Measuring Astronomical Distances: The Light Year

The video tutorial explores the vastness of space and how distances are measured. It begins by comparing the distances to the Moon and Alpha Centauri, highlighting the challenge of expressing such large numbers. The concept of a light year is introduced as a solution, defined as the distance light travels in a year. The historical context of the light year is discussed, including its first use by Friedrich Bessel in 1838. The video also covers the transition from astronomical units to light years and the modern preference for parsecs in measuring astronomical distances.

How far is the Earth's moon from our planet on average?

• 238,855 kilometers

• 384,000 miles

• 238,855 miles

• 384,000 kilometers

What is the distance of Alpha Centauri from Earth?

• 25.6 trillion miles

• 41.32 billion kilometers

• 41.32 trillion kilometers

• 25.6 billion miles

What does a light year measure?

• Mass

• Distance

• Speed

• Time

Who first used the term 'light year' in 1838?

• Albert Einstein

• Galileo Galilei

• Isaac Newton

• Friedrich Bessel

What unit do modern astronomers prefer for measuring distances outside our solar system?

• Parsec

• Astronomical unit

• Light year

• Kilometer