Earth’s Moon 19-4

The Moon There is no atmosphere on the moon. Temperatures on the surface range from over 100°C to -170°C. To survive on the moon the astronauts had to wear bulky spacesuits to keep them warm and carry their oxygen. These suits weighed as much as the astronauts themselves. But because the moon’s gravity is only 1/6 th of the Earth’s, they could move around very easily. The moon is about 384,400-km (240,000-mi) from the Earth. A day on the Moon is two Earth weeks! Also, so is a night on the moon.

Structure of the Moon Diameter is about 3,476- km, a little less than the distance across the USA. This is 1/4 th the Earth’s diameter, but the moon has only 1/80 th the mass of the Earth. Since the Moon’s average density is about the same as the Earth’s outer layers, it is believed the moon lacks a dense core.

Origin of the Moon While there have been many ideas, the theory that best fits the evidence is the collision theory. About 4.5bya, when the Earth was very young, an object the size of Mars collided with the Earth. Lots of material from the outer layer was flung into orbit, where it eventually combined to form the moon.

Features of the Moon The early Greeks thought the moon was perfectly smooth. Galileo was first to use a telescope to study the moon. He saw that the moon had craters, highlands and maria.

Craters Caused by impacts from meteoroids. Some are hundreds of kilometers across. Many are named after famous scientists from long ago. Tycho is the bright crater at the bottom of the picture to the right.

Highlands Mountainous areas covered with craters. Apollo 15 landed near the Apennine Mountains in 1971.

Maria Large, dark, flat areas. Maria is Latin for “seas.” Galileo thought that they might be oceans. They are low, dry areas that were flooded with molten material billions of years ago.

Rilles Are meandering, valley like structures. Thought to be the remains of collapsed lava tubes or extinct lava flows. They usually begin at an extinct volcano, then meander and sometimes split as they are followed across the surface. Pictures from Apollo 15 at the edge of the Hadley Rill.

Apollo to the Moon We choose to go to the moon. We choose to go to the moon in this decade and do the other things, not because they are easy, but because they are hard, because that goal will serve to organize and measure the best of our energies and skills, because that challenge is one that we are willing to accept, one we are unwilling to postpone, and one which we intend to win, and the others, too. John F. Kennedy 1961 First, I believe that this nation should commit itself to achieving the goal, before this decade is out, of landing a man on the moon and returning him safely to the earth. No single space project in this period will be more impressive to mankind, or more important for the long-range exploration of space; and none will be so difficult or expensive to accomplish. John F. Kennedy 1961

Moon Exploration The Apollo missions explored the moon from 1968 to Six missions successfully landed on the moon. Apollo 11 was the first in July Apollo 17 was the last, in December We have not gone back since.

Apollo 11 First lunar landing: July 20, Neil Armstrong and Buzz Aldrin took the Lunar Module Eagle down to the surface of the moon. Michael Collins remained in orbit in the Command Module. “That’s one small step for man, one giant leap for mankind.”

Apollo Contributions Returned 382-kg of rocks. Genesis rock showed that the moon was almost as old as the Earth (4by). Spinoffs include cordless tools, computers, CAT/MRI technologies, kidney dialysis machines, freeze dried food, and countless others have benefited mankind.

Tides Tides occur because of the differences in how much the moon (and sun) pull on different parts of the Earth. Most places will see two high and two low tides per day.

Spring Tides Occur when the Earth, Moon, and Sun are lined up. Highest tides occur, called maximum daily tide range. Occur at new and full moons

Neap Tides Occur when Sun, Earth, and Moon are at 90° to each other. Will have minimum daily tide range. Occur at 1st and 3rd quarter moons

Phases of the Moon Rap Phases of the Moon Rap

The Moon is a sphere, big and white It loves to reflect the sun’s bright light. It goes on a journey every 28 th day Around the Earth, hide and seek it will play. In the beginning, it is new Out of sight from me and you! Then it waxes in white light As it grows on its right. Waxing, Crescent, Quarter, then gibbous, too. When it’s full, the phases are halfway through! Now it shines more to the left and starts to wane As it fades away in its orbit lane. Waning, gibbous, quarter, then crescent, too. It’s completed its orbit and back to new!