The innermost planet is rarely seen
because of the Sun's glare. With less
than half Earth's gravity, Mercury retains only a wisp of an atmosphere (presumed to be helium). The lack of a
significant atmosphere allows temperatures
to fluctuate from 750 degrees Fahrenheit during the day to minus 320 Fahrenheit at night.
Like the other terrestrial planets
-- Venus, Earth and Mars -- Mercury is made
mostly of rock and metal. This small world is scarred by craters and looks somewhat like our Moon.
Historical notes
Mercury has been known since ancient
times. Its elusiveness generated the
name Hermes, given by the Greeks, later translated to Mercurius by the Romans.
The second planet from the sun bakes
under twice as much solar radiation as
Earth and reaches temperatures of 895 degrees Fahrenheit (480 degrees Celsius). Pressure from the dense
atmosphere of sulfuric acid gas is about
95 times greater than Earth's and would crush a human. The thick cloud cover around Venus rotates
much faster than the planet itself --
once every four days. After the moon, Venus is the brightest object in the sky.
The surface of Venus is mostly a
rocky desert (this computer-generated view
shows lava flows around Sif Mons). Like Mercury, Earth and Mars, Venus is composed of mostly rock and metal.
The Greeks believed Venus was two
separate objects -- one in the morning
skyand another in the evening. Because it is often brighter than any other object in the sky -- except for the
sun and moon -- Venus has generated many
UFO reports.
While all of the planets orbit in an
ellipse, Venus' orbit is the closest to a perfect circle. It is the only planet in the
solar system whose day (241 Earth days)
is longer than its year (225 Earth days).
| ! |
Как писать рефераты Практические рекомендации по написанию студенческих рефератов. |
| ! | План реферата Краткий список разделов, отражающий структура и порядок работы над будующим рефератом. |
| ! | Введение реферата Вводная часть работы, в которой отражается цель и обозначается список задач. |
| ! | Заключение реферата В заключении подводятся итоги, описывается была ли достигнута поставленная цель, каковы результаты. |
| ! | Оформление рефератов Методические рекомендации по грамотному оформлению работы по ГОСТ. |
| → | Виды рефератов Какими бывают рефераты по своему назначению и структуре. |