What does 1 EFU represent?

What does 1 EFU represent?

• A. The time interval from today back to Earth's formation
• B. The time interval from today back to the Sun's formation
• C. The time interval since the universe began
• D. The distance light travels in a year

Answer: (A)

EFU is a time unit defined as the amount of time elapsed since Earth formed. So 1 EFU represents the interval from today back to Earth's formation, which is about 4.5 billion years. It’s a measure of how long the Earth has existed, not a distance (that would be a light-year) and not the age of the universe or the Sun’s formation. This makes the option describing the time back to Earth’s formation the best fit.

EFU is a time unit defined as the amount of time elapsed since Earth formed. So 1 EFU represents the interval from today back to Earth's formation, which is about 4.5 billion years. It’s a measure of how long the Earth has existed, not a distance (that would be a light-year) and not the age of the universe or the Sun’s formation. This makes the option describing the time back to Earth’s formation the best fit.