Venus

Venus 

Orbital characteristics Epoch J2000
Aphelion	108,942,109 km 0.728 231 28 AU
Perihelion	107,476,259 km 0.718 432 70 AU
Semi-major axis	108,208,930 km 0.723 332 AU
Eccentricity	0.006 8
Orbital period	224.700 69 day 0.615 197 0 yr 1.92 Venus solar day
Synodic period	583.92 days
Average orbital speed	35.02 km/s
Inclination	3.394 71° to Ecliptic 3.86° to Sun’s equator 2.19° to Invariable plane
Longitude of ascending node	76.670 69°
Argument of perihelion	54.852 29°
Satellites	None
Physical characteristics
Mean radius	6,051.8 ± 1.0 km 0.949 9 Earths
Flattening	0
Surface area	4.60×108 km² 0.902 Earths
Volume	9.38×1011 km³ 0.857 Earths
Mass	4.868 5×1024 kg 0.815 Earths
Mean density	5.204 g/cm³
Equatorial surface gravity	8.87 m/s2 0.904 g
Escape velocity	10.46 km/s
Sidereal rotation period	-243.018 5 day
Rotation velocity at equator	6.52 km/h (1.81 m/s)
Axial tilt	177.3°
Right ascension of North pole	18 h 11 min 2 s 272.76°
Declination of North pole	67.16°
Albedo	0.65 (geometric) or 0.75 (bond)
Surface temperature:    Kelvin    Celsius	min mean max 735 K 461.85 °C
Apparent magnitude	up to -4.6 (crescent) -3.8 (full)
Angular size	9.7" – 66.0"
Adjectives	Venusian or (rarely) Cytherean, Venerean
Atmosphere
Surface pressure	93 bar (9.3 MPa)
Composition	~96.5% Carbon dioxide ~3.5% Nitrogen 0.015% Sulfur dioxide 0.007% Argon 0.002% Water vapor 0.001 7% Carbon monoxide 0.001 2% Helium 0.000 7% Neon trace Carbonyl sulfide trace Hydrogen chloride trace Hydrogen fluoride

This article is about the planet. For other uses, see Venus (disambiguation).

Venus is the second planet from the Sun. It is a terrestrial planet because it has a solid, rocky surface. The other terrestrial planets are Mercury, Earth and Mars. Astronomers have known Venus for thousands of years. The ancient Romans named it after their goddess Venus. Venus is the brightest thing in the night sky except for the Moon. It is sometimes called the morning star or the evening star as it is brightest just before the sun comes up in the morning, and just after the sun goes down in the evening. Venus comes closer to the earth than any other planet does.

Venus is sometimes called the sister planet of Earth as they are quite similar in size and gravity. In other ways the two planets are very different. Venus' atmosphere (air) is mostly carbon dioxide with clouds of sulfuric acid. Sulphuric acid is a chemical that is very poisonous to humans. The thick atmosphere has made it hard to see the surface, and until the twenty-first century many people thought things might live there. The pressure on Venus' surface is 92 times that of Earth. Venus has no moons.

Physical Properties

Global view of the surface of Venus (Magellan spacecraft)

Venus is a terrestrial planet so, like the Earth, its surface is made of rock. Venus is much hotter than Earth. All the carbon dioxide in the atmosphere acts like a blanket, trapping heat from the Sun. This effect is called the greenhouse effect and it is very strong on Venus. This makes Venus the hottest planet in the Solar System with an estimated average temperature of 480 °C (896.0 °F). This is hot enough to melt lead or zinc.

Geography

Venus' surface is about 80% smooth, rocky plains. Two higher areas called continents make up the north and south of the planet. The north is called Ishtar Terra and the south is called Aphrodite Terra. They are named after the Babylonian and Greek goddesses of love.

Atmosphere

Venus' atmosphere is mostly carbon dioxide and nitrogen gas with clouds of sulphuric acid. Because the atmosphere is so thick or dense the pressure is very high. The pressure is 92 times the pressure on Earth, enough to crush many things.

It is impossible to look at the planet's surface from space as the thick cloud layer reflects 60% of the light that hits it. The only way scientists have been able to look is by using infrared and ultraviolet cameras.

Other pages

• List of planets

Other websites

• Nine Planets: Venus
• The Planet Venus
• Images of Venus
• Venus