Venus Definition and 12 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. Andre

    A Presentation: Venus hot break hypothesis

    The idea will be presented at the ancient Venus conference Houston 25 Jul. The abstract: Some of the earliest members may remember a thread about...
  2. 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]
  3. 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...
  4. 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?
  5. 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...
  6. N

    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...
  7. 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...
  8. 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...
  9. 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...
  10. Stephanus

    B Venus, terraforming

    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...
  11. 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...
  12. 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...