Olympiad Test: Earth And Universe - 2 - Class 5 MCQ

The Moon's crust is thinnest on the side nearest to the Earth. This is due to tidal forces caused by the Earth's gravity, which have caused the crust to stretch and become thinner on the side facing the Earth, creating a phenomenon known as tidal locking.

To find the distance between Earth and Jupiter, we subtract Earth's distance from the Sun (93 million miles) from Jupiter's distance (483.4 million miles):

483.4 million miles − 93 million miles = 390.4 million miles

Thus, the distance between Earth and Jupiter is approximately 390.4 million miles. However, the closest option is 393.4 million miles, which might be due to a slight difference in rounding.

A comet is often described as a dirty snowball because it is composed of a mixture of ice, dust, and rocky material. As it orbits the Sun, the heat causes the ice to vaporize, creating a glowing coma and a tail that always points away from the Sun.

A constellation is a group of stars that form a recognizable pattern or shape in the night sky. These patterns are often named after mythological figures, animals, or objects. The stars in a constellation are not necessarily close to each other, but their positions from Earth's perspective create a picture.

Gemini (the Twins) is both the name of a constellation and a group of stars. It is one of the 88 recognized constellations and represents the twins Castor and Pollux from Greek mythology. The two brightest stars in this constellation are named after them.

Earth is closest to the Sun during the winter season in the northern hemisphere. This occurs around early January when the Earth is at its perihelion, the point in its orbit closest to the Sun. However, because of the tilt of the Earth's axis, it is winter in the northern hemisphere during this time.

The Earth's circumference is greatest at the Equator. This is because the Earth is not a perfect sphere but an oblate spheroid—meaning it is slightly flattened at the poles and bulging at the equator. Therefore, the circumference around the equator is larger than at the poles.

Astronauts appear to float in space because they are in a state of free fall. Even though gravity is still acting on them in space, they are moving along with their spacecraft and everything inside it at the same speed. This creates a sensation of weightlessness or floating.

A partial lunar eclipse happens when only a part of the Moon passes through the Earth's umbra, the darkest part of its shadow. During this event, part of the Moon appears darkened, while the remaining part stays bright. This is different from a total lunar eclipse, where the entire Moon is covered by the Earth's shadow.

A new moon happens when the Moon is positioned directly between the Earth and the Sun. During this phase, the side of the Moon that faces the Earth is not illuminated by sunlight, so it is not visible. The new moon marks the beginning of a lunar cycle.

An artificial satellite revolves around the Earth in a fixed direction, typically along a predetermined orbital path. Its orbit is influenced by the Earth's gravity, and its direction of motion remains stable and predictable, depending on the type of orbit (e.g., geostationary, polar).

Aryabhatta was India's first satellite, launched into space on April 19, 1975, by the Soviet Union. It marked India's entry into space exploration and was named after the ancient Indian mathematician and astronomer Aryabhata.

Opaque objects cast shadows because they do not allow light to pass through them. When light is blocked by an opaque object, a shadow is formed. Transparent objects allow light to pass through, and translucent objects let some light through, so they do not cast clear shadows.

• Statement i is incorrect because satellites are natural or artificial objects that revolve around a planet, not the Sun.
• Statement ii is correct; the Milky Way is a spiral-shaped galaxy.
• Statement iii is incorrect; Venus has no moons.
• Statement iv is correct; one revolution of the Earth is complete when it revolves around the Sun.

When Explorer 1 was launched into space on January 31, 1958, it was the first satellite launched by the United States. Following the Soviet Union's Sputnik 1 launch on October 4, 1957, the United States Army Ballistic Missile Agency was directed to launch a satellite using its Jupiter C rocket designed by Dr Wernher von Braun. The Jet Propulsion Laboratory was tasked with designing, building, and operating the artificial satellite that would serve as the rocket's payload.