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Here's a clean explanation from NASA's eclipse site (https://eclipse2017.nasa.gov/why-do-eclipse-tracks-move-eastward-even-though-earth-rotates-west-east https:

by sunw 8y ago

Here's a clean explanation from NASA's eclipse site (https://eclipse2017.nasa.gov/why-do-eclipse-tracks-move-eastward-even-though-earth-rotates-west-east https://eclipse2017.nasa.gov/why-do-eclipse-tracks-move-east...). The moon actually moves much faster than the Earth spins -- it just seems to move westward to humans on the ground because it's so far away from Earth (takes 28 days to go around Earth). During a solar eclipse though, we see the effect of its true blisteringly fast orbital speed. "Because the Moon moves to the east in its orbit at about 3,400 km/hour. Earth rotates to the east at 1,670 km/hr at the equator, so the lunar shadow moves to the east at 3,400 – 1,670 = 1,730 km/hr near the equator. You cannot keep up with the shadow of the eclipse unless you traveled at Mach 1.5."

mrfusion 8y ago
So why would the moon rise in the east and set in the West? That’s the part I’m confused by.
- kazinator 8y ago
  In the eclipse situation, the actual speed of the Moon matters, not the fact that its orbit is so long that it orbits the Earth about once a month. The apparent relative motion with respect to the Sun is what matters. Of course, both bodies are rising in the East and setting in the West. But at the moment of the eclipse, the Moon is a little slower.
  - naasking 8y ago
    There's got to be an animation of this out there. Something like this, but I feel it can be done better: https://youtu.be/jnphuI7hyeM https://youtu.be/jnphuI7hyeM
- sunw 8y ago
  All the stars in the sky are also rising in the east and setting in the west. Our own sun is rising in the east and setting in the west. The earth's spin causes stuff in space to appear to go in the same direction. Stars in general appear to move across the sky (east -> west) faster than the moon does. Does this mean the stars are actually moving faster than the moon? Of course not. The sky is just a stationary backdrop, and the moon is moving along the same direction as Earth's rotation.

by sunw 8y ago

mrfusion 8y ago

So why would the moon rise in the east and set in the West? That’s the part I’m confused by.

kazinator 8y ago
In the eclipse situation, the actual speed of the Moon matters, not the fact that its orbit is so long that it orbits the Earth about once a month. The apparent relative motion with respect to the Sun is what matters. Of course, both bodies are rising in the East and setting in the West. But at the moment of the eclipse, the Moon is a little slower.
- naasking 8y ago
  There's got to be an animation of this out there. Something like this, but I feel it can be done better: https://youtu.be/jnphuI7hyeM https://youtu.be/jnphuI7hyeM
sunw 8y ago
All the stars in the sky are also rising in the east and setting in the west. Our own sun is rising in the east and setting in the west. The earth's spin causes stuff in space to appear to go in the same direction. Stars in general appear to move across the sky (east -> west) faster than the moon does. Does this mean the stars are actually moving faster than the moon? Of course not. The sky is just a stationary backdrop, and the moon is moving along the same direction as Earth's rotation.