Venus is the 2nd planet from the sun and is also the hottest planet in the solar system. Venus is the 2nd brightest natural object in the night sky after the moon and this is a result of the suns light reflecting off the planet's dense atmosphere. Orbiting within Earth's orbit, Venus is an inferior planet and never appears to venture far from the Sun; its maximum angular distance from the Sun (elongation) is 47.8°.
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.
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.
The Atmosphere of Venus
The atmosphere of Venus is composed primarily of carbon dioxide and is much denser and hotter than that of Earth.
The Venusian atmosphere supports opaque clouds made of sulfuric acid, making optical Earth-based and orbital observation of the surface impossible. Information about the topography has been obtained exclusively by radar imaging. Aside from carbon dioxide, the other main component is nitrogen. Other chemical compounds are present only in trace amounts. Mikhail Lomonosov was the first person to hypothesize the existence of an atmosphere on Venus based on his observation of the transit of Venus of 1761 in a small observatory near his house in Saint Petersburg, Russia.
Unlike Earth, Venus lacks a magnetic field. Its ionosphere separates the atmosphere from outer space and the solar wind. This ionised layer excludes the solar magnetic field, giving Venus a distinct magnetic environment. This is considered Venus's induced magnetosphere. Lighter gases, including water vapour, are continuously blown away by the solar wind through the induced magnetotail. It is speculated that the atmosphere of Venus up to around 4 billion years ago was more like that of the Earth with liquid water on the surface. A runaway greenhouse effect may have been caused by the evaporation of the surface water and subsequent rise of the levels of other greenhouse gases.
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 is 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.
The Layers of Venus
Venus is a slightly smaller than the Earth, with a diameter 95% that of Earth (12,103 km) and a mass 81% that of Earth. If we could walk around on the surface of the planet (without being killed by the toxic blast furnace of an atmosphere), gravity would be close to that on the surface of Earth.
The interior of Venus is probably similar to Earth's interior. Venus, like Earth, is one of the terrestrial planets and is made of rock and metal. It probably has a partly molten metallic core, a rocky mantle, and a crust. The planet rotates very slowly, taking more than 243 Earth days to spin once on it's axis (even longer than the time it takes for Venus to orbit the Sun, about 225 Earth days). This may be the reason the planet doesn't have a magnetic field like many of the other planets, including Earth.
The Layers of Venus
- Liquid Core.
- Dense Atmosphere.