Important Facts about Solar System

• Our solar system comprises A star named the Sun, 8 planets, More than 184 moons, Millions of smaller bodies like asteroids and comets, and A huge quantity of dust grains and gases.
•  The Sun is the Centre, while the other components revolve around it, bound by gravity
•  Some celestial bodies do not have their heat and light.
•  They are illuminated by the light of stars. These celestial bodies are called planets

The planets based on their distance from the sun, from nearest to farthest are as follows. They
are:
1. Mercury
2. Venus
3. Earth
4. Mars
5. Jupiter
6. Saturn
7. Uranus
8. Neptune.

•  The eight planets can be divided into two groups. The four closest planets
  to the Sun are called inner planets or Terrestrial planets.
•  These planets are Mercury, Venus, Earth, and Mars. They lie between the sun
  and a belt of asteroids.
• They are called Terrestrial, because they are made up of rock and metals, and have relatively high densitie The other four planets are called Jovian or Gas Giant planets.
• These planets are Jupiter, Saturn, Uranus, and Neptune.
• The meaning of Jovian is, Jupiter-like. These are much greater in sizethan terrestrial/inner planets.
• Their atmosphere is thicker and mostly made of helium and hydrogen.

Mercury

• Rotation: 58.65 days
•  Revolution: 88 days (Fastest revolution in Solar System)
•  Maximum diurnal range of temperature.
•  Its days are scorching hot, and nights freezing.
•  It has no atmosphere and no satellite.

Venus

•  Also called Earth’s Twin, because it is slightly smaller than Earth
  (500 km less in diameter).
•  Slowest rotation in Solar System (257 days).
•  Both the rotation and revolution of Mercury are almost the same
  lengths of time. (224.7 days).
•  Popularly known as Evening Star, and Morning Star.
•  Brightest object after the sun and moon (because of 70% albedo,
  the reflecting power).
•  The closest planet to earth.
•  It is the hottest planet in Solar System. It is because of the greenhouse effect
  as its atmosphere contains 90-95% carbon dioxide.
•  The night and day temperatures are also almost the same. Rotates backward
  (clockwise) unlike others.

Earth

• It is also called the Blue Planet. It is the densest of all planets.
•  Circumference: 40,075 km.
• Area: 510 million sq. km.
• The average distance from the sun: is 149 million km.
• Spins on its imaginary axis from West to East in 23 hours, 56 minutes, and 40.91 seconds.
• Takes 365 days, 5 hours, 48 minutes, and 45.51 seconds in annual movement around the sun.
• This leads to an extra day every four years, we call this year a leap year.

Mars

• It is also called a Red Planet.
• Revolution: 687 days.
• Rotation: 24.6 hours ( almost the same as Earth)
• It has a thin atmosphere comprising nitrogen and argon.
• It is marked by dormant volcanoes and deep chasms where water once
  flowed. Recent explorations have thrown light on the possibilities of the
  existence of life here.
• The highest mountain here is named ‘Nix Olympia’ which is three times
  higher than Mount Everest.
• Mars has 2 satellites – Phobos and Deimos.

Jupiter

• It is the largest of all planets (71% of the total mass of all planets),
  and thus also called Lord of Heavens.
• It has the fastest rotation time (9.8 hours) in the solar system.
• Revolution: 12 years
• Jupiter appears to have stopped halfway to becoming a star. It was too
  massive to solidify as a planet but not massive enough to develop
  ‘nuclear fusion and become a star.
• The planet’s atmosphere contains hydrogen, helium, methane, and ammonia.
• A massive storm like a super hurricane exists on Jupiter. This storm has
  been persistently active for hundreds of years.
• This storm is called The Great Red Spot and is probably powered by
  Jupiter’s internal heat.
• It has 63 satellites. The most prominent satellites are in Europe,
  Ganymede & Calisto.
• Ganymede is the largest satellite in the Solar System.

Saturn

• It is second in size after Jupiter.
• Revolution: 29 years. Rotation: 10.3 hours.
• Least density of all (30 times less dense than Earth).
• A unique feature is its system of rings. (Notably three well-defined rings).
• These are separate particles that move independently in circular orbits.
• Saturn has 60 satellites, the most prominent one being Titan.
• The space probe, Cassini was sent to Saturn to study the planet.

Uranus

• It was identified as a planet in 1781 by William Herschel.
• The planet has an incline to its orbit, a 98-degree angle, which
  seems to make it rotate in a North to South direction.
• Revolution: 84 years. Rotation: 10.8 hours.
• Surrounded by a system of 9 faint rings.
• Has 27 satellites. The most prominent being Miranda, Ariel, etc

Neptune

• Neptune appears as a Greenish Star.
• Revolution: 165 years. Rotation: 15.7 days.
• Has 5 faint rings.
• Discovered by J.G Galle of Berlin in 1846.
• 13 satellites.

Pluto

• Pluto was classified as a dwarf planet in 2006 because it was deemed
  smaller than the defined minimum size for a planet.
• A heavenly body must fulfill certain conditions to be called a planet.
  There are three requirements defined by IAU
•  It should orbit around the Sun.
•  It needs to have enough gravity to pull itself into a spherical shape.
•  It needs to have a clear and separate orbit of its own, away from neighboring orbits.
•  Pluto satisfies the first two conditions, but not the third one.
•  Its orbit cuts through the orbit of Neptune.
•  many satellites are bigger than Pluto.

Important Facts at a Glance-