Venus

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Venus

Global radar view of the surface from Magellan radar imaging between 1990 and 1994
Designations
Pronunciation	i/ˈviːnəs/
Adjectives	Venusian or (rarely) Cytherean, Venerean
Orbital characteristics[2][4]
Epoch J2000
Aphelion	108939000 km 0.728213 AU
Perihelion	107477000 km 0.718440 AU
Semi-major axis	108208000 km 0.723327 AU
Eccentricity	0.0067
Orbital period	224.701 d 0.615198 yr 1.92 Venus solar day
Synodic period	583.92 days[2]
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[3]
Longitude of ascending node	76.678°
Argument of perihelion	55.186°
Satellites	None
Physical characteristics
Mean radius	6051.8±1.0 km[5] 0.9499 Earths
Flattening	0[5]
Surface area	4.60×108 km2 0.902 Earths
Volume	9.28×1011 km3 0.866 Earths
Mass	4.8676×1024 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
Sidereal rotation period	−243.0185 d (Retrograde)
Equatorial rotation velocity	6.52 km/h (1.81 m/s)
Axial tilt	177.36°[2]
North pole right ascension	18h 11m 2s 272.76°[6]
North pole declination	67.16°
Albedo	0.67 (geometric)[7] 0.90 (Bond)[7]
Surface temp. min mean max Kelvin 737 K[2] Celsius 462 °C
Apparent magnitude	brightest −4.9[8][9] (crescent) −3.8[10] (full)
Angular diameter	9.7″ to 66.0″[2]
Atmosphere
Surface pressure	92 bar (9.2 MPa)
Composition	≈ 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, orbiting it every 224.7 Earth days.^[11] It has no natural satellite. It is named after the Roman goddess of love and beauty. After the Moon, it is the brightest natural object in the night sky, reaching an apparent magnitude of −4.6, bright enough to cast shadows.^[12] Because Venus is an inferior planet from Earth, it never appears to venture far from the Sun: its elongation reaches a maximum of 47.8°.

Venus is a terrestrial planet and is sometimes called Earth's "sister planet" because of their similar size, gravity, and bulk composition (Venus is both the closest planet to Earth and the planet closest in size to Earth). However, it has also been shown to be very 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 92 times that of Earth's. With a mean surface temperature of 735 K (462 °C; 863 °F), Venus is by far the hottest planet in the Solar System. It has no carbon cycle to lock carbon back into rocks and surface features, nor does it seem to have any organic life to absorb it in biomass. 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. Venus may have possessed oceans in the past,^[13][14] but these would have vaporized as the temperature rose due to a runaway greenhouse effect.^[15] The water has most probably photodissociated, and, because of the lack of a planetary magnetic field, the free hydrogen has been swept into interplanetary space by the solar wind.^[16] Venus's surface is a dry desertscape interspersed with slab-like rocks and periodically refreshed by volcanism.

Physical characteristics

Venus is one of the four terrestrial planets in the Solar System, meaning that, like Earth, it is a rocky body. In size and mass, it is similar to Earth, and is often described as Earth's "sister" or "twin".^[17] The diameter of Venus is 12,092 km (only 650 km less than Earth's) and its mass is 81.5% of Earth's. Conditions on the Venusian surface differ radically from those on Earth, owing to its dense carbon dioxide atmosphere. The mass of the atmosphere of Venus is 96.5% carbon dioxide, with most of the remaining 3.5% being nitrogen.^[18]

Geography

The Venusian surface was a subject of speculation until some of its secrets were revealed by planetary science in the 20th century. It was finally mapped in detail by Project Magellan in 1990–91. The ground shows evidence of extensive volcanism, and the sulfur in the atmosphere may indicate there have been some recent eruptions.^[19][20]

About 80% of the Venusian surface is covered by smooth, volcanic plains, consisting of 70% plains with wrinkle ridges and 10% smooth or lobate plains.^[21] 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 is 11 km above the Venusian average surface elevation. 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. A network of fractures and faults covers much of this area.^[22]

The absence of evidence of lava flow accompanying any of the visible caldera remains an enigma. The planet has few impact craters, demonstrating the surface is relatively young, approximately 300–600 million years old.^[23][24] In addition to the impact craters, mountains, and valleys commonly found on rocky planets, Venus has some unique surface features. Among these are flat-topped volcanic features called "farra", which look somewhat like pancakes and range in size from 20 to 50 km across, and from 100 to 1,000 m high; radial, star-like fracture systems called "novae"; features with both radial and concentric fractures resembling spider webs, known as "arachnoids"; and "coronae", circular rings of fractures sometimes surrounded by a depression. These features are volcanic in origin.^[25]

Most Venusian surface features are named after historical and mythological women.^[26] Exceptions are Maxwell Montes, named after James Clerk Maxwell, and highland regions Alpha Regio, Beta Regio and Ovda Regio. The former three features were named before the current system was adopted by the International Astronomical Union, the body that oversees planetary nomenclature.^[27]

The longitudes of physical features on Venus are expressed relative to its prime meridian. The original prime meridian passed through the radar-bright spot at the center of the oval feature Eve, located south of Alpha Regio.^[28] After the Venera missions were completed, the prime meridian was redefined to pass through the central peak in the crater Ariadne.^[29][30]

Size comparison of Mercury, Venus, Earth and the Moon, Mars, and Ceres on the far right. This may not be exactly to scale, because the visual disc of Venus with its atmosphere makes it look bigger than its solid-body diameter.

Surface geology

Maat Mons with a vertical exaggeration of 22.5

Much of the Venusian surface appears to have been shaped by volcanic activity. Venus has several times as many volcanoes as Earth, and it possesses 167 large volcanoes that are over 100 km across. The only volcanic complex of this size on Earth is the Big Island of Hawaii.^[25] This is not because Venus is more volcanically active than Earth, but because its crust is older. Earth's oceanic crust is continually recycled by subduction at the boundaries of tectonic plates, and has an average age of about 100 million years,^[31] whereas the Venusian surface is estimated to be 300–600 million years old.^[23][25]

Several lines of evidence point to ongoing volcanic activity on Venus. During the Soviet Venera program, the Venera 11 and Venera 12 probes detected a constant stream of lightning, and Venera 12 recorded a powerful clap of thunder soon after it landed. The European Space Agency's Venus Express recorded abundant lightning in the high atmosphere.^[32] Although rainfall drives thunderstorms on Earth, there is no rainfall on the surface of Venus (though sulfuric acid rain falls in the upper atmosphere, then evaporates around 25 km above the surface). One possibility is that ash from a volcanic eruption was generating the lightning. Another piece of evidence comes from measurements of sulfur dioxide concentrations in the atmosphere, which dropped by a factor of 10 between 1978 and 1986. This may imply the levels had earlier been boosted by a large volcanic eruption.^[33] Almost a thousand impact craters on Venus are evenly distributed across its surface. On other cratered bodies, such as Earth and the Moon, craters show a range of states of degradation. On the Moon, degradation is caused by subsequent impacts, whereas on Earth it is caused by wind and rain erosion. On Venus, about 85% of the craters are in pristine condition. The number of craters, together with their well-preserved condition, indicates the planet underwent a global resurfacing event about 300–600 million years ago,^[23][24] followed by a decay in volcanism.^[34] Whereas Earth's crust is in continuous motion, Venus is thought to be unable to sustain such a process. Without plate tectonics to dissipate heat from its mantle, Venus instead undergoes a cyclical process in which mantle temperatures rise until they reach a critical level that weakens the crust. Then, over a period of about 100 million years, subduction occurs on an enormous scale, completely recycling the crust.^[25] In March 2014, the first direct evidence for ongoing volcanism was located, in the form of infrared "flashes" over the rift zone Ganiki Chasma, near the shield volcano Maat Mons. These flashes, ranging from 40 to 320°C above the ambient, are believed to be either hot gases or lava released from volcanic eruptions.^[35]

Venusian craters range from 3 km to 280 km in diameter. No craters are smaller than 3 km, because of the effects of the dense atmosphere on incoming objects. Objects with less than a certain kinetic energy are slowed down so much by the atmosphere that they do not create an impact crater.^[36] Incoming projectiles less than 50 metres in diameter will fragment and burn up in the atmosphere before reaching the ground.^[37]

Cloud structure in the Venusian atmosphere in 1979, revealed by ultraviolet observations by Pioneer Venus Orbiter

A real-colour image of Venus processed from two filters. The surface is obscured by a thick blanket of clouds

Impact craters on the surface of Venus (image reconstructed from radar data)

Internal structure

Without seismic data or knowledge of its moment of inertia, little direct information is available about the internal structure and geochemistry of Venus.^[38] The similarity in size and density between Venus and Earth suggests they share a similar internal structure: a core, mantle, and crust. Like that of Earth, the Venusian core is at least partially liquid because the two planets have been cooling at about the same rate.^[39] The slightly smaller size of Venus suggests pressures are significantly lower in its deep interior than Earth. The principal difference between the two planets is the lack of evidence for plate tectonics on Venus, possibly because its crust is too strong to subduct without water to make it less viscous. 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.^[40] Instead, Venus may lose its internal heat in periodic major resurfacing events.^[23]

Atmosphere and climate

Venus has an extremely dense atmosphere, which consists mainly of carbon dioxide and a small amount of nitrogen. The atmospheric mass is 93 times that of Earth's atmosphere, whereas the pressure at the planet's surface is about 92 times that at Earth's surface—a pressure equivalent to that at a depth of nearly 1 kilometre under Earth's oceans. The density at the surface is 65 kg/m³, 6.5% that of water. The CO₂-rich atmosphere, along with thick clouds of sulfur dioxide, generates the strongest greenhouse effect in the Solar System, creating surface temperatures of at least 462 °C (864 °F).^[11][41] This makes the Venusian surface hotter than Mercury's, which has a minimum surface temperature of −220 °C (−364.0 °F) and maximum surface temperature of 420 °C (788 °F),^[42] even though Venus is nearly twice Mercury's distance from the Sun and thus receives only 25% of Mercury's solar irradiance. The surface of Venus is often described as hellish.^[43] This temperature is higher than temperatures used to achieve sterilization.
Studies have suggested that billions of years ago, the Venusian atmosphere was much more like Earth's than it is now, and that there may have been substantial quantities of liquid water on the surface, but, after a period of 600 million to several billion years,^[44] a runaway greenhouse effect was caused by the evaporation of that original water, which generated a critical level of greenhouse gases in its atmosphere.^[45] Although the surface conditions on the planet are no longer hospitable to any Earthlike life that may have formed prior to this event, it is possible that life could exist in the lower and middle cloud layers of Venus.^[46][47][48]

Thermal inertia and the transfer of heat by winds in the lower atmosphere mean that the temperature of the Venusian surface does not vary significantly between the night and day sides, despite the planet's extremely slow rotation. Winds at the surface are slow, moving at a few kilometres per hour, but because of the high density of the atmosphere at the Venusian surface, they exert a significant amount of force against obstructions, and transport dust and small stones across the surface. This alone would make it difficult for a human to walk through, even if the heat, pressure and lack of oxygen were not a problem.^[49]

Above the dense CO₂ layer are thick clouds consisting mainly of sulfur dioxide and sulfuric acid droplets.^[50][51] These clouds reflect and scatter about 90% of the sunlight that falls on them back into space, and prevent visual observation of the Venusian surface. The permanent cloud cover means that although Venus is closer than Earth to the Sun, the Venusian surface is not as well lit. Strong 300 km/h (190 mph) winds at the cloud tops circle the planet about every four to five earth days.^[52] Venusian winds move at up to 60 times the speed of the planet's rotation, whereas Earth's fastest winds are only 10–20% rotation speed.^[53]

The surface of Venus is effectively isothermal; it retains a constant temperature not only between day and night but between the equator and the poles.^[2][54] The planet's minute axial tilt—less than 3°, compared to 23° on Earth—also minimizes seasonal temperature variation.^[55] The only appreciable variation in temperature occurs with altitude. The highest point on Venus, Maxwell Montes, is therefore the coolest point on the planet, with a temperature of about 380°C (716°F) and an atmospheric pressure of about 45 bar (44 atm).^[56][57] In 1995, the Magellan probe imaged a highly reflective substance at the tops of the highest mountain peaks that bore a strong resemblance to terrestrial snow. This substance arguably formed from a similar process to snow, albeit at a far higher temperature. Too volatile to condense on the surface, it rose in gas form to cooler higher elevations, where it then fell as precipitation. The identity of this substance is not known with certainty, but speculation has ranged from elemental tellurium to lead sulfide (galena).^[58]

The clouds of Venus are capable of producing lightning much like the clouds on Earth.^[59] The existence of lightning had been controversial since the first suspected bursts were detected by the Soviet Venera probes. In 2006–2007 Venus Express clearly detected whistler mode waves, the signatures of lightning. Their intermittent appearance indicates a pattern associated with weather activity. The lightning rate is at least half of that on Earth.^[59] In 2007 the Venus Express probe discovered that a huge double atmospheric vortex exists at the southern pole.^[60][61]

Another discovery made by the Venus Express probe in 2011 is that an ozone layer exists high in the atmosphere of Venus.^[62]

On January 29, 2013, ESA scientists reported that the ionosphere of the planet Venus streams outwards in a manner similar to "the ion tail seen streaming from a comet under similar conditions."^[63][64]

Atmospheric composition

Synthetic stick absorption spectrum of a simple gas mixture corresponding to the Earth's atmosphere

Venusian atmosphere composition based on HITRAN data^[65] created using Hitran on the Web system.^[66]

Green colour – water vapour, red – carbon dioxide, WN – wavenumber (other colours have different meanings, lower wavelengths on the right, higher on the left).

Magnetic field and core

In 1967, Venera 4 found the Venusian magnetic field to be much weaker than that of Earth. This magnetic field is induced by an interaction between the ionosphere and the solar wind,^[67][68] rather than by an internal dynamo in the core like the one inside Earth. Venus's small induced magnetosphere provides negligible protection to the atmosphere against cosmic radiation. This radiation may result in cloud-to-cloud lightning discharges.^[69]

The lack of an intrinsic magnetic field at Venus was surprising given it is similar to Earth in size, and was expected also to contain a dynamo at its core. A dynamo requires three things: a conducting liquid, rotation, and convection. The core is thought to be electrically conductive and, although its rotation is often thought to be too slow, simulations show it is adequate to produce a dynamo.^[70][71] This implies the dynamo is missing because of a lack of convection in the Venusian core. On Earth, convection occurs in the liquid outer layer of the core because the bottom of the liquid layer is much hotter than the top. On Venus, a global resurfacing event may have shut down plate tectonics and led to a reduced heat flux through the crust. This caused the mantle temperature to increase, thereby reducing the heat flux out of the core. As a result, no internal geodynamo is available to drive a magnetic field. Instead, the heat energy from the core is being used to reheat the crust.^[72]

One possibility is that Venus has no solid inner core,^[73] or that its core is not currently cooling, so that the entire liquid part of the core is at approximately the same temperature. Another possibility is that its core has already completely solidified. The state of the core is highly dependent on the concentration of sulfur, which is unknown at present.^[72]

The weak magnetosphere around Venus means that the solar wind is interacting directly with its outer atmosphere. Here, ions of hydrogen and oxygen are being created by the dissociation of neutral molecules from ultraviolet radiation. The solar wind then supplies energy that gives some of these ions sufficient velocity to escape Venus's gravity field. This erosion process results in a steady loss of low-mass hydrogen, helium, and oxygen ions, whereas higher-mass molecules, such as carbon dioxide, are more likely to be retained. Atmospheric erosion by the solar wind probably led to the loss of most of Venus's water during the first billion years after it formed. The erosion has increased the ratio of higher-mass deuterium to lower-mass hydrogen in the upper atmosphere by 150 times compared to the ratio in the lower atmosphere.^[74]

Orbit and rotation

Venus orbits the Sun at an average distance of about 108 million kilometres (about 0.7 AU) and completes an orbit every 224.65 days. Venus is the second planet from the Sun and it revolves round the Sun approximately 1.6 times (yellow trail) in Earth's 365 days (blue trail)

Venus orbits the Sun at an average distance of about 0.72 AU (108,000,000 km; 67,000,000 mi), and completes an orbit every 224.65 days. Although all planetary orbits are elliptical, Venus's orbit is the closest to circular, with an eccentricity of less than 0.01.^[2] When Venus lies between Earth and the Sun, a position known as inferior conjunction, it makes the closest approach to Earth of any planet at an average distance of 41 million km.^[2] The planet reaches inferior conjunction every 584 days, on average.^[2] Owing to the decreasing eccentricity of Earth's orbit, the minimum distances will become greater over tens of thousands of years. From the year 1 to 5383, there are 526 approaches less than 40 million km; then there are none for about 60,158 years.^[75]

All the planets of the Solar System orbit the Sun in an anti-clockwise direction as viewed from above the Earth's north pole. Most planets also rotate on their axes in an anti-clockwise direction, but Venus rotates clockwise (called "retrograde" rotation) once every 243 Earth days—the slowest rotation period of any planet. Because its rotation is so slow, it is highly spherical.^[76] A Venusian sidereal day thus lasts longer than a Venusian year (243 versus 224.7 Earth days). Venus's equator rotates at 6.5 km/h (4.0 mph), whereas Earth's is approximately 1,670 km/h (1,040 mph).^[77] Venus's rotation has slowed down by 6.5 min per Venusian sidereal day since the Magellan spacecraft visited it 16 years ago.^[78] Because of the retrograde rotation, the length of a solar day on Venus is significantly shorter than the sidereal day, at 116.75 Earth days (making the Venusian solar day shorter than Mercury's 176 Earth days); one Venusian year is about 1.92 Venusian (solar) days long.^[79] To an observer on the surface of Venus, the Sun would rise in the west and set in the east.^[79]

Venus may have formed from the solar nebula with a different rotation period and obliquity, reaching its current state because of chaotic spin changes caused by planetary perturbations and tidal effects on its dense atmosphere, a change that would have occurred over the course of billions of years. The rotation period of Venus may represent an equilibrium state between tidal locking to the Sun's gravitation, which tends to slow rotation, and an atmospheric tide created by solar heating of the thick Venusian atmosphere.^[80][81] The 584-day average interval between successive close approaches to Earth is almost exactly equal to 5 Venusian solar days,^[82] but the hypothesis of a spin–orbit resonance with Earth has been discounted.^[83]

Venus has no natural satellites,^[84] though the asteroid 2002 VE₆₈ presently maintains a quasi-orbital relationship with it.^[85][86] Besides this quasi-satellite, it has two other temporary co-orbitals, 2001 CK32 and 2012 XE133.^[87] In the 17th century, Giovanni Cassini reported a moon orbiting Venus, which was named Neith and numerous sightings were reported over the following 200 years, but most were determined to be stars in the vicinity. Alex Alemi's and David Stevenson's 2006 study of models of the early Solar System at the California Institute of Technology shows Venus likely had at least one moon created by a huge impact event billions of years ago.^[88] About 10 million years later, according to the study, another impact reversed the planet's spin direction and caused the Venusian moon gradually to spiral inward until it collided and merged with Venus.^[89] If later impacts created moons, these were absorbed in the same way. An alternative explanation for the lack of satellites is the effect of strong solar tides, which can destabilize large satellites orbiting the inner terrestrial planets.^[84]

Observation

Venus is always brighter than the brightest stars outside our solar system, as can be seen here over the Pacific Ocean

Phases of Venus and evolution of its apparent diameter

Venus is always brighter than any star (apart from the Sun). The greatest luminosity, apparent magnitude −4.9,^[9] occurs during crescent phase when it is near Earth. Venus fades to about magnitude −3 when it is backlit by the Sun.^[8] The planet is bright enough to be seen in a mid-day clear sky,^[90] and the planet can be easy to see when the Sun is low on the horizon. As an inferior planet, it always lies within about 47° of the Sun.^[10]

Venus "overtakes" Earth every 584 days as it orbits the Sun.^[2] As it does so, it changes from the "Evening Star", visible after sunset, to the "Morning Star", visible before sunrise. Although Mercury, the other inferior planet, reaches a maximum elongation of only 28° and is often difficult to discern in twilight, Venus is hard to miss when it is at its brightest. Its greater maximum elongation means it is visible in dark skies long after sunset. As the brightest point-like object in the sky, Venus is a commonly misreported "unidentified flying object". U.S. President Jimmy Carter reported having seen a UFO in 1969, which later analysis suggested was probably Venus. Countless other people have mistaken Venus for something more exotic.^[91]

As it moves around its orbit, Venus displays phases like those of the Moon in a telescopic view. The planet presents a small "full" image when it is on the opposite side of the Sun. It shows a larger "quarter phase" when it is at its maximum elongations from the Sun, and is at its brightest in the night sky, and presents a much larger "thin crescent" in telescopic views as it comes around to the near side between Earth and the Sun. Venus is at its largest and presents its "new phase" when it is between Earth and the Sun. Its atmosphere can be seen in a telescope by the halo of light refracted around it.^[10]

Transits

2004 transit of Venus

The Venusian orbit is slightly inclined relative to Earth's orbit; thus, when the planet passes between Earth and the Sun, it usually does not cross the face of the Sun. Transits of Venus occur when the planet's inferior conjunction coincides with its presence in the plane of Earth's orbit. Transits of Venus occur in cycles of 243 years with the current pattern of transits being pairs of transits separated by eight years, at intervals of about 105.5 years or 121.5 years—a pattern first discovered in 1639 by English astronomer Jeremiah Horrocks.^[92]

The latest pair was June 8, 2004 and June 5–6, 2012. The transit could be watched live from many online outlets or observed locally with the right equipment and conditions.^[93]

The preceding pair of transits occurred in December 1874 and December 1882; the following pair will occur in December 2117 and December 2125.^[94] Historically, transits of Venus were important, because they allowed astronomers to determine the size of the astronomical unit, and hence the size of the Solar System as shown by Horrocks in 1639.^[95] Captain Cook's exploration of the east coast of Australia came after he had sailed to Tahiti in 1768 to observe a transit of Venus.^[96][97]

Ashen light

A long-standing mystery of Venus observations is the so-called ashen light—an apparent weak illumination of the dark side of the planet, seen when the planet is in the crescent phase. The first claimed observation of ashen light was made in 1643, but the existence of the illumination has never been reliably confirmed. Observers have speculated it may result from electrical activity in the Venusian atmosphere, but it may be illusory, resulting from the physiological effect of observing a bright, crescent-shaped object.^[98]

Studies

Early studies

The "black drop effect" as recorded during the 1769 transit

Venus was known to ancient civilizations both as the "morning star" and as the "evening star", names that reflect the early understanding that these were two separate objects. The Venus tablet of Ammisaduqa, dated 1581 BCE, shows the Babylonians understood the two were a single object, referred to in the tablet as the "bright queen of the sky", and could support this view with detailed observations.^[99] The Greeks thought of the two as separate stars, Phosphorus and Hesperus, until the time of Pythagoras in the sixth century BC.^[100] The Romans designated the morning aspect of Venus as Lucifer, literally "Light-Bringer", and the evening aspect as Vesper, both literal translations of the respective Greek names.

The transit of Venus was first observed in 1032 by the Persian astronomer Avicenna, who concluded Venus is closer to Earth than the Sun,^[101] and established Venus was, at least sometimes, below the Sun.^[102] In the 12th century, the Andalusian astronomer Ibn Bajjah observed "two planets as black spots on the face of the Sun", which were later identified as the transits of Venus and Mercury by the Maragha astronomer Qotb al-Din Shirazi in the 13th century.^[103] The transit of Venus was also observed by Jeremiah Horrocks on 4 December 1639 (24 November under the Julian calendar in use at that time), along with his friend, William Crabtree, at each of their respective homes.^[104]

Galileo's discovery that Venus showed phases (although remaining near the Sun in Earth's sky) proved that it orbits the Sun and not Earth

When the Italian physicist Galileo Galilei first observed the planet in the early 17th century, he found it showed phases like the Moon, varying from crescent to gibbous to full and vice versa. When Venus is furthest from the Sun in the sky, it shows a half-lit phase, and when it is closest to the Sun in the sky, it shows as a crescent or full phase. This could be possible only if Venus orbited the Sun, and this was among the first observations to clearly contradict the Ptolemaic geocentric model that the Solar System was concentric and centered on Earth.^[105]

The atmosphere of Venus was discovered in 1761 by Russian polymath Mikhail Lomonosov.^[106][107] Venus's atmosphere was observed in 1790 by German astronomer Johann Schröter. Schröter found when the planet was a thin crescent, the cusps extended through more than 180°. He correctly surmised this was due to scattering of sunlight in a dense atmosphere. Later, American astronomer Chester Smith Lyman observed a complete ring around the dark side of the planet when it was at inferior conjunction, providing further evidence for an atmosphere.^[108] The atmosphere complicated efforts to determine a rotation period for the planet, and observers such as Italian-born astronomer Giovanni Cassini and Schröter incorrectly estimated periods of about 24 h from the motions of markings on the planet's apparent surface.^[109]

Ground-based research

Modern telescopic view of Venus from Earth's surface

Little more was discovered about Venus until the 20th century. Its almost featureless disc gave no hint what its surface might be like, and it was only with the development of spectroscopic, radar and ultraviolet observations that more of its secrets were revealed. The first UV observations were carried out in the 1920s, when Frank E. Ross found that UV photographs revealed considerable detail that was absent in visible and infrared radiation. He suggested this was due to a very dense, yellow lower atmosphere with high cirrus clouds above it.^[110]

Spectroscopic observations in the 1900s gave the first clues about the Venusian rotation. Vesto Slipher tried to measure the Doppler shift of light from Venus, but found he could not detect any rotation. He surmised the planet must have a much longer rotation period than had previously been thought.^[111] Later work in the 1950s showed the rotation was retrograde. Radar observations of Venus were first carried out in the 1960s, and provided the first measurements of the rotation period, which were close to the modern value.^[112]

Radar observations in the 1970s revealed details of the Venusian surface for the first time. Pulses of radio waves were beamed at the planet using the 300 m (980 ft) radio telescope at Arecibo Observatory, and the echoes revealed two highly reflective regions, designated the Alpha and Beta regions. The observations also revealed a bright region attributed to mountains, which was called Maxwell Montes.^[113] These three features are now the only ones on Venus that do not have female names.^[114]

Exploration

Early efforts

Mariner 2, launched in 1962

The first robotic space probe mission to Venus, and the first to any planet, began on 12 February 1961, with the launch of the Venera 1 probe. The first craft of the otherwise highly successful Soviet Venera program, Venera 1 was launched on a direct impact trajectory, but contact was lost seven days into the mission, when the probe was about 2 million km from Earth. It was estimated to have passed within 100,000 km of Venus in mid-May.^[115]

The United States exploration of Venus also started badly with the loss of the Mariner 1 probe on launch. The subsequent Mariner 2 mission, after a 109-day transfer orbit on 14 December 1962, became the world's first successful interplanetary mission, passing 34,833 km above the surface of Venus. Its microwave and infrared radiometers revealed that although the Venusian cloud tops were cool, the surface was extremely hot—at least 425 °C, confirming previous Earth-based measurements^[116] and finally ending any hopes that the planet might harbour ground-based life. Mariner 2 also obtained improved estimates of its mass and of the astronomical unit, but was unable to detect either a magnetic field or radiation belts.^[117]

Atmospheric entry

Pioneer Venus Multiprobe

The Soviet Venera 3 probe crash-landed on Venus on 1 March 1966. It was the first man-made object to enter the atmosphere and strike the surface of another planet. Its communication system failed before it was able to return any planetary data.^[118] On 18 October 1967, Venera 4 successfully entered the atmosphere and deployed science experiments. Venera 4 showed the surface temperature was even hotter than Mariner 2 had measured, at almost 500 °C, and the atmosphere was 90 to 95% carbon dioxide. The Venusian atmosphere was considerably denser than Venera 4's designers had anticipated, and its slower than intended parachute descent meant its batteries ran down before the probe reached the surface. After returning descent data for 93 minutes, Venera 4's last pressure reading was 18 bar at an altitude of 24.96 km.^[118]

One day later on 19 October 1967, Mariner 5 conducted a fly-by at a distance of less than 4000 km above the cloud tops. Mariner 5 was originally built as backup for the Mars-bound Mariner 4; when that mission was successful, the probe was refitted for a Venus mission. A suite of instruments more sensitive than those on Mariner 2, in particular its radio occultation experiment, returned data on the composition, pressure and density of the Venusian atmosphere.^[119] The joint Venera 4 – Mariner 5 data was analysed by a combined Soviet-American science team in a series of colloquia over the following year,^[120] in an early example of space cooperation.^[121]

Armed with the lessons and data learned from Venera 4, the Soviet Union launched the twin probes Venera 5 and Venera 6 five days apart in January 1969; they encountered Venus a day apart on 16 and 17 May. The probes were strengthened to improve their crush depth to 25 bar and were equipped with smaller parachutes to achieve a faster descent. Because then-current atmospheric models of Venus suggested a surface pressure of between 75 and 100 bar, neither was expected to survive to the surface. After returning atmospheric data for a little over 50 minutes, they were both crushed at altitudes of approximately 20 km before going on to strike the surface on the night side of Venus.^[118]

Surface and atmospheric science

The Pioneer Venus orbiter

Venera 7 represented an effort to return data from the planet's surface, and was constructed with a reinforced descent module capable of withstanding a pressure of 180 bar. The module was precooled before entry and equipped with a specially reefed parachute for a rapid 35-minute descent. While entering the atmosphere on 15 December 1970, the parachute is believed to have partially torn, and the probe struck the surface with a hard, yet not fatal, impact. Probably tilted onto its side, it returned a weak signal, supplying temperature data for 23 minutes, the first telemetry received from the surface of another planet.^[118]

The Venera program continued with Venera 8 sending data from the surface for 50 minutes, after entering the atmosphere on 22 July 1972. Venera 9, which entered the atmosphere of Venus on 22 October 1975, and Venera 10, which entered the atmosphere three days later, sent the first images of the Venusian landscape. The two landing sites presented very different terrains in the immediate vicinities of the landers: Venera 9 had landed on a 20-degree slope scattered with boulders around 30–40 cm across; Venera 10 showed basalt-like rock slabs interspersed with weathered material.^[122]

In the meantime, the United States had sent the Mariner 10 probe on a gravitational slingshot trajectory past Venus on its way to Mercury. On 5 February 1974, Mariner 10 passed within 5790 km of Venus, returning over 4000 photographs as it did so. The images, the best then achieved, showed the planet to be almost featureless in visible light, but ultraviolet light revealed details in the clouds that had never been seen in Earth-bound observations.^[123]

The American Pioneer Venus project consisted of two separate missions.^[124] The Pioneer Venus Orbiter was inserted into an elliptical orbit around Venus on 4 December 1978, and remained there for over 13 years, studying the atmosphere and mapping the surface with radar. The Pioneer Venus Multiprobe released a total of four probes, which entered the atmosphere on 9 December 1978, returning data on its composition, winds and heat fluxes.^[125]

Venera 13 landing site

Position of Venera landing sites returning images form the surface

Four more Venera lander missions took place over the next four years, with Venera 11 and Venera 12 detecting Venusian electrical storms;^[126] and Venera 13 and Venera 14, landing on 1 and 5 March 1982, returning the first colour photographs of the surface. All four missions deployed parachutes for braking in the upper atmosphere, then released them at altitudes of 50 km, the dense lower atmosphere providing enough friction to allow for unaided soft landings. Both Venera 13 and 14 analysed soil samples with an on-board X-ray fluorescence spectrometer, and attempted to measure the compressibility of the soil with an impact probe.^[126] Venera 14 struck its own ejected camera lens cap and its probe failed to contact the soil.^[126] The Venera program came to a close in October 1983, when Venera 15 and Venera 16 were placed in orbit to conduct mapping of the Venusian terrain with synthetic aperture radar.^[127]

In 1985, the Soviet Union took advantage of the opportunity to combine missions to Venus and Comet Halley, which passed through the inner Solar System that year. En route to Halley, on 11 and 15 June 1985, the two spacecraft of the Vega program each dropped a Venera-style probe (of which Vega 1's partially failed) and released a balloon-supported aerobot into the upper atmosphere. The balloons achieved an equilibrium altitude of around 53 km, where pressure and temperature are comparable to those at Earth's surface. They remained operational for around 46 hours, and discovered the Venusian atmosphere was more turbulent than previously believed, and subject to high winds and powerful convection cells.^[128][129]

Radar mapping

Magellan radar topographical map of Venus (false colour)

Early Earth-based radar provided a basic idea of the surface. The Pioneer Venus and the Veneras provided improved resolution.

The United States' Magellan probe was launched on 4 May 1989, with a mission to map the surface of Venus with radar.^[27] The high-resolution images it obtained during its 4½ years of operation far surpassed all prior maps and were comparable to visible-light photographs of other planets. Magellan imaged over 98% of the Venusian surface by radar,^[130] and mapped 95% of its gravity field. In 1994, at the end of its mission, Magellan was sent to its destruction into the atmosphere of Venus to quantify its density.^[131] Venus was observed by the Galileo and Cassini spacecraft during fly-bys on their respective missions to the outer planets, but Magellan was the last dedicated mission to Venus for over a decade.^[132][133]

Current and future missions

NASA's MESSENGER mission to Mercury performed two fly-bys of Venus in October 2006 and June 2007, to slow its trajectory for an eventual orbital insertion of Mercury in March 2011. It collected scientific data on Venus during both fly-bys.^[134]

The Venus Express probe was designed and built by the European Space Agency. Launched on 9 November 2005 by a Russian Soyuz-Fregat rocket procured through Starsem, it successfully assumed a polar orbit around Venus on 11 April 2006.^[135] The probe is undertaking a detailed study of the Venusian atmosphere and clouds, including mapping of the planet's plasma environment and surface characteristics, particularly temperatures. One of the first results from Venus Express is the discovery that a huge double atmospheric vortex exists at the southern pole.^[135]

Artist's impression of a Stirling cooled Venus Rover devised by NASA.^[136]

The Japan Aerospace Exploration Agency (JAXA) devised a Venus orbiter, Akatsuki (formerly "Planet-C"), which was launched on 20 May 2010, but the craft failed to enter orbit in December 2010. Hopes remain that the probe can successfully hibernate and make another insertion attempt in six years. Planned investigations included surface imaging with an infrared camera and experiments designed to confirm the presence of lightning, as well as the determination of the existence of current surface volcanism.^[137]

The European Space Agency (ESA) hopes to launch a mission to Mercury in 2014, called BepiColombo, which will perform two fly-bys of Venus before it reaches Mercury orbit in 2020.^[138]

Under its New Frontiers Program, NASA has proposed a lander mission called the Venus In-Situ Explorer to land on Venus to study surface conditions and investigate the elemental and mineralogical features of the regolith. The probe would be equipped with a core sampler to drill into the surface and study pristine rock samples not weathered by the harsh surface conditions. A Venus atmospheric and surface probe mission, "Surface and Atmosphere Geochemical Explorer" (SAGE), was selected by NASA as a candidate mission study in the 2009 New Frontiers selection,^[139] but the mission was not selected for flight.

Venus aircraft concept

The Venera-D (Russian: Венера-Д) probe is a proposed Russian space probe to Venus, to be launched around 2016, to make remote-sensing observations around the planet and deploying a lander, based on the Venera design, capable of surviving for a long duration on the surface. Other proposed Venus exploration concepts include rovers, balloons, and aeroplanes.^[140]

In late 2013 the Venus Spectral Rocket Experiment took place, which launched a sub-orbital space telescope.

Manned fly-by concept

A manned Venus fly-by mission, using Apollo program hardware, was proposed in the late 1960s.^[141] The mission was planned to launch in late October or early November 1973, and would have used a Saturn V to send three men to fly past Venus in a flight lasting approximately one year. The spacecraft would have passed approximately 5,000 km (3,100 mi) from the surface of Venus about four months later.^[141] Inspiration Mars includes a manned Venus flyby in their 2021 mission.^[142]

Sample return

Various concepts for a Venus sample return include a high-speed upper atmosphere collection, an atmosphere sample return by slowing down and entering then returning, and a surface sample return.^[143]

Spacecraft timeline

This is a list of attempted and successful spacecraft that have left Earth to explore Venus more closely.^[144] Venus has also been imaged by the Hubble Space Telescope in Earth orbit, and distant telescopic observations are another source of information about Venus.

Timeline by NASA Goddard Space Flight Center (up to 2011)^[144]

Responsible	Mission	Launch	Elements and result	Notes
USSR	Sputnik 7	4 February 1961	Impact (attempted)
USSR	Venera 1	12 February 1961	Fly-by (contact lost)
USA	Mariner 1	22 July 1962	Fly-by (launch failure)
USSR	Sputnik 19	25 August 1962	Fly-by (attempted)
USA	Mariner 2	27 August 1962	Fly-by	First successful planetary flyby[145]
USSR	Sputnik 20	1 September 1962	Fly-by (attempted)
USSR	Sputnik 21	12 September 1962	Fly-by (attempted)
USSR	Cosmos 21	11 November 1963		Attempted Venera test flight?
USSR	Venera 1964A	19 February 1964	Fly-by (launch failure)
USSR	Venera 1964B	1 March 1964	Fly-by (launch failure)
USSR	Cosmos 27	27 March 1964	Fly-by (attempted)
USSR	Zond 1	2 April 1964	Fly-by (contact lost)
USSR	Venera 2	12 November 1965	Fly-by (contact lost)
USSR	Venera 3	16 November 1965	Lander (contact lost)
USSR	Cosmos 96	23 November 1965	Lander (attempted?)
USSR	Venera 1965A	23 November 1965	Fly-by (launch failure)
USSR	Venera 4	12 June 1967	Probe
USA	Mariner 5	14 June 1967	Fly-by
USSR	Cosmos 167	17 June 1967	Probe (attempted)
USSR	Venera 5	5 January 1969	Probe
USSR	Venera 6	10 January 1969	Probe
USSR	Venera 7	17 August 1970	Lander
USSR	Cosmos 359	22 August 1970	Probe (attempted)
USSR	Venera 8	27 March 1972	Probe
USSR	Cosmos 482	31 March 1972	Probe (attempted)
USA	Mariner 10	4 November 1973	Fly-by	Mercury fly-by
USSR	Venera 9	8 June 1975	Orbiter and lander
USSR	Venera 10	14 June 1975	Orbiter and lander
USA	Pioneer Venus 1	20 May 1978	Orbiter
USA	Pioneer Venus 2	8 August 1978	Probes
USSR	Venera 11	9 September 1978	Fly-by bus and lander
USSR	Venera 12	14 September 1978	Fly-by bus and lander
USSR	Venera 13	30 October 1981	Fly-by bus and lander
USSR	Venera 14	4 November 1981	Fly-by bus and lander
USSR	Venera 15	2 June 1983	Orbiter
USSR	Venera 16	7 June 1983	Orbiter
USSR	Vega 1	15 December 1984	Lander and balloon	Comet Halley fly-by
USSR	Vega 2	21 December 1984	Lander and balloon	Comet Halley fly-by
USA	Magellan	4 May 1989	Orbiter
USA	Galileo	18 October 1989	Fly-by	Jupiter orbiter/probe
USA	Cassini	15 October 1997	Fly-by	Saturn orbiter
USA	MESSENGER	3 August 2004	Flyby (x2)	Mercury orbiter
ESA	Venus Express	9 November 2005	Orbiter
JPN	Akatsuki	7 December 2010	Orbiter (attempted)	Possible reattempt in 2016 or 2018
ESA JPN	BepiColombo		Two flybys planned	Planned Mercury orbiter

Venera-D is a possible Russian mission in the 2020s^[146]

In culture

Throughout history and cultures, the planet has been of remarkable importance as an especial object of observation, reflection and projection. Popular beliefs and observations resulted in different and in parts similar patterns in mythology as well as phenomenological descriptions, attributions and depictions, e. g. in the field of astrology. Such developments in manifestations of human thought reflect the planet's image as a result of early observations of Venus and their impact on culture and science.

Etymology

The adjective Venusian is commonly used for items related to Venus, though the Latin adjective is the rarely used Venerean; the archaic Cytherean is still occasionally encountered. Venus is the only planet in the Solar System that is named after a female figure.^[a] (Three dwarf planets – Ceres, Eris and Haumea – along with many of the first discovered asteroids^[147] and some moons (such as the Galilean moons) also have feminine names. Earth and the Moon also have feminine names in many languages—Gaia/Terra, Selene/Luna—but the female mythological figures who personified them were named after them, not the other way around.)^[148]

Venus symbol

The astronomical symbol for Venus is the same as that used in biology for the female sex: a circle with a small cross beneath.^[149] The Venus symbol also represents femininity, and in Western alchemy stood for the metal copper.^[149] Polished copper has been used for mirrors from antiquity, and the symbol for Venus has sometimes been understood to stand for the mirror of the goddess.^[149]

Colonization and terraforming

Artist's conception of a terraformed Venus

Owing to its extremely hostile conditions, a surface colony on Venus is not possible with current technology. The atmospheric pressure and temperature approximately fifty kilometres above the surface are similar to those at Earth's surface and Earth air (nitrogen and oxygen) would be a lifting gas in the Venusian atmosphere of mostly carbon dioxide. This has led to proposals for "floating cities" in the Venusian atmosphere.^[150] Aerostats (lighter-than-air balloons) could be used for initial exploration and ultimately for permanent settlements.^[150] Among the many engineering challenges are the dangerous amounts of sulfuric acid at these heights.^[150]

I am a Rock -- Simon & Garfunkle

A winter's day, in a deep and dark December
I am alone, gazing from my window to the streets below
On a freshly fallen silent shroud of snow
I am a rock, I am an island

I've built walls, a fortress deep and mighty that none may penetrate
I have no need of friendship, friendship causes pain
It's laughter and it's loving I disdain
I am a rock, I am an island

Don't talk of love well I've heard the words before
It's sleeping in my memory
And I won't disturb the slumber of feelings that have died
If I never loved I never would have cried
I am a rock, I am an island

I have my books and my poetry to protect me
I am shielded in my armor, hiding in my room, safe within my womb
I touch no one and no one touches me
I am a rock, I am an island

And a rock can feel no pain
And an island never cries

Songwriters
SIMON, PAUL

Published by
Lyrics © EMI Music Publishing, Universal Music Publishing Group

Read more: Paul Simon - I Am A Rock Lyrics | MetroLyrics

Simon & Garfunkel

From Wikipedia, the free encyclopedia

Simon & Garfunkel
Simon & Garfunkel performing in Dublin, 1982
Background information
Also known as	Tom and Jerry
Origin	Forest Hills, Queens, New York City, U.S.
Genres	Folk rock, folk, soft rock, worldbeat
Years active	1957–1965, 1966–1970, (1975, 1981–83, 1993, 2003–04, 2009–10) (Reunion)
Labels	Columbia
Website	Simonandgarfunkel.com
Past members	Paul Simon Art Garfunkel

Simon & Garfunkel were an American music duo consisting of guitarist,^[1] singer-songwriter Paul Simon and singer Art Garfunkel (both born in 1941). They formed the group Tom & Jerry in 1957 and had their first success with the minor hit "Hey, Schoolgirl". As Simon & Garfunkel, the duo rose to fame in 1965, largely on the strength of the hit single "The Sound of Silence". Their music was featured in the landmark film The Graduate (1967), propelling them further into the public consciousness.

They are well known for their vocal harmonies and were among the most popular recording artists of the 1960s. Their biggest hits—including "The Sound of Silence" (1964), "I Am a Rock" (1965), "Homeward Bound" (1965), "Scarborough Fair/Canticle" (1966), "A Hazy Shade of Winter" (1966), "Mrs. Robinson" (1968), "Bridge over Troubled Water" (1969), "The Boxer" (1969), and "Cecilia" (1969)—reached number one in several charts. They have received several Grammy Awards and were inducted into the Rock and Roll Hall of Fame in 1990 and the Long Island Music Hall of Fame in 2007.^[2]

Their sometimes rocky relationship led to their last album, Bridge over Troubled Water, being delayed several times due to artistic disagreements, and as a result the duo broke up in 1970. It was their most successful album worldwide to date, reaching number one in several countries, including the United States, and receiving 8× platinum certification from the Recording Industry Association of America, making it their highest-selling studio album in the U.S. and second-highest album overall. Simon & Garfunkel have, at times, reunited to perform and sometimes tour together. They have done so in every decade since the 1970 breakup, most famously for 1981's "The Concert in Central Park", which attracted more than 500,000 people, making it the 7th-most attended concert in the history of music.^[3] In 2004, they were ranked No. 40 on Rolling Stone's list of the 100 greatest artists of all time.

History

Early history

Promotional copies issued in 1957 to radio station deejays of the two 45 rpm releases of Tom & Jerry's "Hey, Schoolgirl." On the left is Big#613 and on the right is King #5167.

Close friends through childhood, Paul Simon and Art Garfunkel grew up in the predominantly Jewish neighborhood Kew Gardens Hills, Queens, New York, just three blocks away from each other.^[4] They met in elementary school in 1953, when they both appeared in the school play Alice in Wonderland (Simon as the White Rabbit, Garfunkel as the Cheshire Cat).^[5] They were classmates at Parsons Junior High School and Forest Hills High School, and began performing together in their junior year as Tom and Jerry, with Simon as Jerry Landis and Garfunkel as Tom Graph (names they were given by the recording studio).^[6]

The duo began recording Simon's original songs in 1955, and made their first professional recording, "Hey, Schoolgirl," for Sid Prosen of Big Records in 1957. Released on 45 rpm and 78 rpm records, with the flip-side song "Dancin' Wild," the recording sold 100,000 copies,^[7] hitting No. 49 on the Billboard charts. Both Simon and Garfunkel have acknowledged the tremendous impact of the Everly Brothers on their style, and many of their early songs (including "Hey, Schoolgirl") bear the mark of this influence.

They later performed their hit on Dick Clark's American Bandstand, right after Jerry Lee Lewis performed "Great Balls of Fire."

Subsequent efforts in 1958 did not reach near their initial success, and after high school the duo went to separate colleges, with Simon enrolling at Queens College and Garfunkel at Columbia University.
While enrolled in college, they both joined their campus chapters of Alpha Epsilon Pi fraternity.^[8]

In 1963, they found prominence as part of the Greenwich Village folk music scene. Simon, who had finished college but dropped out of Brooklyn Law School, had—like Garfunkel—developed an interest in the folk scene. Simon showed Garfunkel a few songs that he had written in the folk style: "Sparrow," "Bleecker Street," and "He Was My Brother," which was later dedicated to Andrew Goodman, a friend of both Simon and Garfunkel and a classmate of Simon's at Queens College, who was one of three civil rights workers murdered in Neshoba County, Mississippi, on June 21, 1964.

These three efforts were among five original songs by Simon included on their first album for Columbia Records, Wednesday Morning, 3 A.M., which initially flopped upon its release on October 19, 1964.

First breakup

Simon & Garfunkel at Schiphol Airport, the Netherlands in 1966.

Shortly after finishing recording, the duo split and Simon moved to the United Kingdom, where he performed at Les Cousins and the Troubadour in London and toured provincial folk clubs. While in England, he recorded his solo The Paul Simon Songbook in 1965. Recorded on three different dates in June and July at Levy's Studio, London, the album was released as an LP. By agreement, the album was supposed to go out of print after ten years. However, Billboard reported in early 1978 that Simon filed legal papers to get CBS to delete the album, noting that they were violating their agreement by keeping it in print and stating that it was "not representative of the performer's style."^[9] Many years later in March 2004, Simon responded to fan requests by re-releasing the album on CD with bonus tracks.^[10] During this period in London he also collaborated on a number of songs with Bruce Woodley of the Seekers, including "I Wish You Could Be Here", "Cloudy", and "Red Rubber Ball", which would be a U.S. No. 2 hit for the Cyrkle in 1966.

While Simon was in England that summer of 1965, radio stations around Cocoa Beach and Gainesville, Florida, began to receive requests for a song from the album Wednesday Morning, 3 A.M. called "The Sound of Silence". The song also began to receive radio airplay in Boston. Seizing the chance, the duo's U.S. producer, Tom Wilson, inspired by the Byrds' hugely popular electric versions of Bob Dylan songs, used Dylan's studio band (who had collaborated with him on his landmark hit "Like a Rolling Stone" that year) to dub electric guitars, bass and drums onto the original "Sound of Silence" track, and released it as a single, backed with "We've Got a Groovy Thing Goin'".^[11] The dubbing turned folk into folk rock, the debut of a new genre for the Top 40, much to Simon's surprise. A few months earlier Simon and Garfunkel had briefly reunited and experimented with a more contemporary sound and recorded a couple of songs including "Groovy Thing".

In September 1965, Simon first learned that The Sound of Silence had entered the pop charts while he was about to go on stage in a Danish folk club. The song hit No. 1 on the pop charts by New Year's Day, 1966.

Reformation and success

A red vinyl promotional copy of Simon & Garfunkel's single "I Am a Rock", from 1966.

Simon immediately returned to the United States and the duo re-formed to record more tracks in a similar style, though neither approved of what Wilson had done with "The Sound of Silence".^[12] The result was a sequence of folk rock records which have endured as well as any in the genre. On January 17, 1966, the duo released the album Sounds of Silence, which—helped by the title track's success—hit No. 21, while Wednesday Morning, 3 A.M. was re-released and reached No. 30. Among the tracks on The Paul Simon Songbook that were rerecorded (some with electric backing) for Sound of Silence were "I Am a Rock" (which as a single reached U.S. No. 3 in the summer of 1966), "Leaves That Are Green", "April Come She Will", "A Most Peculiar Man", and "Kathy's Song".

Further hit singles came, including "Scarborough Fair/Canticle", based on a traditional English ballad with an arrangement by Martin Carthy, and "Homeward Bound" (later U.S. No. 5), about life on the road while Simon was touring in England in 1965.

Paul Simon was inspired to write "Homeward Bound" while waiting at Ditton railway station on the outskirts of Widnes in North West England. A plaque commemorating this claim to fame was displayed at Ditton railway station until it was closed in 1994 when the plaque was moved to the ticket office on the Liverpool bound platform of the nearby Widnes railway station. Simon is quoted as saying "if you'd ever seen Widnes, then you'd know why I was keen to get back to London as quickly as possible."

More tracks from The Paul Simon Songbook were included along with recent compositions on their October 10, 1966, album Parsley, Sage, Rosemary and Thyme, which refined the folk rock sound hastily released on Sound of Silence. "Cloudy", co-written earlier with Bruce Woodley, was included on Parsley, Sage, Rosemary and Thyme. However, a Woodley credit was incorrectly omitted. The following year, Woodley's band The Seekers recorded it for their studio album Seen in Green, on which Simon received a credit.

In early 1967, Pickwick Records decided that it would capitalize on the duo's newfound fame by releasing an album titled The Hit Sounds of Simon and Garfunkel. This album consisted of ten tracks recorded from the late 1950s and early 1960s while the duo still called themselves Tom & Jerry, including their hit "Hey, Schoolgirl", and its B-side, "Dancin' Wild". Simon and Garfunkel then sued Pickwick because the company was presenting the music as recently recorded material, not as songs written and released over five years earlier. Soon afterwards, Pickwick withdrew The Hit Sounds of Simon and Garfunkel from the market.

On June 16, 1967, the duo performed at the Monterey Pop Festival. That same year, Simon and Garfunkel contributed heavily to the soundtrack to Mike Nichols' film The Graduate, which was released on January 21, 1968, and instantly rose to No. 1 as an album. According to a Variety article by Peter Bart in the May 15, 2005, issue, Nichols had become obsessed with Simon and Garfunkel's music while shooting the film. Larry Turman, his producer, made a deal for Simon to write three new songs for the film. By the time they were nearly finished editing the film, Simon had written only one new song. Nichols begged him for more but Simon, who was touring constantly, told him he didn't have the time. He did play him a few notes of a new song he had been working on; "It's not for the movie. ... it's a song about times past—about Mrs. Roosevelt and Joe DiMaggio and stuff." Nichols advised Simon, "It's now about Mrs. Robinson, not Mrs. Roosevelt."^[13]

As their albums became progressively more adventurous, The Graduate soundtrack album was immediately followed in March 1968 at the top of the charts by Bookends, which dealt with increasingly complex themes of old age and loss. It features the top 25 hit singles "A Hazy Shade of Winter", "Fakin' It", "At the Zoo", "America" and a full version of "Mrs. Robinson"—the classic No. 1 single from The Graduate soundtrack. Simon and Garfunkel returned to England in the fall of 1968 and did a concert appearance at Kraft Hall which was broadcast on the BBC, and also featured Paul's brother Ed sitting in on a performance of the instrumental "Anji".

At the March 1969 Grammy Awards, "Mrs. Robinson" was named Record of the Year, while Simon was also honored with the Grammy for Best Original Score Written for a Motion Picture or a Television Special.^[14]

Second breakup

The cover sleeve to Simon & Garfunkel's single "Cecilia," from 1970, shows them during a recording session in a studio.

Simon & Garfunkel's single "El Condor Pasa" came with a picture sleeve when it was released in France, but not in the United States.

By 1969, the duo's success began to take its toll. Garfunkel had begun to pursue a career in acting and was featured in the role of Nately in Nichols's film adaptation of the novel Catch-22. Garfunkel's filming leave conflicted with and subsequently delayed the recording of the duo's next album. The part in the film which had initially been promised to Simon was completely cut from the script.

The duo's deteriorating personal relationship continued into their late 1969 tour, which featured performances at Miami University in Oxford, Ohio, on November 11 and Southern Illinois University in Carbondale, Illinois, on November 8. Video footage of the tour was shown on their controversial November 30 television special Songs of America, which TV sponsors refused to endorse because of its anti-Vietnam War message.^[15]

The recording of what would be their final album, Bridge over Troubled Water, was not without tension. The LP was originally supposed to feature twelve tracks, but the duo could not agree on the twelfth track: Simon refused to record a Bach chorale track favored by Garfunkel, while Garfunkel refused to record a song Simon had written called "Cuba Si, Nixon No". No middle ground was reached, so the album was released with only eleven songs.

Bridge over Troubled Water was at last released on January 26, 1970. Its title track, featuring Garfunkel's soaring vocals, was a massive hit and one of the best-selling records of the decade, staying No. 1 on the charts for six weeks and remaining on the charts for far longer. The album includes three other top-twenty hits: "El Cóndor Pasa" (US No. 18), "Cecilia" (US No. 4), and "The Boxer"—which, finished in 1968, hit No. 7 on the charts the following year—as well as a live recording of The Everly Brothers' "Bye Bye, Love" from a 1969 tour concert in Ames, Iowa.

At the subsequent March 1971 Grammy Awards, the album and single were named Album of the Year and Record Of The Year, and also won the awards for Best Engineered Record, Best Contemporary Song, Song Of The Year, and Best Arrangement Accompanying Vocalists. Their 1972 Greatest Hits album has sold over 14 million copies in the U.S. becoming the number-one selling album by a duo. The duo finally split in 1970 and both went their separate ways.

Simon continued writing and went on to a very successful solo music career, recording several classic albums, including There Goes Rhymin' Simon, Still Crazy After All These Years, and his most highly celebrated solo album, Graceland, collaborating with the Zulu choir Ladysmith Black Mambazo, among others.

Garfunkel split his time between acting and recording solo and collaboration albums, to mixed reviews. His most critically acclaimed album was the 1977 effort Watermark, almost all of the songs for which were penned by acclaimed songwriter Jimmy Webb.

Reunions

Simon and Garfunkel's first reunion after their second breakup was at a June 1972 benefit concert at Madison Square Garden for presidential candidate George McGovern. On October 18, 1975, the duo made an appearance on the second episode of NBC's new show NBC's Saturday Night, on which they performed "The Boxer", "Scarborough Fair", and "My Little Town". The last song was the first new Simon and Garfunkel recording in five years, appearing on both men's solo albums released in 1975 (Simon's Still Crazy After All These Years and Garfunkel's Breakaway) and reaching No. 9 on the U.S. Billboard Hot 100 chart.

Simon, along with James Taylor, provided harmony vocals on Garfunkel's cover of Sam Cooke's "Wonderful World", on Garfunkel's 1977 album Watermark; the single release of that song reached No. 1 on the Billboard Adult Contemporary chart and No. 17 on the Hot 100. Simon also contributed backing vocals to "In Cars", a song on Garfunkel's 1981 solo album Scissors Cut.

The group performing in The Netherlands in 1982.

The Everly Brothers were the duo whom Simon & Garfunkel tried to emulate in their early years. They later covered many of the tunes that the Everlys had previously released.

The Colosseum hosted Simon & Garfunkel for a concert in 2004 that drew 600,000 fans.

Simon and Garfunkel reunited again for a free concert in New York City's Central Park on September 19, 1981. The concert was attended by over 500,000 people, and a recording of it was subsequently released as a live album, with their cover of "Wake Up Little Susie" released as a single. A video recording was likewise televised by HBO and issued on home video. The success of the Central Park concert prompted the duo to go on a world tour in 1982–83, including a performance at Shea Stadium in August 1983.

Simon and Garfunkel went on to complete the recording of their first new studio album in more than a decade, provisionally titled Think Too Much and featuring some songs previewed on their recent concert jaunt. However, creative differences, coupled with the record company's negative reaction to the decidedly un-Simon-and-Garfunkel-like album, led Simon to remove Garfunkel's vocal tracks and rework the songs himself. The 1983 Simon solo album Hearts and Bones was the result, and a long period of estrangement for the duo followed.

Their next joint public concert performance was in 1990, when the two performed at a ceremony for their induction into the Rock and Roll Hall of Fame. Simon and Garfunkel appeared together in 1993 for 21 sold out concerts in New York, with half of the show being Paul Simon solo with a band and the other half Simon and Garfunkel. Later the same year, they did some charity concerts, including the Bridge School Benefit concerts and a benefit for United Way Children's Charities at SkyDome in Toronto, which included Canadian singer / songwriter Gordon Lightfoot and Blue Rodeo as support acts.

In July 2002, Columbia Legacy issued a previously unreleased live recording of a Simon and Garfunkel concert, Live from New York City, 1967. It features an almost-complete recording of a performance given by the duo at Philharmonic Hall, at Lincoln Center in New York City on January 22, 1967. The album includes a rendition of "A Church Is Burning", one of the songs that originally appeared on Paul Simon's 1965 solo album, The Paul Simon Songbook.

On February 23, 2003, Simon and Garfunkel reunited to perform in public for the first time in a decade, singing "The Sound of Silence" as the opening act of the Grammy Awards.^[16] Before the show, the duo was presented with the Grammy Lifetime Achievement Award, honoring their musical contributions over the past four and a half decades. They were introduced by Dustin Hoffman, who made his debut in the film The Graduate, which extensively featured their music.

The good feelings generated by their appearance on the Grammys led to another thaw in their relationship. Soon, Simon and Garfunkel launched a two-month long reunion tour of the United States (and Toronto, Canada), which began October 16 and culminated in Tampa on December 21, 2003. Entitled Old Friends, their first tour in over twenty years included forty shows in twenty-eight cities and featured special guests the Everly Brothers. The tour featured in its opening video montage a short series of clips and photos taken during the day leading up to the concert around the venue. Simon and Garfunkel performed "Hey, Schoolgirl", which they said was the first song they had written and recorded together. At the tour concert at Continental Airlines Arena in East Rutherford, New Jersey, they performed "Leaves That Are Green" in place of "Song for the Asking", which had been on their set list for the other concerts on this tour, following an announcement that they had not played it in concert since 1967. They also played "Leaves That Are Green" at concerts in Cleveland and Boston after making a similar announcement.

The success of the first Old Friends tour led to an encore in June and July 2004 with over 25 shows, this time also in Europe. In July 2004, they completed the tour with a flourish, with a finale at the Colosseum in Rome before an audience which, according to the Mayor of Rome, exceeded 600,000—even larger than the audience at the famous 1981 Central Park concert.^[17][18]

A live CD and DVD from their Old Friends tour was released in late 2004. It featured a "new" studio duo song, "Citizen of the Planet", one of the songs from the rejected 1983 reunion album that did not originally feature Garfunkel's vocal participation.

In 2007, PBS hosted the first Gershwin Awards, at which Paul Simon was honored. Simon introduced Garfunkel (for a cameo appearance) as "my partner in arguments" and the two sang "Bridge over Troubled Water" together.

Simon and Garfunkel together in 2009

Columbia/Legacy announced the September 18, 2007, release of Live 1969, which was said to feature recently discovered masters recorded on their 1969 tour. Most of the arrangements remain virtually unchanged.^{[citation needed]} That 1969 tour would be their last for over a decade, immediately preceding the release of the 1970 album Bridge over Troubled Water. The tour was recorded preparing for a subsequent live album, but the release of the live album did not happen, until now, as reported in Billboard.^[19]

On February 13, 2009, Simon and his band re-opened New York's legendary Beacon Theatre, which had been closed for seven months for a renovation. As an encore, Simon brought out his "old friend" Art Garfunkel. They sang 3 songs: "Sound of Silence", "The Boxer", and "Old Friends".

On April 2, 2009, the duo announced a tour of Australia, New Zealand and Japan for June/July 2009.^[20] On October 29–30, they participated together in the 25th anniversary of Rock and Roll Hall of Fame concerts at New York's Madison Square Garden. Other artists on the bill included Bruce Springsteen & The E Street Band; U2; Metallica; Aretha Franklin; Stevie Wonder and Crosby, Stills & Nash.^[21]

In March 2010, Simon & Garfunkel announced a 13-date spring tour, to perform in April at the New Orleans Jazz & Heritage Festival. Most performances were scheduled for Canada, with four shows in the upper Midwest of the U.S. According to a press release, the set list would focus on their classic catalog, as well as songs from each of their solo careers.^[22] On June 17, 2010, Simon & Garfunkel canceled the tour, earlier rescheduled for July 2010, now postponed indefinitely as Garfunkel continues to recover from a vocal cord paresis.^[23]

Legacy

Simon & Garfunkel's last release as Tom & Jerry was on the Ember label in 1963: "I'm Lonesome," was backed with "Looking At You." The recording was produced by Sid Prosen, who had also produced the duo's releases on the Big label a few years before.

Simon & Garfunkel's performance on January 22, 1967 at Lincoln Center in New York City, seen here, was recorded and partially released on CD in 2004.

From the very beginning of their fame, through the present time years after their break-up, Simon and Garfunkel have had an impact on the popular culture as evidenced by the many references to them made in television, film, music and other aspects of pop culture.

Among the earliest pop culture references or homages came in the late 1960s, when the comedy television show Rowan & Martin's Laugh-In had a running skit featuring members of the "Farkle" Family, including Fred & Fanny Farkle "and the twins, Simon and Garr Farkle". In the early '70s sitcom The Partridge Family, the two youngest Partridge children name their pet goldfish "Simon and Garfunkel".

The lyrics of Simon and Garfunkel songs continue to be referenced many times on television, long after their initial popularity. On an episode of How I Met Your Mother, Marshall commissions a Venn diagram in which one section represents the "people who are breaking his heart" while the other represents "people who are shaking his confidence daily". The section where the two overlap is labelled "Cecilia". The end of the "Lady Bouvier's Lover" episode of The Simpsons contains one of the series' many homages to The Graduate, and features a parody of "The Sound of Silence" over the closing credits. ("Hello grandpa my old friend/your busy day is at an end/your words are always sad and boring/they tell a tale that's worth ignoring".) In another episode, Mr. Burns spins around a lamp post singing, "Hello lamp post. What ya knowin'? I've come to watch your power flowin'", a reference to the lyrics of "The 59th Street Bridge Song (Feelin' Groovy)".

The episode "Bendin' in the Wind" of Futurama, in a double send-up of Simon and Garfunkel and Battlestar Galactica, features the singing duo "Cylon and Garfunkel" performing a rendition of "Scarborough Fair" in which the robot Cylon's singing is entirely monotone, and Garfunkel—who explains during the performance that he is the descendant of Art—states that he will give Bender the check "over my dead career!"

In an episode of Saturday Night Live's "Celebrity Jeopardy" parody, there was a category entitled "Members of Simon and Garfunkel". The clue read, "Of Simon and Garfunkel, the one who is not Garfunkel." Once the Sean Connery character rang in, he asked for the question to be repeated and said in response, "I Garfunkeled your mother!" This was one of the running gags of the parody. In another SNL skit, Will Forte and Jason Sudeikis pose as Bon Jovi opposite band, Jon Bovi, but when accused of sounding exactly like Bon Jovi, they say, "Well, if you didn't like that, you're going to love our new opposite folk rock band, Gimon & Sarfunkel." They then sing the opposite "Bridge over Troubled Water", "Tunnel Under Peaceful Fire".

In an episode of Flight of the Conchords, the lead characters form a Simon and Garfunkel tribute band performing "Scarborough Fair". Garfunkel himself later appears in the episode. In the episode "Unnatural Love", the song "Carol Brown" is an homage to the Paul Simon song "50 Ways to Leave Your Lover".

The Nickelodeon sitcom How to Rock uses the artists' family names as those of the main characters.

Discography

• Wednesday Morning, 3 A.M. (1964)
• Sounds of Silence (1966)
• Parsley, Sage, Rosemary and Thyme (1966)
• Bookends (1968)
• Bridge over Troubled Water (1970)

Awards

Grammy Awards

The Grammy Awards are awarded annually by the National Academy of Recording Arts and Sciences. Simon & Garfunkel have won 10 total awards.^[24]

Year	Recipient	Award	Result
1969	"Mrs. Robinson"	Record of the Year	Won
		Best Contemporary Pop Performance - Vocal Duo or Group	Won
	The Graduate	Best Original Score Written for a Motion Picture or a Television Special	Won
1971	Bridge over Troubled Water	Album of the Year	Won
	"Bridge over Troubled Water"	Record of the Year	Won
		Song of the Year	Won
		Best Contemporary Song	Won
		Best Instrumental Arrangement Accompanying Vocalist(s)	Won
		Best Engineered Recording	Won
2003	Simon & Garfunkel	Grammy Lifetime Achievement Award	Won

• BRIT Awards (1978) – Best International Album (of the past 25 years) (for Bridge over Troubled Water)
• Rock and Roll Hall of Fame (1990) – Inductee