SOLAR SYSTEM

The Solar System comprises the Sun and the objects that orbit it. These objects include celestial bodies’ like– the planets, their satellites, planetoids, comets and meteoroids.The study of Universe is known as Cosmology.

THE SUN

An ordinary, middle-age star, the radiant energy emitted by the Sun arises from nuclear reactions taking place on the Sun. The enormous energy is locked up in the nucleus of the hydrogen atom which is released by Nuclear Fusion.

• In this process of fusion, four hydrogen nuclei (four protons) fuse to form a helium nucleus (two protons and two neutrons). The mass of the helium nucleus is about 0.7 % less than the sum of the four hydrogen nuclei.
• This lost mass is converted to a quantum of energy in the form of gamma (y) radiation. Some of the energy produced by nuclear fusion is used to bind the helium nucleus together. The rest of the energy is radiated and converted to the Sun’s surface, from where this energy is radiated off to space.

PLANETS

There are eight planets in the Solar System. In order of increasing distance from the Sun, they are the four terrestrials, Mercury, Venus, Earth, and Mars, then the four gas giants, Jupiter, Saturn, Uranus, and Neptune.

MERCURY

• The Nearest planet to the Sun
• Smallest Planet
• Revolution = 88 days
• No atmosphere and No satellite.
• Days = Scorching Hot and Nights = Frigid.

 VENUS

• Its size and shape are very much similar to that the earth => ‘Earth’s Twin’
• Called as ‘Morning Star’ and ‘EveningStar’
• Atmosphere = 90%- 95% CO2 gas
• Hottest Planet
• Day Temp =Night Temp
• No Satellite
• Rotates from east to west.

MARS

• Marked with dormant volcanoes and deep chasms where once water flowed.
• Atmosphere = Thin (Nitrogen and Argon)
• Mars is barren, covered with pink soil and boulder => RED PLANET
• Satellites = ‘Phobos’ and ‘Deimos’.

JUPITER

• Largest planet of the solar system.
• Atmosphere = Hydrogen, Helium, Methane and Ammonia.
• Satellites = 67 (Largest are Ganymede Callisto, and Europa)
• Gannymeda, satellite of Jupiter is the largest satellite in the solar system.

SATURN

• Second largest planet after the Jupiter.
• Has a celebrated ring composed of thousands of rippling, spiraling bands of icy rock and dust just 200 feet thick and 270,000 km in diameter.

Satellites- 62 (in which 24 are regular satellites)

• Titan – largest moon of Saturn.
• Other important satellites – Phobe, Tethys and Mimas.

URANUS

• The axis of rotation is tilted sideways, nearly into the plane of its revolution about the Sun.
• North and South poles lie where most other planets have their equators.
• One pole or the other faces the sun as it orbits.
• 9 dark compact rings around the planet.
• Corkscrew shaped magnetic field
• Satellites = 15 (Aerial, Ambrial, Titania, Miranda)
• Atmosphere = Hydrogen, Cold Planet (Temp= -223°C), Frozen Methane cloud,
• The landscape is barren
• Rotates from east to west

NEPTUNE

There are five rings of Neptune.

• Outer ring = icy moonlets
• Inner ring = Narrow and Solid
• Satellites = 8 (Titron, Merid)
• Atmosphere = Hydrocarbon compounds.
• Appears blue, with quickly changing white icy ethane clouds often suspended high above an apparent surface.

MOON

• Earth’s Natural Satellite = the moon revolves around the earth in about 27 days.
• Moon’s Rotation Period = 27 Days = Moon’s Revolution Period.
• Only one side of the moon is visible to us on the earth.
• The rise and fall of the tides on Earth is caused by the Moon
• The Moon has no atmosphere.
• The first spacecraft to reach the Moon was ‘Luna-I’ in 1959

FACTS ABOUT SOLAR SYSTEM

Largest, most massive planet                                                  Jupiter

Fastest orbiting planet                                                             Mercury

Planet with Largest Moon                                                       Jupiter

Greatest Density                                                                        Earth (Blue Planet)

Tallest mountain                                                                        Mars (Red Planet)

Strongest magnetic fields                                                        Jupiter

Shortest Day (Synodic)                                                             Jupiter

Longest (synodic) day                                                                Mercury (Smallest Planet)

Hottest Planet                                                                             Venus (Morning Star, Brightest Planet)

No Moons                                                                                    Mercury, Venus

Planet with moon with most eccentric orbit                                 Neptune

Deepest oceans                                                                         Jupiter

Slowest Rotation in Solar system                                               Venus

Only Satelite with an atmosphere like earth                              Titan