# Venus

Venus | Image of Venus, as captured by MESSENGER. A cloud layer permanently obscures the surface. |
| Designations |
| Pronunciation | /ˈviːnəs/ (listen) |
| Adjectives | Venusian or (rarely) Cytherean, Venerean |
| Orbital characteristics |
| Epoch J2000 |
| Aphelion | * 0.728213 AU
* 108,939,000 km
 |
| Perihelion | * 0.718440 AU
* 107,477,000 km
 |
| Semi-major axis | * 0.723332 AU
* 108,208,000 km
 |
| Eccentricity | 0.006772 |
| 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
* 2.19° 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
* 0.866 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) |
| Sidereal rotation period | −243.025 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 |  | 462 °C |  |
| Fahrenheit |  | 864 °F |  |

 |
| Apparent magnitude | −4.92 to −2.98 |
| Angular diameter | 9.7″–66.0″ |
| Atmosphere |
| Surface pressure | 92 bar (9.2 MPa) |
| Composition by volume | * 96.5% carbon dioxide
* 3.5% nitrogen
* 0.015% sulfur dioxide
* 0.007% argon
* 0.002% 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. Venus is the only planet in the Solar System that has a day longer than a year. The year length of Venus is 225 Earth days. The day length of Venus is 243 Earth days.

## Overview

Venus is a *terrestrial planet* because it has a solid, rocky surface like other planets in the inner Solar System. Astronomers have known Venus for thousands of years. The ancient Romans named it after their goddess Venus, goddess of love and beauty.

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 at some elongations it is easily seen just before the Sun comes up in the morning. At other times, it can be seen just after the sun goes down in the evening. Venus comes closer to the Earth than any other planet does.

### Composition

Venus is sometimes called the sister planet of Earth as they are quite similar in size and gravity. In other ways the planets are very different. Venus' atmosphere is mostly carbon dioxide (CO2) with clouds of sulphuric acid (H2SO4). H2SO4 is a chemical that is poisonous to life. For this it is sometimes known as the Earth's "evil twin".

The thick atmosphere makes it hard to see the surface. Until the late twentieth century many thought there might be life there. The pressure on Venus' surface is 92 times that of Earth. Venus is one of only two planets in the Solar System (the other being Mercury) that has no moons. Venus spins very slowly on its axis and it spins in the opposite direction to the other planets.

## Physical properties

Radar 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 the surface of Venus the hottest of any planet's surface in the Solar System with an estimated average temperature of 753.1 K (480.0 °C; 895.9 °F). This is hot enough to melt lead or zinc.

### Geography

Venus has no oceans because it is much too hot for water. Venus' surface is a dry desert. Because of the clouds, only radar can map the surface. It is about 80% smooth, rocky plains, made mostly of basalt. 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.

The surface of Venus looks like it has been shaped by volcanic activity. Venus has a lot of volcanoes. The surface of Venus is estimated to be 300–600 million years old.

Unlike Earth or Mars, Venus does not have defined highlands or lowlands, and it does not have tectonic plates.

### 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 see the planet's surface from space as the thick cloud layer reflects 60% of the light that hits it. The only way scientists are able to see it is by using infrared and ultraviolet cameras and radar.

Scientists believe that billions of years ago, the atmosphere of Venus could have been like Earth's atmosphere. There may have been lots of water on the surface of Venus. But after 600 million to several billion years, the evaporation of the water put greenhouse gases into its atmosphere.

### Magnetic field

In 1967, Venera 4 found that the magnetic field of Venus was much weaker than that of Earth. This magnetic field is induced by an interaction between the ionosphere and the solar wind. Venus' magnetosphere is not strong enough to protect the atmosphere from cosmic rays.

### Transit of Venus

Venus can sometimes be seen passing between the Sun and Earth. Venus looks like a black dot when seen through a special telescope. These passages are called "transits". These "transits" happen in pairs eight years apart. Then it is more than a hundred years to the next pair.

## Orbit and rotation

Orbit of Venus compared to the orbit of the EarthVenus orbits the Sun at an average distance of about 108 million km (68~ million mi). It completes an orbit every 224.7 days. The rotation of Venus is slow. A Venusian sidereal day is longer than a Venusian year.

## List of satellites sent to Venus

Many man-made satellites have been sent to Venus to study it. They are:

### Mariner

| Name | Launch Date | Country(s) | Date of Arrival at Venus | **Date of Last Radio Signal** | Did It Work as Planned? | Source(s) |
| --- | --- | --- | --- | --- | --- | --- |
| **Mariner 1** | July 22, 1962 | United States | Never happened because of launch failure | July 22, 1962 | No |  |
| **Mariner 2** | August 27, 1962 | United States | December 14, 1962 | Janaury 3, 1963 | Yes |  |
| **Mariner 5** | June 14, 1967 | United States | June 19, 1967 | October 14, 1968 | Yes |  |
| **Mariner 10** | November 3, 1973 | United States | February 5, 1974 | March 24, 1975 | Yes |  |

### Venera

| Name | Launch Date | Country(s) | Date of Arrival at Venus | Date of Last Radio Signal (lander/impactor) | Date of Last Radio Signal (orbiter/fly-by craft/kickstage) | **Did It Work as Planned?** | Source(s) |
| --- | --- | --- | --- | --- | --- | --- | --- |
| **Sputnik 7** | February 4, 1961 | Soviet Union | Never happened because of failure to leave Low Earth orbit | No lander | February 26, 1961 | No |  |
| **Sputnik 19** | August 25, 1962 | Soviet Union | Never happened because of failure to leave Low Earth orbit | No lander | August 28, 1962 | No |  |
| **Venera 1** | February 12, 1961 | Soviet Union | May 19, 1961 | No lander | February 17, 1961 | No |  |
| **Venera 2** | November 12, 1965 | Soviet Union | February 27, 1966 | No lander | February 1966 | No |  |
| **Venera 3** | November 16, 1965 | Soviet Union | March 1, 1966 | February 16, 1966 | February 16, 1966 | No |  |
| **Venera 4** | June 12, 1967 | Soviet Union | October 18, 1967 | No lander | October 18, 1967 | Yes |  |
| **Venera 5** | January 5, 1969 | Soviet Union | May 16, 1969 | May 16, 1969 | May 16, 1969 | Yes |  |
| **Venera 6** | January 10, 1969 | Soviet Union | May 17, 1969 | May 17, 1969 | May 17, 1969 | Yes |  |
| **Venera 7** | August 17, 1970 | Soviet Union | December 15, 1970 | December 15, 1970 | December 15, 1970 | Landed but rolled and returned very little data |  |
| **Venera 8** | March 27, 1972 | Soviet Union | July 22, 1972 | July 22, 1972 | July 22, 1972 | Yes |  |
| **Venera 9** | June 8, 1975 | Soviet Union | October 22, 1975 | October 22, 1975 | March 22, 1976 | Yes |  |
| **Venera 10** | June 14, 1975 | Soviet Union | October 25, 1975 | October 25, 1975 | June 1976 |  |  |
| **Venera 11** | September 9, 1978 | Soviet Union | December 25, 1978 | December 25, 1978 | February 1980 | Yes, small issues with the some of the tools on the mission |  |
| **Venera 12** | September 14, 1978 | Soviet Union | December 21, 1978 | December 21, 1978 | December 21, 1978 | Yes, small issues with the some of the tools on the mission |  |
| **Venera 13** | October 30, 1981 | Soviet Union | March 1, 1982 | March 1, 1982 | April 25, 1983 | Yes |  |
| **Venera 14** | November 4, 1981 | Soviet Union | March 5, 1982 | March 5, 1982 | April 9, 1983 | Yes |  |
| **Venera 15** | June 2, 1983 | Soviet Union | October 1983 | No lander | July 1984 | Yes |  |
| **Venera 16** | June 7, 1983 | Soviet Union | October 1983 | No lander | July 1984 | Yes |  |

## Related pages

* List of planets

## Other websites

* Nine Planets: Venus
* The Planet Venus
* Images of Venus
* Venus Archived May 20, 2011, at the Wayback Machine