pogoda: Observations and explorations of Venus

Evidence: 42 • authority: 88

Venus dayside observation campaign performed by multiple space missions and ground-based facilities. Despite a long history of Venus observations, we still miss information about the spectral and solar phase angle dependences of the Venus dayside. Recently, the Venus atmosphere was found to undergo temporal variations [1-3]. But variability of scattering properties of the Venus disk is not yet quantified, and only a long-term average is known [4-6]. In Aug-Sep 2020 we performed a unique Venus dayside campaign (Fig. 1) by 3 spacecraft and 6 ground-based telescopes over a broad spectral range (45-1700 nm) (Fig. 2). During the cruise to Mercury, BepiColombo’s UV spectrometer PHEBUS condu…

Evidence: 42 • authority: 88

Habitability Timeline of Venus: Past and Present. Venus is commonly known as the beautiful Evening Star of the night sky. Despite its bulk composition and size being similar (Interior ESI 0.98) to those of Earth, Venus is an extremely hot and dry planet, with temperatures ranging from 630 - 740K. With the current physical conditions, a potential areal biosphere could exist on the sulphuric acid-dominated clouds, providing moderate temperatures and pressures due to high altitudes. A theorised Iron or Sulphur metabolism could support exotic life in these extremely acidic (pH 0) conditions. The past habitability for regular life could be connected to the present habitability for exotic life th…

Evidence: 42 • authority: 72

Galileo di Vincenzo Bonaiuti de' Galilei (15 February 1564 – 8 January 1642), commonly referred to as Galileo Galilei or mononymously as Galileo, was an Italian astronomer, physicist, engineer and polymath. He was born in Pisa, then part of the Duchy of Florence. Galileo has been called the father of observational astronomy, classical physics, the scientific method, and modern science. He studied speed and velocity, gravity and free fall, the principle of relativity, inertia, projectile motion, and also worked in applied science and technology, describing the properties of the pendulum and "hydrostatic balances". He was one of the earliest developers of the thermoscope and the inventor of v…

Evidence: 42 • authority: 72

Venus is the second planet from the Sun. Similar in size and mass to Earth, Venus has no liquid water, and its atmosphere is far thicker and denser than that of any other rocky body in the Solar System. The atmosphere is composed mostly of carbon dioxide and has a thick cloud layer of sulfuric acid that spans the whole planet. At the mean surface level, the atmosphere reaches a temperature of 737 K (464 °C; 867 °F), making it the hottest planet in the solar system and also a pressure 92 times greater than Earth's at sea level, turning the lowest layer of the atmosphere into a supercritical fluid. From Earth, Venus is visible as a star-like point of light, appearing brighter than any other n…

Evidence: — • authority: 72

There have been 47 space missions to the planet Venus (including gravity-assist flybys). Missions to Venus constitute part of the exploration of Venus. The Soviet Union, followed by the United States, have soft landed probes on the surface. Venera 7 was the first lander overall and first for the Soviet Union, touching down on 15 December 1970. Pioneer Venus 2 contained the first spacecraft to land from the United States, the Day Probe. It soft landed on 9 December 1978. The most recent lander was part of the Vega 2 mission, which soft landed on 15 June 1985.

Evidence: — • authority: 72

The history of longitude describes the centuries-long effort by astronomers, cartographers and navigators to discover a means of determining the longitude (the east-west position) of any given place on Earth. The measurement of longitude is important to both cartography and navigation. In particular, for safe ocean navigation, knowledge of both latitude and longitude is required, however latitude can be determined with good accuracy with local astronomical observations. Finding an accurate and practical method of determining longitude took centuries of study and invention by some of the greatest scientists and engineers. Determining longitude relative to the meridian through some fixed loca…

Evidence: — • authority: 72

The phases of Venus are the variations of lighting seen on the planet's surface, similar to lunar phases. The first recorded observations of them are thought to have been telescopic observations by Galileo Galilei in 1610. Although the extreme crescent phase of Venus has since been observed with the naked eye, there are no indisputable historical pre-telescopic records of it being described or known.

Evidence: — • authority: 72

A transit of Venus takes place when Venus passes directly between the Sun and the Earth (or any other superior planet), becoming visible against (and hence obscuring a small portion of) the solar disk. During a transit, Venus is visible as a small black circle moving across the face of the Sun. Transits of Venus reoccur periodically. A pair of transits takes place eight years apart in December (Gregorian calendar) followed by a gap of 121.5 years, before another pair occurs eight years apart in June, followed by another gap, of 105.5 years. The dates advance by about two days per 243-year cycle. The periodicity is a reflection of the fact that the orbital periods of Earth and Venus are clos…

Evidence: — • authority: 72

The possibility of life on Venus is a subject of interest in astrobiology due to Venus's 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. With extreme surface temperatures reaching nearly 735 K (462 °C; 863 °F) and an atmospheric pressure 92 times that of Earth, the conditions on…

Evidence: — • authority: 80

GALILEO'S TELESCOPIC OBSERVATIONS OF VENUS AND MARS

Evidence: — • authority: 88

Venus atmosphere dynamics: digging into the Venus Express observations. Dynamics of the Venus atmosphere is still an unsolved fundamental problem in the planetary physics. ESA’s Venus Express collected long imaging time series in several wavelengths from UV to near-IR. It was later complemented by JAXA’s Akatsuki observations, thus providing the longest almost uninterrupted monitoring of the Venus atmosphere dynamics for about 26 Venus years. Tracking of cloud features allowed determination of wind speed at different levels within the cloud deck thus enabling significant progress in characterization of the mean atmospheric circulation. The analysis revealed wind variability incl…

Evidence: — • authority: 92

Possible Effects of Volcanic Eruptions on the Modern Atmosphere of Venus.. This work reviews possible signatures and potential detectability of present-day volcanically emitted material in the atmosphere of Venus. We first discuss the expected composition of volcanic gases at present time, addressing how this is related to mantle composition and atmospheric pressure. Sulfur dioxide, often used as a marker of volcanic activity in Earth's atmosphere, has been observed since late 1970s to exhibit variability at the Venus' cloud tops at time scales from hours to decades; however, this variability may be associated with solely atmospheric processes. Water vapor is identified as a particularly va…