150 likes | 288 Views
Moon Phases. Why does the Moon look that way?. About the Moon . . . . The Moon is about 240,000 miles from the Earth. The Moon rotates slowly on its axis once every 28 days & orbits the Earth once, about every 28 days
E N D
Moon Phases Why does the Moon look that way?
About the Moon . . . • The Moon is about 240,000 miles from the Earth. • The Moon rotates slowly on its axisonce every 28 days & orbits the Earth once, about every 28 days • This means that one side of the Moon always faces the Earth and the “far side” is never seen unless, like the Apollo astronauts, you take a spaceship and orbit the Moon.
The Moon! • The moon completes one orbit around the Earth in 4 weeks (1 week = 7 days; 4 weeks = 28 days) • The Moon travels at a speed of 64,000 km/day or 1,700 miles/hr. • 1 Earth day or 24 hours=1 rotation on the Earth’s axis • 1 Moon day or 28 days or 672 hours=1 rotation on the Moon’s axis
Any observer on the Earth (no matter what longitude or location) will see the same phase on a given night. • The Moon, like any other body in our solar system, reflects the light of the Sun. • Depending on where the Moon is in it’s orbit, we can see a different part of the “lit” Moon.
New Moon This is Day One of a new Lunar cycle. The New Moon is entirely dark. The Moon is positioned so it is not reflecting ANY light towards Earth.
Waxing Crescent or ‘finger nail” Moon. The Moon is moving in it’s orbit. In about 3.5 days, we can see more of the reflected surface. Waxing means growing!
First Quarter Moon. Now, 7days after the “New Moon,” The Moon has orbited to where half of the Moon is reflecting sunlight.
Waxing Gibbous Moon This is what we see after 10.5 days in the new Lunar Cycle. The Moon is 3/4 ‘s ‘Full.”
Full Moon The Moon is 14 days - half way - through it’s orbit around the Earth. All of the Moon is lit by the Sun.
What now? • We just watched as the Mooned orbited around the Earth. We saw more of the moon become illuminated by the Sun’s light. What is going to happen next?? • Will the Moon continue to orbit the Earth?? • Will the Moon change appearance?? • How??
Waning Gibbous 17 days into the Lunar Cycle, the Moon’s illuminated surface begins to grow smaller. We see less Moon being illuminated by the Sun. Waning means getting smaller
Third Quarter Moon The Moon is 20.5 days or 3/4’s thru the Lunar cycle. It appears smaller, but we know that we are seeing less Sun light reflected from the surface of the Moon.
Waning Crescent – Fingernail Moon The Moon is now 24 days through the Lunar Cycle and is getting darker. The part able to reflect sunlight, “smaller.”
New Moon. And on the 28th day of the Lunar Cycle we start all over again . . .