# The Universe, Solar System and Shape of the Earth - Link: https://thecuriosi.com/lessons/aptet-evs-universe-solar-system/ - Published: 2026-11-03T19:00:52+05:30 - Author: MAHENDRA MANCHIKALAPATI 1. [Courses](https://thecuriosi.com/courses/) 2. [APTET EVS Social: Our Universe and Livelihoods](https://thecuriosi.com/courses/aptet-evs-social-universe-livelihoods/) 3. Lesson 1 of 8 EVS Social Studies in Paper I(A) begins with the place where all human life happens: the Earth and its place in the universe. This lesson covers the **shape of the Earth**, the **universe** (its origin), the **solar system**, **celestial bodies** and ** constellations**. Children’s natural curiosity about the night sky makes this an exciting topic to teach, and APTET questions here are short and factual. ## The universe and the solar system The **universe** is everything that exists: all space, matter and energy. Most scientists explain its origin by the **Big Bang theory**, which says it began expanding from an extremely hot, dense state about **13.8 billion years ago**. A **galaxy** is a huge system of billions of stars, gas and dust. Our galaxy is the **Milky Way** (Akash Ganga). Distances between stars are measured in **light years**: the distance light travels in one year. The **Sun** is a star, the nearest star to the Earth; light from the Sun takes about **8 minutes** to reach us. The next nearest star, Proxima Centauri, is about 4.2 light years away. The **solar system** is the Sun and everything that revolves around it: **eight planets**, dwarf planets, moons, asteroids, comets and meteoroids. The Sun’s gravity holds the system together. | Planet (in order from the Sun) | Key facts | | Mercury | **closest** to the Sun; **smallest** planet; shortest year (88 days); no moon | | Venus | **hottest** planet (thick carbon dioxide atmosphere traps heat); brightest planet, seen as the “morning star” or “evening star”; rotates in the opposite direction to most planets; no moon | | Earth | the **“blue planet”**; the only planet known to support life; one moon | | Mars | the **“red planet”** (iron oxide in its soil); two small moons | | Jupiter | **largest** planet; a gas giant with many moons | | Saturn | famous for its bright **rings** | | Uranus | rotates lying almost on its side | | Neptune | farthest planet from the Sun | Memory aid for the order: **“My Very Efficient Mother Just Served Us Nuts.”** The first four planets are **inner (terrestrial, rocky) planets**; the last four are **outer planets (gas and ice giants)**. **Pluto** was reclassified as a **dwarf planet** in **2006** by the International Astronomical Union. ## Other celestial bodies | Body | Description | | Moon | the Earth’s natural **satellite**, about 3,84,400 km away; it takes about 27 days to go round the Earth, so the same side always faces us; it shines by reflected sunlight and shows **phases** | | Asteroids | rocky pieces orbiting the Sun, mostly in the **asteroid belt between Mars and Jupiter** | | Comets | bodies of ice and dust; near the Sun they form a glowing **tail that points away from the Sun**; **Halley’s comet** appears about every 76 years | | Meteors and meteorites | small pieces of rock that burn up in the air as “**shooting stars**“; those that reach the ground are meteorites | | Artificial satellites | human-made objects orbiting the Earth for communication, weather and mapping; India’s first satellite was **Aryabhata (1975)** | India’s rockets are launched from the **Satish Dhawan Space Centre, Sriharikota**, in Andhra Pradesh. **Chandrayaan-3** landed near the Moon’s south pole on **23 August 2023**, a day now celebrated as National Space Day. ## Constellations and the Pole Star A **constellation** is a group of stars that forms a recognisable pattern in the sky. | Constellation | Notes | | Ursa Major (Great Bear; **Saptarishi** in India) | seven bright stars look like a ladle or “Big Dipper”; two **pointer stars** point towards the Pole Star | | Orion (the Hunter; Mriga) | visible in winter evenings; three stars in a row form the “belt” | | Cassiopeia | five bright stars in a **W** or M shape | The **Pole Star (Dhruva Tara)** lies almost directly above the North Pole, so it appears **fixed** in the northern sky while other stars seem to move. Travellers used it to find the north. ## Shape of the Earth The Earth is not a perfect sphere: it is **slightly flattened at the poles and bulging at the equator**. This shape is called a **geoid** (“Earth-shaped”). Evidence that the Earth is round: * when a ship sails away, its hull disappears before its mast; * photographs taken from space; * ships and aircraft can travel all the way round it (Magellan’s expedition, 1519– 1522, completed the first voyage round the world); * the Earth’s shadow on the Moon during a lunar eclipse is always curved. ### Exam focus * Largest planet Jupiter; smallest and closest Mercury; hottest Venus; red planet Mars. * Pluto: dwarf planet since 2006. * Asteroid belt: between Mars and Jupiter; comet tails point away from the Sun. * Pole Star: found using the pointer stars of Ursa Major (Saptarishi). * Earth’s shape: a geoid. ### Example Mrs Rajani asks Class 5 to observe the Moon at the same time every evening for two weeks and draw its shape in a “Moon diary”. In class, they arrange their drawings in order and discover the phases themselves. One child spots Venus near the Moon and the class finds out why it shines so brightly. ## Key takeaways * The universe began with the Big Bang about 13.8 billion years ago; our galaxy is the Milky Way. * The solar system has the Sun, eight planets, dwarf planets, moons, asteroids, comets and meteoroids. * Mercury is closest, Jupiter largest, Venus hottest and Mars the red planet; Pluto is a dwarf planet. * The Moon is the Earth’s natural satellite; Aryabhata (1975) was India’s first artificial satellite. * Constellations are star patterns; the Pole Star marks the north. * The Earth is a geoid, slightly flattened at the poles. ## Practice 1. The largest planet of the solar system is: 2. * (A) Saturn * (B) Jupiter * (C) Earth * (D) Neptune 3. The planet closest to the Sun is: 4. * (A) Venus * (B) Earth * (C) Mars * (D) Mercury 5. The hottest planet of the solar system is: 6. * (A) Venus * (B) Mercury * (C) Mars * (D) Jupiter 7. The planet known as the “red planet” is: 8. * (A) Jupiter * (B) Venus * (C) Mars * (D) Saturn 9. Pluto was reclassified as a dwarf planet in: 10. * (A) 1930 * (B) 1986 * (C) 2006 * (D) 2016 11. The Pole Star can be located with the help of the pointer stars of: 12. * (A) Ursa Major (Saptarishi) * (B) Orion * (C) Cassiopeia * (D) Scorpio 13. The asteroid belt lies between the orbits of: 14. * (A) Earth and Mars * (B) Venus and Earth * (C) Saturn and Uranus * (D) Mars and Jupiter 15. The shape of the Earth is best described as: 16. * (A) a perfect sphere * (B) a geoid, slightly flattened at the poles * (C) a flat disc * (D) a cube Answers and explanations (tap to show) 1. (B) Jupiter is the largest planet. 2. (D) Mercury is the closest to the Sun. 3. (A) Venus is the hottest because its thick atmosphere traps heat, even though Mercury is closer to the Sun. 4. (C) Iron oxide in its soil makes Mars look red. 5. (C) The International Astronomical Union reclassified Pluto in 2006. 6. (A) The two pointer stars of Saptarishi point towards the Pole Star. 7. (D) Most asteroids orbit between Mars and Jupiter. 8. (B) The Earth bulges at the equator and is flattened at the poles. [Log in](https://thecuriosi.com/wp-login.php?redirect_to=https%3A%2F%2Fthecuriosi.com%2Flessons%2Faptet-evs-universe-solar-system%2F) to mark lessons complete and track your progress. [ Next lesson Globe, Latitudes, Earth’s Movements and Maps ](https://thecuriosi.com/lessons/aptet-evs-globe-latitudes-maps/) [Back to course overview](https://thecuriosi.com/courses/aptet-evs-social-universe-livelihoods/) Share this