Computer Simulated Global View of Venus.
📷 NASA/Jet Propulsion Laboratory-Caltech
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.
Venus is the second planet from the Sun, orbiting it every 224.7 Earth days. It has the longest rotation period (243 days) of any planet in the Solar System and rotates in the opposite direction to most other planets.
It does not have any natural satellites. It is named after the Roman goddess of love and beauty.
It is the second-brightest natural object in the night sky after the Moon, reaching an apparent magnitude of −4.6 – bright enough to cast shadows at night and, rarely, visible to the naked eye in broad daylight.
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 92 times that of Earth, or roughly the pressure found 900 m (3,000 ft) underwater on Earth. Venus is by far the hottest planet in the Solar System, with a mean surface temperature of 735 K (462 °C; 863 °F), even though Mercury is closer to the Sun.
As the closest planet 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.
Much of the Venusian surface appears to have been shaped by volcanic activity. Venus has several times as many volcanoes as Earth, and it has 167 large volcanoes that are over 100 km (62 mi) across. The only volcanic complex of this size on Earth is the Big Island of Hawaii. This is not because Venus is more volcanically active than Earth, but because its crust is older. Earth’s oceanic crust is continually recycled by subduction at the boundaries of tectonic plates, and has an average age of about 100 million years, whereas the Venusian surface is estimated to be 300–600 million years old.
As it orbits the Sun, Venus displays phases like those of the Moon in a telescopic view. The planet appears as a small and “full” disc when it is on the opposite side of the Sun (at superior conjunction). Venus shows a larger disc and “quarter phase” at its maximum elongations from the Sun, and appears its brightest in the night sky. The planet presents a much larger thin “crescent” in telescopic views as it passes along the near side between Earth and the Sun. Venus displays its largest size and “new phase” when it is between Earth and the Sun (at inferior conjunction). Its atmosphere is visible through telescopes by the halo of sunlight refracted around it.
The Venusian orbit is slightly inclined relative to Earth’s orbit; thus, when the planet passes between Earth and the Sun, it usually does not cross the face of the Sun. Transits of Venus occur when the planet’s inferior conjunction coincides with its presence in the plane of Earth’s orbit. Transits of Venus occur in cycles of 243 years with the current pattern of transits being pairs of transits separated by eight years, at intervals of about 105.5 years or 121.5 years—a pattern first discovered in 1639 by the English astronomer Jeremiah Horrocks.
In 1967, Venera 4 found Venus’s magnetic field to be much weaker than that of Earth. This magnetic field is induced by an interaction between the ionosphere and the solar wind, rather than by an internal dynamo as in the Earth’s core. Venus’s small induced magnetosphere provides negligible protection to the atmosphere against cosmic radiation.
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images: Mattias Malmer/NASA/JPL, Peter Barvoets, Soviet Planetary Exploration Program, NSSDC, Marc Lecleire, ESA, C. Carreau,
Try bringing two of your fingers closer in the back drop of a light source and you would observe this:
Long before your fingers actually touch, the edges magically seem to touch each other. How is this even possible?
When scientists were observing the transit of Venus from Earth i.e when the planet Venus passes directly between the Sun and Earth,they faced a similar problem.
At the moment when Venus should nearly touch the edge of the sun, the circular planet began to elongate.
PC: NASA
And they noticed the same phenomenon for Mercury as well (which has no atmosphere).
The physics behind this beautifully bizarre optical phenomenon will be revealed tomorrow on FYP!.
But since this is something that you can all try at home, we strongly encourage you to play around with this and get a feel for it. It requires only your hands and a source of light.
Once you do, try to hypothesize a solution for this behavior.
Have fun!
Die Startfolge der Hörspielserie Mark Brandis, Raumkadett überrascht die Commander-Perkins-Fans mit einer Wiedervereinigung der Stimmen ihrer Helden: Nach 34 Jahren sind Horst Stark, Gabi Libbach und Gernot Endemann erstmals wieder zusammen in einem Science-Fiction-Werk zu hören …
Alle Links in unserer “Ortungsleitzentrale” (olz)…
Night sky just after sunset on March 24, 2012 with crescent moon and backlight, Jupiter, Venus and the Pleiades.
by Ritzelmut
Bruce McCandless II (June 8, 1937 – December 21, 2017)
Rest In Peace
Solar System Infographs
Radar Image of the surface of Venus, centered at 180 degrees east longitude. Magellan imaging 1990-94
via reddit
Artist’s concept of Pioneer Venus mission approaching the planet.
During a 14-year orbit of Venus, Pioneer Venus 1 used radar to map the surface at a resolution of 75 km (47 miles). It found the planet to be generally smoother than Earth, though with a mountain higher than Mt. Everest and a chasm deeper than the Grand Canyon. The orbiter also found Venus to be more spherical than Earth, consistent with the planet’s much slower rotation rate (one Venus day equals 243 Earth days). It confirmed that Venus has little, if any, magnetic field and found the clouds to consist mainly of sulfuric acid. Measurements of this chemical’s decline in the atmosphere over the course of the mission suggested that the spacecraft arrived soon after a large volcanic eruption, which may also account for the prodigious lightning it observed.
After a course correction on 16 August 1978, Pioneer Venus 2 released the 1.5-m diameter large probe on 16 November 1978, at about 11.1 million km from the planet. Four days later, the bus released the three small probes while 9.3 million km from Venus. All five components reached the Venusian atmosphere on 9 December 1978, with the large probe entering first.
Data from the probes indicated that between 10 and 50 km, there is almost no convection in the Venusian atmosphere. Below a haze layer at 30 km, the atmosphere appears to be relatively clear. Amazingly, two of three probes survived the hard impact. The so-called Day Probe transmitted data from the surface for 67.5 minutes before succumbing to the high temperatures and power depletion.
Credit: NASA/Rick Guidice
Thoughts on revisting Venus
Image of the clouds of Venus via the European Space Agency
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