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SOLAR
SYSTEM
STARS
BLACK
HOLES
METEORS
AND METEORITES
ASTEROIDS
COMETS
GALAXIES
NEBULAE
GLOSSARY
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Mars:The Fourth
Planet
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| Name of
the Planet |
Mars |
| Position
in Solar System |
Venus is
the second planet from the Sun. It is named after the Roman
goddess of love and beauty. |
| Constituents |
rocky,
ferrous |
| Atmosphere |
carbon
dioxide |
| Average
Distance from Sun |
108,000,000
km/67,000,000 mi |
| Orbit
Time |
0.615 Earth
years |
| Diameter |
12,100
km/7,510 mi |
| Average
Density (water=1) |
5.2 |
| Satellites |
none |
| Average
Surface Temp |
482ºC
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| Rotational
Period |
243.02 days |
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Description:
Mars has long been known as
the Red Planet and is the representative of the mythological Roman
God of War because of its distinctive brilliant red appearance.Mars
has since long fascinated mankind because of the possibility to
find some kind of extraterrestrial life there.For several decades
it was thought that the planet supported an Earth-like environment
and also that intelligent life had evolved to a significant level
over there.Prominent markings were noted on the martian surface.Shortly
after the invention of the telescope and 17th century onwards many
generations have carefully observed these markings and mapped them.Mars
is smaller than the Earth, with a diameter of 6,786 km but its rotation
period is somewhat similar to the Earth, i.e.. 24 hours, 37 mins,
23 sec.
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Top: Image taken from an
approaching Viking space probe.
Bottom: Volcanic crater photographed by Viking 1 in 1977.
Source:Hutchinson's Encyclopedia
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 An
artist's concept of Odyssey aerobraking in the Martian atmosphere.
Image: NASA/JPL
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Spring and summer in the northern hemisphere
of Mars lasts for 194 and 178 martial days respectively, as against
93 and 94 days on the Earth. This is because the orbit of Mars is
distinctly elliptical.
The revolution period of Mars around the Sun is 687 Earth days.It
lies at an average distance of 227.94 million kms away from the
Sun.Mars has rocky interior which does not contain much iron,making
it only 1/10th of the Earth's mass and 2/3rd of its density.It also
has a weak surface gravity just over a third that on the Earth.The
Martian surface is quite rugged, covered with dead volcanoes and
rocks of hardened carbon dioxide also known as Dry Ice.The soil
of Mars is red in color due to significant quantities of iron oxide
being present in the grains of the surface soil.On the poles of
the planet, there are polar ice caps made up of frozen carbon dioxide.Their
sizes varies according to the seasons.
Mars has two moons,each of which look like a giant potato.More than
300 years ago, Johannes Kepler speculated that Mars had two moons
though he did not have evidence for his claim.
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Kepler
figured out that since Earth had one moon and Jupiter had four which
were known then, the planet in between - Mars -ought have two.Asalph
Hall in 1976, with the 26-inch refracting telescope at the Washington
Observatory,observed these moons and confirmed the speculation.The
moons are named after the chariot horses of Roman God of War - Phobos
and Demios-means Fear and Terror.
It
is said that both the satellites are captured asteroids which in the
past approached Mars too closely and were set into new orbits around
Mars.Phobos speeds up around Mars in 7 hours and 40 mins. The distance
Demios takes is more than a day.From Mars,the moons are seen to move
in opposite directions because of the difference in speed.
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An artist's concept of
Mars Express. Image: ESA
Source:
www.astronomynow.com/index.html
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This high-resolution
mosaic of Phobos was
created from three Viking
orbiter images.The
striking feature in this image is the giant
Stickney crater. Grooved fractures caused from
the impact that created Stickney extend away
from the crater.
Source:http://solarsystem.nasa.gov
/features/planets/mars/deimos.html |
A
small chunk of rock and debris, Deimos circles Mars every 30
hours.
Source:http://solarsystem.nasa.gov/
features/planets/mars/deimos.html |
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Interesting facts:
-Under favourable night time conditions, the
light from Mars may cast a visible shadow.
-From Mars, the Sun appears 44% as bright as from the Earth.
-Mars has a total of 1345 named features, of which 845 are craters.The
larges crater named Schiaparelli is 461 km in diameter.
-The earth is 9.3 times as massive as Mars.
-On 27 August,2003, Mars will reach its maximum brightness, shining
almost as bright as magnitude - 3.0.
-The average atmospheric pressure on Mars, approximately 709 pascals,
is equivalent to the atmospheric pressure 30 km above the surface
of the Earth. |
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Historical Events
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| 30 July, 358 |
Venus occults Mars, observed
from China. |
| 1576-1601 |
Tycho-Brahe recorded very
accurate positions for Mars. |
| 1604 |
Johannes Kepler calculated
the elliptical orbit of Mars. |
| 1609 |
Galileo first observed Mars.
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| 1671 |
Cassini, now the Director
of the Paris Observatory, calculated the distance from Earth
to Mars. |
| 1719 |
Maraldi raised the possibility
that the white spots could be ice caps. |
| 1840 |
The first global
maps of Mars were created by Wilhelm Beer and Johann Madler. |
| 11 August, 1877 |
US astronomer
Asalph Hall discovered Deimos and Phobos. |
| 1927 |
Large temperature
diiferences between the day and night sides of Mars were measured
by William Weber Coblentz and Carl Otto Lampland. |
| 1947 |
Using infrared
spectroscopy, Dutch-born US astronomer Gerard Peter Kuiper detected
carbon dioxide but no oxygen. |
| 1 November,
1962 |
USSR probe Mars
1 launched, but radio contact lost after 9,55,00,000 km. |
| 10 May, 1972 |
USSR probe Mars
2 launched, entered Mars orbit on 27 November, 1971. |
| 4 December,
1996 |
US probe Mars
Pathfinder launched aboard a Delta 2 rocket. |
| 4 July, 1997 |
US probe Mars
Pathfinder arrived on the surface of Mars. |
| 10 November,
2084 |
The next transit
of Earth, as seen on Mars will occur. |
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