2. Ancient astronomers didn’t really know what Venus was. They knew it was an
object that moved in the sky from night to night, sometimes being obscured by
the glare of the Sun. But it wasn’t until Copernicus developed his model of the
Solar System that placed the Sun at the center, and the planets orbiting it. At that
point, both Venus and Earth were recognized to be planets.
Galileo pointed his telescope at Venus in 1610, and confirmed Copernicus’
theory by showing that Venus went through distinct phases, just like the Moon.
The phases matched the predictions made by Copernicus, and demonstrated that
Venus was really a planet, orbiting the Sun and not the Earth.
This model was confirmed even more when Venus made a transit across the
surface of the Sun on December 4, 1639. The most recent transit of Venus
happened in 2004, and the next one will occur in 2012.
WHO DISCOVERED VENUS?
3. Venus is a beautiful planet at
night. It is one of the brightest
objects in the night sky. Only
the moon is brighter
WHY VENUS?
• Venus is very bright in the sky
“Evening star”
“Morning star”
Fun Fact!
The ancients named Venus after the
goddess of love and beauty because it
is the brightest planet.
4. Early civilizations thought Venus was two different
bodies, called Phosphorus and Hesperus by the Greeks,
and Lucifer and Vesper by the Romans. This is because
when its orbit around the Sun overtakes Earth’s orbit, it
changes from being visible after sunset to being visible
before sunrise. Mayan astronomers made detailed
observations of Venus as early as 650 AD.
MORNING STAR AND THE EVENING STAR
5. THE PLANET VENUS
• Venus is the planet nearest to
Earth, sometimes approaching
to within 40 million km
• The orbit of Venus is nearly
circular at a distance of 108
million km (0.72 AU)
• Venus can get as close as 40
million km from the Earth. This
is called an inferior conjunction
every 584 days, on average.
6. Mass: 4,867,320,000,000,000 billion kg (0.815 x Earth)
Equatorial Diameter: 12,104 km
Polar Diameter: 12,104 km
Equatorial Circumference: 38,025 km
Known Satellites: none
Notable Satellites: none
Orbit Distance: 108,209,475 km (0.73 AU)
Orbit Period: 224.70 Earth days
Surface Temperature: 462 °C
First Record: 17th
century BC
Recorded By: Babylonian astronomers
PLANET PROFILE
7. Venus looks very bright to the
naked eye and even a small
telescope shows that Venus goes
through phases like the Moon
The surface of Venus is always
obscured by a very dense cloud
cover
Reflects 70% of the sunlight
Various bands are visible in
different wavelength light
APPEARANCE OF VENUS
Enhanced picture of Venus shot through
a violet filter by the Galileo spacecraft
8. Venus appears to go through phases
Different from Moon because distance changes drastically
PHASES OF VENUS
8
9. 12,102 km in
diameter(12,756 km
for Earth)
82% the mass of
Earth
Similar density, 5.3
g/cm3
(5.5 g/cm3
for
Earth)
Venus takes 2,243days
to rotate on it axis and
it rotates the opposite
direction of Earth
Venus is nearly the same
size as Earth
Venus takes 223 days to
orbit the Sun
BASIC PROPERTIES OF VENUS
9
10. The atmosphere of
Venus causes a very high
surface temperature and
gives the surface a
perpetual red twilight
The weather at the
surface is hot, dry, calm
The pressure at the
surface is 90 times the
Earth’s atmospheric
pressure
THE ATMOSPHERE OF VENUS
Gas %
Carbon
Dioxide
(CO2)
95.3
Nitroge
n (N2)
2.7
Argon
(Ar)
1.6
Oxygen
(O2)
0.15
Neon
(Ne)
0.0003
11. The surface
temperature of Venus is
700 K
800 degrees Fahrenheit
Caused by the
greenhouse effect
Venus has 1 million
times more CO2
than Earth
Sunlight that diffuses
through the atmosphere heats
the surface and the CO2 acts
as a blanket
The surface heats up
until the radiation of heat is the
same as the absorption of heat
from the Sun
The dense atmosphere
makes the temperature the
same everywhere on the
surface of Venus
Little weather
SURFACE TEMPERATURE OF VENUS
12. The first successful flyby of the Planet Venus was accomplished by Mariner 2 in
1962.
In 1970, the Soviet Venera 7 lander became the first probe to return data from
the surface of Venus. Later Venera landers would return images from the
surface.
America sent two spacecraft to the planet in 1978. The Pioneer Venus Orbiter
went into orbit around the planet, while the Pioneer Venus Multi-
Probe deployed four atmospheric entry probes to investigate the atmosphere.
The twin Vega spacecraft each deployed a surface lander and an instrumented
atmospheric balloon in 1985.
The American Magellan mission, launched on the Space Shuttle in 1989, used a
radar system to create high-resolution maps of the planets surface.
Launched in 2005, the European Venus Express mission continues to orbit the
planet.
THE EXPLORATION OF VENUS
13. The Magellan mission to Venus was launched May 4, 1989
and arrived at Venus on August 10, 1990
Magellan used high resolution radar to map the surface of
Venus through the opaque clouds
Magellan worked for 4 years and mapped 98% of the surface
of Venus
THE MAGELLAN MISSION TO VENUS
13
14. False color picture of Venus constructed from radar
images from the Magellan space craft
The Magellan data can be processed into 3-D views of the surface of
Venus
THE SURFACE OF VENUS
3-D view of three impact crater on the
surface of Venus
15. The largest crater on Venus is the
Mead Crater
CRATERS ON THE SURFACE OF VENUS
The Mead Crater - 280 km in diameter
Larger than the largest crater on
Earth
16. Computer generated 3-D view of Sif Mons using data
from Magellan
Venus is a planet with wide-scale
volcanic activity
In the lowland plains, lava
renews the surface and erases
craters
There are many volcanoes
associated with surface hot spots
VOLCANOES ON VENUS
• The largest volcano on
Venus is Sif Mons
3 km high, 500 km
across
Caldera is 40 km across
• These volcanoes result
from magma reaching
the surface
• Pressure under the
surface can cause
bulges called coronae
17. Venus rotates counter-clockwise:
Also known as retrograde rotation. A possible reason
might be a collision in the past with an asteroid or other
object that caused the planet to alter its rotational path. It
also differs from most other planets in our solar system by
having no natural satellites.
FACTS ABOUT VENUS
