VENUS
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Usually referred to as the “evening star” or
“morning star”
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It is named for the Roman goddess of love, Venus
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It is considered as a twin of the Earth. It is
most like the earth in diameter and mass
·
Its surface has a perpetual layer of thick
clouds that completely covers the planet
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History:
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Venus is the Roman name of the Greek goddess of
love; Aphrodite. But there are references to Venus as far back as Babylonian
cuneiformic texts, like the Venus table of Ammisaduqa which can be as old as
1600 BC
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Ancient Egyptians thought that Venus was
actually two separate objects… a morning star, and then a completely different
evening star. The tradition carried on with the ancient Greeks as well.
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The early mathematician Pythagoras was one of
the first to recognize that the morning evening stars were actually the same
object: Venus. So perhaps he was the first to “discover Venus”
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The Maya civilization held Venus in high regard,
and the planet figured prominently in their religious calendar
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Major
Features:
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Equatorial diameter (12104 km)
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Average distance from the sun (1.08 x 108
km)
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Inclination of equator to orbit (177’’)
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Orbital period (0.6152 yr. (224.7 days))
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Period of Rotation (243 days)
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Mass (4.7 x 1024 kg)
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Average Density (5.24 gm/cm3)
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Surface gravity (0.9 earth gravity)
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Escape velocity (10.3 km/s)
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Surface temperature (472 0c)
·
Structure
of Interior
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The deep interior of Venus is probably like the
Earth’s iron core and rock mantle
·
Orbit and
Rotational Motion
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Venus rotates backward or from east to west for
a period of 243 days)
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The sun rises in west and sets in the east
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Venus rotates slowly that it cannot generate a
strong magnetic field like the earth does
·
Surface
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Rolling plains which cover 65% of the planet’s
surface
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Highlands which cover 8% of the planet’s surface
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Lowlands which cover 27% percent of the planet’s
surface
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Venus’
temperature and atmosphere
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96% carbon dioxide
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3.5% Nitrogen
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The rest are:
-
Water, sulfuric acid, hydrochloric acid, and
hydrofluoric acid
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The pressure of the atmosphere is 90 times that
on earth
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Venussian clouds composed of sulfuric acid
droplets and sulfuric crystals
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The highest layer of clouds stretch from 58 – 68
km from the planet’s surface
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The rest lies from 52 – 56 km above the surface
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The rest lies from 52 – 56 km above the surface
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The third and densest layer extends from 48 – 52
km
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A thin laze ranges from 48 km down to 33 km
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The Venus’ carbon dioxide atmosphere creates an
extremely strong green house effect
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The Warm surface radiates infrared radiation
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No magnetic field is present, thus the solar
wind is deflected by the uppermost layers of the atmosphere
Ø
The high temperature and density of Venus’
atmosphere create a high atmospheric pressure on the planet
·
Greenhouse
effect in the atmosphere
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Venus is now a furnace uninhabitable.
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The greenhouse effect is caused by its
atmosphere rich in carbon dioxide is its surface temperature over 400 0c,
and any water present in the atmosphere is equivalent to a layer of only three
inches thick on the surface of the planet
MARS
·
IS THE 4TH planet from the sun in the
solar system
·
Named after the Roman god of war “Mars”
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The Martian atmosphere is generally clear enough
for astronomers on Earth to view its surface clearly
·
The force of gravity on the surface of Mars is
about 1/3 of that on Earth. Mars has twice the diameter and twice the surface
gravity of Earth’s moon
·
Often described as the red planet as the iron
oxide prevalent on its surface gives it a reddish appearance
·
Mariner and Viking reveal the true marvels of
Mars
·
The Valles Marineris the grand canyon of Mars
stretches 500 km (3000 miles) long 100
·
These frozen regions change in size during the
cycles of the Martian seasons
·
A cycle resulting from the tilt of mars rotation
axis in the same way that our cycle of seasons is caused by the tilt of earth’s
rotation axis
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Interior
Surface
Ø
Scientist believe that Mars interior
consists of a crust, mantle and core as
if Earth’s interior but they do not know the relative sizes of these components
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Mars probably has a relatively thick crust
beneath the _ bulge, an area of volcanic activity in the northern hemisphere.
It may be as thick as
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The core is
·
Interior
surface
Ø
Mars does not, and probably did not ever, have
active plate tectonics, or a crust made of separate sections that move about
and sometimes crash into each other.
Ø
Though the Martian crust is not broken into
separate plates, mars says liquid mantle has sculpted the surface of the
planet.
·
Surface
features
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The surface of Mars would be a harsh place for
surface of Earth than any other planet
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The surface is probably cooler
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Mars
orbit and rotational motion
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Mars’ average distance from the sun is roughly
230 million km (1.5 AU) and its orbital period is 687 (Earth) days
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The solar day (or sol) on Mars is only slightly
longer than an earth day: 24 hours, 39 minutes and 35.224 seconds
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A Martian year is equal to 1.8809 earth years,
or 1 year, 320 days and 18.2 hours
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The axial tilt of Mars is 25.19 degrees, which
is similar to the axial tilt of the Earth
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Currently the orientation of the north pole of
Mars is close to the star Deneb
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Mars passed an aphelion in March 2010 and its
perihelion in March 2011. The next aphelion came in February 2012 and the next
perihelion came in February 2012 and the next perihelion comes in January 2013
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Mars has relatively pronounced “orbital
eccentricity” of about 0.09 of the
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