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| Sunday, 31 October 2004 |
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Junior Observer |  |
| News Business Features Editorial
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The changing Moon The Moon tours around our Planet Earth once every 29 days. And all that time one half of the Moon is bathed in sunlight and that is why we always see part of the Moon. The angle that the Moon makes with Earth and Sun keeps changing, altering the amount of Moon we can see from Earth. We call these phases.When the Moon lies between the Earth and Sun, the side of the Moon facing the Earth is dark. We call this the new moon phase. The thin slice of the Moon that shows up a day later is also described as the new moon. As the Moon moves around the Earth it waxes or seems to grow larger. The thin slice then becomes a crescent. One week after the new moon, the Moon assembles a half circle. This half circle stage is known as the first quarter. The whole face of
the Moon is seen one week after this and it is the full moon stage. It is
known as the second quarter.Then the Moon starts to Wane. A week after
full moon stage comes the last or third quarter. It is another half
circle. In its last phase, the visible Moon is a crescent that thins to
nothing.When the Moon appears between full and half circle in shape, it is
called gibbous by astronomers. ###### Why have space probes ? Space probes are what helps scientists and astronomers gather information about our solar system.There are many space probes conducted by the USA and Russian Federation. Most probes are not designed to return to Earth. Some of these probes have been successful in landing on other planets and sending back photographs taken from it.
The Cassini probe to Saturn was launched on October 15, 1997. It took Cassini seven long years to reach Saturn, the second largest planet in the solar system.The Cassini Space Mission is the biggest and most expensive probe to ever visit a planet and today scientists are excited with the information it is sending back to Earth about Saturn's rings and moons. On October 26, Cassini was due to near Titan ,one of Saturn's moons to take pictures with the aid of radar, according to NASA. In July too the probe passed Titan, but this October the probe was due to come within 1,200 kilometres (745 miles) of Titan. That is 250 times closer than before. Cassini has so far discovered that Titan is covered with thick fumes, Saturn has two new moons and a new ring around the planet. Cassini facts * One of the largest interplanetary spacecraft ever built, Cassini is about the same size as a 30-passenger school bus (The Yellow school buses we see in movies in the USA). * It weighs roughly 5,650 kg (6 tons) of which more than half is rocket fuel. It is the third heaviest unmanned spacecraft ever launched into space. * The spacecraft is 4 metres (13.1 feet) wide. * It has 12 high-tech instruments capable of 27 different science investigations. To operate them, it has an elaborate electronic system. And guess how much cables, wires and circuits there are in this system? More than 12 kilometres (almost 7.5 miles) of cabling, some 20,000 wire connections, and 1,630 interconnect circuits!* Cassini communicates with Earth through Deep Space Network's largest antennas which are upto 70 metres (230 feet) in diameter. * Cassini's senses are more powerful than ours. It can 'see' in wavelengths of light and energy which the human eye cannot, and 'feel' things about magnetic field and tiny dust particles we humans could never detect. |
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Others have just flown past planets and relayed pictures, so that
people down here on Earth can study these photographs and learn about
other planets.There are some space probes that have been designed to go
into orbit around other planets and conduct studies over long periods of
time. The information gathered by these space probes help us to know
what's happening in the solar system and also plan space missions such as
the Mars Pathfinder and Cassini.
