mosikhafan74
Registered User
- تاریخ عضویت
- 12 سپتامبر 2009
- نوشتهها
- 15
- لایکها
- 0
سلام دوستان.یک متن انگلیسی ا رو که از سایت ناسا گرفتم می خوام یک حرفه ای ترجمه کنه.
ممنون میشم اگه سرعتر باشه.تا تاریخ 89/2/19
متن:
Humans have gazed at the heavens and tried to understand the cosmos for thousands of years. Ancient civilizations placed great emphasis on careful astronomical observations. Early Greek astronomers were among the first to leave a written record of their attempts to explain the cosmos. For them, the universe was Earth, the Sun, the Moon, the stars, comets and five glowing points of light that moved among the stars. The Greeks named the five points of light - called planetos, or wanderers - after their gods. The Romans later translated the names into Latin - Mercury, Venus, Mars, Jupiter, and Saturn - and these are the names astronomers use today. Planetary features are named by the International Astronomical Union, founded in 1919.
Ancient observers believed that the Sun and all the other celestial bodies revolved around Earth. But astronomers gradually realized that the Earth-centered model did not account for the motions of the planets. In 1610, Galileo Galilei's discoveries using the recently invented telescope strongly supported the concept of a solar system in which all the planets, including Earth, revolve around a central star - the Sun.
Planetary moons, the rings of Saturn, and more planets were eventually discovered: Uranus (in 1781) and Neptune (1846). The largest known asteroid, Ceres, was discovered between Mars and Jupiter in 1801. Originally classified as a planet, Ceres is now designated a dwarf planet (but retains its asteroid label), along with Pluto, which was discovered in 1930; Eris, found in 2003; Haumea, found in 2004; and Makemake, found in 2005. Most of the asteroids orbit in a region between the orbits of Mars and Jupiter, while the home of comets lies far beyond the orbit of Pluto, in the Oort Cloud.
Our solar system formed about 4.6 billion years ago. The four planets closest to the Sun - Mercury, Venus, Earth, and Mars - are called the terrestrial planets because they have solid, rocky surfaces. Two of the outer planets beyond the orbit of Mars - Jupiter and Saturn - are known as gas giants; the more distant Uranus and Neptune are called ice giants.
Earth's atmosphere is primarily nitrogen and oxygen. Mercury has a very tenuous atmosphere, while Venus has a thick atmosphere of mainly carbon dioxide. Mars' carbon dioxide atmosphere is extremely thin. Jupiter and Saturn are composed mostly of hydrogen and helium, while Uranus and Neptune are composed mostly of water, ammonia, and methane, with icy mantles around their cores. The Voyager 1 and 2 spacecraft visited the gas giants, and Voyager 2 flew by and imaged the ice giants. Ceres and the outer dwarf planets - Pluto, Eris, Haumea, and Makemake - have similar compositions and are solid with icy surfaces. NASA spacecraft are en route to two of the dwarf planets to study them - the Dawn mission will visit Ceres in 2015 and the New Horizons mission will reach Pluto in that same year. Neither Ceres nor Pluto has been visited by a spacecraft. New Horizons is on a course that may allow it to investigate other Kuiper Belt Objectsin the future.
Moons, rings, and magnetic fields characterize the planets.There are 146 known planetary moons, with at least 21 moons awaiting official recognition. Many of these were discovered by planetary spacecraft. Three dwarf planets also have moons: Pluto has three, Eris has one, and Haumea has two. The planetary moons are not all alike: Saturn's Titan has a thick atmosphere and Jupiter's Io has active volcanoes. An ocean may lie beneath the frozen crust of Jupiter's moon Europa, while images of Jupiter's moon Ganymede show historical motion of icy crustal plates.
Rings are an intriguing planetary feature. From 1659 to 1979, Saturn was thought to be the only planet with rings. NASA's Voyager missions to the outer planets showed that Jupiter, Uranus, and Neptune also have ring systems. Saturn's remains by far the largest.
Most of the planets have magnetic fields that extend into space and form a magnetosphere around each planet. These magnetospheres rotate with the planet, sweeping charged particles with them.[/LEFT
ممنون میشم اگه سرعتر باشه.تا تاریخ 89/2/19
متن:
Humans have gazed at the heavens and tried to understand the cosmos for thousands of years. Ancient civilizations placed great emphasis on careful astronomical observations. Early Greek astronomers were among the first to leave a written record of their attempts to explain the cosmos. For them, the universe was Earth, the Sun, the Moon, the stars, comets and five glowing points of light that moved among the stars. The Greeks named the five points of light - called planetos, or wanderers - after their gods. The Romans later translated the names into Latin - Mercury, Venus, Mars, Jupiter, and Saturn - and these are the names astronomers use today. Planetary features are named by the International Astronomical Union, founded in 1919.
Ancient observers believed that the Sun and all the other celestial bodies revolved around Earth. But astronomers gradually realized that the Earth-centered model did not account for the motions of the planets. In 1610, Galileo Galilei's discoveries using the recently invented telescope strongly supported the concept of a solar system in which all the planets, including Earth, revolve around a central star - the Sun.
Planetary moons, the rings of Saturn, and more planets were eventually discovered: Uranus (in 1781) and Neptune (1846). The largest known asteroid, Ceres, was discovered between Mars and Jupiter in 1801. Originally classified as a planet, Ceres is now designated a dwarf planet (but retains its asteroid label), along with Pluto, which was discovered in 1930; Eris, found in 2003; Haumea, found in 2004; and Makemake, found in 2005. Most of the asteroids orbit in a region between the orbits of Mars and Jupiter, while the home of comets lies far beyond the orbit of Pluto, in the Oort Cloud.
Our solar system formed about 4.6 billion years ago. The four planets closest to the Sun - Mercury, Venus, Earth, and Mars - are called the terrestrial planets because they have solid, rocky surfaces. Two of the outer planets beyond the orbit of Mars - Jupiter and Saturn - are known as gas giants; the more distant Uranus and Neptune are called ice giants.
Earth's atmosphere is primarily nitrogen and oxygen. Mercury has a very tenuous atmosphere, while Venus has a thick atmosphere of mainly carbon dioxide. Mars' carbon dioxide atmosphere is extremely thin. Jupiter and Saturn are composed mostly of hydrogen and helium, while Uranus and Neptune are composed mostly of water, ammonia, and methane, with icy mantles around their cores. The Voyager 1 and 2 spacecraft visited the gas giants, and Voyager 2 flew by and imaged the ice giants. Ceres and the outer dwarf planets - Pluto, Eris, Haumea, and Makemake - have similar compositions and are solid with icy surfaces. NASA spacecraft are en route to two of the dwarf planets to study them - the Dawn mission will visit Ceres in 2015 and the New Horizons mission will reach Pluto in that same year. Neither Ceres nor Pluto has been visited by a spacecraft. New Horizons is on a course that may allow it to investigate other Kuiper Belt Objectsin the future.
Moons, rings, and magnetic fields characterize the planets.There are 146 known planetary moons, with at least 21 moons awaiting official recognition. Many of these were discovered by planetary spacecraft. Three dwarf planets also have moons: Pluto has three, Eris has one, and Haumea has two. The planetary moons are not all alike: Saturn's Titan has a thick atmosphere and Jupiter's Io has active volcanoes. An ocean may lie beneath the frozen crust of Jupiter's moon Europa, while images of Jupiter's moon Ganymede show historical motion of icy crustal plates.
Rings are an intriguing planetary feature. From 1659 to 1979, Saturn was thought to be the only planet with rings. NASA's Voyager missions to the outer planets showed that Jupiter, Uranus, and Neptune also have ring systems. Saturn's remains by far the largest.
Most of the planets have magnetic fields that extend into space and form a magnetosphere around each planet. These magnetospheres rotate with the planet, sweeping charged particles with them.[/LEFT
How big is our solar system? To think about the large distances, we use a cosmic ruler based on the astronomical unit (AU). One AU is the distance from Earth to the Sun, which is about 150 million kilometers or 93 million miles. The area of the Sun's influence stretches far beyond the planets, forming a giant bubble called the heliosphere. The enormous bubble of the heliosphere is created by the solar wind, a stream of charged gas blowing outward from the Sun. As the Sun orbits the center of the Milky Way, the bubble of the heliosphere moves also, creating a bow shock ahead of itself in interstellar space - like the bow of a ship in water - as it crashes into the interstellar gases. The area where the solar wind is abruptly slowed by pressure from gas between the stars is called the termination shock.
A spacecraft that reached the termination shock would be able to measure the slowing effect, and that is exactly what happened when Voyager 1 began sending unusual data to Earth in late 2003. In December 2004, scientists confirmed that Voyager 1 had crossed the termination shock at about 94 AU, approximately 13 billion kilometers (8.7 billion miles) from the Sun, venturing into the vast, turbulent expanse where the Sun's influence diminishes. Voyager 2, 16 billion kilometers (10 billion miles) from Voyager 1, crossed the termination shock in August 2007.
Voyager 1 may reach interstellar space sometime between 2014 and 2017; the spacecraft should have enough electrical power to continue to send data until at least 2020. It will be thousands of years before the two Voyagers exit the enormous Oort Cloud, a vast spherical shell of icy bodies surrounding the solar system.
As we explore the universe, we wonder: Are there other planets where life might exist? Are we alone? These are the great questions that science is now probing. Only recently have astronomers had the tools to detect large planets around other stars other solar systems using telescopes on Earth and in space.
How Our Solar System Got its Name
A solar system describes a group of celestial bodies orbting a star. Our solar system is one of many in our galaxy.
A spacecraft that reached the termination shock would be able to measure the slowing effect, and that is exactly what happened when Voyager 1 began sending unusual data to Earth in late 2003. In December 2004, scientists confirmed that Voyager 1 had crossed the termination shock at about 94 AU, approximately 13 billion kilometers (8.7 billion miles) from the Sun, venturing into the vast, turbulent expanse where the Sun's influence diminishes. Voyager 2, 16 billion kilometers (10 billion miles) from Voyager 1, crossed the termination shock in August 2007.
Voyager 1 may reach interstellar space sometime between 2014 and 2017; the spacecraft should have enough electrical power to continue to send data until at least 2020. It will be thousands of years before the two Voyagers exit the enormous Oort Cloud, a vast spherical shell of icy bodies surrounding the solar system.
As we explore the universe, we wonder: Are there other planets where life might exist? Are we alone? These are the great questions that science is now probing. Only recently have astronomers had the tools to detect large planets around other stars other solar systems using telescopes on Earth and in space.
How Our Solar System Got its Name
A solar system describes a group of celestial bodies orbting a star. Our solar system is one of many in our galaxy.
