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Mars
The planet Mars is the fourth planet from the Sun and the last of
the rocky planets and on the surface it looks like a rocky desert. Mars was known to Babylonian astronomers. Aristotle tried
to match the planets’ characteristics (e.g.. colour, speed and brightness) to the gods’ personalities. The red
colour of the planet reminded people of their god who gloried in fighting and bloodshed. The god’s constant companions
were phobos (fear) and deimos (terror) so these names were used for the moons. From Earth, using a telescope (Galileo Galilei
was first to do this in 1609), Mars looks like a reddish-orange ball; it has this colour because of red dust that is blown
from the surface every day. Sometimes the huge winds pick up large amounts of dust and create
planet wide dust-storms.
Mars’ diameter is about 6 786 km, making it the third smallest
planet in our Solar System. At its nearest, Mars is 207 million Km from the Sun, and at its furthest 249 million Km. Mars
is only 78 million Km from Earth on average.
The rotation period, Day, is similar to our own, only 24 hours and
37 minutes but the year is almost 2 of ours, 687 days.
The highest point on Mars is Olympus Mons, an old volcano that we
believe is extinct but we can’t be sure about it. The lowest point is Valles Marineris, a system of parallel canyons
that is about 4000 Km long, up to 7 Km deep and has an average width of 200 Km; making the Grand Canyon in the United States
look like a mark in the dirt made by someone with a stick.
The surface temperature on Mars ranges in summer from about
15oC in daylight down to -80oC at night and in winter it can get down to a freezing -145oC. The poles are made up of water-ice
and dry-ice (frozen carbon dioxide); these shrink with the seasons as it does on Earth. The atmosphere is made up of mainly
Carbon Dioxide (95%), Nitrogen (7.2%), Argon (1.6%) and Carbon Monoxide (0.08%). The planet is made up of a thin rocky crust,
a mantle that takes up most of the planet and an iron core, which scientists think has stopped spinning, giving the planet
a weak gravity. To find out how much you weigh on Mars, multiply your weight by 0.38.
Mars has 2 moons, called Phobos, in Greek meaning terror and Deimos,
fear. Phobos, the inner of the two, is only 9 378 Km from Mars’ centre and has an average diameter of 24 Km. Deimos
is 23 459 Km from Mars’ centre and has an average width of 13 Km. The moons’ colour is not at all like Mars’,
they are both a dark brown/black, suggesting they might have once been asteroids pulled into orbit by Mars’ gravity.
Phobos has an unstable orbit and will crash into Mars in about 30
million years. The moons were predicted in the stories Gullivers Travels and Micromegas long before they were observed by
telescope.
Some of the exploratory probes from Earth that have gone to Mars
have been successful, but not all. The first successful Mars probe was the U.S. Mariner 4 (1965), a fly-by that took 21 photos
of the southern hemisphere and measured atmospheric pressure.
The attached sheet shows how many attempts there have actually
been, particularly from 1962 to 1975. Some of the failures were due to human errors: for example, during one mission, one
of the ground teams calculated distances in kilometres and meters, while the other measured in miles and feet. The latest
landers / rovers, Spirit and Opportunity, have successfully landed and are sending back information constantly to N.A.S.A.
headquarters.
Scientists are planning for the near future. Humans may be able
to go to Mars by 2015. If astronauts ever visited Mars, they would some times have to wait 44 minutes for a reply from mission
control but only 8 minutes when Mars was at the closest point to Earth. Mars would be a relatively easy planet to terraform,
that is, to turn Earth like. The amount of atmosphere must be increased & changed to suit humans and the planet must be
warmed. The latest scientific studies show that it would take between 10 000 and 100 000 years.
To establish the first colony, we would have to construct huge domes
that would be super strong in case of meteors and asteroids. We would also have to get some type of tree that could
survive the harsh conditions of Mars. Putting up a satellite betwee
Earth & Mars would help shorten the time lag between
the two planets when communicating.
The Mars base would be the first step to colonising other planets in the Solar System
and exploring the rest of the universe.
Bibliography
Kingdom of the Sun
Jacqueline Mitton
Koala Books,
2001: Mascot, NSW
The Red Planet
Isaac Asimov
Gareth Stevens Publishing,
1994: Milwaukee, USA
Space
Readers Digest Pathfinders
Readers Digest Children’s
Publishing Ltd, 1999: Bath, UK
"Destination Mars"
Classmate, Northern Territory News, April
17th 2004
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