Introduction to Earth & Universe MCQs for UPPSC (UP) Exam

Before and after the quarter-moon phases are the gibbous and crescent phases. During the gibbous moon phase, the moon is more than half lit but not full.  During the crescent moon phase, the moon is less than half lit and is seen as only a sliver or crescent shape.

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According to the Big Bang theory, everything in the universe developed from a point known as singularity, 15 billion years ago at an affixed moment in time. “As the universe expanded for 15 billion years, the hot radiation in the original fireball also expanded with it, and cooled as a result.”

Explanation:

The Goldilocks Zone, also known as the habitable zone, is the range of distance from a star within which liquid water can exist on the surface of a planet. It is not too hot nor too cold for life as we know it to exist.

Factors affecting the Goldilocks Zone:
The habitable zone is affected by various factors such as the size and type of the star, the planet's atmosphere, and its distance from the star.

Star size and type:
The size and type of the star play a crucial role in determining the habitable zone. A larger and hotter star will have a larger habitable zone, while a smaller and cooler star will have a smaller habitable zone.

Planet's atmosphere:
The planet's atmosphere also plays an important role in determining the habitable zone. A thicker atmosphere can trap more heat and expand the habitable zone, while a thinner atmosphere can decrease the habitable zone.

Distance from the star:
The distance of a planet from its star is another critical factor in determining the habitable zone. Planets that are too close to their star will be too hot, while planets that are too far from their star will be too cold.

Importance of the Goldilocks Zone:
The Goldilocks Zone is important because it is believed to be the most likely place to find life as we know it. Scientists have discovered several planets in the habitable zone of their star, and some of them may have the potential to support life.

Conclusion:
In conclusion, the Goldilocks Zone is the habitable zone around a star where liquid water can exist on the surface of a planet. It is not too hot nor too cold for life as we know it to exist. The habitable zone is affected by various factors such as the size and type of the star, the planet's atmosphere, and its distance from the star. The Goldilocks Zone is important because it is the most likely place to find life as we know it.

The rotatory motion of the planets (expect Venus and Uranus) is in the same direction as their revolution around the sun.

1. Meteoroids: These are small rocky or metallic fragments that travel through space and enter the Earth's atmosphere. They are typically the size of a pebble or smaller.

2. Asteroids: These are larger rocky fragments that orbit the Sun and occasionally cross paths with Earth's orbit. When they enter the Earth's atmosphere, they are called meteors.

3. Cometary debris: Comets are made up of ice, dust, and rocky fragments. When a comet gets close to the Sun, the heat causes the ice to vaporize, releasing debris into space. Some of this debris can enter the Earth's atmosphere as meteors.

4. Space debris: This includes fragments of satellites, rockets, and other human-made objects that have been left in space. When these objects re-enter the Earth's atmosphere, they can burn up and become meteors.

5. Tektites: These are glassy fragments that are formed when a large meteorite impacts the Earth's surface. The intense heat and pressure from the impact melt the surrounding rocks, creating tektites that are ejected into the atmosphere.

6. Lunar meteorites: These are fragments of the Moon's surface that are ejected during meteorite impacts on the Moon. Some of these fragments can escape the Moon's gravity and enter the Earth's atmosphere as meteors.

7. Martian meteorites: Similar to lunar meteorites, these are fragments of Mars that are ejected during meteorite impacts on the Martian surface. Some of these fragments can make their way to Earth as meteors.

It's important to note that while these rocky fragments can endure passage through the Earth's atmosphere, most of them burn up due to the intense heat generated by friction with the air. Only a small fraction of the original fragments survive and reach the Earth's surface as meteorites.

Spiral galaxy, milky way galaxy have four spirals, so the correct answer is option 'C'.

According to the Tidal Hypothesis, there was a great impact of the tidal force of the intruding star on the surface of the primitive sun. When the ‘intruding star’ came nearest to the ‘primitive sun’ its gravitational force became maximum, resulting in a giant cigar-shaped mass called a filament- thick in the centre and thin and sharp at the ends.

Collision Hypothesis by Harold Jeffreys

Introduction:
Harold Jeffreys was a British mathematician and geophysicist who proposed the Collision Hypothesis in the 1930s. This hypothesis explains the formation of celestial bodies, especially the formation of stars.

Theory:
The Collision Hypothesis suggests that three stars collided with each other and merged to form a single star. This single star then attracted more matter from the surrounding space and eventually became a full-fledged star.

Explanation:
According to the Collision Hypothesis, the three stars that collided were relatively small and had a low mass. These stars were moving in close proximity to each other and eventually collided due to the gravitational attraction between them.

The collision resulted in the formation of a single star that had a much larger mass than the individual stars that collided. This new star then started attracting more matter from its surroundings due to its increased gravitational force.

Over time, this process of accretion continued, and the star grew in size and mass. Eventually, it became a full-fledged star and started emitting light and heat.

Conclusion:
In conclusion, the Collision Hypothesis proposed by Harold Jeffreys suggests that the formation of stars can be attributed to the collision of three small stars that merge to form a larger star. This hypothesis helps in understanding the formation and evolution of stars and has been widely accepted by the scientific community.

According to the Collision Hypothesis proposed by Harold Jeffreys, there were three stars in the Universe before the origin of the solar system. primitive sun, the ‘companion star’ and the ‘intruding star’ which was moving towards ‘companion star’.

Out of the eight planets, Mercury, Venus, Earth and Mars are called “the inner planets” as they lie between the Sun and the belt of asteroids.

A nebula is an interstellar cloud of dust, hydrogen, helium, and other gases. Nebulae are often star-forming regions, where gas, dust 'clump' together to form larger masses, which eventually become massive enough to form stars.

In 1838, Sir George Darwin suggested that initially, the earth and the moon formed a single rapidly rotating body.

Overview of the Kuiper Belt
The Kuiper Belt is an essential region of our solar system, situated beyond the orbit of Neptune.
Key Characteristics
- Location: It is located approximately 30 to 55 astronomical units (AU) from the Sun.
- Composition: The belt contains a diverse collection of icy bodies, including dwarf planets like Pluto, Haumea, and Makemake.
- Structure: The Kuiper Belt is similar to the asteroid belt but is significantly larger and predominantly made up of icy materials.
Origin of Short-Period Comets
- Comet Formation: The Kuiper Belt is considered the source of many short-period comets.
- Orbital Characteristics: These comets typically have orbits that take less than 200 years to complete a trip around the Sun, often originating from the Kuiper Belt's icy bodies that are disturbed by gravitational interactions.
Conclusion
Both statements about the Kuiper Belt are accurate:
1. It is indeed a distant region of the solar system beyond Neptune, filled with icy bodies and dwarf planets.
2. It serves as the origin for many short-period comets, confirming the importance of this region in understanding our solar system's dynamics.
Thus, the correct answer is option 'C': Both statements 1 and 2 are correct.

Understanding Comets
Comets are fascinating celestial objects that offer insight into the early solar system. Let's analyze the statements provided to determine their accuracy.
Statement 1: Comets are icy balls that form in the outer solar system.
- This statement is true. Comets primarily consist of ice, dust, and rocky material. They originate from the outer regions of the solar system, particularly from areas like the Kuiper Belt and the Oort Cloud.
Statement 2: Several comets have circular orbits that cut across the orbits of planets.
- This statement is false. Most comets have highly elliptical orbits, not circular ones. Their orbits can extend far beyond the planets and then come close to the Sun, but they do not typically have circular paths that intersect planetary orbits.
Statement 3: Their surfaces are warm and fickle materials vaporize.
- This statement is ambiguous. While comets warm up as they approach the Sun, causing their icy components to vaporize (creating a coma and tail), the term "fickle" is subjective and does not accurately describe their behavior.
Statement 4: They are the remains and the leftovers from solar system formation.
- This statement is true. Comets are indeed considered remnants from the early solar system, preserving materials that provide clues about its formation and evolution.
Conclusion
Based on the analysis:
- Statements 1 and 4 are accurate.
- Statement 2 is incorrect.
- Statement 3 is unclear and not definitively true.
Thus, the correct answer is option C: 1 and 4 only.