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Inner or Terrestrial Planets:
Mercury | Venus |
| Smallest and closest planet to the Sun | Second planet from the Sun |
| Airless and waterlessplanet. | Earth’s Twin (almost the same size as the Earth) |
| No atmosphere | No atmosphere |
| Experiences extremes of temperature | Longest rotation period (\(243\) days) |
| No satellites | No satellites |
| Mercury can be viewed in the morning and evening with naked eye. | Visible in the mornings and the evenings. Also called as the Morning Star and the Evening Star. |
| Rotates from West to East. | It rotates in the opposite direction to all other planets except Uranus, i.e. East to West. |
| After the Moon, it is the brightest natural object in the night sky. | |
| Named after the Roman deity ‘Mercury’, the Messenger to the Gods. | Named after the Roman Goddess of love and beauty. |
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- Mercury is only about as wide as the Atlantic Ocean.
- Venus has yellowish clouds made of sulphur and sulphuric acid cover the entire planet causing light to reflect off the surface.
Inner or Terrestrial Planets:
Earth | Mars |
| Third Planet from Sun and fifth largest planet. | Fourth planet from the Sun and second smallest planet in the solar system. |
| Only planet known to support life. | It also has polar ice. |
| Atmosphere mainly made of: Nitrogen (\(78\)%) and Oxygen (\(21\)%) | Thin atmosphere |
Rotation period: \(23\)hours, \(56\)minutes | |
| Satellite: Moon | Satellites: Phobos and Deimos |
| Also known as Blue planet’ or ‘Watery planet’ because three-fourth of the Earth is covered by water. | Appears red, due to the presence ofiron oxide on its surface Often described as The Red Planet. |
Rotates from West to East | Rotates from West to East |
| The only planet in the solar system which is not named after any Greek or Roman deity. | Named after the Roman God of war. |
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Other important facts about Earth
Equatorial diameter: \(12,756\) km
The Earth revolves around the Sun at a speed of about \(30\) kmper second.
Important!
The distance between the Sun and the Earth is about \(150\) million kilometres (or \(1\)\(Astronomical\)\(Unit\)).
Note: The below image is from the textbook - to be restructured
Planets in Order of Size
Jupiter (Largest)> Saturn > Uranus > Neptune > Earth > Venus > Mars > Mercury (Smallest)
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