How Do You Measure the Size of the Universe?

The video explores the vastness of the universe, focusing on astronomical distances measured in light years. It explains the concept of the observable universe, which is about 90 billion light years in diameter, and how space expansion affects our perception of distance. The video introduces the concept of cosmological redshift, which helps measure the universe's expansion history. By understanding redshift, scientists can determine the universe's size and age, estimated at 13.8 billion years. The video uses the analogy of raisin bread to illustrate space expansion and discusses the challenges in measuring the universe's size due to variable expansion rates.

What is the approximate diameter of the Milky Way galaxy in light years?

• 46 billion light years

• 2.5 million light years

• 100,000 light years

• 8 light hours

How do astronomers estimate the size of the observable universe?

• By counting the number of galaxies

• By measuring with a ruler

• By using the speed of light

• By calculating the age of the universe and expansion of space

What analogy is used to explain the expansion of space?

• A loaf of raisin bread rising

• A rubber band stretching

• A balloon being inflated

• A sponge soaking up water

What happens to light from distant galaxies due to the expansion of space?

• It becomes brighter

• It speeds up

• It changes direction

• Its wavelength is stretched, causing redshift

How is the relationship between redshift and distance used in astronomy?

• To measure the temperature of stars

• To determine the age of galaxies

• To find new planets

• To calculate the expansion history of the universe

What is the estimated age of the universe based on the expansion history?

• 10 billion years

• 13.8 billion years

• 20 billion years

• 4.5 billion years

What is the diameter of the observable universe?

• 100 billion light years

• 90 billion light years

• 46 billion light years

• 13.8 billion light years