SSC Selection Post 2025 PYQ — Question 2

Correct Answer: Venus

Explanation

Venus is known as both the 'Morning Star' and the 'Evening Star.' It is the second planet from the Sun and the brightest natural object in Earth's night sky after the Moon. Because its orbit is closer to the Sun than Earth's, Venus always appears close to the Sun from our perspective. It can be seen shining brilliantly either in the western sky just after sunset (as the Evening Star) or in the eastern sky shortly before sunrise (as the Morning Star).

Venus's extreme brightness is caused by its thick, dense atmosphere, which is composed primarily of carbon dioxide. This atmosphere is packed with heavy clouds of sulfuric acid that act like a giant cosmic mirror, reflecting about 70% of the sunlight it receives back into space. This high reflectivity is why it looks so radiant to the naked eye.

Key Points

Venus is also referred to as 'Earth's Twin' or 'Earth's Sister Planet' because the two worlds share very similar sizes, masses, compositions, and internal structures.

Despite being further from the Sun than Mercury, Venus is the hottest planet in our solar system due to a runaway greenhouse effect trapped by its dense atmosphere, creating surface temperatures hot enough to melt lead.

Venus exhibits a unique retrograde rotation, meaning it rotates on its axis clockwise from East to West, opposite to Earth and most other planets.

Important Questions and Answers

Question: Why does Venus experience a higher surface temperature than Mercury despite being further away from the Sun?

Answer: Venus has a dense, heat-trapping atmosphere made of carbon dioxide that triggers a runaway greenhouse effect, whereas Mercury lacks a thick atmosphere to retain heat.

Question: What is the approximate percentage of sunlight reflected by the cloud cover of Venus back into space?

Answer: Venus reflects roughly 70% of the sunlight it receives, giving it the highest albedo of any planet in the solar system.