The Moon

BASIC FACTS ABOUT THE MOON

The following questions were answered by astronomer Dr. Cathy Imhoff of the Space Telescope Science Institute.

How big is the moon?

The moon is about 2,000 miles across.

How far is it from Earth to the moon?

It is about 250,000 miles from Earth to the moon.

How old is the moon?

The moon is the same age as the Earth and the rest of the solar system — about 4.5 billion years. Our solar system was all formed at that time.

How did the moon form?

We think that the moon and Earth formed at about the same time, back when our whole solar system was formed. Earth was forming from many chunks of rock and icy material. Possibly a big chunk hit the new Earth and knocked loose a big piece, which became the moon.

How hot and cold does it get on the moon?

As y

ou may have learned, the moon doesn't have any air around it. The air that surrounds our earth acts as a nice blanket to keep us warm and comfy! But the moon, since it doesn't have this blanket, gets much colder than the earth — and much hotter than the earth. On the side of the moon that the sun is shining on, the temperature reaches 260°Fahrenheit! That is hotter than boiling. On the dark side of the moon, it gets very cold, -280° Fahrenheit.

What is the surface of the moon like?

The surface of the moon has about two inches of dust. Much of this dust has fallen to the moon from the spaces between the planets over the last several billions years. It probably feels pretty soft. You can see this in some pictures taken by the astronauts of their footprints on the moon.

How many holes are in the moon?

We call those holes "craters." They are the places where many years ago meteors hit the surface of the moon and put dents into it. There are thousands of big craters, but even more little ones. There are probably millions of little craters on the moon! Some are only an inch or so across.

Why

does the moon have big rocks?

The moon is made up of various kinds of rocks. These rocks are fairly similar to the rocks on earth. But on earth, we have wind and rain that help wear the rocks down into sand and dirt. There is no air or wind on the moon, so the rocks don't get worn down as they do on the earth.

How many moons are there all together?

Earth has only one moon. If you count all the moons around all the planets in our solar system, there are 61 (Earth has one, Mars has two, Jupiter has 16, Saturn has 18, Uranus has 15, Neptune has 8, and Pluto has one). There may be more that we haven't discovered yet!

Why does the moon change its shape (as in full, half, and quarter moon)?

The bright part of the moon is the part that the sun is shining on. This is like daytime on earth. The dark part is in shadow, like night on earth. Now the moon goes around the earth once every 29 days (approximately).

At new moon, the moon and the sun are on the same side of Earth. We see the part of the moon that is in shadow, so the moon is dark. Then the moon moves around in its orbit. At first quarter, it has gone one-fourth of the way around Earth. Now we can see part of the moon that is sunlit, but part still in shadow. Note that if the sun is setting in the west, the bright part of the moon is on the side toward the sun and the dark part is away.

About a week later, the moon has moved halfway around its orbit. Now it is on the opposite side of Earth, away from the sun. Now we see only the sunlit side — that is the full moon. Note that if the sun is setting in the west, the moon is just rising in the east.

About a week later, the moon has moved now three-fourths of the way around in its circle around Earth. Once again only part of the moon is sunlit and part is dark. Now you can see the moon in the morning, and note that once again the sunlit side is on the side towards the sun, and the shadow side away. Another week and we are back to the new moon.

It's easier to demonstrate if you have a ball to represent the moon and a flashlight for the sun. Have someone stand several feet away, holding the flashlight so it shines on the ball. Hold the "moon" ball and slowly turn around, watching the moon go around you (you are Earth). Do you see the moon's phases?

Go on your own virtual tour of the moon with Google Moon!

More Moon Facts

The Moon was probably made 4.5 billion years ago when a large object hit the Earth and blasted out rocks that came together to orbit round the Earth. They eventually melted together, cooled down and became the Moon. For another 500 million years pieces of rock kept striking against the surface of the Moon.
You can see the surface of the Moon by using a pair of binoculars or a small telescope. The Moon’s surface shows the damage caused by these large pieces of rock hitting it billions of years ago. The surface is covered in craters, pits and scars.
From the Earth we can only see one side of the Moon; the other side is always turned away from us. Photographs from space show a similar scarred surface on the other side.
The Earth has a much greater surface than the Moon and was also hit by debris (the rocks from explosions and collisions) but over time the damage has disappeared. The wind and rain in the Earth’s atmosphere has helped to erode the pits and craters.
The Moon has no atmosphere and so we can still see the damage caused billions of years ago.
If you look at the Moon when it is nearly full you can see the dark areas which are known as the seas. (They are all given Latin names, such as Mare Serenitatis – the Sea of Serenity, or Mare Frigoris – the Sea of Cold).These are not really seas but are huge expanses of smooth dark lava.

Figure 1. A map of the Moon.

All parts of the Moon are lit in turn by the Sun. As it rotates round the Earth we see different fractions of the sunlit half, or hemisphere, of the Moon. These are known as the phases of the Moon, or lunar phases. The Moon changes from a thin crescent to a full moon and back again to a crescent in one month (actually 29 days, which is a lunar month).

Figure 2. The Phases of the Moon.

This diagram shows the phases of the moon, from a new moon, which you can hardly see at all, round to a full moon and back again in just over four weeks. Follow the phases in an anticlockwise direction(the opposite way from how the hands of a clock move).
The waxing Moon. “Waxing” means growing. After the new moon appears in the sky as a tiny sliver of light the moon waxes. It grows into a crescent, curving to your left as you look at it and then into a half moon. This takes a week and so the period is described as the Moon’s first quarter.
The waxing gibbous Moon. Gibbous means humped and describes the shape of the Moon as it grows from a half moon to a full moon. Another week has passed and this is the Moon’s second quarter.
The waning Moon. “Waning” means shrinking. Now the Moon begins to get smaller again – it “wanes”. The third quarter takes us from a full moon to a half moon again, but this time it is the right hand side of the moon that shines.
The waning crescent Moon. The last quarter takes us from a half moon back to a crescent moon, facing right, and to a point where the moon disappears.
When the Moon is a crescent and only the crescent is being illuminated by the Sun, you can often see the shadow of the rest of the Moon. This is caused by reflection of sunlight from the Earth. It is sometimes called “the old moon in the new moon’s arms”.

Figure 3. The effect of earth shine on the moon.

The gravity of the Moon, the pull which it exerts on the Earth, causes two high tides on the Earth every day – one every 12 hours and 25 minutes.
The first man to make proper maps of the moon was Galileo. Galileo did not invent the telescope but by 1609 he had developed a telescope that could magnify objects to 20 times, and with this telescope he began his careful study of the Moon’s surface.
The first person to walk on the Moon was the American astronaut, Neil Armstrong, who stepped out of his space landing craft, the Eagle, on 21 July 1969 with these famous words, “That’s one small step for man, one giant leap for mankind”.

Figure 4. A photograph of the Earth taken from the surface of the Moon.

The Moon is 239,000 miles, or 384,000 kilometres away from the Earth.

The Moon is much smaller than the Earth, with a diameter of 2159 miles, or 3476 kilometres. It is airless, waterless and lifeless

The History of the Moon

You can see the surface of the Moon by using a pair of binoculars or a small telescope. The Moon’s surface shows the damage caused by these large pieces of rock hitting it billions of years ago. The surface is covered in craters, pits and scars.

In the 1950’s the USA considered detonating a nuclear bomb on the Moon. What? It was a super-secret project that probably only spies knew about. It was at the heights of the cold war and was known as “A Study of Lunar Research Flights” or “Project A119″ and it was meant to show their strength when they were falling a bit behind in the big space race. Luckily that didn’t

In 1968 President John F. Kennedy sent out an American spacecraft that did a little whirl around the moon and came back

Ever heard of Neil Armstrong? Well in case you haven’t, he was the very first person, to put his footsteps on the moon, isn’t that amazing! He stepped out of his spacecraft, the Eagle, on 21 July 1969 and said these very famous words, “That’s one small step for man, one giant leap for mankind”.

It is the fifth largest moon in the Solar System.

The Moon is about 4.5 billion years old and is the only natural satellite in our Solar System. Wow. The moon formed about 30–50 million years after the Earth formed. The moon came about when a large object hit the Earth and blasted out rocks that all came together and orbited round the Earth. Eventually they all melted together like in a big heated pot, cooled down and became the Moon. For another 500 million years pieces of rock kept striking against the surface of the Moon.

The first man to make proper maps of the moon was Galileo. He didn’t invent the telescope but by 1609 he had developed a telescope that could magnify objects up to 20 times. It was with this that he started to study that awesome moon. Glad he did so that we know all this cool stuff and it was the start of the telescope as we know it today.

The first spacecraft to reach the Moon was Luna 1 in 1959 which was a Soviet craft launched by the USSR. It didn’t land on the moon but passed within 3,725 miles (5,995) kilometers of the surface of the moon before going into orbit around the

The reason we can still see this damage is that the Moon has no atmosphere, so we can still see what happened billions of years ago. Cool huh! It’s not often we get to see stuff that happened so long ago, and that’s still there. Get out those binoculars and have a

And the very first manned Moon landing was in 1969 from the famous NASA Apollo 11

How the Moon Works

We mentioned already that the Moon is the Earth’s only natural satellite. This is when a space body orbits a planet, a planet-like object, or an asteroid.

The average distance from the Moon to the Earth is 238,857 miles (384,403 kilometers). If you had to drive from the moon to the earth at 65 mph (just over 100kph) it would take you 3,674 hours to get there, or 153 days driving non-stop 24 hours a day. That would be quite some trip. Guess you’d be asking your parents many, many times about whether you’re there yet.

Its rocky mantle is about 825 miles (1,330 km) thick and made up of dense rocks rich in iron and magnesium.

The Moon goes round the Earth every 27.3 days. Seems kind of strange when we see light during the day and dark at night.

The side that we can see from Earth is called the near side while the other side is called the far side. Some people call it the dark side, but that’s actually not correct, as the sun is shining on it brightly on the other side.

The moon very likely has a very small core which is only about 1 to 2 percent of the moon’s mass and roughly 420 miles (680 km) wide. It probably consists mostly of iron, but may also contain large amounts of sulfur and other elements.

But did you know you can always only see one side of the moon; the other side is always turned away from us?The Moon revolves on its axis in about the same length of time it takes to orbit the Earth. What this means is that from Earth we will only ever see about 60% of its surface. That’s not a lot at all. Sometimes it seems as if we can see it all, but we actually can’t.

The far side of the Moon looks very different to the near side and this is because it doesn’t have ancient pools of solidified lava, which is actually called maria.

Now we move onto waning. And this is just the opposite of waxing…this means the moon is getting smaller. This is the third quarter and what happens is that it takes us from a full moon to a half moon again, but now it is the right hand side of the moon that is shining. The third quarter takes us from a full moon to a half moon again, but this time it is the right hand side of the moon that shines.

Now we move onto the last quarter which is the waning crescent Moon. Now the half moon becomes a crescent shape again. Interesting stuff.

Gravity on Earth is much stronger than that on the Moon which is why astronauts have to wear all that space gear as they can just float away. The gravity on the moon is only about 1/5 when compared to the earth. At least we know we’re not going to float away!

******

So you must know that we get two tides on our beaches. But did you know that this is caused by the Moon? There are two bulges in the Earth due to the gravitational pull from the Moon; one on the side facing the Moon, and the other on the opposite side that faces away from the Moon, The bulges move around the oceans as the Earth rotates, and causes high and low tides around the world.

The Moon is slowly moving away from earth at about 3.8 cm every year. Doesn’t it like us anymore? Well scientists say it will keep on moving away for about 50 billion years. By the time that happens, the Moon will take around 47 days to orbit the Earth instead of the current 27.3 days. Apparently when that happens, the Earth and the Moon will be tidally locked to each other – it will look like the Moon is always in the same spot.

In our article on the sun, we spoke about the fact that the Sun might be a bit greedy and eat up the Moon in about 5 billion years, so this might not happen anyway.

******

The Moon is much smaller than the Earth, and its diameter is just 2,159 miles (3,476 kilometers). When we compare this to the Earth you will see how much smaller it is. The diameter of the earth is 7,917 miles (12, 742 kilometers). The Moon would fit into the Earth nearly 4 times!

The crust on top averages about 42 miles (70 km) deep. The outermost part of the crust is broken and jumbled due to all the large knocks it has had.

The Moon is airless, waterless and lifeless.

The Earth has a much bigger surface than the Moon and was also hit by debris many years ago. But because we’ve got wind and rain from our atmosphere, which the moon doesn’t have, most of the damaged has disappeared into thin air.

******

If you look at the Moon when it is nearly full you can see the dark areas and these are known as seas. They’ve all got Latin names, so give pronouncing them a try. The first Mare Serenitatis, which means the Sea of Serenity, then Mare Frigoris, the Sea of Cold. But even though they’re called seas they actually aren’t, they’re huge areas of dark lava. Why would they call it a sea then if it wasn’t? Hmmm, something to think about.

******

All parts of the Moon are lit by the Sun at different times. We know it rotates round the Earth and as it does this we see different parts of the sunlit half. These are known as the phases of the Moon, or lunar phases. You can sometimes see a thin crescent and then eventually a full moon in one month; well it’s actually 29 days which is a lunar month. Hey they’ve got different months to us!

******

Ever heard of a waxing moon? Well it actually means that it’s growing. Once you’ve seen the new moon in the sky, which is tiny little sliver of light, the moon is waxing. It then grows into a crescent, and then into a half moon. It takes a week for this to happen and it’s called the Moon’s first quarter. Interesting stuff.

Now some more big words. Next comes the waxing of gibbous Moon. Gibbous means humped and is used to describe the shape of the moon as it’s growing from a half to a full moon. This is called the second quarter and just like the first quarter it takes a week. You’re going to have to spend a couple of nights outside to study what goes on with this fascinating satellite.

When the Moon is a crescent and only the crescent is being lit up by the Sun, you can often see the shadow of the rest of the Moon. This is from a reflection of sunlight from the Earth. Who would have thought? It is sometimes called “the old moon in the new moon’s arms”. Cool, quite like that name.

Other Interesting Moon Facts

Did you know there was a tall mountain on the Moon? Well there is and it’s called Mons Huygens. It is nearly 3 miles (4700 meters) tall. That’s just over half the height of Mount Everest at just over 5 miles (8848 meters). Wow.

******

This is one big number! The Moon weight 73,476,730,924,573,500 million kilograms 161,988,463,175,810,240 pounds. That is just so heavy it’s unbelievable. The Earth is only 0.0123 times that weight, so much, much lighter!

The temperature of the moon changes all the time and goes from -451 degrees Fahrenheit (-233 degrees Celsius) to 253 degrees Fahrenheit (123 degrees Celsius). Wow, one minute you’ll be freezing off your toes, the next minute you’ll be burning up!

If you’re on the Moon you’ll be much lighter, so here’s the place to go if you want to feel like you’re weightless. You’ll weight about one sixth of your weight on Earth. Super skinny you’ll be. That’s why astronauts could leap and bound so high in the air.

The Moon has only been walked on by 12 people; all American men. The first man to set foot on the Moon in 1969 was Neil Armstrong, while the last man to walk on the Moon in 1972 was Gene Cernan on the Apollo 17 mission. Since then the Moon has only be visited by unmanned vehicles.

******

Just imagine, if you weighed 100 kg on Earth, you would feel like you only weighed 17 kg when you were on the Moon. You would be able to jump 6 times further and carry objects 6 times as heavy. In fact, if you had wings attached to your arms, you could even fly around inside a dome on the Moon just from your muscle power. Cool. What a place to visit.

******

The Moon has quakes, when it’s time for us to go visit, we had better be careful when we go! These are caused by the gravitational pull of the Earth. Astronauts found that small moon quakes occurred several kilometers beneath the surface, which caused ruptures and cracks just like earthquakes on Earth. Scientists actually think the Moon has a molten core, just like Earth.

Think all the moon missions are over? Well they’re not. NASA wants to return astronauts to the moon and set up a permanent space station. It would be so interesting to go and have a look at that. If all goes to plan, mankind could be putting their feet on the moon again in 2019 (well of course with space boots on!).

******

Wow, the moon is one very interesting place! Hope you learned some cool facts to share! Do you know anything else about the moon?

And one last cool fact. Did you know that there is no wind on the moon, so all those footsteps will stay there forever, unless of course somebody else stands on top of them! It’s like having your foot cast in stone there forever!

Page updated

Google Sites

Report abuse