Atmosphere of Venus
ppm | |
Argon | 70 ppm |
---|---|
Water vapor | 20 ppm |
Carbon monoxide | 17 ppm |
Helium | 12 ppm |
Neon | 7 ppm |
Hydrogen chloride | 0.1–0.6 ppm |
Hydrogen fluoride | 0.001–0.005 ppm |
The atmosphere of Venus is the very dense layer of gasses surrounding the planet
Aside from the very surface layers, the atmosphere is in a state of vigorous circulation.
Unlike Earth, Venus lacks a magnetic field. Its
Despite the harsh conditions on the surface, the atmospheric pressure and temperature at about 50 km to 65 km above the surface of the planet are nearly the same as that of the Earth, making its upper atmosphere the most Earth-like area in the Solar System, even more so than the surface of Mars. Due to the similarity in pressure and temperature and the fact that breathable air (21% oxygen, 78% nitrogen) is a lifting gas on Venus in the same way that helium is a lifting gas on Earth, the upper atmosphere has been proposed as a location for both exploration and colonization.[9]
History
Christiaan Huygens was the first to hypothesize the existence of an atmosphere on Venus. In the Book II of Cosmotheoros, published in 1698, he writes:[10]
I have often wonder’d that when I have viewed Venus at her nearest to the Earth, when she resembled an Half-moon, just beginning to have something like Horns, through a Telescope of 45 or 60 Foot long, she always appeared to me all over equally lucid, that I can’t say I observ’d so much as one spot in her, tho in Jupiter and Mars, which seem much less to us, they are very plainly perceived. For if Venus had any such thing as Sea and Land, the former must necessarily show much more obscure than the other, as anyone may satisfy himself, that from a very high Mountain will but look down upon our Earth. I thought that perhaps the too brisk Light of Venus might be the occasion of this equal appearance; but when I used an Eye-glass that was smok’d for the purpose, it was still the same thing. What then, must Venus have no Sea, or do the Waters there reflect the Light more than ours do, or their Land less? or rather (which is most probable in my opinion) is not all that Light we see reflected from an Atmosphere surrounding Venus, which being thicker and more solid than that in Mars or Jupiter, hinders our seeing any thing of the Globe it self, and is at the same time capable of sending back the Rays that it receives from the Sun?
Decisive evidence for the atmosphere of Venus was provided by Mikhail Lomonosov, based on his observation of the transit of Venus in 1761 in a small observatory near his house in Saint Petersburg, Russia.[11]
Structure and composition
Composition
The atmosphere of Venus is composed of 96.5% carbon dioxide, 3.5% nitrogen, and traces of other gases, most notably sulfur dioxide.[12] The amount of nitrogen in the atmosphere is relatively small compared to the amount of carbon dioxide, but because the atmosphere is so much thicker than that on Earth, its total nitrogen content is roughly four times higher than Earth's, even though on Earth nitrogen makes up about 78% of the atmosphere.[1][13]
The atmosphere contains a range of compounds in small quantities, including some based on
Phosphine
In 2020, there was considerable discussion regarding whether phosphine (PH3) might be present in trace amounts in Venus's atmosphere. This would be noteworthy as phosphine is a potential biomarker indicating the presence of life. This was prompted by an announcement in September 2020 that this compound had been detected in trace amounts. No known abiotic source present on Venus could produce phosphine in the quantities detected.[18][19] On review, an interpolation error was discovered that resulted in multiple spurious spectroscopic lines, including the spectral feature of phosphine. Re-analysis of data with the fixed algorithm either do not result in the detection of the phosphine[20][21] or detected it with much lower concentration of 1 ppb.[22]
The announcement promoted re-analysis of Pioneer Venus data which found part of chlorine and all of hydrogen sulfide spectral features are instead phosphine-related, meaning lower than thought concentration of chlorine and non-detection of hydrogen sulfide.[23] Another re-analysis of archived infrared spectral measurements by the NASA Infrared Telescope Facility in 2015 did not reveal any phosphine in the Venusian atmosphere, placing an upper limit for phosphine concentration at 5 ppb—a quarter of the spectroscopic value reported in September.[24]
In 2022, no phosphine detection with an upper limit concentration of 0.8 ppb was announced for Venusian altitudes of 75–110 km.[25]
Ammonia
The ammonia in the atmosphere of Venus was tentatively detected by two atmospheric probes - Venera 8 and Pioneer Venus Multiprobe, although the detection was rejected that time due to poorly characterized sensors behavior in Venusian environment and ammonia believed to be chemically unstable in the strongly oxidizing atmosphere of Venus.[26]
Troposphere
The atmosphere is divided into a number of sections depending on altitude. The densest part of the atmosphere, the troposphere, begins at the surface and extends upwards to 65 km. The winds are slow near the surface,[1] but at the top of the troposphere the temperature and pressure reaches Earth-like levels and clouds pick up speed to 100 m/s (360 km/h).[3][27]
The atmospheric pressure at the surface of Venus is about 92 times that of the Earth, similar to the pressure found 900 m (3,000 ft) below the surface of the ocean. The atmosphere has a mass of 4.8×1020 kg, about 93 times the mass of the Earth's total atmosphere.[28] The density of the air at the surface is 65 kg/m3,[28] which is 6.5% that of liquid water on Earth.[29] The pressure found on Venus's surface is high enough that the carbon dioxide is technically no longer a gas, but a supercritical fluid. This supercritical carbon dioxide forms a kind of sea, with a 6.5% density of water,[29] that covers the entire surface of Venus. This sea of supercritical carbon dioxide transfers heat very efficiently, buffering the temperature changes between night and day (which last 56 terrestrial days).[30] Particularly at possible higher atmospheric pressures in Venus' past might have created an even more fluid-like layer of supercritical carbon dioxide shaping Venus' landscape; altogether, it is unclear how the supercritical environment behaves and is shaped.[31]
The large amount of CO2 in the atmosphere together with water vapour and
Height (km) |
Temp. (°C) |
Atmospheric pressure ( atm )
|
---|---|---|
0 | 462 | 92.10 |
5 | 424 | 66.65 |
10 | 385 | 47.39 |
15 | 348 | 33.04 |
20 | 306 | 22.52 |
25 | 264 | 14.93 |
30 | 222 | 9.851 |
35 | 180 | 5.917 |
40 | 143 | 3.501 |
45 | 110 | 1.979 |
50 | 75 | 1.066 |
55 | 27 | 0.531 4 |
60 | −10 | 0.235 7 |
65 | −30 | 0.097 65 |
70 | −43 | 0.036 90 |
80 | −76 | 0.004 760 |
90 | −104 | 0.000 373 6 |
100 | −112 | 0.000 026 60 |
The troposphere on Venus contains 99% of the atmosphere by mass. 90% of the atmosphere of Venus is within 28 km (17.5 mi) of the surface; by comparison, 90% of the atmosphere of Earth is within 16 km (10 mi) of the surface. At a height of 50 km (31 mi) the atmospheric pressure is approximately equal to that at the surface of Earth.[33] On the night side of Venus clouds can still be found at 80 km (50 mi) above the surface.[34]
The altitude of the troposphere most similar to Earth is near the tropopause—the boundary between troposphere and mesosphere. It is located slightly above 50 km.
Circulation
The circulation in Venus's troposphere follows the so-called
All winds on Venus are ultimately driven by
Odd structures known as
The first vortex on Venus was discovered at the north pole by the Pioneer Venus mission in 1978.[40] A discovery of the second large "double-eyed" vortex at the south pole of Venus was made in the summer of 2006 by Venus Express, which came with no surprise.[39]
Images from the Akatsuki orbiter revealed something similar to jet stream winds in the low and middle cloud region, which extends from 45 to 60 km in altitude. The wind speed maximized near the equator. In September 2017, JAXA scientists named this phenomenon "Venusian equatorial jet".[41]
Upper atmosphere and ionosphere
The mesosphere of Venus extends from 65 km to 120 km in height, and the thermosphere begins at approximately 120 km, eventually reaching the upper limit of the atmosphere (exosphere) at about 220 to 350 km.[27] The exosphere begins when the atmosphere becomes so thin that the average number of collisions per air molecule is less than one.
The mesosphere of Venus can be divided into two layers: the lower one between 62 and 73 km[42] and the upper one between 73 and 95 km.[27] In the first layer the temperature is nearly constant at 230 K (−43 °C). This layer coincides with the upper cloud deck. In the second layer, the temperature starts to decrease again, reaching about 165 K (−108 °C) at the altitude of 95 km, where mesopause begins.[27] It is the coldest part of the Venusian dayside atmosphere.[2] In the dayside mesopause, which serves as a boundary between the mesosphere and thermosphere and is located between 95 and 120 km, temperature increases to a constant—about 300–400 K (27–127 °C)—value prevalent in the thermosphere.[2] In contrast, the nightside Venusian thermosphere is the coldest place on Venus with temperature as low as 100 K (−173 °C). It is even called a cryosphere.[2]
The circulation patterns in the upper mesosphere and thermosphere of Venus are completely different from those in the lower atmosphere.
The Venus Express probe has shown through stellar occultation that the atmospheric haze extends much further up on the night side than the day side. On the day side the cloud deck has a thickness of 20 km and extends up to about 65 km, whereas on the night side the cloud deck in the form of a thick haze reaches up to 90 km in altitude—well into mesosphere, continuing even further to 105 km as a more transparent haze.[34] In 2011, the spacecraft discovered that Venus has a thin ozone layer at an altitude of 100 km.[44]
Venus has an extended ionosphere located at altitudes 120–300 km.[27] The ionosphere almost coincides with the thermosphere. The high levels of the ionization are maintained only over the dayside of the planet. Over the nightside the concentration of the electrons is almost zero.[27] The ionosphere of Venus consists of three layers: v1 between 120 and 130 km, v2 between 140 and 160 km and v3 between 200 and 250 km.[27] There may be an additional layer near 180 km. The maximum electron volume density (number of electrons in a unit of volume) of 3×1011 m−3 is reached in the v2 layer near the subsolar point.[27] The upper boundary of the ionosphere (the ionopause) is located at altitudes 220–375 km and separates the plasma of the planetary origin from that of the induced magnetosphere.[45][46] The main ionic species in the v1 and v2 layers is O2+ ion, whereas the v3 layer consists of O+ ions.[27] The ionospheric plasma is observed to be in motion; solar photoionization on the dayside and ion recombination on the nightside are the processes mainly responsible for accelerating the plasma to the observed velocities. The plasma flow appears to be sufficient to maintain the nightside ionosphere at or near the observed median level of ion densities.[47]
Induced magnetosphere
Venus is known not to have a
At the subsolar point the bow shock stands 1900 km (0.3 Rv, where Rv is the radius of Venus) above the surface of Venus. This distance was measured in 2007 near the solar activity minimum.
Due to the lack of the intrinsic magnetic field on Venus, the
Clouds
Venusian clouds are thick and are composed mainly (75–96%) of sulfuric acid droplets.
The cloud cover is such that it reflects more than 60% of the solar light Venus receives, leaving the surface with typical light levels of 14,000 lux, comparable to that on Earth "in the daytime with overcast clouds".[54] The equivalent visibility is about three kilometers, but this will likely vary with the wind conditions. Little to no solar energy could conceivably be collected by solar panels on a surface probe. In fact, due to the thick, highly reflective cloud cover, the total solar energy received by the surface of the planet is less than that of the Earth, despite its proximity to the Sun.
Sulfuric acid is produced in the upper atmosphere by the Sun's
Surface level humidity is less than 0.1%.[57] Venus's sulfuric acid rain never reaches the ground, but is evaporated by the heat before reaching the surface in a phenomenon known as virga.[58] It is theorized that early volcanic activity released sulfur into the atmosphere and the high temperatures prevented it from being trapped into solid compounds on the surface as it was on the Earth.[59] Besides sulfuric acid, cloud droplets can contain a wide array of sulfate salts, raising pH of droplet to 1.0 in one of scenarios explaining the sulfur dioxide measurements.[60]
In 2009, a prominent bright spot in the atmosphere was noted by an amateur astronomer and photographed by Venus Express. Its cause is currently unknown, with surface volcanism advanced as a possible explanation.[61]
Lightning
The clouds of Venus may be capable of producing lightning,[62] but the debate is ongoing, with volcanic lightning and sprites also under discussion.[63][64] The Soviet Venera 9 and 10 orbiters obtained ambiguous optical and electromagnetic evidence of lightning.[65][66] There have been attempts to observe lightning from the Venera 11, 12, 13, and 14 landers, however no lightning activity was recorded,[67] but very low frequency (VLF) waves were detected during descent.[68] The European Space Agency's Venus Express in 2007 detected whistler waves which could be attributed to lightning.[69][70] Their intermittent appearance indicates a pattern associated with weather activity. According to the whistler observations, the lightning rate is at least half of that on Earth[62] and may possibly be similar,[68] but this is incompatible with data from the JAXA Akatsuki spacecraft which indicate a very low flash rate.[71]
The Pioneer Venus Orbiter (PVO) was equipped with an electric field detector specifically to detect lightning. There were other missions that were equipped with instruments to search for lightning including the Venera 9 which had the visible spectrometer; Pioneer which had the star sensor; and VEGA which had a photometer.[67]
The mechanism generating lightning on Venus, if present, remains unknown. Whilst the sulfuric acid cloud droplets can become charged, the atmosphere may be too electrically conductive for the charge to be sustained, preventing lightning.[72]
Lightning could potentially contribute to atmospheric chemistry, through heating which could break apart molecules that contain carbon, oxygen, sulfur, nitrogen, and hydrogen molecules (carbon dioxide, nitrogen gas, sulfuric acid, and water), that will recombine to form new molecules ("carbon oxides", "suboxides", "sulfur oxides", "oxygen", "elemental sulfur", "nitrogen oxides", "sulfuric acid clusters", "polysulfur oxides", "carbon soot", etc.).[68] Lightning could contribute to the production of carbon monoxide and oxygen gas by converting sulfur and sulfur dioxide into sulfuric acid, and water and sulfuric dioxide to sulfur to sustain clouds. Regardless of how frequent lightning on Venus is, it is important to study as it can be a potential hazard for spacecraft.[67]
Throughout the 1980s, it was thought that the cause of the night-side glow ("ashen light") on Venus was lightning[73][67] however, there may be the possibility that Venus lightning would be too weak to cause it.[67]
Possibility of life
Due to the harsh conditions on the surface, little of the planet has been explored; in addition to the fact that life as currently understood may not necessarily be the same in other parts of the universe, the extent of the tenacity of
The surface temperature of Venus (over 450 °C) is far beyond the extremophile range, which extends only tens of degrees beyond 100 °C. However, the lower temperature of the cloud tops means that life could plausibly exist there, the same way that bacteria have been found living and reproducing in clouds on Earth.[75] Any such bacteria living in the cloud tops, however, would have to be hyper-acidophilic, due to the concentrated sulfuric acid environment. Microbes in the thick, cloudy atmosphere could be protected from solar radiation by the sulfur compounds in the air.[74]
The Venusian atmosphere has been found to be sufficiently out of equilibrium as to require further investigation.[74] Analysis of data from the Venera, Pioneer, and Magellan missions has found hydrogen sulfide (later disputed[23]) and sulfur dioxide (SO2) together in the upper atmosphere, as well as carbonyl sulfide (OCS). The first two gases react with each other, implying that something must produce them. Carbonyl sulfide is difficult to produce inorganically, but it is present in the Venusian atmosphere.[75] However, the planet's volcanism could explain the presence of carbonyl sulfide.[75] In addition, one of the early Venera probes detected large amounts of toxic chlorine just below the Venusian cloud deck.[76]
It has been proposed that microbes at this level could be soaking up ultraviolet light from the Sun as a source of energy, which could be a possible explanation for the "unknown UV absorber" seen as dark patches on UV images of the planet.[77][78] The existence of this "unknown UV absorber" prompted Carl Sagan to publish an article in 1963 proposing the hypothesis of microorganisms in the upper atmosphere as the agent absorbing the UV light.[79] In 2012, the abundance and vertical distribution of these unknown ultraviolet absorbers in the Venusian atmosphere have been investigated from analysis of Venus Monitoring Camera images,[80] but their composition is still unknown.[74] In 2016, disulfur dioxide was identified as a possible candidate for causing the so far unknown UV absorption of the Venusian atmosphere.[81] The dark patches of "unknown UV absorbers" are prominent enough to influence the weather on Venus.[82] In 2021, it was suggested the color of "unknown UV absorber" match that of "red oil" - a known substance comprising a mixed organic carbon compounds dissolved in concentrated sulfuric acid.[83]
In September 2020, research studies led by Cardiff University using the James Clerk Maxwell and ALMA radio telescopes noted the detection of phosphine in Venus's atmosphere that was not linked to any known abiotic method of production present, or possible under Venusian conditions. It is extremely hard to make, and the chemistry in the Venusian clouds should destroy the molecules before they could accumulate to the observed amounts. The phosphine was detected at heights of at least 48 km above the surface of Venus, and was detected primarily at mid-latitudes with none detected at the poles of Venus. Scientists note that the detection itself could be further verified beyond the use of multiple telescopes detecting the same signal, as the phosphine fingerprint described in the study could theoretically be a false signal introduced by the telescopes or by data processing.[84][85][86][87] The detection was later suggested to be a false positive[21] or true signal with much over-estimated amplitude, compatible with 1 ppb concentration of phosphine.[22] The re-analysis of ALMA dataset in April 2021 have recovered the 20 ppb phosphine signal, with signal-to-noise ratio of 5.4,[22] and by August 2021 it was confirmed the suspected contamination by sulfur dioxide was contributing only 10% to the tentative signal in phosphine spectral line band.[88]
Evolution
Through studies of the present cloud structure and geology of the surface, combined with the fact that the luminosity of the Sun has increased by 25% since around 3.8 billion years ago,[89] it is thought that the early environment of Venus was more like that of Earth with liquid water on the surface. At some point in the evolution of Venus, a runaway greenhouse effect occurred, leading to the current greenhouse-dominated atmosphere. The timing of this transition away from Earthlike is not known, but is estimated to have occurred around 4 billion years ago. The runaway greenhouse effect may have been caused by the evaporation of the surface water and the rise of the levels of greenhouse gases that followed. Venus's atmosphere has therefore received a great deal of attention from those studying climate change on Earth.[7][90]
There are no geologic forms on the planet to suggest the presence of water over the past billion years. However, there is no reason to suppose that Venus was an exception to the processes that formed Earth and gave it its water during its early history, possibly from the original rocks that formed the planet or later on from comets. The common view among research scientists is that water would have existed for about 600 million years on the surface before evaporating, though some such as David Grinspoon believe that up to 2 billion years could also be plausible.[91] This longer timescale for the persistence of oceans is also supported by General Circulation Model simulations incorporating the thermal effects of clouds on an evolving Venusian hydrosphere.[92]
The early Earth during the Hadean eon is believed by most scientists to have had a Venus-like atmosphere, with roughly 100 bar of CO2 and a surface temperature of 230 °C, and possibly even sulfuric acid clouds, until about 4.0 billion years ago, by which time plate tectonics were in full force and together with the early water oceans, removed the CO2 and sulfur from the atmosphere.[93] Early Venus would thus most likely have had water oceans like the Earth, but any plate tectonics would have ended when Venus lost its oceans.[citation needed] Its surface is estimated to be about 500 million years old, so it would not be expected to show evidence of plate tectonics.[94]
Observations and measurement from Earth
In 1761, Russian polymath Mikhail Lomonosov observed an arc of light surrounding the part of Venus off the Sun's disc at the beginning of the egress phase of the transit and concluded that Venus has an atmosphere.[95][96] In 1940, Rupert Wildt calculated that the amount of CO2 in the Venusian atmosphere would raise surface temperature above the boiling point for water.[97] This was confirmed when Mariner 2 made radiometer measurements of the temperature in 1962. In 1967, Venera 4 confirmed that the atmosphere consisted primarily of carbon dioxide.[97]
The upper atmosphere of Venus can be measured from Earth when the planet crosses the sun in a rare event known as a
A solar transit of Venus is an extremely rare event, and the last solar transit of the planet before 2004 was in 1882. The most recent solar transit was in 2012; the next one will not occur until 2117.[99][100]
Space missions
Recent and current spaceprobes
The
The
Proposed missions
The
A craft called the Venus Mobile Explorer has been proposed by the Venus Exploration Analysis Group (VEXAG) to study the composition and isotopic measurements of the surface and the atmosphere, for about 90 days. The mission has not been selected for launch.[106]
After missions discovered the reality of the harsh nature of the planet's surface, attention shifted towards other targets such as Mars. There have been a number of proposed missions afterward, however, and many of these involve the little-known upper atmosphere. The
A solar flyer has also been proposed by Geoffrey A. Landis in place of a balloon,[36] and the idea has been featured from time to time since the early 2000s. Venus has a high albedo, and reflects most of the sunlight that shines on it making the surface quite dark, the upper atmosphere at 60 km has an upward solar intensity of 90%, meaning that solar panels on both the top and the bottom of a craft could be used with nearly equal efficiency.[52] In addition to this, the slightly lower gravity, high air pressure and slow rotation allowing for perpetual solar power make this part of the planet ideal for exploration. The proposed flyer would operate best at an altitude where sunlight, air pressure, and wind speed would enable it to remain in the air perpetually, with slight dips down to lower altitudes for a few hours at a time before returning to higher altitudes. As sulfuric acid in the clouds at this height is not a threat for a properly shielded craft, this so-called "solar flyer" would be able to measure the area in between 45 km and 60 km indefinitely, for however long it takes for mechanical error or unforeseen problems to cause it to fail. Landis also proposed that rovers similar to Spirit and Opportunity could possibly explore the surface, with the difference being that Venus surface rovers would be "dumb" rovers controlled by radio signals from computers located in the flyer above,[108] only requiring parts such as motors and transistors to withstand the surface conditions, but not weaker parts involved in microelectronics that could not be made resistant to the heat, pressure and acidic conditions.[109]
Russian space science plans include the launch of the Venera-D (Venus-D) probe in 2029.[110] The main scientific goals of the Venera-D mission are investigation of the structure and chemical composition of the atmosphere and investigation of the upper atmosphere, ionosphere, electrical activity, magnetosphere, and escape rate.[111] It has been proposed to fly together with Venera-D an inflatable aircraft designed by Northrop Grumman, called Venus Atmospheric Maneuverable Platform (VAMP).[112][113][114]
The
In June 2021, NASA selected the
See also
References
- ^ S2CID 250815558.
- ^ S2CID 4421875.
- ^ S2CID 1242297.
- PMID 20448159.
- ^ DK Space Encyclopedia: Atmosphere of Venus p 58.
- ^ S2CID 4422507.
- ^ PMID 11538226.
- ^ "How Hot is Venus?". May 2006.
- ^ doi:10.1063/1.1541418. Archived from the originalon 2012-07-11.
- ^ "The Cosmotheoros of Christiaan Huygens - Book II". webspace.science.uu.nl. Retrieved 2022-10-06.
- S2CID 53394126.
- ISBN 9780124158450. Retrieved 12 January 2016.
- ^ a b "Clouds and atmosphere of Venus". Institut de mécanique céleste et de calcul des éphémérides. Archived from the original on 2011-07-21. Retrieved 2008-01-22.
- ISBN 978-0-19-286218-1.
- .
- Harvard-Smithsonian Center for Astrophysics. Archivedfrom the original on 14 August 2012. Retrieved 8 August 2012.
HITRAN is a compilation of spectroscopic parameters that a variety of computer codes use to predict and simulate the transmission and emission of light in the atmosphere.
- ^ "HITRAN on the Web Information System". V.E. Zuev Institute of Atmospheric Optics. Archived from the original on 19 April 2013. Retrieved 11 August 2012.
- S2CID 221655755. Retrieved 16 September 2020.
- ^ Sample, Ian (14 September 2020). "Scientists find gas linked to life in atmosphere of Venus". The Guardian. Retrieved 16 September 2020.
- S2CID 224803085
- ^ S2CID 225103303
- ^ S2CID 233296859
- ^ S2CID 231854943
- S2CID 222377688
- S2CID 253086965
- ^ S2CID 4415782.
- ^ a b "Venus Fact Sheet". nssdc.gsfc.nasa.gov. Retrieved 2022-12-02.
- ^ S2CID 133864520.
- ISBN 978-0-8165-1830-2.
- ^ Choi, Charles Q. (2014-12-28). "Venus Gets Weirder: CO2 Oceans May Have Covered Surface". Space.com. Retrieved 2023-04-13.
- ISBN 9780393912104.)
{{cite book}}
: CS1 maint: multiple names: authors list (link - ^ a b "Flying over the cloudy world – science updates from Venus Express". Venus Today. 2006-07-12. Archived from the original on 2007-09-28. Retrieved 2007-01-17.
- ^ "Venus Atmosphere Temperature and Pressure Profiles". Shade Tree Physics. Archived from the original on 2008-02-05. Retrieved 2008-01-23.
- ^ a b c Landis, Geoffrey A.; Colozza, Anthony; LaMarre, Christopher M (January 14–17, 2002). "Atmospheric Flight on Venus" (PDF). Proceedings. 40th Aerospace Sciences Meeting and Exhibit sponsored by the American Institute of Aeronautics and Astronautics. Reno, Nevada. pp. IAC–02–Q.4.2.03, AIAA–2002–0819, AIAA0. Archived from the original (PDF) on 2011-10-16.
- ^ S2CID 4420096.
- Bibcode:1979KosIs..17..280M.
- ^ a b "Double vortex at Venus South Pole unveiled!". European Space Agency. 2006-06-27. Archived from the original on 7 January 2008. Retrieved 2008-01-17.
- ^ Lakdawalla, Emily (2006-04-14). "First Venus Express VIRTIS Images Peel Away the Planet's Clouds". Archived from the original on 22 December 2007. Retrieved 2008-01-17.
- ^ "Venus: Jet-setting atmosphere". Japan Aerospace Exploration Agency (JAXA). 5 September 2017. Retrieved 2017-09-26.
- ^ This thickness corresponds to the polar latitudes. It is narrower near the equator—65–67 km.
- ^ S2CID 4344611.
- ^ Carpenter, Jennifer (7 October 2011). "Venus springs ozone layer surprise". BBC. Retrieved 2011-10-08.
- ^ S2CID 250897924.
- ^ S2CID 4412430.
- .
- ^ S2CID 4419879.
- ^ 2004 Venus Transit information page, Venus Earth and Mars, NASA
- ^ Wilson, C.F. "Beyond sulphuric acid – what else is in the clouds of Venus?" (PDF). Venus Exploration Targets Workshop ( 2014 ). Retrieved 21 September 2017.
- ^ This is the spherical albedo. The geometrical albedo is 85%.
- ^ S2CID 129272536.
- ^ Lee, Yeon Joo (2012). "Venus Cloud Structure and Radiative Energy Balance of the Mesosphere" (PDF). p. 14.
- JSTOR 3960800.
100 watts per square meter ... 14,000 lux ... corresponds to ... daytime with overcast clouds
- ^ "VenusExpress: Acid clouds and lightning". European Space Agency (ESA). Retrieved 2016-09-08.
- S2CID 4369293.
- Bibcode:1982S&W....21..282K.
- ^ "Planet Venus: Earth's 'evil twin'". BBC News. 7 November 2005.
- ^ "The Environment of Venus". hyperphysics.phy-astr.gsu.edu. Retrieved 2014-04-06.
- arXiv:2101.08582
- ^ "Experts puzzled by spot on Venus". BBC News. 1 August 2009.
- ^ S2CID 4418778.
- ^ The Strange Case of Missing Lightning at Venus. Meghan Bartels, Space. 26 August 2019.
- ISSN 2197-4284.
- doi:10.1016/0273-1177(90)90174-X. Archived from the originalon 2015-12-08. Retrieved 2016-09-08.
- ^ V. A. Krasnopol'skii, Lightning on Venus according to information obtained by the satellites Venera 9 and 10. Kosmich. Issled. 18, 429-434 (1980).
- ^ S2CID 189774459.
- ^ ISSN 0032-0633.
- S2CID 4418778. Archived from the original(PDF) on 4 March 2016. Retrieved 8 September 2016.
- ^ "Venus also zapped by lightning". CNN. 29 November 2007. Archived from the original on 30 November 2007. Retrieved 2007-11-29.
- S2CID 198423897.
- ISSN 0148-0227.
- S2CID 11234166.
- ^ .
- ^ Bibcode:2003JBIS...56..250L. Archived from the original(PDF) on August 7, 2011.
- ISBN 978-0-201-32839-4.
- ^ "Venus could be a haven for life". ABC News. 2002-09-28. Archived from the original on August 14, 2009.
- ^ "Acidic clouds of Venus could harbour life". NewScientist.com. 2002-09-26.
- ^ Mysterious dark patches in Venus' clouds are affecting the weather there. What the dark patches are is still a mystery, though astronomers dating back to Carl Sagan have suggested they could be extraterrestrial microorganisms. Erica Naone, Astronomy. 29 August 2019.
- .
- .
- ^ "Mysterious dark patches in Venus' clouds are affecting the weather there". 29 August 2019. Retrieved 29 August 2019.
- arXiv:2108.02286
- ^ Drake, Nadia (14 September 2020). "Possible sign of life on Venus stirs up heated debate". National Geographic. Archived from the original on September 14, 2020. Retrieved 14 September 2020.
- S2CID 221655755. Retrieved 14 September 2020.
- ^ Stirone, Shannon; Chang, Kenneth; Overbye, Dennis (14 September 2020). "Life on Venus? Astronomers See a Signal in Its Clouds - The detection of a gas in the planet's atmosphere could turn scientists' gaze to a planet long overlooked in the search for extraterrestrial life". The New York Times. Retrieved 14 September 2020.
- ^ "Possible sign of life on Venus stirs up heated debate". www.msn.com. Retrieved 2020-09-14.
- PMID 17779689.
- ^ Paul M. Sutter (2019). "How Venus Turned Into Hell, and How the Earth Is Next". space.com. Retrieved 2019-08-30.
- ^ Bortman, Henry (2004-08-26). "Was Venus Alive? 'The Signs are Probably There'". Astrobiology Magazine. Retrieved 2008-01-17.
- ^ M. Way et al. "Was Venus the First Habitable World of Our Solar System?" Geophysical Research Letters, Vol. 43, Issue 16, pp. 8376–8383.
- PMID 11259665.
- .
- .
- ^ Britannica online encyclopedia: Mikhail Vasilyevich Lomonosov
- ^ a b Weart, Spencer, The Discovery of Global Warming Archived 2012-05-21 at the Wayback Machine, "Venus & Mars Archived 2012-05-21 at the Wayback Machine ", June 2008
- ^ Britt, Robert Roy (2001-11-27). "First Detection Made of an Extrasolar Planet's Atmosphere". Space.com. Archived from the original on May 11, 2008. Retrieved 2008-01-17.
- ^ a b "Venus' Atmosphere to be Probed During Rare Solar Transit". Space.com. 2004-06-07. Archived from the original on February 13, 2006. Retrieved 2008-01-17.
- ^ a b "NCAR Scientist to View Venus's Atmosphere during Transit, Search for Water Vapor on Distant Planet". National Center for Atmospheric Research and UCAR Office of Programs. 2004-06-03. Archived from the original on 2012-03-05. Retrieved 2008-01-17.
- ^ "Venus Climate Orbiter "AKATSUKI" Inserted Into Venus' Orbit" http://global.jaxa.jp/press/2015/12/20151209_akatsuki.html; accessed 2015-12-09
- ^ Imamura, Takeshi. "The World's First Planetary Meteorological Satellite: Exploring the Mystery of the Wind on Venus". JAXA. Retrieved 2018-10-18.
- ^ Oshima, Takeshi; Sasaki, Tokuhito (2011). "Development of the Venus Climate Orbiter PLANET-C (Akatsuki )" (PDF). NEC. Retrieved 2018-10-18.
- ^ "Venus Exploration Mission PLANET-C". Japan Aerospace Exploration Agency. 2006-05-17. Archived from the original on 2006-12-08. Retrieved 2008-01-17.
- ^ "New Frontiers Program – Program Description". NASA. Archived from the original on 26 February 2008. Retrieved 2008-01-17.
- ^ "Venus Mobile Explorer—Description". NASA. Archived from the original on 2007-02-17. Retrieved 2008-12-23.
- ^ Myers, Robert (2002-11-13). "Robotic Balloon Probe Could Pierce Venus's Deadly Clouds" (PDF). SPACE.com. Retrieved 2011-03-23.
- .
- ^ Marks, Paul (2005-05-08). "To conquer Venus, try a plane with a brain". NewScientist.com. Archived from the original on 2 January 2008. Retrieved 2008-01-17.
- ^ Zak, Anatoly (5 March 2021). "New promise for the Venera-D project". RussianSpaceWeb. Retrieved 7 March 2021.
- ^ "Scientific goals of the Venera-D mission". Russian Space Research Institute. Archived from the original on 2013-05-10. Retrieved 2012-02-22.
- ^ Venus Atmospheric Maneuverable Platform (VAMP) – Future Work and Scaling for a Mission. (PDF). S. Warwick, F. Ross, D. Sokol. 15th Meeting of the Venus Exploration Analysis Group (VEXAG) 2017.
- ^ Astronomers ponder possible life adrift in Venus' clouds. Deborah Byrd, Earth & Sky. 31 March 2018.
- ^ Scientists Explore The Possibility Of Life Hidden Inside The Clouds Of Venus. Kritine Moore, The Inquisitr. 1 April 2018.
- ^ A Venus Aircraft Could Be in NASA's Plans. Leonard David, Space. 29 June 2018.
- ^ Potter, Sean (2 June 2021). "NASA Selects 2 Missions to Study "Lost Habitable" World of Venus". NASA. Retrieved 2021-06-02. This article incorporates text from this source, which is in the public domain.
External links
Media related to Atmosphere of Venus at Wikimedia Commons