Why Days Are Getting Longer

The video discusses how Earth's rotation is slowing, making days longer by 1.8 milliseconds per century. This is due to the moon's gravitational pull and other factors like post-Ice Age pole rebound. Historical records and modern technology help track these changes. Additionally, new research suggests smallpox may be only a few hundred years old, challenging previous beliefs about its history.

What historical method was used to measure the length of a day before telescopes were invented?

• Using sundials

• Tracking the movement of planets

• Recording solar and lunar eclipses

• Observing the position of stars

How much longer is a day on Earth getting every century, according to recent research?

• 1.7 milliseconds

• 1.8 milliseconds

• 3.0 milliseconds

• 2.3 milliseconds

What natural phenomenon is primarily responsible for slowing down Earth's rotation?

• Atmospheric pressure changes

• Tectonic plate movements

• Solar flares

• Gravitational pull of the moon

What recent discovery has led scientists to reconsider the timeline of smallpox's history?

• A child mummy with the virus from the 17th century

• Ancient texts describing the disease

• A fossilized virus sample

• A new strain of the virus

According to DNA analysis, when did smallpox likely start spreading globally?

• In the 1500s

• In the 1700s

• In the 2000s

• In the 1200s