and is often referred to as the Morning Star or as the Evening Star.

A terrestrial planet, it is sometimes called Earth's "sister planet", as the two are similar in size and bulk composition. The planet is covered with an opaque layer of highly reflective clouds and its surface cannot be seen from space in visible light. Venus was a subject of great speculation until some of its secrets were revealed by planetary science in the 20th century. Venus has the densest atmosphere of the terrestrial planets, consisting mostly of carbon dioxide, and the atmospheric pressure at the planet's surface is 90 times that of the Earth.

Venus' surface has been mapped in detail only in the last 20 years. It shows evidence of extensive volcanism, and some of its volcanoes may still be active today. In contrast to the constant crustal movement seen on Earth, Venus is thought to undergo periodic episodes of plate tectonics, in which the crust is subducted rapidly within a few million years separated by stable periods of a few hundred million years.

The planet is named after Venus, the Roman goddess of love, and most of its surface features are named after famous and mythological women. The adjective Venusian is commonly used for items related to Venus, though the Latin adjective is the rarely used Venereal; the now-archaic Cytherean is still occasionally encountered.

Semi-major axis 108,208,926 km
0.723 331 99 AU
Orbital circumference 680,000,000 km
4.545 AU
Eccentricity 0.006 773 23
Perihelion 107,476,002 km
0.718 432 70 AU
Aphelion 108,941,849 km
0.728 231 28 AU
Orbital period 224.700 69 d
(0.615 197 0 a)
Synodic period 583.92 d
Avg. orbital speed 35.020 km/s
Max. orbital speed 35.259 km/s
Min. orbital speed 34.784 km/s
Inclination 3.394 71°
(3.86° to Sun's equator)
Longitude of the
ascending node 76.680 69°
Argument of the
perihelion 54.852 29°
Number of satellites 0
Physical characteristics
Equatorial diameter 12,103.7 km
(0.949 Earths)
Surface area 4.60×108 km2
(0.902 Earths)
Volume 9.28×1011 km³
(0.857 Earths)
Mass 4.8685×1024 kg
(0.815 Earths)
Mean density 5.204 g/cm3
Equatorial gravity 8.87 m/s2
(0.904 g)
Escape velocity 10.36 km/s
Rotation period −243.0185 d
Rotation velocity 6.52 km/h (at the equator)
Axial tilt 2.64°
Right ascension
of North pole 272.76° (18 h 11 min 2 s) 1
Declination 67.16°
Albedo 0.65
Surface* temp. min* mean max
228 K 737 K 773 K

Adjective Venusian or (rarely) Cytherean
(*min temperature refers to cloud tops only)
Atmospheric characteristics
Atmospheric pressure 9.3 MPa
Carbon dioxide ~96.5%
Nitrogen ~3.5%
Sulfur dioxide .015%
Argon .007%
Water vapor .002%
Carbon monoxide .0017%
Helium .0012%
Neon .0007%
Carbonyl sulfide
Hydrogen chloride
Hydrogen fluoride trace
Structure:-
Venus is one of the four terrestrial planets, meaning that, like the Earth, it is a rocky body. In size and mass, it is very similar to the Earth, and is often described as its 'twin'. The diameter of Venus is only 650 km less than the Earth's, and its mass is 80% of the Earth's. However, conditions on the Venusian surface differ radically from those on Earth, due to its dense carbon dioxide atmosphere.
Internal structure
Though there is little direct information about its internal structure, the similarity in size and density between Venus and Earth suggests that it has a similar internal structure: a core, mantle and crust. Like that of Earth, the Venusian core is at least partially liquid. The slightly smaller size of Venus suggests that pressures are significantly lower in its deep interior than Earth. The principal difference between the two planets is the lack of plate tectonics on Venus, likely due to the dry surface and mantle. This results in reduced heat loss from the planet, preventing it from cooling and providing a likely explanation for its lack of an internally generated magnetic field.

Geography:-
About 80% of Venus' surface consists of smooth volcanic plains. Two highland 'continents' make up the rest of its surface area, one lying in the planet's northern hemisphere and the other just south of the equator. The northern continent is called Ishtar Terra, after Ishtar, the Babylonian goddess of love, and is about the size of Australia. Maxwell Montes, the highest mountain on Venus, lies on Ishtar Terra. Its peak lies 11 km above Venus' average surface elevation; in contrast, Earth's highest mountain, Mount Everest, rises to just under 9 km above sea level. The southern continent is called Aphrodite Terra, after the Greek goddess of love, and is the larger of the two highland regions at roughly the size of South America. Much of this continent is covered by a network of fractures and faults.

As well as the impact craters, mountains and valleys commonly found on rocky planets, Venus has a number of unique surface features. Among these are flat-topped volcanic features called farra, which look somewhat like pancakes and range in size from 20–50 km across, and 100–1000 m high; radial, star-like fracture systems called novae; features with both radial and concentric fractures resembling spiders' webs, known as arachnoids; and coronae, circular rings of fractures sometimes surrounded by a depression. All of these features are volcanic in origin.

Almost all Venusian surface features are named after historical and mythological women.[4] The only exceptions are Maxwell Montes, named after James Clerk Maxwell, and two highland regions, Alpha Regio and Beta Regio. These three features were named before the current system was adopted by the International Astronomical Union, the body that oversees planetary nomenclature.