The Leap Second Explained

The video explains how Earth's rotation is slowing, causing the day to lengthen by about 2 milliseconds every 100 years. Leap seconds are added to synchronize clocks with Earth's rotation, but the frequency of leap seconds is higher than expected due to historical definitions of a second. The second was redefined in 1960 and 1967 to align with atomic clocks, but discrepancies remain. These discrepancies arise from the difference between the SI second and the solar day. As Earth's rotation continues to slow, leap seconds will become more frequent.

How much longer does a day get on average every 100 years due to Earth's slowing rotation?

• 5 milliseconds

• 2 milliseconds

• 10 milliseconds

• 1 millisecond

What was the original definition of a second based on?

• Atomic clocks

• Ephemeris second

• Solar day

• Lunar cycles

In which year was the SI second redefined based on atomic clocks?

• 1950

• 1960

• 1975

• 1967

Why do we need to insert leap seconds into our timekeeping?

• To adjust for Earth's faster rotation

• To synchronize atomic time with solar time

• To account for changes in the lunar cycle

• To correct for errors in atomic clocks

What causes irregularities in Earth's rotation that affect leap seconds?

• Solar flares

• Earthquakes and other effects

• Tidal forces

• Atmospheric pressure changes