Hypothetical image of Venus billions of years ago
Image of Venus now
Water on Venus refers to the hypothesis that water was once on the surface of the planet Venus.
Water on Venus refers to the hypothesis that water was once on the surface of the planet Venus.
Scientists and authors long proposed Venus was habitable, although information from the Soviet Unions Venera missions, and from the Pioneer Venus Orbiter probe, Magellan spacecraft and many more Venus studying spacecraft proved that Venus was the complete opposite. [1]
Several hypotheses have been considered for how Venus lost its water. One hypothesis states that when Venus had water, solar radiation was as low as 30% less than it is today. This means the habitable zone was stretched from Venus to Earth (and possibly to Mars), before eventually Solar maxima began creating greenhouse gases in Venus’ atmosphere, making the atmosphere thicker, evaporating away all liquid water on the planets surface. Studies have proven that Venus needed liquid water three billion years ago to be able to have such high concentrations of water-related minerals and gases on its surface and in its atmosphere today. However, such studies proved that the liquids would only have lasted up until 700 million to 750 million years ago, before eventually evaporating as Venus’ atmosphere heated up from the greenhouse effect. [2]
Data from the Venus Express satellite, made by the European Space Agency (ESA), took pictures of Venus, officially unveiling that Venus could have potentially had liquid, although how the liquid formed on Venus is still unclear. [3] New simulations using this previous data have been created at NASA’s Goddard Institute for Space Studies in New York. [1]
Other studies of Venus’ surface via various probes proved that hematite is present on its surface, proving water once interacted with Venus’ surface. [4] Hematite is an iron oxide mineral that often forms if water is present. Hematite can be formed within water-related processes as well. However, hematite could form from volcanic activity and geological formations, or could originate from comets or asteroids. [5] [6]
Venus’ cloud data prove that Venus' clouds contain a small amount of water, possibly proving that Venus once had a functioning water cycle. [7] Using image data from Magellan, scientists could fill lowlands of Venus’ surface area with water, leaving only Venusian continents visible. This maneuver done in the test further proved Venus could have had land, meaning that terrestrial animals could have roamed Venus at some time. The test also used measurements from the Pioneer Venus project from the 1980s. Scientists concluded from data that Venus could have been exposed to much sunlight for two months, and then no light for two months, evaporating or freezing leftover liquids on Venus’ surface. Later, this would destroy water-vapor molecules as the Sun’s ultraviolet radiation would spread rapidly on Venus over time, removing crucial elements from Venus’ atmosphere, including hydrogen, which is an important molecule in liquids. Hydrogen later was stripped from Venus, creating a runaway greenhouse effect because there was no water. GISS also proved that Venus had drier land than modern day Earth. [1]
The Magellan probe detected valleys and channels on Venus, which directly links to erosion of land, sedimentary deposits, and most recently and commonly volcanic activity and tectonic activity.
Most common studies of Venus’ surface via the Magellan probe prove that Venus has valleys and channels, which are not directly connected to volcanic activity, but may be linked to tectonic activity on Venus. Asteroid impacts on Venus are another common phenomenon that could have shaped Venus’ surface to evolve with these geological features, although such an asteroid would have to be huge because asteroids burn up in Venus’s atmosphere and pass through clouds sulfuric and other acids. [6]
NASA’s VERITAS (Venus Emissivity, Radio Science, InSAR, Topography, and Spectroscopy) mission will help look for geological surface features on Venus, with better technology then Magellan, giving a better understanding of Venus’ past, including possible presence of water. VERITAS will also analyze surface materials and map out its surface temperatures, which could help explain the presence of water-related minerals, and may also contribute to understanding Venus’s hydrothermal activity. Instruments will spectroscope the planet’s surface. VERITAS will also use past and present data to analyze specific minerals and rocks with hydrated minerals or other water-related materials on the surface. This data could help scientists better understand past climate, geological evolution and water composition. [8]
One way to revive such liquids on Venus’ surface is to strip greenhouse gases from its atmosphere, and replace it with breathable gases, which will release trapped heat, cooling down the planet to an average temperature like Earth's. Over time, the reduction of such greenhouse gases will thin Venus’ thick atmosphere, lowering atmospheric pressure. Satellites orbiting Venus on its day side that reflect heat can help reduce temperatures and compensate for greenhouse gases getting back into the atmosphere. Using space mirrors, similar to that of the Znamya satellite, could expose the night side of the planet to light for the same duration as the average day on Earth. Manufacturing a proper magnetosphere would also help. Using data from two Japanese scientists, it is possible to make an artificial magnetosphere around Venus by building a system of refrigerated latitudinal superconducting rings. Using this, scientists could build an artificial magnetosphere around Venus to prevent the loss of hydrogen from its atmosphere. After all the foregoing processes, hydrogen must be added to the atmosphere to help revive liquid water on the surface. Hydrogen would combine with chemicals in the atmosphere to create liquid water.
Terraforming or terraformation ("Earth-shaping") is the hypothetical process of deliberately modifying the atmosphere, temperature, surface topography or ecology of a planet, moon, or other body to be similar to the environment of Earth to make it habitable for humans to live on.
Venus is the second planet from the Sun. It is a terrestrial planet and is the closest in mass and size to its orbital neighbour Earth. Venus has by far the densest atmosphere of the terrestrial planets, composed mostly of carbon dioxide with a thick, global sulfuric acid cloud cover. At the surface it has a mean temperature of 737 K and a pressure of 92 times that of Earth's at sea level. These extreme conditions compress carbon dioxide into a supercritical state at Venus's surface.
In astronomy and astrobiology, the habitable zone (HZ), or more precisely the circumstellar habitable zone (CHZ), is the range of orbits around a star within which a planetary surface can support liquid water given sufficient atmospheric pressure. The bounds of the HZ are based on Earth's position in the Solar System and the amount of radiant energy it receives from the Sun. Due to the importance of liquid water to Earth's biosphere, the nature of the HZ and the objects within it may be instrumental in determining the scope and distribution of planets capable of supporting Earth-like extraterrestrial life and intelligence.
The geology of Venus is the scientific study of the surface, crust, and interior of the planet Venus. Within the Solar System, it is the one nearest to Earth and most like it in terms of mass, but has no magnetic field or recognizable plate tectonic system. Much of the ground surface is exposed volcanic bedrock, some with thin and patchy layers of soil covering, in marked contrast with Earth, the Moon, and Mars. Some impact craters are present, but Venus is similar to Earth in that there are fewer craters than on the other rocky planets that are largely covered by them. This is due in part to the thickness of the Venusian atmosphere disrupting small impactors before they strike the ground, but the paucity of large craters may be due to volcanic re-surfacing, possibly of a catastrophic nature. Volcanism appears to be the dominant agent of geological change on Venus. Some of the volcanic landforms appear to be unique to the planet. There are shield and composite volcanoes similar to those found on Earth, although these volcanoes are significantly shorter than those found on Earth or Mars. Given that Venus has approximately the same size, density, and composition as Earth, it is plausible that volcanism may be continuing on the planet today, as demonstrated by recent studies.
Planetary habitability is the measure of a planet's or a natural satellite's potential to develop and maintain environments hospitable to life. Life may be generated directly on a planet or satellite endogenously or be transferred to it from another body, through a hypothetical process known as panspermia. Environments do not need to contain life to be considered habitable nor are accepted habitable zones (HZ) the only areas in which life might arise.
A runaway greenhouse effect will occur when a planet's atmosphere contains greenhouse gas in an amount sufficient to block thermal radiation from leaving the planet, preventing the planet from cooling and from having liquid water on its surface. A runaway version of the greenhouse effect can be defined by a limit on a planet's outgoing longwave radiation which is asymptotically reached due to higher surface temperatures evaporating water into the atmosphere, increasing its optical depth. This positive feedback means the planet cannot cool down through longwave radiation and continues to heat up until it can radiate outside of the absorption bands of the water vapour.
The terraforming of Mars or the terraformation of Mars is a hypothetical procedure that would consist of a planetary engineering project or concurrent projects aspiring to transform Mars from a planet hostile to terrestrial life to one that could sustainably host humans and other lifeforms free of protection or mediation. The process would involve the modification of the planet's extant climate, atmosphere, and surface through a variety of resource-intensive initiatives, as well as the installation of a novel ecological system or systems.
The terraforming of Venus or the terraformation of Venus is the hypothetical process of engineering the global environment of the planet Venus in order to make it suitable for human habitation. Adjustments to the existing environment of Venus to support human life would require at least three major changes to the planet's atmosphere:
The atmosphere of Venus is the very dense layer of gasses surrounding the planet Venus. Venus's atmosphere is composed of 96.5% carbon dioxide and 3.5% nitrogen, with other chemical compounds present only in trace amounts. It is much denser and hotter than that of Earth; the temperature at the surface is 740 K, and the pressure is 93 bar (1,350 psi), roughly the pressure found 900 m (3,000 ft) under water on Earth. The atmosphere of Venus supports decks of opaque clouds of sulfuric acid that cover the entire planet, preventing optical Earth-based and orbital observation of the surface. Information about surface topography has been obtained exclusively by radar imaging.
An ocean world, ocean planet or water world is a type of planet that contains a substantial amount of water in the form of oceans, as part of its hydrosphere, either beneath the surface, as subsurface oceans, or on the surface, potentially submerging all dry land. The term ocean world is also used sometimes for astronomical bodies with an ocean composed of a different fluid or thalassogen, such as lava, ammonia or hydrocarbons. The study of extraterrestrial oceans is referred to as planetary oceanography.
A Super-Earth or super-terran is a type of exoplanet with a mass higher than Earth's, but substantially below those of the Solar System's ice giants, Uranus and Neptune, which are 14.5 and 17 times Earth's, respectively. The term "super-Earth" refers only to the mass of the planet, and so does not imply anything about the surface conditions or habitability. The alternative term "gas dwarfs" may be more accurate for those at the higher end of the mass scale, although "mini-Neptunes" is a more common term.
Extraterrestrial liquid water is water in its liquid state that naturally occurs outside Earth. It is a subject of wide interest because it is recognized as one of the key prerequisites for life as we know it and is thus surmised to be essential for extraterrestrial life.
Whether there is life on Titan, the largest moon of Saturn, is currently an open question and a topic of scientific assessment and research. Titan is far colder than Earth, but of all the places in the Solar System, Titan is the only place besides Earth known to have liquids in the form of rivers, lakes, and seas on its surface. Its thick atmosphere is chemically active and rich in carbon compounds. On the surface there are small and large bodies of both liquid methane and ethane, and it is likely that there is a layer of liquid water under its ice shell. Some scientists speculate that these liquid mixes may provide prebiotic chemistry for living cells different from those on Earth.
The possibility of life on Venus is a subject of interest in astrobiology due to Venus' proximity and similarities to Earth. To date, no definitive evidence has been found of past or present life there. In the early 1960s, studies conducted via spacecraft demonstrated that the current Venusian environment is extreme compared to Earth's. Studies continue to question whether life could have existed on the planet's surface before a runaway greenhouse effect took hold, and whether a relict biosphere could persist high in the modern Venusian atmosphere.
An Earth analog, also called an Earth analogue, Earth twin, or second Earth, is a planet or moon with environmental conditions similar to those found on Earth. The term Earth-like planet is also used, but this term may refer to any terrestrial planet.
Kepler-22b is an exoplanet orbiting within the habitable zone of the Sun-like star Kepler-22. It is located about 640 light-years from Earth in the constellation of Cygnus. It was discovered by NASA's Kepler Space Telescope in December 2011 and was the first known transiting planet to orbit within the habitable zone of a Sun-like star, where liquid water could exist on the planet's surface. Kepler-22 is too dim to be seen with the naked eye.
Planetary oceanography, also called astro-oceanography or exo-oceanography, is the study of oceans on planets and moons other than Earth. Unlike other planetary sciences like astrobiology, astrochemistry, and planetary geology, it only began after the discovery of underground oceans in Saturn's moon Titan and Jupiter's moon Europa. This field remains speculative until further missions reach the oceans beneath the rock or ice layer of the moons. There are many theories about oceans or even ocean worlds of celestial bodies in the Solar System, from oceans made of liquid carbon with floating diamonds in Neptune to a gigantic ocean of liquid hydrogen that may exist underneath Jupiter's surface.
TRAPPIST-1d is a small exoplanet, which orbits on the inner edge of the habitable zone of the ultracool dwarf star TRAPPIST-1, located 40.7 light-years away from Earth in the constellation of Aquarius. The exoplanet was found by using the transit method. The first signs of the planet were announced in 2016, but it was not until the following years that more information concerning the probable nature of the planet was obtained. TRAPPIST-1d is the second-least massive planet of the system and is likely to have a compact hydrogen-poor atmosphere similar to Venus, Earth, or Mars. It receives just 4.3% more sunlight than Earth, placing it on the inner edge of the habitable zone. It has about <5% of its mass as a volatile layer, which could consist of atmosphere, oceans, and/or ice layers. A 2018 study by the University of Washington concluded that TRAPPIST-1d might be a Venus-like exoplanet with an uninhabitable atmosphere. The planet is an eyeball planet candidate.
TRAPPIST-1e, also designated as 2MASS J23062928-0502285 e, is a rocky, close-to-Earth-sized exoplanet orbiting within the habitable zone around the ultracool dwarf star TRAPPIST-1, located 40.7 light-years away from Earth in the constellation of Aquarius. Astronomers used the transit method to find the exoplanet, a method that measures the dimming of a star when a planet crosses in front of it.
Planetary habitability in the Solar System is the study that searches the possible existence of past or present extraterrestrial life in those celestial bodies. As exoplanets are too far away and can only be studied by indirect means, the celestial bodies in the Solar System allow for a much more detailed study: direct telescope observation, space probes, rovers and even human spaceflight.