Olympiad Test: Stars And The Solar System - 2 - Class 8 MCQ

The location of the sun:
- The sun is located at the center of the solar system.
- It is not located at the center of the universe or the Milky Way.
- The center of the solar system is defined as the point around which all the planets, asteroids, comets, and other celestial bodies orbit.
- The sun's enormous mass creates a gravitational pull that keeps all the planets in their respective orbits.
- The sun's location is approximately 93 million miles (150 million kilometers) away from Earth.
- It takes about 8 minutes and 20 seconds for light from the sun to reach Earth.
- The sun is a star, specifically a medium-sized, main-sequence star known as a G-type star or a yellow dwarf.
- The sun is composed mainly of hydrogen and helium and has a diameter of about 1.4 million kilometers (870,000 miles).
- It is the source of heat and light for our planet and sustains life on Earth.
- The sun also plays a crucial role in the Earth's climate and weather systems.
- It is important to note that while the sun is at the center of our solar system, it is not at the exact geometric center. The center of mass of the solar system, called the barycenter, is slightly off-center due to the gravitational interactions between the sun and the planets.
In conclusion, the sun is located at the center of the solar system and not at the center of the universe or the Milky Way. Its position is crucial for the stability and functioning of our solar system.

The large number of rocks that lie between the orbits of Mars and Jupiter are called asteroids.
Explanation:
The correct answer is option D, asteroids. Here is a detailed explanation:
- Asteroids are rocky objects that orbit the Sun and are primarily located in the asteroid belt, which lies between the orbits of Mars and Jupiter.
- The asteroid belt is a region of space where numerous small and irregularly shaped asteroids are found.
- These asteroids are remnants from the early formation of the solar system, and they vary in size from small boulders to large objects several hundred kilometers in diameter.
- Comets, option A, are icy bodies that also orbit the Sun, but they typically have more elliptical and elongated orbits than asteroids.
- Meteors, option B, are small particles or fragments of matter that enter the Earth's atmosphere and burn up, creating a streak of light commonly known as a shooting star.
- Meteorites, option C, are the remnants of meteors that survive the journey through the Earth's atmosphere and reach the ground.
In conclusion, the large rocks that lie between the orbits of Mars and Jupiter are called asteroids.

Constellation in the shape of a hunting man:
- The correct answer is Orion.
- The constellation Orion is named after a mythical Greek hunter.
- It is one of the most recognizable constellations in the night sky.
- Orion is visible in both the northern and southern hemispheres during different times of the year.
- The constellation is made up of several prominent stars that form the shape of a man holding a club and a shield.
- The three bright stars in a straight line represent Orion's belt.
- The two stars above the belt represent his shoulders, while the two stars below the belt represent his legs.
- The brightest star in Orion is Betelgeuse, which is located on the hunter's right shoulder.
- Another notable star in Orion is Rigel, which is located on the hunter's left foot.
- Orion is often associated with the winter season and can be seen in the evening sky during this time.
- The constellation has been a subject of fascination and mythology for centuries, with various cultures interpreting its shape and significance differently.

The Red Planet: Mars
- Mars is commonly referred to as the "red planet" due to its reddish appearance.
- The color of Mars comes from iron oxide (rust) that is present on its surface.
- The reddish hue is visible even from Earth, making it easily distinguishable among the other planets.
- Mars is the fourth planet from the Sun in our solar system.
- It is often considered a terrestrial planet, meaning it has a solid surface and is composed primarily of rock and metal.
- Mars has a thin atmosphere composed mostly of carbon dioxide, with traces of nitrogen and argon.
- The planet has intriguing features such as valleys, polar ice caps, and the largest volcano in the solar system, Olympus Mons.
- Mars has been a subject of great interest for scientists and space exploration missions due to its potential to support past or present microbial life.
- Multiple missions have been sent to Mars to study its geology, climate, and the possibility of human colonization in the future.
- Overall, Mars is known as the red planet due to its distinct reddish color caused by iron oxide and is a fascinating celestial body in our solar system.

Jupiter is the largest planet of the solar system.
Reasoning:
- Jupiter is the largest planet in our solar system. It has a diameter of about 86,881 miles (139,822 kilometers), which is more than 11 times the diameter of Earth.
- It is a gas giant composed mostly of hydrogen and helium and has a mass 2.5 times that of all the other planets in the solar system combined.
- Jupiter is known for its iconic Great Red Spot, a massive storm that has been raging for centuries.
- Its strong gravitational pull has also led to the discovery of numerous moons, with the current count standing at 79.
- Jupiter plays a significant role in the dynamics of the solar system, acting as a sort of "vacuum cleaner" by attracting and capturing many asteroids and comets with its gravity.
Summary:
Jupiter is the largest planet of the solar system, with a diameter more than 11 times that of Earth. It is a gas giant composed mostly of hydrogen and helium and is known for its Great Red Spot and numerous moons. Jupiter's gravitational pull influences the dynamics of the solar system.

The largest asteroid in the universe is Ceres.
Explanation:
Ceres is the largest object in the asteroid belt between Mars and Jupiter. It is considered a dwarf planet and is the largest member of the asteroid belt. Here's a detailed explanation:
- Ceres:
Ceres is a dwarf planet and the largest object in the asteroid belt. It has a diameter of about 940 kilometers (590 miles) and accounts for about one-third of the total mass of the entire asteroid belt. It was discovered on January 1, 1801, by Italian astronomer Giuseppe Piazzi. Ceres is composed of rock and ice, and its surface is covered with numerous impact craters.
- Halley:
Halley is not an asteroid but a famous comet. It is named after the English astronomer Edmond Halley and is known for its periodic returns to the inner solar system. Halley's Comet is visible from Earth approximately every 76 years.
- Orion:
Orion is not an asteroid either. It is a prominent constellation located on the celestial equator and visible throughout the world. It is known for its distinctive pattern of three stars forming Orion's Belt.
- Sorpius:
Sorpius (sometimes spelled Scorpius) is another constellation and not an asteroid. It is one of the zodiac constellations and is known for its resemblance to a scorpion.
In conclusion, the largest asteroid in the universe is Ceres.

Answer:
The first satellite launched by India in March 1975 is Aryabhata.
Explanation:
The Indian Space Research Organisation (ISRO) successfully launched its first satellite, Aryabhata, on March 19, 1975. Here is a detailed explanation of the answer:
- Aryabhata:
- Aryabhata was named after the famous Indian mathematician and astronomer, Aryabhata.
- It was a 360-kilogram satellite that was built by ISRO.
- The primary objective of Aryabhata was to conduct experiments in X-ray astronomy, solar physics, and atmospheric studies.
- It was launched using a Soviet Kosmos-3M launch vehicle from Kapustin Yar, a Russian spaceport.
- Aryabhata had a lifespan of about four years and operated successfully until its re-entry on February 11, 1992.
Other options mentioned in the question are not correct:
- Bhaskara - I:
- Bhaskara - I was the second satellite launched by India on June 7, 1979.
- It was developed to conduct remote sensing experiments.
- The satellite was named after the famous Indian mathematician and astronomer, Bhaskara.
- INSAT - 2C:
- INSAT - 2C was launched by ISRO on December 7, 1995.
- It was a communication satellite and played a crucial role in providing various services including telecommunication, television broadcasting, and meteorological data.
- Antariksh:
- There is no record of a satellite named Antariksh being launched by India in 1975 or any other year.
Therefore, the correct answer is option C: Aryabhata.

The Earth's Rotation and the Movement of Stars
The rotation of the Earth on its axis affects the apparent movement of stars in the sky. Here is a detailed explanation of how this works:
1. Earth's Rotation
- The Earth rotates from west to east, completing one full rotation in approximately 24 hours.
- This rotation is responsible for the cycle of day and night on Earth.
2. Celestial Sphere
- To understand the movement of stars, astronomers use an imaginary sphere called the celestial sphere.
- The celestial sphere is an imaginary projection of the sky, with the Earth at its center.
- Stars, planets, and other celestial objects are considered to be located on the surface of this sphere.
3. Apparent Movement of Stars
- Due to the Earth's rotation, it appears as though the stars are moving across the sky.
- However, it is important to note that the stars themselves are relatively fixed in their positions.
- The apparent movement of stars is caused by the rotation of the Earth beneath them.
4. East to West Movement
- Because the Earth rotates from west to east, the stars appear to move from east to west.
- If you observe the night sky over the course of several hours, you will notice that the stars appear to rise in the east and set in the west.
5. Other Factors
- It is essential to consider that the movement of stars is also influenced by other factors, such as the Earth's orbit around the Sun.
- The combination of the Earth's rotation and its orbital motion leads to more complex patterns of star movements over longer periods of time.
In conclusion, due to the Earth's rotation from west to east, the stars appear to move from east to west in the sky. This apparent movement is a result of the Earth's rotation beneath the fixed positions of the stars on the celestial sphere.

Stars are classified on the basis of their physical attributes such as:
1. Size:
- Stars can vary greatly in size, ranging from small, compact stars to massive, giant stars.
- Size is determined by the mass of the star, with larger stars having more mass.
2. Temperature:
- The temperature of a star is a crucial factor in determining its classification.
- Stars can have a wide range of temperatures, from cool stars with temperatures below 3,500 Kelvin to extremely hot stars with temperatures exceeding 30,000 Kelvin.
3. Colour and Brightness:
- The color of a star is directly related to its temperature. Hotter stars appear bluer, while cooler stars appear redder.
- Brightness is a measure of how much light a star emits. It can vary significantly between stars.
4. All of these:
- Stars are classified based on a combination of their size, temperature, color, and brightness.
- The classification system, known as the Hertzsprung-Russell diagram, allows astronomers to categorize stars into different types such as main sequence stars, red giants, white dwarfs, and more.
In conclusion, stars are classified based on their physical attributes including size, temperature, color, and brightness. These attributes provide valuable information about the characteristics and evolution of stars.

The planet having maximum number of moons is Saturn.
Explanation:
- Saturn is a gas giant planet in our solar system and it has a large number of moons.
- It is known to have a total of 82 moons as of 2021.
- The largest moon of Saturn is called Titan, which is even bigger than the planet Mercury.
- Other notable moons of Saturn include Enceladus, Mimas, and Rhea.
- These moons vary in size, composition, and characteristics.
- Some of the moons have unique features, such as geysers on Enceladus and a prominent ridge on Iapetus.
- The moons of Saturn have been studied by spacecraft missions like Cassini, which provided valuable data and images of these celestial bodies.
- The large number of moons around Saturn is due to its strong gravitational pull, which can capture and retain smaller objects in its orbit.
In summary, Saturn is the planet in our solar system that has the maximum number of moons, with a total of 82 known moons. These moons vary in size and characteristics, and they have been studied by spacecraft missions like Cassini.

Explanation:
The different phases of the moon can be observed because of the relative position of the moon, the earth, and the sun. This can be explained in detail as follows:
1. Relative Positions:
The moon orbits around the earth, while the earth orbits around the sun. The phases of the moon occur as a result of the changing positions of these celestial bodies.
2. Illumination by the Sun:
The moon does not emit its own light, but it reflects sunlight. As the moon orbits the earth, the angle at which sunlight falls on the moon changes. This changing angle of illumination results in different portions of the moon being visible to us on earth.
3. Phases of the Moon:
The moon goes through eight distinct phases: new moon, waxing crescent, first quarter, waxing gibbous, full moon, waning gibbous, third quarter, and waning crescent. These phases are determined by the alignment of the sun, earth, and moon. The different positions and angles of these bodies cause varying amounts of the moon's surface to be illuminated and visible from earth.
4. Moon's Orbit:
The moon's orbit around the earth is slightly tilted, which means that it does not always pass through the shadow of the earth (as in a lunar eclipse). However, there are times when the moon's orbit aligns with the earth and the sun, causing a partial or total eclipse of the moon.
Conclusion:
In conclusion, the different phases of the moon can be observed due to the relative positions of the moon, the earth, and the sun. The changing angles of illumination and the alignment of these celestial bodies result in the various phases that we see from earth.

To calculate the time taken by sunlight to reach the earth, we need to consider the distance between the sun and the earth.
Key information:
- The average distance between the sun and the earth is approximately 93 million miles (or 150 million kilometers).
- The speed of light is approximately 186,282 miles per second (or 299,792 kilometers per second).
Calculations:
1. Convert the distance between the sun and the earth to kilometers: 93 million miles * 1.60934 (conversion factor) = 149.6 million kilometers.
2. Divide the distance by the speed of light: 149.6 million kilometers / 299,792 kilometers per second = 499.004 seconds.
3. Convert seconds to minutes: 499.004 seconds / 60 seconds per minute = 8.31673 minutes (rounded to the nearest minute).
4. Since the question asks for the answer in minutes, the correct option is C: 8.3 minutes.
Answer:
The sunlight takes approximately 8.3 minutes to reach the earth.

Geostationary Orbit for Communication Network:
Geostationary orbit is the type of orbit required for communication networks. Here is a detailed explanation of why geostationary orbit is the preferred choice:
What is a Geostationary Orbit?
A geostationary orbit is a circular orbit around the Earth at an altitude of approximately 35,786 kilometers (22,236 miles). In this orbit, a satellite moves at the same rotational speed as the Earth, appearing to be stationary from the ground.
Advantages of Geostationary Orbit for Communication Network:
1. Coverage: Geostationary satellites provide coverage over a large portion of the Earth's surface, typically a third of the planet. This wide coverage allows for global communication services.
2. Stability: Satellites in geostationary orbit remain fixed relative to a specific location on Earth. This stability is crucial for communication networks as it ensures a consistent connection without the need for frequent handovers between different satellites.
3. Line-of-Sight: Geostationary satellites maintain a constant line-of-sight with ground stations. This direct line-of-sight enables uninterrupted communication between the satellite and the ground station, minimizing signal loss and latency.
4. Antenna Size: In a geostationary orbit, the signal transmission from the satellite to the ground station requires smaller and simpler antennas compared to other orbit types. This reduces the cost and complexity of ground-based infrastructure.
5. Broadcasting and Telecommunication: Geostationary orbit is ideal for broadcasting and telecommunication purposes, such as television signals, internet connectivity, voice communication, and data transmission. The stationary nature of the satellites allows for efficient distribution of signals to a large audience.
Conclusion:
In summary, the geostationary orbit is the most suitable orbit for communication networks due to its wide coverage, stability, constant line-of-sight, smaller antenna requirements, and its ability to facilitate broadcasting and telecommunication services effectively.

Explanation:
Orion is a constellation that is easily recognizable due to its distinct pattern of stars. It is located on the celestial equator and is visible from both the northern and southern hemispheres.
The number of stars in Orion can vary depending on the specific pattern that is recognized. However, the most commonly recognized pattern in Orion consists of seven stars. These stars form the shape of a hunter or warrior holding a club and a shield.
The seven stars that make up the pattern of Orion are:
1. Betelgeuse: This is a red supergiant star and is one of the brightest stars in the night sky.
2. Rigel: This is a blue supergiant star and is also very bright.
3. Bellatrix: This star is located on Orion's left shoulder.
4. Saiph: This star is located on Orion's right knee.
5. Mintaka: This star is located on Orion's belt.
6. Alnilam: This star is also located on Orion's belt.
7. Alnitak: This star is the third star on Orion's belt.
In addition to these seven stars, there are several other stars that are often included as part of the Orion constellation, bringing the total number of stars to around 20. However, the key pattern that is recognized as Orion consists of these seven stars.
Therefore, the correct answer is option B: 7 or 8.

Answer:
Introduction:
The discovery of planets using telescopes has played a crucial role in expanding our knowledge of the universe. In this question, we are asked to identify the first planet discovered through the use of a telescope.

The first planet to be discovered by the telescope was Uranus. Here is a detailed explanation of the discovery:
1. Background:
- Before the invention of the telescope, the only planets known to ancient civilizations were Mercury, Venus, Mars, Jupiter, and Saturn.
- These five planets are visible to the naked eye and were known since ancient times.
2. The Discovery:
- In the 18th century, astronomers began using telescopes to explore the night sky in more detail.
- On March 13, 1781, the British astronomer Sir William Herschel observed an object in the constellation of Gemini.
- At first, Herschel believed it to be a comet, but further observations revealed that it was a planet.
- The discovery of Uranus marked the first time a planet had been identified using a telescope.
3. Confirmation and Recognition:
- Herschel initially named the newly discovered planet "Georgium Sidus" in honor of King George III of England.
- However, the name Uranus was eventually adopted, following the tradition of naming planets after ancient Greek and Roman deities.
- The discovery of Uranus was a significant achievement for Herschel and brought him international recognition as an astronomer.
Conclusion:
The first planet to be discovered using a telescope was Uranus. This discovery by Sir William Herschel in 1781 marked a significant milestone in our understanding of the solar system and expanded our knowledge of the planets beyond the five known since ancient times.