The Solar System

The Solar System consists of the Sun and its eight main planets, their satellites, asteroids, comets, meteors and other dwarf planets. The Sun is at the one of the two Centers of the Solar system and the planets revolving around it in elliptical orbits. Let us take a look at some quick facts about the Solar System:

The closest planet to Sun is Mercury and the farthest is Neptune.
Pluto is a dwarf planet-relegated from its status as the ninth planet.
The eight planets of the solar system are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune.
You can remember the order using the mnemonic: My Very Educated Mother Just Showed Us Nine Planets.

The Sun

The sun us the primary Source Of Energy for life on earth. It is closest star of Earth, about 150 million kilometers from earth. The temperature of the Sun’s visible surface (photosphere) is about 6000 degree Celsius. However, the outer layer of sun’s Atmosphere, known as the Corona, is, on an Average, about 2 million degree Celsius. The core of the sun is the center and is about 15 million degree Celsius.

The sun is made up of 73 % hydrogen and 25 % helium. It also has trace amounts of Oxygen, carbon, iron and other Elements. It is classified as a G-Type Main Sequence Star. It is about 4.6 billion years old and will continue to shine for another 5 billion years. After that it will grow into a Red Giant and then finally end its life as a white dwarf.

The Planets

There are a total eight planets in the solar system-

The planets are divided in the 2 groups-Inner planets and Outer planets.
Inner planets-Mercury, Venus, Earth, Mars. These are also known as territorial planets or rocky planets. These are denser and have a shorter period of revolution.
Outer planets-Jupiter, Saturn, Uranus, Neptune. These are also known as Gas giants or Gaseous planets. They are big in size and have a longer period of revolution.
Jupiter is the biggest planet in the Solar System and Mercury is the smallest.

Mercury

Closest planet to the Sun.
Orbits the sun the quickest.
No significant atmosphere.
Rotation period is longer than its orbital (revolution) period.
No natural satellites (moons)
Spacecrafts to Mercury: Mariner 10, Messenger, BepiColombo.
Can be seen from the earth only before sunrise and after sunset.

Venus

Known as Earth’s twin.
Longest rotation period of any planet.
Rotation period is longer than its orbital (revolution) period.
Hottest planet in the Solar System.
Dense atmosphere of gases and chemicals including sulphuric acid clouds.
Revolves around the sun in clockwise manner while most others are revolving in anti-clockwise.
Second brightest natural object in the night sky (after Moon).
Can be seen form the Earth only before sunrise (Morning Star) and after sunset (Evening Star).
No natural satellites (moons).
First planet visited by a spacecraft.
Spacecrafts to Venus: Mariner 2, Venera 7, Magellan etc.

Earth

Only planet in the solar system to be known to support life.
Has water in all three states-liquid, solid and gas.
Gasses present in the earth’s atmosphere are Nitrogen, Hydrogen, Oxygen, Carbon dioxide etc.
It takes 23 hours 56 minutes 46 seconds to rotate around its axis.
It takes 365.26 days to revolve around the Sun.
The ozone layer present in Earth’s atmosphere protects it from the Ultra violet rays.
Moon is the only natural satellite of the Earth.

Mars

Known as the ‘Red planet’ due to presence of iron-rich red Soil.
Despite its red color, it is cold because it has lost most of its atmosphere.
Phobos and Deimos are 2 moons of Mars.
Has polar ice caps and traces of sub-terrestrial liquid water has been found.
Has the largest known volcano (and second tallest mountain) in the solar system-Mons Olympus.
Spacecrafts to Mars: Mariner 4,2001 Mars Odyssey, Mars Orbiter Mission (India), MAVEN etc.
Rover on Mars: Opportunity, Curiosity, Spirit (Decommissioned).

Jupiter

Largest planet of the solar system
Has two and a half times the mass of all other planets put together.
Has the shortest rotation period
A gas giant primarily composed of hydrogen and helium with no discernible solid surface.
Has a giant storm (three times the diameter of earth) since 1831 called the ‘Great Red Spot’
Has a faint ring around it.
Has 67 moons.
4 largest moons discovered by Galileo-Ganymede (largest moon in the solar system-bigger than Mercury), Callisto, lo (Volcanic), Europa (has water-ice).
Missions to Jupiter: Galileo, Juno (upcoming)

Saturn

Second largest planet in the Solar system.
Its density os less than the water.
Has a band of concentric rings revolving around it made up of tiny rocks and pieces of ice.
Has 62 moons.
Moons of Saturn: Titan is the largest (has a major atmosphere, complex organic chemistry and ICE Volcanoes-2/”>Volcanoes), Rhea (may have its own ring system), Enceladus.
Missions to Saturn: Cassini-Huygens.

Uranus

Discovered by Sir William Herschel.
Blue-green (cyan) in color.
Third biggest planet of the Solar System.
Composed of Hydrogen, Helium, Water, Ammonia, Methane.
It is tilted sideways so that its poles lie where most other planets have their equators.
Has faint rings.
Has 27 known moons (5 main-Miranda, Ariel, Umbriel, Titania and Oberon)
Spacecraft Flyby: Voyager 2

Neptune

Discovered by mathematical predictions and disturbances in Uranus orbit.
First proposed by Alexis Bouvard, and first observed by Johann Galle.
Farthest planet from the sun.
Primarily composed of Hydrogen, Helium, Nitrogen, Water, Ammonia, Methane.
Is blue in color because of methane.
Has a storm called ‘Great Dark Spot’
Has 14 known moons (Triton-Largest).
Spacecraft Flyby: Voyager 2

Pluto

Used to be the Ninth planet.
Demoted to status of ‘Dwarf Planet’.
Icy and cold.
Has five moons-Charon, Styx, Nix, Kerberos, Hydra.

Asteroids

Almost like planets but smaller in size.
Not spherical in appearance.
Revolve around the sun.
Most of them are found in a belt between Mars and Jupiter.
The largest asteroid in the Asteroid Belt is Ceres.

Meteorites

Meteorites are formed due to collision between asteroids.
They are fragments of rocks floating about in space.
Sometimes they come across earth and fall into the earth’s atmosphere. That’s when they become meteors or ‘shooting star”.
Most of these meteors can’t reach earth’s surface and burn up in the atmosphere due to friction with air.
The meteors that do reach the earth’s surface are known as Meteorites.
There was a latest Meteor shower named Geminid that was seen from some parts of the world on 14^th December 2018.

Comets

Tiny icy and rocky bodies that travel in highly elliptical orbits around the sun.
When they pass close to the sun, they water, and gases heat up.
This leads to the formation of a tail behind the rocky core in the direction opposite to the sun.
Most famous comet is Halley’s Comet which reappears every 75-76 years.
Last appeared in 1986. Next appearance in 2061

The Solar System is a vast and complex place, home to a variety of different objects. The Sun, Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, dwarf planets, asteroids, comets, meteoroids, interplanetary dust, the heliosphere, the Oort cloud, and the Kuiper belt are all part of this system.

The Sun is the largest object in the Solar System and is responsible for providing Light and heat to the planets. It is a giant ball of hot gas that is made up of hydrogen and helium. The Sun’s surface temperature is about 9941 degrees Fahrenheit (5505 degrees Celsius).

Mercury is the smallest planet in the Solar System and is closest to the Sun. It is a rocky planet that is covered in craters. Mercury’s surface is very hot during the day and very cold at night.

Venus is the second planet from the Sun and is the hottest planet in the Solar System. It is a rocky planet that is covered in clouds. Venus’s atmosphere is very thick and is made up of carbon dioxide.

Earth is the third planet from the Sun and is the only planet in the Solar System that is known to support life. It is a rocky planet that has a liquid ocean and an atmosphere that is made up of nitrogen, oxygen, and other gases.

Mars is the fourth planet from the Sun and is the second smallest planet in the Solar System. It is a rocky planet that is covered in red dust. Mars has no liquid water on its surface, but it does have ice caps at its poles.

Jupiter is the fifth planet from the Sun and is the largest planet in the Solar System. It is a gas giant that is made up of hydrogen and helium. Jupiter has a very strong Magnetic Field and a large number of moons.

Saturn is the sixth planet from the Sun and is the second largest planet in the Solar System. It is a gas giant that is made up of hydrogen and helium. Saturn has a very distinctive ring system that is made up of ice, dust, and rock.

Uranus is the seventh planet from the Sun and is the third largest planet in the Solar System. It is an ice giant that is made up of hydrogen, helium, and ice. Uranus has a very tilted axis and orbits the Sun on its side.

Neptune is the eighth planet from the Sun and is the fourth largest planet in the Solar System. It is an ice giant that is made up of hydrogen, helium, and ice. Neptune has a very strong magnetic field and a large number of moons.

Dwarf planets are smaller than planets and are not massive enough to clear their orbit of other objects. Pluto was once considered to be the ninth planet from the Sun, but it was reclassified as a dwarf planet in 2006. Other dwarf planets in the Solar System include Eris, Makemake, and Haumea.

Asteroids are small, rocky bodies that orbit the Sun. They are found mostly between the orbits of Mars and Jupiter. Asteroids can be very large, with some reaching hundreds of miles in diameter. However, most asteroids are much smaller.

Comets are small, icy bodies that orbit the Sun. They have long, thin tails that are made up of gas and dust. Comets come from the Oort cloud, which is a vast cloud of icy bodies that surrounds the Sun.

Meteoroids are small pieces of rock or Metal that orbit the Sun. They can be very small, like grains of sand, or they can be much larger. Meteoroids that enter Earth’s atmosphere burn up and create streaks of light called meteors. If a meteoroid survives its journey through Earth’s atmosphere and hits the ground, it is called a meteorite.

Interplanetary dust is a fine dust that is found throughout the Solar System. It is made up of tiny particles of rock and metal. Interplanetary dust can come from asteroids, comets, and meteoroids.

The heliosphere is a bubble of plasma that surrounds the Sun. It is created by the Sun’s solar wind, which is a stream of charged particles that flows out from the Sun. The heliosphere protects the Solar System from harmful radiation from the outside.

The Oort cloud is a vast cloud of icy bodies that surrounds the Sun. It is thought to be the source of long-period comets. The Oort cloud is very far from the Sun, and it is estimated to be about 50,000 astronomical units from the Sun.

The Kuiper belt is a region of the Solar System that is located beyond the orbit of Neptune. It is a disk-shaped region that is made up of icy bodies. The Kuiper belt is thought to be the source of short-period comets.

What is a galaxy?

A galaxy is a large group of stars, gas, and dust held together by gravity. Galaxies come in a variety of shapes and sizes, from the small dwarf galaxies to the large spiral galaxies.

What is the Milky Way?

The Milky Way is the galaxy that our solar system is located in. It is a spiral galaxy, with a central bulge and four spiral arms. The Milky Way is about 100,000 light-years across.

What is a star?

A star is a giant ball of hot gas that emits light and heat. Stars are made up of hydrogen and helium, and they produce energy through nuclear fusion.

What is a planet?

A planet is a large, round object that orbits a star. Planets are made up of rock, gas, or ice, and they do not produce their own light.

What is a moon?

A moon is a natural satellite that orbits a planet. Moons are typically much smaller than planets, and they are not made of the same materials.

What is an asteroid?

An asteroid is a small, rocky object that orbits the sun. Asteroids are typically found in the asteroid belt, which is located between the orbits of Mars and Jupiter.

What is a comet?

A comet is a small, icy object that orbits the sun. Comets have a long, thin tail that is made up of dust and gas. Comets are typically found in the Oort cloud, which is a spherical cloud of icy objects that surrounds the sun.

What is a meteoroid?

A meteoroid is a small piece of rock or metal that orbits the sun. Meteoroids are typically much smaller than asteroids, and they can be found in the asteroid belt, the Oort cloud, and the Kuiper belt.

What is a meteor?

A meteor is a meteoroid that enters the Earth’s atmosphere and burns up. Meteors are also known as shooting stars.

What is a meteorite?

A meteorite is a meteoroid that survives its passage through the Earth’s atmosphere and hits the ground. Meteorites can be made of rock, iron, or a combination of both.

What is a black hole?

A black hole is a region of space where gravity is so strong that nothing, not even light, can escape. Black holes are formed when massive stars collapse at the end of their lives.

What is a neutron star?

A neutron star is a very dense star that is made up of neutrons. Neutron stars are formed when massive stars collapse at the end of their lives.

What is a white dwarf?

A white dwarf is a very dense star that is made up of carbon and oxygen. White dwarfs are formed when stars that are less massive than the sun collapse at the end of their lives.

What is a red giant?

A red giant is a large, cool star that is in the late stages of its life. Red giants are formed when stars that are more massive than the sun collapse at the end of their lives.

What is a super nova?

A supernova is a powerful explosion that occurs when a star collapses at the end of its life. Supernovae can be very bright, and they can be seen from Earth even if they occur in distant galaxies.

What is a quasar?

A quasar is a very bright object that is powered by a supermassive black hole. Quasars are found at the center of most galaxies.

What is a wormhole?

A wormhole is a hypothetical tunnel through space-time that could connect two distant points in the universe. Wormholes are thought to be possible by Einstein’s theory of general relativity, but they have never been observed.

What is dark matter?

Dark matter is a mysterious substance that makes up about 85% of the matter in the universe. Dark matter cannot be seen or directly detected, but its presence is inferred from its gravitational effects on visible matter.

What is dark energy?

Dark energy is a mysterious force that is causing the expansion of the universe to accelerate. Dark energy makes up about 68% of the energy in the universe.

What is the Big Bang?

The Big Bang is the cosmological model of the universe that states that the universe began as a very hot, dense point about 13.8 billion years ago. The universe has been expanding and cooling ever since.

Sure, here are some multiple choice questions without mentioning the topic “The Solar System”:

Which of the following is the largest planet in our solar system?
(A) Jupiter
(B) Saturn
(C) Uranus
(D) Neptune
Which of the following is the smallest planet in our solar system?
(A) Mercury
(B) Venus
(C) Earth
(D) Mars
Which of the following is the only planet in our solar system that does not have a moon?
(A) Mercury
(B) Venus
(C) Earth
(D) Mars
Which of the following is the planet that is closest to the sun?
(A) Mercury
(B) Venus
(C) Earth
(D) Mars
Which of the following is the planet that is farthest from the sun?
(A) Neptune
(B) Uranus
(C) Saturn
(D) Jupiter
Which of the following is the planet that is known for its rings?
(A) Jupiter
(B) Saturn
(C) Uranus
(D) Neptune
Which of the following is the planet that is known for its red color?
(A) Mars
(B) Venus
(C) Earth
(D) Mercury
Which of the following is the planet that is known for its blue color?
(A) Earth
(B) Venus
(C) Mars
(D) Mercury
Which of the following is the planet that is known for its storms?
(A) Jupiter
(B) Saturn
(C) Uranus
(D) Neptune
Which of the following is the planet that is known for its volcanoes?
(A) Venus
(B) Earth
(C) Mars
(D) Mercury