Astronomy: Part 2
Astronomy: Part 2
Phases of the Moon
The Moon passes through four major shapes during a cycle
that repeats itself every 29.5 days. The phases always follow one another in the
same order:New moon
First quarterFull moon
Third quarterNew moon
Phases of the Moon
• The lighted side of the moon faces away from the Earth.
• This means that the sun, Earth, and moon are almost in a straight line, with the moon in between the sun and the Earth.
The right half of the Moon appears lighted and the left side of the Moon appears dark
The lighted side of the moon faces the Earth and the Sun
The Earth, Sun, and moon are almost in a straight line, with the Earth in the middle
Photo by Robin Afinowich
• Also called a last quarter moon.
• Only the left side of the moon appears lighted
• The next main phase will be a new moon again
There are other phases that fall between the ones we already looked at
Like… Waxing cresent Waxing gibbous Waning gibbous Waning cresent
Solar Eclipse Lunar Eclipse
The moon gets between the sun and the Earth
So the moon’s shadow is cast on the Earth
Occurs during a new moon
Occurs during a full moon
The Earth is between the Sun and the Moon
The Earth’s shadow is cast on the moon
The moon is ¼ the size of the Earth or 3475 km in diameter (the Earth is 12,756 km in dia.)
Gravity is only 1/6 that of Earth – a 150lb man would weigh only 25lbson the moon
Caused by impact from another moving body
The moon has many, the Earth only a few
The light colored part of the moon are highlands
These contains the moon’s mountain ranges
The dark colored parts are called mare or maria – smooth areas of the moon
These are long valleys or trenches found in the maria
Possibly caused by lava flows
The Giant-Impact Theory: A Mars sized body slammed into the early Earth
What was knocked out formed the moon