1. THE INNER PLANETS
INSIDE THE PLANETS OF THE SOLAR SYSTEM
MERCURY
10 Need-to-Know Things About Mercury
1. Mercury is the smallest planet in our solar system - only slightly larger
than the Earth's moon.
2. It is the closest planet to the sun at a distance of about 58 million km
(36 million miles) or 0.39 AU.
3. One day on Mercury (the time it takes for Mercury to rotate or spin
once) takes 59 Earth days. Mercury makes a complete orbit around the
sun (a year in Mercury time) in just 88 Earth days.
4. Mercury is a rocky planet, also known as a terrestrial planet. Mercury
has a solid, cratered surface, much like Earth's moon.
5. Mercury's thin atmosphere, or exosphere, is composed mostly of
oxygen (O2), sodium (Na), hydrogen (H2), helium (He), and potassium
(K). Atoms that are blasted off the surface by the solar wind and
micrometeoroid impacts create Mercury's exosphere.
6. Mercury has no moons.

2. 7. There are no rings around Mercury.
8. Only two spacecraft have visited this rocky planet: Mariner 10 in 19745 and MESSENGER, which flew past Mercury three times before going
into orbit around Mercury in 2011.
9. No evidence for life has been found on Mercury. Daytime
Temperatures can reach 430 degrees Celsius (800 degrees Fahrenheit)
and drop to -180 degrees Celsius (-290 degrees Fahrenheit) at night. It
is unlikely life (as we know it) could survive on this planet.
10. Standing on on Mercury's surface at its closest point to the sun, the sun
would appear more than three times larger than it does on Earth.
VENUS
The time of orbit of Venus is 225 days.
The time of one rotation is 243 days.
They have 0 moons.
The atmosphere of carbon dioxide with thick clouds of toxic
sulphuric acid.
They aren`t have water.
It is a hottest planet.
It is rocky with iron core.
Venus is the second planet from the Sun, orbiting it every 224.7
Earth days. It has no natural satellite. It is named after the Roman
goddess of love and beauty. After the Moon, it is the brightest
natural object in the night sky, reaching an apparent magnitude of

3. −4.6, bright enough to cast shadows. Because Venus is an inferior
planet from Earth, it never appears to venture far from the Sun: its
elongation reaches a maximum of 47.8°. Venus reaches its
maximum brightness shortly before sunrise or shortly after sunset,
for which reason it has been referred to by ancient cultures as the
Morning Star or Evening Star.
Venus is a terrestrial planet and is sometimes called Earth's "sister
planet" because of their similar size, gravity, and bulk
composition (Venus is both the closest planet to Earth and the
planet closest in size to Earth). However, it has also been shown
to be very different from Earth in other respects. It has the densest
atmosphere of the four terrestrial planets, consisting of more than
96% carbon dioxide. The atmospheric pressure at the planet's
surface is 92 times that of Earth's. With a mean surface
temperature of 735 K (462 °C; 863 °F), Venus is by far the hottest
planet in the Solar System. It has no carbon cycle to lock carbon
back into rocks and surface features, nor does it seem to have any
organic life to absorb it in biomass. Venus is shrouded by an
opaque layer of highly reflective clouds of sulfuric acid,
preventing its surface from being seen from space in visible light.
Venus may have possessed oceans in the past. But these would
have vaporized as the temperature rose due to a runaway
greenhouse effect. The water has most probably photodissociated,
and, because of the lack of a planetary magnetic field, the free
hydrogen has been swept into interplanetary space by the solar
wind .Venus's surface is a dry desertscape interspersed with slablike rocks and periodically refreshed by volcanism.

4. THE
EARTH
Earth is the third planet from the Sun. It is the densest and fifth-largest of
the eight planets in the Solar System. It is also the largest of the Solar
System's four terrestrial planets. Earth formed approximately 4.54 billion
years ago, and life appeared on its surface within its first billion year.
Earth's biosphere then significantly altered the atmospheric and other basic
physical conditions, which enabled the proliferation of organisms.
On earth we have got three layers which support life:

5. 1) THE ATMOSPHERE;
2) THE HYDROSPHERE;
3) THE GEOSPHERE.
1-The atmosphere is a leyer of gases which surrounds the
Earth. Made nitrogen and oxigen .There are gases, such as
ozone, carbon dioxide and water vapour .The ozone layer
is important because it reduces the amount of harmful
radiation, such as ultraviolet radiation .It also helps
maintain the Earth’s temperature.
2-The hydrosphere on Earth, which covers about threequarters of the planet .Thanks to the Earth’s moderate
temperature, most water on the Earth is in a liquid state
.There is saltwater in the oceans and seas, and freshwater
in rivers and lakes and under the ground.
3-The geosphere is the solid part of the Earth and it has
three layers .The inner layer is caller the core and it’s
made of iron .The rotation of the Earth moves the liquid
iron and creates a magnetic field .The other two layers of
the geosphere are the mantle and the crust.

6. MARS
The time for one orbit is 687 days.
The time for one rotation is 25 hours.
They have 2 moons.
Polar icecaps and evidence of liquid water.
Has highest volcano in the solar system (about 25 km high)
Has valleys and canyons.
Thin atmosphere mostly made up of carbon dioxide.
Called the red planet because its surface is covered in the red
iron dioxide.
Mars is the fourth planet from the Sun and the second smallest planet in the Solar
System. Named after the Roman god of war, it is often described as the "Red Planet"
because the iron oxide prevalent on its surface gives it a reddish appearance.] Mars is a
terrestrial planet with a thin atmosphere, having surface features reminiscent both of the
impact craters of the Moon and the volcanoes, valleys, deserts, and polar ice caps of
Earth. The rotational period and seasonal cycles of Mars are likewise similar to those of
Earth, as is the tilt that produces the seasons. Mars is the site of Olympus Mons, the
second highest known mountain within the Solar System (the tallest on a planet), and of
Valles Marineris, one of the largest canyons. The smooth Borealis basin in the northern
hemisphere covers 40% of the planet and may be a giant impact feature. Mars has two
known moons, Phobos and Deimos, which are small and irregularly shaped. These may
be captured asteroids, similar to 5261 Eureka, a Martian trojan asteroid.
Until the first successful Mars flyby in 1965 by Mariner 4, many speculated about the
presence of liquid water on the planet's surface. This was based on observed periodic
variations in light and dark patches, particularly in the polar latitudes, which appeared to
be seas and continents; long, dark striations were interpreted by some as irrigation
channels for liquid water. These straight line features were later explained as optical
illusions, though geological evidence gathered by unmanned missions suggest that Mars

7. once had large-scale water coverage on its surface In 2005, radar data revealed the
presence of large quantities of water ice at the poles and at mid-latitudes. The Mars
rover Spiris sampled chemical compounds containing water molecules in March 2007.
The Phoenix lander directly sampled water ice in shallow Martian soil on July 31,
2008.]
Mars is currently host to five functioning spacecraft: three in orbit – the Mars Odysse,
Mars Express, and Mars Reconnaissance Orbiter – and two on the surface – Mars
Exploration Rover Opportunity and the Mars Science Laboratory Curiosity. Defunct
spacecraft on the surface include MER-A Spirit and several other inert landers and
rovers such as the Phoenix lander, which completed its mission in 2008. Observations
by the Mars Reconnaissance Orbiter have revealed possible flowing water during the
warmest months on Mars.] In 2013, NASA's Curiosity rover discovered that Mars' soil
contains between 1.5% and 3% water by mass (about two pints of water per cubic foot
or 33 liters per cubic meter, albeit attached to other compounds and thus not freely
accessible).]
Mars can easily be seen from Earth with the naked eye, as can its reddish coloring. Its
apparent magnitude reaches −3.0,] which is surpassed only by Jupiter, Venus, the Moon,
and the Sun. Optical ground-based telescopes are typically limited to resolving features
about 300 km (186 miles) across when Earth and Mars are closest because of Earth's
atmosphere.]
NASA estimates that the comet C/2013 A1 will pass extremely close to Mars on
October 19, 2014. The latest calculations suggest the comet will not impact the planet