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كود:
A solar eclipse occurs when the Moon passes in front of the Sun as seen from Earth, and can happen only at new Moon. During a total eclipse the Sun’s corona can be seen. A total solar eclipse can last up to 7.5 minutes. When the Moon is at its farthest from the Earth it does not completely cover the face of the Sun, leaving a ring of sunlight visible. This is an annular eclipse. Between two and five solar eclipses occur each year but each is visible only from a specific area. A lunar eclipse occurs when the Moon passes into the shadow of the Earth, becoming dim until emerging from the shadow. Lunar eclipses may be partial or total, and they can happen only at full Moon. Total lunar eclipses last up to 100 minutes; the maximum number each year is three.
A total solar eclipse visible from southwestern England took place on 11 August 1999 and lasted for two minutes. This was the first total solar eclipse to be visible from the UK since 1927, the next will be in 2090.
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كود:
The Moon is an earth satellite orbiting our planet from a distance of 384,000kms on average, and its orbit is in a west-to-east direction. Its surface gravity is only 0.16 that of the Earth (one sixth), and it does not seem to have life on it, since it has neither atmosphere nor water. Minimum and maximum temperatures on it are wide apart, with +110˚C on the sunlit side and –170˚C in lunar nights. The geology of this satellite is rock only, and its age is about 4,6 billion years.
Plans to reach the Moon on space crafts have been on scientists’ minds since early 20th century. But they became more concrete when the Russians launched space crafts Sputnik 1 and Sputnik 2 in 1957, the second one carrying dog Laika. In 1961, Yuri Gagarin orbited the Earth, followed by the American astronaut John Glenn in 1962. Finally, America won the honour of reaching the Moon before Russia, when Neil Armstrong set foot on it on July 21st 1969.
There are at present plans to build a space base on the Moon, to set a giant telescope and launch space ships from there to distant planets, and perhaps to other solar systems.
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2015-06-02, 21:53
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