Explanation

• Greenwich is an area in south-east London, England.
• It lies on the south bank of the River Thames in the historic county of Kent.
• It is famous for the Prime Meridian (0° longitude).
• It is used as the reference for Greenwich Mean Time (GMT).
• It is famous for calculating the time for all countries.

The Greenwich meridian, also known as the prime meridian, passes through the following countries:

• England
• France
• Spain
• Algeria
• Mali
• Burkina Faso
• Togo
• Ghana 
• Antarctica

Last verified on 31-03-2026

Explanation

• Author: Stephen Hawking
• Book Title: A Brief History of Time
• Main Topic: Universe (origin, structure, evolution, and fate)
• First Published: 1988
• Publisher: Bantam Dell Publishing Group
• Copies Sold: ~10 million
• Languages: 40 languages

Last verified on 01-06-2026

Explanation

• Nicolaus Copernicus is called the Father of Modern Astronomy.
• He introduced the heliocentric theory in 1543.
• This theory stated that the Sun is at the center of the solar system.
• His ideas changed the old belief that Earth is the center.

Additional information:

• Galileo Galilei, a later figure, is often called the "father of observational astronomy".

Last verified on 01-06-2026

Explanation

• The Earth’s circumference at the equator is about 40,075 km (24,901 miles).
• Measured through the poles, it is slightly smaller: 40,008 km (24,860 miles).
• The difference is due to the equatorial bulge caused by Earth's rotation.
• Diameter: ~12,756 km (7,926 miles).
• Age of Earth: ~4.453 billion years.

Last verified on 31-03-2026

Explanation

• The next leap year after recent cycle is 2028.
• A leap year comes after every 4 years.
• A year divisible by 4 is usually a leap.
• It has 366 days instead of 365 days.
• The extra day is added in February (29th February).

Last verified on 01-06-2026