Venus

Orbital period: 224.701 d (0.615198 yr)

1.92 Venus solar day

Synodic period: 583.92 days

Average orbital speed: 35.02 km/s

Mean anomaly: 50.115°

Inclination: 3.39458° to ecliptic, 3.86° to Sun's equator, 2.15° to invariable plane

Longitude of ascending node, 76.680°

Argument of perihelion

54.884°

Satellites

None

Physical characteristics

Mean radius

6,051.8±1.0 km

0.9499 Earths

Flattening

0

Surface area

4.6023×108 km2

0.902 Earths

Volume

9.2843×1011 km3

0.857 Earths

Mass

4.8675×1024 kg

0.815 Earths

Mean density

5.243 g/cm3

Surface gravity

8.87 m/s2

0.904 g

Escape velocity

10.36 km/s (6.44 mi/s)

Rotation period

−116.75 d (synodic; solar day; retrograde)

Sidereal rotation period

−243.0226 d (retrograde)

Equatorial rotation velocity

6.52 km/h (1.81 m/s)

Axial tilt

2.64° (for retrograde rotation)

177.36° (to orbit)

North pole right ascension

18h 11m 2s

272.76°

North pole declination

67.16°

Albedo

0.689 (geometric)

0.76 (Bond)

Surface temp.

min

mean

max

Kelvin

737 K

Celsius

464 °C

Fahrenheit

867 °F

Apparent magnitude

−4.92 to −2.98

Angular diameter

9.7″–66.0″

Atmosphere

Surface pressure

93 bar (9.3 MPa)

92 atm

Composition by volume

96.5% carbon dioxide

3.5% nitrogen

0.015% sulfur dioxide

0.0070% argon

0.0020% water vapour

0.0017% carbon monoxide

0.0012% helium

0.0007% neon

Trace carbonyl sulfide

Trace hydrogen chloride

Trace hydrogen fluoride

Venus is the second planet from the Sun. It is named after the Roman goddess of love and beauty. As the brightest natural object in Earth's night sky after the Moon, Venus can cast shadows and can be, on rare occasions, visible to the naked eye in broad daylight. Venus lies within Earth's orbit, and so never appears to venture far from the Sun, either setting in the west just after dusk or rising in the east a little while before dawn. Venus orbits the Sun every 224.7 Earth days. It has a synodic day length of 117 Earth days and a sidereal rotation period of 243 Earth days. As a consequence, it takes longer to rotate about its axis than any other planet in the Solar System, and does so in the opposite direction to all but Uranus. This means the Sun rises in the west and sets in the east. Venus does not have any moons, a distinction it shares only with Mercury among the planets in the Solar System.

Venus is a terrestrial planet and is sometimes called Earth's "sister planet" because of their similar size, mass, proximity to the Sun, and bulk composition. It is radically different from Earth in other respects. It has the densest atmosphere of the four terrestrial planets, consisting of more than 96% carbon dioxide. The atmospheric pressure at the planet's surface is about 92 times the sea level pressure of Earth, or roughly the pressure at 900 m (3,000 ft) underwater on Earth. Even though Mercury is closer to the Sun, Venus has the hottest surface of any planet in the Solar System, with a mean temperature of 737 K (464 °C; 867 °F). Venus is shrouded by an opaque layer of highly reflective clouds of sulfuric acid, preventing its surface from being seen from space in visible light. It may have had water oceans in the past, but these will have vaporized as the temperature rose under a runaway greenhouse effect. The water has probably photodissociated, and the free hydrogen has been swept into interplanetary space by the solar wind because of the lack of a planetary magnetic field.

As one of the brightest objects in the sky, Venus has been a major fixture in human culture for as long as records have existed. It has been made sacred to gods of many cultures, and has been a prime inspiration for writers and poets as the "morning star" and "evening star". Venus was the first planet to have its motions plotted across the sky, as early as the second millennium BC.