Solar and lunar eclipses

TL;DR

Solar and lunar eclipses do not occur with every new moon or full moon because the moon's orbit is at a five-degree angle to the Earth's orbit around the sun.

Transcript

• [Instructor] In a previous video, we asked ourselves a very important question. As the moon has its 28-day cycle around the Earth, we talked about how a new moon is when the moon is between the earth and the sun, and so from the Earth's point of view, or from the point of view of someone standing on Earth, you're seeing the side of the moon that ... Read More

Key Insights

• 🌑 Solar eclipses do not occur with every new moon because the moon's orbit is tilted at a five-degree angle to the Earth's orbit around the sun.
• 🥮 Lunar eclipses do not occur with every full moon because the moon's orbit can vary up to five degrees above or below the plane of the Earth's rotation.
• 😵 The moon's shadow only falls on Earth during a solar eclipse when it crosses through the plane of the Earth's rotation around the sun.
• 🥮 The umbra of the moon represents the area where the moon completely blocks out the sun during a solar eclipse.
• 🥮 The penumbra of the moon represents the area where the moon partially blocks out the sun during a solar eclipse.
• 🥳 Observing the orientation of the moon can help determine the position of the sun and the time of day.
• 🛰️ The moon's orbit is at a five-degree angle to the Earth's orbit, resulting in the variations in solar and lunar eclipses.

Questions & Answers

Q: Why doesn't a solar eclipse occur with every new moon?

Solar eclipses do not occur with every new moon because the moon's orbit is tilted at a five-degree angle to the Earth's orbit around the sun. The moon's shadow only falls on Earth when it crosses through the plane of the Earth's rotation around the sun.

Q: Why doesn't a lunar eclipse occur with every full moon?

Lunar eclipses do not occur with every full moon because the moon's orbit can vary up to five degrees above or below the plane of the Earth's rotation. A lunar eclipse only happens when the moon falls into the shadow of the Earth.

Q: What are the yellow and blue lines in the picture depicting a solar eclipse?

The yellow lines represent the umbra of the moon, where the moon completely blocks out the sun. The blue lines represent the penumbra, the outer shadow where the moon partially blocks out the sun.

Q: How can we determine the orientation of the moon with respect to the Earth by looking at it?

By observing the moon at night, we can determine the location of the sun and therefore determine the time of day. We can also identify the cardinal directions (east, west, north, south) based on the moon's orientation.

Summary & Key Takeaways

• Solar eclipses do not occur with every new moon because the moon's orbit is at a five-degree angle to the Earth's orbit around the sun. The moon's shadow only falls on Earth when it crosses through the plane of the Earth's rotation around the sun.

• Lunar eclipses do not occur with every full moon for the same reason. The moon's orbit can vary up to five degrees above or below the plane of the Earth's rotation, and a lunar eclipse only happens when the moon falls into the shadow of the Earth.