Wednesday, October 2, 2019
Venus :: essays research papers
Venus is the second planet from the sun and the sixth largest. Venusââ¬â¢ orbit is the most circular of any planet, with an eccentricy of less than 1%. Venus, perhaps because it is the brightest of planets known to the ancients, Is named after the Greek goddess of love and beauty. The planet of Venus has been known since prehistoric times and is the brightest object in the sky with the exception of the sun and the moon. Venusââ¬â¢ rotation is somewhat unusual in that it is both very slow ( 243 Earth days per Venus day) and retrograde. In addition, the periods of Venusââ¬â¢ rotation and of its orbit are synchronized such that it always presents the same face toward Earth when the two planets are at their closest approach. The pressure of the planetââ¬â¢s atmosphere at the surface is 90 atmospheres and is composed mostly of carbon dioxide. There are several layers of clouds which are many kilometers thick and composed of sulfuric acid. This dense atmosphere produces a run-away greenhouse effect that raises Venusââ¬â¢ surface temperature by about 400 degrees to over 740 K. The planet of Venus is often regarded as Earthââ¬â¢s sister planet, in some ways they are very similar. For example, Venus is only slightly smaller than Earth (95% of Earthââ¬â¢s diameter, 80% of Earthââ¬â¢s mass.) Both have few craters indicating relatively young surfaces. Their densities and chemical compositions are also similar. Because of these similarities, it was once thought that below itââ¬â¢s dense clouds, Venus might be very earthlike, perhaps to the point of containing life. However, a more detailed study of Venus revealed that many aspects of Venusââ¬â¢ atmosphere was much different from that of Earth. There are no small craters on Venus. It appears that small meteoroids burn up in Venusââ¬â¢ dense atmosphere before reaching the surface. Craters on Venus seem to come in bunches indicating that the large meteoroids that do reach the surface usually break up in the atmosphere. The oldest terrains on Venus seem to be about 800 million years old. Extensive volcanisms at the time wiped out the earlier surface including any large craters from early Venusââ¬â¢ history. The interior of Venus is probably very similar to that of Earth. It consists of an iron core about 3000 km in radius, a molten rocky mantle comprising the majority of the planet. Venus probably once had large
Subscribe to:
Post Comments (Atom)
No comments:
Post a Comment
Note: Only a member of this blog may post a comment.