Humans have looked out from Earth for millennia and seen the bright “morning” or “evening” star. It is the planet Venus, called after the Roman goddess of love, the only planet called after a goddess, rather than a God. Although people call Venus Earth’s sister planet, because it has similarities with our Earth, there are many features, which make Venus unique in the solar system.
Venus sits between Mercury and Earth in the solar system and is the sixth largest planet in the solar system. It is very similar to Earth in size, mass, and density. Venus’s chemistry is also the same as that of the Earth and it is made of similar materials and in roughly the same amounts. Just like Earth, Venus is a terrestrial planet, and has sand, volcanoes, and mountains. Early in its history, Venus would have seemed very similar to Earth. Scientists now believe that Venus had oceans like the Earth but that the Sun’s heat boiled them away beginning a warming effect that made Venus the inferno that it now is. Like Earth, Venus has a magnetic field, but Venus’s magnetic field differs from Earth’s in that it comes not from the planets core, but from the interaction between the ionosphere and solar wind. Although, Venus has a rotating-liquid-core, like Earth, but its core unlike the Earth’s core, cannot move heat by convection because the encrusted volcanic rock on its surface does not allow it to do so.
Venus differs greatly from Earth in that its temperature, atmospheric pressure, sulphuric-acid clouds and rain; make it impossible for human exploration. Radar exploration reveals that Venus has a very thick reflective atmosphere. Venus reflects over 70% of the sun’s light and it is the most reflective of all the planets. The planet’s surface and its thick clouds make it very reflective. These properties are what make Venus so bright and visible. Venus, like Mercury, has no satellites.
Venus differs in many ways from every other planet in the solar system. Venus has a much longer day than any other planet in the solar system. Three times longer than any other planet. This is because its orbital passage is very slow. Venus spins more slowly than other planets and completes its orbit in 243 days. Whilst the other planets all spin counter-clockwise, Venus spins in a clockwise direction. Scientists now think that Venus originally spun in the same direction as the other planets, but that something happened to change this. Scientists class Venus as a terrestrial planet, like Earth, Mars, and Mercury, however Venus’s atmosphere is the denser than any of their atmospheres. Venus is the hottest planet in the solar system and the only planet having no apparent ice. Scientists believe that Venus has no liquid water and almost no hydrogen.
Humans have looked at Venus, with wondering eyes, since earliest times. It is the most familiar object in the sky. Humans often see it in the morning or at dusk. We still refer to Venus as the morning or evening star. Famous scientists, such as Galileo and Copernicus have studied Venus. In modern times, humans sent spaceships to study Venus. From the Mariner 2 Venus mission more than 20 spaceships have studied Venus adding to scientific knowledge. The Russian spaceship Venera 9 took the first photographs of Venus’s surface. The US Magellan orbiter mission used radar to compile detailed maps of the planet’s surface. Venus Express is the latest space mission and its sophisticated instruments will further enhance human understanding of Earth’s nearest neighbour and ‘sister’ planet. Though humans thought Venus so similar to Earth, that we would find life resembling humans on Venus, what scientists did find is so interesting that it really does not matter. They found that though Venus is similar to Earth in some ways, she is unique in the solar system. Perhaps the ancients named Venus, uniquely after the goddess of love, rather than a god, because they instinctively knew Venus was unique.