<script>on mouseUpput the short name of this card into xTempput char 2 to 6 of xTemp & ".mov" into Movie--put Movieif Movie is not empty then-- put "Videos:NASA:" & Movie into pMovieplayMovie Movie,"Videos:NASA:"end ifend mouseUp</script>
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<text><span class="style10">he Inner Planets (2 of 5)Venus</span><span class="style7">Venus is the Earth's nearest neighbor and is often the brightest object in the night sky, apart from the Moon. Like Mercury, Venus can only be seen with the naked eye in the morning or evening. Venus, like Mercury, also shows phases, which binoculars or a small telescope will reveal.Venus is covered by a dense atmosphere, so telescopes cannot show any surface detail. In 1962 astronomers managed to bounce radio waves off the planet and these showed that Venus was rotating backwards (i.e. in the opposite direction to the Sun and nearly all the other planets) once every 243 days.Venus's atmosphere is composed mainly of carbon dioxide and has clouds of sulfuric acid floating in it. Carbon dioxide acts rather like the glass in a greenhouse, letting in the energy from the Sun, but without allowing much heat to escape. The upper clouds race around the planet once every four days - much faster than the planet itself is turning.The first spacecraft to transmit from the surface of Venus was the Soviet </span><span class="style26">Venera 7</span><span class="style7">, which found a temperature of 470 deg C (878 deg F) and an atmospheric pressure 90 times that on Earth. The later probes, </span><span class="style26">Veneras 9, 10, 13</span><span class="style7"> and </span><span class="style26">14</span><span class="style7">, returned pictures from the surface of Venus.In 1978, the American </span><span class="style26">Pioneer-Venus</span><span class="style7"> spacecraft was put into orbit around the planet to start making a map of the surface, using radar to penetrate Venus's thick clouds. This revealed a complex surface with low-lying plains, upland areas, volcanoes and rift valleys. The American </span><span class="style26">Magellan</span><span class="style7"> spacecraft, launched in 1989, will produce a more detailed radar map of the planet's surface. Mission planners hope to detect features as small as 250 m (820 ft) across and the probe will study 92% of the planet.</span><span class="style10">The Earth</span><span class="style7">The Earth is the largest of the inner planets and the only planet able to support life. Its atmosphere consists mainly of nitrogen (78%) and oxygen (21%). Two thirds of its surface is covered by water, which has an average depth of 3700 m (12 140 ft). The land rises above the oceans to an average height of 860 m (2800 ft). More detailed information on the Earth's interior, atmosphere and magnetic field will be found on pp. 76-7.</span></text>
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<text><span class="style10">enus</span><span class="style7"> is seen revolving. However, due to its dense atmosphere the surface of the planet can not be seen. Venus is the closest planet to the Earth, but revolves in a direction opposite to that of the Sun, the Earth, and other planets.</span></text>
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<text>ΓÇó TIMEΓÇó THE SUN AND THE SOLAR SYSTEMΓÇó THE OUTER PLANETSΓÇó THE HISTORY OF ASTRONOMYΓÇó SPACE EXPLORATIONΓÇó THE EARTH'S STRUCTURE AND ATMOSPHERE</text>
