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 14th December 2018.
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
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The Solar System is a vast and complex place, home to a variety of objects, including the Sun, the planets, dwarf planets, moons, asteroids, comets, and meteoroids.
The Sun is the largest object in the Solar System and is responsible for providing Light and heat to the planets. It is a star, which means that it is a giant ball of hot gas. The Sun is made up of hydrogen and helium, and it is so hot that the hydrogen atoms are constantly fusing together to form helium atoms. This process releases a tremendous amount of energy, which is what powers the Sun.
The planets are smaller than the Sun, but they are still much larger than Earth. The four inner planets, Mercury, Venus, Earth, and Mars, are made up of rock and Metal. The four outer planets, Jupiter, Saturn, Uranus, and Neptune, are much larger than the inner planets and are made up of gas and ice.
The dwarf planets are smaller than the planets, but they are still larger than the moons. Ceres, Pluto, Eris, Makemake, and Haumea are the five dwarf planets in the Solar System. Ceres is located in the asteroid belt, while Pluto, Eris, Makemake, and Haumea are located in the Kuiper belt.
The moons are smaller than the planets, but they are still much larger than asteroids. The planets all have moons, and some of the moons are even larger than Pluto. The largest moon in the Solar System is Ganymede, which is larger than the planet Mercury.
The asteroid belt is a region of space between the orbits of Mars and Jupiter that is home to millions of asteroids. Asteroids are small, rocky bodies that orbit the Sun. The Kuiper belt is a region of space beyond the orbit of Neptune that is home to billions of icy bodies. The Oort cloud is a spherical region of space that surrounds the Solar System and is home to trillions of icy bodies.
Comets are small, icy bodies that orbit the Sun. When a comet comes close to the Sun, the heat from the Sun causes the ice to vaporize, creating a long tail of gas and dust. Meteoroids are small, rocky bodies that orbit the Sun. When a meteoroid enters Earth’s atmosphere, it burns up and creates a streak of light called a meteor. 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 that have been ejected from asteroids and comets.
The Solar System is a dynamic and ever-changing place. The planets orbit the Sun, the moons orbit the planets, and the asteroids, comets, and meteoroids orbit the Sun. The Solar System is also home to a variety of other objects, such as the asteroid belt, the Kuiper belt, and the Oort cloud. The Solar System is a fascinating place to study, and there is still much that we do not know about it.
Black Holes
What is a black hole?
A black hole is a place in space where gravity pulls so much that even light can not get out. The gravity is so strong because matter has been squeezed into a tiny space. This can happen when a star is dying.
What happens if you fall into a black hole?
If you fall into a black hole, you would be stretched out and crushed by the gravity. You would also be stretched out and crushed by the gravity.
What are the different types of black holes?
There are three main types of black holes: stellar black holes, supermassive black holes, and intermediate-mass black holes. Stellar black holes are the smallest type of black hole, and they are formed when a star collapses at the end of its life. Supermassive black holes are the largest type of black hole, and they are found at the center of most galaxies. Intermediate-mass black holes are between stellar black holes and supermassive black holes in size, and they are not as well understood as the other two types of black holes.
What is the event horizon?
The event horizon is the boundary around a black hole beyond which nothing, not even light, can escape.
What is the singularity?
The singularity is the center of a black hole, where the gravity is infinite.
What is Hawking radiation?
Hawking radiation is a theoretical form of radiation that is emitted by black holes. It is named after Stephen Hawking, who first proposed the theory in 1974.
Can black holes be destroyed?
It is not known if black holes can be destroyed. Some scientists believe that black holes may evaporate over time due to Hawking radiation. Others believe that black holes may be stable and will exist forever.
Dark Matter
What is dark matter?
Dark matter is a mysterious substance that makes up about 85% of the matter in the universe. It is invisible and does not interact with light or other forms of electromagnetic radiation.
What are the properties of dark matter?
Dark matter is thought to be weakly interacting massive particles (WIMPs). WIMPs are particles that interact with gravity but not with other forces. They are thought to be very heavy, about 100 times the mass of a proton.
How do we know dark matter exists?
We know dark matter exists because of its gravitational effects on visible matter. For example, galaxies rotate much faster than they should if they were made up of only visible matter. This suggests that there is a lot of invisible matter in galaxies that is providing the extra gravity needed to keep them from flying apart.
What is the role of dark matter in the universe?
Dark matter is thought to play a major role in the formation and evolution of galaxies. It is also thought to be responsible for the large-scale structure of the universe, such as the formation of clusters of galaxies.
What are the challenges of studying dark matter?
The biggest challenge of studying dark matter is that it is invisible. We can only detect it through its gravitational effects. This makes it very difficult to study and understand.
Dark Energy
What is dark energy?
Dark energy is a mysterious force that is causing the universe to expand at an accelerating rate. It is thought to make up about 68% of the energy in the universe.
What are the properties of dark energy?
Dark energy is thought to be a form of energy that is not affected by gravity. It is also thought to be very spread out, with very little of it in any one place.
How do we know dark energy exists?
We know dark energy exists because of its effects on the expansion of the universe. The expansion of the universe has been accelerating over time, and this can only be explained by the presence of dark energy.
What is the role of dark energy in the universe?
Dark energy is thought to be the driving force behind the expansion of the universe. It is also thought to be responsible for the accelerating expansion of the universe.
What are the challenges of studying dark energy?
The biggest challenge of studying dark energy is that we don’t know what it is. We can only detect its effects, not its properties. This makes it very difficult to study and understand.
Sure, here are some MCQs without mentioning the topic Solar System:
Which of the following is not a planet in our solar system?
(A) Earth
(B) Mars
(C) Jupiter
(D) Pluto
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 planets has the most moons?
(A) Jupiter
(B) Saturn
(C) Uranus
(D) Neptune
Which of the following planets is the only planet in our solar system that is known to have liquid water on its surface?
(A) Earth
(B) Mars
(C) Venus
(D) Mercury
Which of the following planets is the closest planet to the sun?
(A) Mercury
(B) Venus
(C) Earth
(D) Mars
Which of the following planets is the farthest planet from the sun?
(A) Neptune
(B) Uranus
(C) Pluto
(D) Saturn
Which of the following planets is the only planet in our solar system that is known to have rings?
(A) Jupiter
(B) Saturn
(C) Uranus
(D) Neptune
Which of the following planets is the only planet in our solar system that is known to have a polar ice cap?
(A) Earth
(B) Mars
(C) Venus
(D) Mercury
Which of the following planets is the only planet in our solar system that is known to have volcanoes?
(A) Earth
(B) Mars
(C) Venus
(D) Mercury