Grade 7 Solar System Quiz

Explanation
Pluto was no longer regarded as a planet in 2006 due to its size. This is because scientists discovered that Pluto shares its orbit with other celestial bodies in the Kuiper Belt, and its rotation is more similar to that of a dwarf planet rather than a traditional planet. This led to the reclassification of Pluto as a dwarf planet, as it did not meet the criteria to be considered a full-fledged planet.

Explanation
Non-luminous objects do not emit light. Luminous objects, such as the sun or a light bulb, produce their own light through a process called luminescence. However, non-luminous objects do not have this ability and therefore do not emit light. They can only reflect or absorb light that falls on them from a luminous source.

Explanation
The correct answer is "axis." An axis is an imaginary line that goes through the center of the Earth from the North Pole to the South Pole. It is around this axis that the Earth rotates, causing day and night.

Explanation
A satellite is the correct answer because it refers to an object that revolves around another object in outer space. Satellites can be natural, like moons, or artificial, like man-made spacecraft. They orbit planets, moons, stars, or other celestial bodies. Satellites are used for various purposes, such as communication, navigation, weather monitoring, and scientific research. They play a crucial role in modern technology and our understanding of the universe.

Explanation
The correct answer is rotation. Earth takes 1 day/24 hours to complete one rotation. Rotation refers to the spinning of Earth on its axis, which causes day and night.

Explanation
The correct answer is Moon. Different craters and ridges are seen on the surface of the Moon. The Moon's surface is heavily pockmarked with craters, which are formed by the impact of asteroids and meteoroids over billions of years. These craters and ridges provide evidence of the Moon's violent past and its history of being bombarded by space debris.

Explanation
The approximate distance of the sun from the earth is 150 million km. This distance is an estimation based on scientific measurements and calculations. It is important to note that the distance between the sun and the earth is not constant and can vary due to the elliptical shape of the earth's orbit around the sun.

Explanation
Stars in a group or congregation are called galaxies. Galaxies are vast systems of stars, gas, and dust held together by gravity. They come in different shapes and sizes and contain billions or even trillions of stars. The Milky Way, our own galaxy, is just one of the many galaxies in the universe.

Explanation
The correct answer is Sun. The question describes a huge ball of hot gases, which is a characteristic of the Sun. The Sun is often referred to as a star because it is a massive, luminous sphere of plasma held together by its own gravity and undergoing nuclear fusion in its core. It emits heat and light, making it a source of energy for our solar system.

Explanation
During the summer season, the northern hemisphere tilts towards the sun. This tilt causes the sun's rays to be more direct and concentrated in the northern hemisphere, leading to longer days and warmer temperatures. As a result, the northern hemisphere experiences summer during this time.