Pin It

Solar System

The Solar System comprises the Sun and the objects that orbit it, either directly or indirectly.

Of those objects that orbit the Sun directly, the largest eight are the planets that form the planetary system around it, while the remainder are significantly smaller objects, such as dwarf planets and small Solar System bodies (SSSBs) such as comets and asteroids.


4.568 billion years


From the gravitational collapse of a giant interstellar molecular cloud.


Local Interstellar Cloud -->Local Bubble--->OrionCygnus Arm-->Milky Way.

The Solar System is located in the Orion Arm, 26,000 light years from the center of the Milky Way.

Nearest star

Proxima Centauri  (4.22 ly).

Nearest known planetary system

Alpha Centauri system  (4.37 ly)


1 -- Sun


8 Planets:

Four terrestrial planets(composed of rock and metal).

  1. Mercury
  2. Venus
  3. Earth
  4. Mars

Two gas giants:

  1. Jupiter
  2. Saturn

Two ice giants:

  1. Uranus
  2. Neptune

Known dwarf planets

5  Dwarf planets

  1. Ceres
  2. Pluto
  3. Haumea
  4. Makemake
  5. Eris

Known natural satellites

442 natural satellites

  1. 173 planetary
  2. 269 minor planetary

Asteroid belt

The asteroid belt, which lies between Mars and Jupiter, mostly contains objects composed, like the terrestrial planets, of rock and metal.

Kuiper belt

Beyond Neptune's orbit lie the Kuiper belt and scattered disc, populations of trans-Neptunian objects composed mostly of ices, and beyond them a newly discovered population of sednoids. Such objects are categorized as dwarf planets.


Comets are small Solar System bodies(SSB's), typically only a few kilometres across, composed largely of volatile ices. They have highly eccentric orbits, generally a perihelion within the orbits of the inner planets and an aphelion far beyond Pluto.

Categories of comets:

  1. Short-period comets: have orbits lasting less than two hundred years. Short-period comets are believed to originate in the Kuiper belt.
  2. Long-period comets: have orbits lasting thousands of years. Whereas long-period comets, such as Hale–Bopp, are believed to originate in the Oort cloud(exist at a distance roughly a thousand times further than the heliosphere).

Why Comets have a tail?

When a comet enters the inner Solar System, its proximity to the Sun causes its icy surface to sublimate and ionise, creating a coma: a long tail of gas and dust often visible to the naked eye.

Some comets with hyperbolic orbits may originate outside the Solar System, but determining their precise orbits is difficult.


Asteroids are minor planets, especially those of the inner Solar System.

Old comets that have had most of their volatiles driven out by solar warming are often categorised as asteroids. The larger ones have also been called planetoids.


A meteoroid is a small rocky or metallic body travelling through space. Meteoroids are significantly smaller than asteroids, and range in size from small grains to 1 meter-wide objects. Smaller objects than this are classified as micrometeoroids or space dust.

Most are fragments from comets or asteroids, while others are collision impact debris ejected from bodies such as the Moon or Mars.

When such an object enters the Earth's atmosphere at a speed typically in excess of 20 km/s, aerodynamic heating produces a streak of light, both from the glowing object and the trail of glowing particles that it leaves in its wake. This phenomenon is called a meteor, or colloquially a "shooting star" or "falling star". A series of many meteors appearing seconds or minutes apart, and appearing to originate from the same fixed point in the sky, is called a meteor shower. Incoming objects larger than several meters (asteroids or comets) can explode in the air. If a meteoroid, comet or asteroid or a piece thereof withstands ablation from its atmospheric entry and impacts with the ground, then it is called a meteorite.

Around 15,000 tonnes of meteoroids, micrometeoroids and different forms of space dust enter Earth's atmosphere each year.

How to use Mind maps?

  1. Use Mind maps to read the topics faster with a complete topic coverage.
  2. Try to write sentences or paragraphs using Mind maps. This will help you to write better in your Mains examination. It also aids in engraving the topic better in your mind.
  3. Use them as flash cards to revise topics.
  4. Download the images into your devices to study in your leisure times or while travelling.
  5. Use Mind maps to read and revise faster during last minute preparations.

Connect with facebook page to get regular updates on new mind maps:  https://www.facebook.com/mindmapcharts/

For any other queries kindly mail to:  mindmapcharts@gmail.com