What is Venus: Definition and 114 Discussions

Venus is the second planet from the Sun. It is named after the Roman goddess of love and beauty. As the brightest natural object in Earth's night sky after the Moon, Venus can cast shadows and can be, on rare occasions, visible to the naked eye in broad daylight. Venus lies within Earth's orbit, and so never appears to venture far from the Sun, either setting in the west just after dusk or rising in the east a little while before dawn. Venus orbits the Sun every 224.7 Earth days. With a sidereal rotation period of 243 Earth days and a synodic day length of 117 Earth days, it takes significantly longer to rotate about its axis than any other planet in the Solar System, and does so in the opposite direction to all but Uranus (meaning the Sun rises in the west and sets in the east). Venus does not have any moons, a distinction it shares only with Mercury among the planets in the Solar System.Venus is a terrestrial planet and is sometimes called Earth's "sister planet" because of their similar size, mass, proximity to the Sun, and bulk composition. It is radically 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 about 92 times the sea level pressure of Earth, or roughly the pressure at 900 m (3,000 ft) underwater on Earth. Even though Mercury is closer to the Sun, Venus has the hottest surface of any planet in the Solar System, with a mean temperature of 737 K (464 °C; 867 °F). 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. It may have had water oceans in the past, but these would have vaporized as the temperature rose due to a runaway greenhouse effect. The water has probably photodissociated, and the free hydrogen has been swept into interplanetary space by the solar wind because of the lack of a planetary magnetic field.As one of the brightest objects in the sky, Venus has been a major fixture in human culture for as long as records have existed. It has been made sacred to gods of many cultures, and has been a prime inspiration for writers and poets as the "morning star" and "evening star". Venus was the first planet to have its motions plotted across the sky, as early as the second millennium BC.Due to its proximity to Earth, Venus has been a prime target for early interplanetary exploration. It was the first planet beyond Earth visited by a spacecraft (Mariner 2 in 1962), and the first to be successfully landed on (by Venera 7 in 1970). Venus's thick clouds render observation of its surface impossible in visible light, and the first detailed maps did not emerge until the arrival of the Magellan orbiter in 1991. Plans have been proposed for rovers or more complex missions, but they are hindered by Venus's hostile surface conditions. The possibility of life on Venus has long been a topic of speculation, and in recent years has received active research.

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  1. S

    I Comparing the formation of the atmospheres on Earth vs Venus

    Read Venus stats for first time yesterday. Could the spin rate at accretion time reduce Earth's atmosphere relative to Venus, or are there moon tidal effects, e.g. mixing and carrying heat to upper atmosphere allowing escape velocity losses, to explain the 100 fold difference? I have heard...
  2. xpell

    B At what distance would a Venus-like planet have a HZ temperature?

    Well... that: Please, could you please assist me in obtaining a rough estimate of the distance from the Sun at which a planet resembling Venus or a hypothetical Venus-like planet (for the sake of simplicity) would have a habitable-zone surface temperature? A "back-of-the-envelope" educated...
  3. Andre

    A Presentation: Venus hot break hypothesis

    The idea will be presented at the ancient Venus conference https://www.hou.usra.edu/meetings/ancientvenus2022/pdf/ancientvenus2022_program.htm Houston 25 Jul. The abstract: https://www.hou.usra.edu/meetings/ancientvenus2022/pdf/2024.pdf Some of the earliest members may remember a thread about...
  4. E

    A Venus' non-relativistic contribution to Mercury's precession

    Mercury's orbit is rather eccentric, its perigee brings it much nearer to the sun than its apogee. Venus by contrast has practically a circular orbit. When Mercury is approaching apogee, it can get close to venus if it is in the similar part of its orbit. At this point, Mercury's precession...
  5. W

    I History of astronomy and the Phases of Venus

    Does anyone know when it was first realized that a heliocentric model of the cosmos should show the phases of Venus in the way Galileo saw them in the 17th century.?Was it known in the time of Aristarchus or did people only realize this was a consequence of helicoentrism later on, perhaps only...
  6. D

    Stargazing Better than Mars Colonization in many aspects.

    Venus is not at the top of the priority list when it comes to the colonizing of space. Mars mostly takes the top spot but when checked deeply, it is very comparable to Mars Colonization and in some aspects it is even better than Mars Colonization. [Spammy link redacted by the Mentors]
  7. yucheng

    I Issue with Stellarium: transit of Venus (find the parallax)

    These are the two snapshot (on Stellarium) of the Third Contact between Venus and the Sun at the same time at different locations on Earth. The top image is viewd from Quito, Ecuador, the bottom image is from Harrisburg. I am supposed to determine the parallax. The angles were calculated using...
  8. Astronuc

    NASA NASA - Venus Technology Plan (DRAFT) December, 2018

    This discussion relates to another thread on the feasibility of operating a nuclear reactor on Venus. https://www.physicsforums.com/threads/could-a-high-very-high-temperature-nuclear-reactor-operate-in-venus.1003619/ Venus represents a hostile environment with a surface temperature of ~470°C...
  9. xpell

    Could a high / very high temperature nuclear reactor operate in Venus?

    Hi. I'm just a curious person with high-school-level scientific knowledge. However, I was wondering if a specially-engineered Generation IV high or very high temperature (800-1,000ºC) nuclear reactor could work in Venus using the local atmosphere at 450ºC as "coolant", just like a "typical"...
  10. A

    I Question Regarding Determining the Mass of Venus

    Venus is in the news! I looked up this well-regarded paper by A. S. Konopliv, W. B. Banerdt, and W. L. Sjogren Venus Gravity: 180th Degree and Order Model They list values for GM (see attached picture), such as GM 324858.63 ± 0.01 so in principle calculating M should be trivial. The problem...
  11. Greg Bernhardt

    Biological Agent Phosphine Found on Venus

    Paper https://www.nature.com/articles/s41550-020-1174-4
  12. J

    A Is this evidence that Venus originally had a nitrogen atmosphere?

    Has MESSENGER found evidence that Venus originally had a nitrogen atmosphere, and might have been more habitable, and the present amount of CO2 was released by some cataclysm afterwards? https://phys.org/news/2020-04-lucky-messenger-upends-long-held-idea.html
  13. E

    Venera 13 photos from the surface of Venus

    In 1982, the USSR sent a space probe named Venera 13 to land on the planet Venus. The lander lasted only two hours before succumbing to the extreme temperatures and crushing pressures on the surface of Venus, but not before it sent back these stunning photographs.
  14. G

    B Cloud Cities on Venus: Viability & Feasibility

    There are plans for almost everything. https://www.space.com/29140-venus-airship-cloud-cities-incredible-technology.html Like build floating cities on Venus in the far future, since gravity is Earth like at there, and the upper atmosphere isn't so harsh. I would like to hear your opinions...
  15. Y

    Push Mercury out to Venus' orbit?

    So it would be cooler and mine-able? Given unlimited tech and wealth in a fictional setting.
  16. sophiecentaur

    B Using Venus in the Parker Solar Probe mission

    The Parker Solar Probe mission will be launched soon and I was reading that it will use gravity assist from Venus to bring its orbit closer and closer to the Sun over about seven years. The diagram in this link shows the plan for seven flyby's of Venus to lower the orbit. Now, to get down close...
  17. I

    Continuous Grey Atmosphere Model

    Homework Statement In the grey atmosphere radiative energy balance model, we replace the multi-layer approximation used above with still simplified but significantly more realistic model involving a continuous atmosphere with a continuously varying temperature. The variation with temperature is...
  18. N

    Venus' temperature, radiation values and altitude

    Hi, I have a list of measured temperature values of Venus at altitudes from several missions to the planet. This temperature is a combination of outgoing thermal emission from the planet, incoming thermal emission from the sun and any chemical reactions going on in the atmosphere. Can I use...
  19. R

    Why does Venus always appear close to the Sun in the sky?

    1. The problem statement, all variables, and given/known data Venus is sometimes described as either the “Morning Star” or the “Evening Star”, since it can only be seen near sunrise and sunset, very close to the Sun in the sky. Why does Venus always appear close to the Sun in the sky for an...
  20. L

    B Exploring Possibility of Microbes Living in Clouds of Venus

    I've read a number of articles (including one from Astrobiology at NASA) about the possibility of microbes living in the clouds of Venus. It seems that scientists believe microbes could survive there if they're not there already. I would like to see some hardy Earth-based bacteria released in...
  21. Hawksteinman

    B Seeing Venus with the Naked Eye - Light Pollution

    I live in a light polluted area, and the last few weeks I have been walking down my street to see one very bright point of light. Other than the moon, it was the only astronomical object I could see with the naked eye, as well as occasionally a few fainter points. I was wondering what this was...
  22. BenAS

    Stargazing Can Venus be seen during the day from sea level right now?

    The last couple of days I have been able to spot Venus with the naked eye in the middle of the day. I'm in Denver Colorado, just curious as to how often this happens and if it's visible from sea level during the day right now. I can't find much about on Google.
  23. L

    B Venus -- a more attractive target than Mars for human colonization?

    If Venus had an atmosphere similar to that of Mars, would Venus then be a more attractive target than Mars for human colonization?
  24. N

    Can UV Light be the Key to Changing Venus' Atmosphere?

    I thought a bit about the prospect of terraforming other worlds starting with the ones closest to us, Mars and Venus. Personally even though I don't mind the hype over Mars, I prefer thinking of Venus as the main target for terraforming. it's just a lot more tempting. for example: It's surface...
  25. Battlemage!

    B Albedo, atmosphere, and predicted temperature of Venus

    The reason I am making this thread is because I have a question regarding predicted temperatures of planets based on their area, distance from the sun, and albedo. Going by the planetary equilibrium temperature, T4 = [L(1-a)]/(16σπD2), I have seen numerous websites state that Venus would...
  26. R

    Using Kepler's 3rd Law to find Period of Venus

    Homework Statement Deduce, from the equations employed in Q4 and Q5, the exponent n in the equation: T = k rn where k is a constant and T is the period of a satellite which orbits at a radius r from a massive object in space. Hence, how long is the “year” on Venus if its distance from the Sun...
  27. E

    I How does mars have a magnetic field, with a cooled core?

    I have been studying astronomy and astrophysics for about 2 years now, though on my own time and by my self. A recent question came into my mind, Can arctic planets exist close to their star? Now, in my understanding of planetary science, in order for a planet to be cool and close to the sun, it...
  28. twiz_

    Venus to be humanity's next destination?

    I once read a year or so ago that Venus, despite its harsh lower atmospheric conditions, is actually very "earth-like" at a certain level near the upper part of the atmosphere, including an relatively low pH, rain, and a suitable temperature. Not only that, but directly below the earth-like...
  29. Sei

    I Is it possible to create an independent Venus aerostat?

    "Is it possible to create an independent Venus aerostats?" Introduction to Venus. Almost everybody here knows the planet Venus. Our bright sister planet, and the hell of all. But at the altitude of about 53 km, conditions here is so far the most Earth-like in the solar system, with near-Earth...
  30. A

    Aerostat on Venus vs Surface Colony on Mars

    Idk where i picked this up, but there is one other plausible colony destination for humans: Venus. After a few trips on the net, I've come to the "Aerostat on Venus" side instead of a colony on mars. I'll mention some of the reasons I've picked up as to why: 1. Tons of CO2, we can use that. 2...
  31. S

    Venus' Synodic Year: Why Does It Take Longer Than Earth's?

    Why do venus take more number of days for one complete rotation around sun than Earth when the gravitational pull towards venus is higher than Earth ?
  32. azizlwl

    Transit of Venus: Venus Passes Directly Between Sun & Superior Planet

    A transit of Venus across the Sun takes place when thplanet"etVenus passes directly between the Sun and a superior planet, becoming visible against (and hence obscuring a small portion of) the solar disk. During a transit, Venus can be seen from Earth as a small black disk moving across the face...
  33. I

    Why did Venus lose its oceans?

    I watched an episode of the new Cosmos series and in it the astronomer mentioned that Venus receives 30% more solar radiation than the Earth but that was not the cause of the out of control global warming on Venus. Further he said that Venus had oceans similar to Earth but lost them early. I...
  34. I

    Earth's orbit & precession affected by Venus & Jupiter?

    I watched a program that said that some of Earth's past climate change was due to variations in Earth's orbit and precession due to the the gravitational perturbations caused by Venus and Jupiter. Why would that be so? I know that the orbits of the planets are eliiptical generally and they...
  35. marmstrong941

    Venus Info: Is It Hot & How to Cool It Down?

    Is venus hot because heat from the sun or is it from internal heat? How much of the suns light would have to be blocked in order to get it to cool down? No its not nuts some day we will mine rocks in space and a few flat rings around venus might do the trick.
  36. Stephanus

    B Terraforming Venus: Why Nobody Discusses It?

    Dear PF Forum, Why nobody ever thinks of terraforming Venus? Many propose Mars, even as far as Europa (not the continent!) or Titan. Mars has very little atmosphere compared to Earth. Titan has thick atmosphere but too cold. I once read that Carl Sagan proposed the idea by spreading bacterias in...
  37. Y

    Help with Venus Transit AU calculations

    Hello! So I've been looking at making a decent calculation of the AU from the 2012 transit. As you can see from the first picture (Taken with the South Pole at the top), this is the method I'm using from the following video: I use 2*(Pi)/Period of Earth to calculate the angular speed from...
  38. Mazin Nasralla

    Venus Transit - What should be a simple problem

    I was given a question which I have worked out, but not to my satisfaction... "if the inclination of Earth and Venus orbit was the same, how often would the transit occur?" I am given 4 options and I have got the right answer, but I did it by trial and error, and I am sure that there must be a...
  39. R

    Venusian Angular Units (vau): Describe & Calculate Sun's Parallax

    Homework Statement Like humans, astronomers of Venus use the same method for definitions of parallaxes and of parsec but measure them in different (their own) units. For example, the distance to Sirius equals to 19.6 vpc (19.6 venusial parsec). - Describe the most evident system of angular...
  40. lpetrich

    High-temperature semiconductors -- mission to Venus

    I was motivated to research this by discovering plans for a Venus rover: Windsurfing on a Wicked World | NASA That planet has the problem of a surface temperature of about 450 C and pressure around 92 bar. Its atmosphere is mostly CO2 with a few percent N2 and much less of various other gases...
  41. Hercuflea

    NASA NASA proposes "Cloud City" above Venus

    http://www.cnet.com/news/nasa-wants-to-build-a-floating-city-above-the-clouds-of-venus/ This is something I've been hoping they would do for a long time. Let's hope it gets approved. What are your thoughts?
  42. A

    A few very specific questions about Venus

    Hi, I am working on an animated short movie about a mission to Venus. I have a few very specific questions to help me get an authentic look. Firstly, would an object in long term orbit around Venus (say a hundred thousand years or so) become coated in dust? If so, what colour? Secondly, what...
  43. N

    Can someone explain the mathematics of this formula for Venus' orbit

    I've always been interested by the pattern within venus' orbit around the sun. I found this image and the formula of its retrograde motion in the upper right hand corner which confused me. What does it mean? can someone break this down in layman's terms...
  44. MattRob

    How Did The CCCP See Past Venus' Clouds Prior to Landing?

    So, this is something that's got me wondering; The CCCP landed crafts on Venus, and more recently, NASA landed the Huygens on Titan. Both of these worlds are shrouded in clouds that block any visible light from coming back from the surface, though. But to send a lander, you obviously...
  45. Greg Bernhardt

    August 18 - Conjunction of Venus and Jupiter

    August 18 - Conjunction of Venus and Jupiter. Conjunctions are rare events where two or more objects will appear extremely close together in the night sky. The two bright planets will come unusually close to each other, only a quarter of a degree, in the early morning sky. Also, the beehive...
  46. Nostalgia00

    Atmospheric Transmittance Venus?

    Hi guys this is my first post! I've been trying to find a plot of the atmospheric transmittance of Venus but I've had no luck. I'm particularly interested in the C-band transmittance. Thanks for any information you have!
  47. T

    What substance could potentially flow and pool on the surface of Venus?

    I realize that there are no lakes or rivers on Venus, but, given the surface temperature, pressure, etc. what substance COULD flow and pool on Venus the way water and liquid ethane flow and pool on the surfaces of Earth and Titan respectively?
  48. F

    Venus Jupiter and Moon Conjunction HD Timelapse

    Venus Jupiter and Moon Conjunction HD Timelapse Huge Full Moon Rise - Realtime 2600mm 720p http://www.youtube.com/watch?annotation_id=annotation_177268&feature=iv&src_vid=ZiYhzJ8jiAg&v=n_wt0M8vm0c MOON ZOOM 1600x digital zoom Ive been quite impressed with the latest digital...
  49. A

    New Theory: Moon Formation & Potential Venus Collision

    I have recently come across a new theory about the formation of the moon. It says that the Earth was rotating faster than it is now and was side-swiped by an object larger than Mars. Is it possible that object was Venus and the collision caused the Earth to slow down and the rotation of Venus...
  50. W

    Asteroid Impacting Venus: Will it Strike or Explode?

    Lets say you have a 20 km wide stony/iron asteroid hurtling towards Venus at 18 km per second at a 45 degree angle. Would an asteroid of this size hit the surface of Venus or just blow up in the atmosphere? I know that an asteroid of this size would hit the surface of Earth but I am...