The Moon

The Moon is the only natural satellite of the Earth, and the only celestial body where humans have landed. It is approximately 384,403 kilometers (238,857 miles) away from the Earth, and has an approximate diameter of 3,476 kilometers (2,160 miles).

60,968 Questions
The Moon
Planet Earth

How far is the Moon from the Earth?

A lunar distance (LD) is an astronomical measurement of the distance from the Earth to the Moon. The average distance from Earth to the Moon is 384,403 kilometers or 238,857 miles, but the actual distance varies over the course of the orbit of the moon. Depending on the Moon's location in its orbit, it is between 225,623 and 252,088 miles away from Earth. This is about 30 times the diameter of the Earth.

Measurements of the lunar distance are made by measuring the time it takes for light to travel between the LIDAR stations on Earth and the retroreflectors placed on the Moon. Experiments show that the Moon is spiraling away from Earth at an average rate of 3.8 cm per year.

Orbital distances are calculated between the center of the Earth and the center of the Moon. So the actual surface-to-surface distance is shorter by about 7457 kilometers (4634 miles).

Because tides spin faster than the Moon moves, the tidal reaction pulls the Moon forward a tiny bit. The moon recedes at a rate of approximately 3.8 cm (1.5 inches) per year. When there was only one continent, the rate was less.


The moon is on an elliptical orbit, so it it not consistently the same distance from earth. When the moon is the closest to earth, it is 225,623 miles away; when the moon is farthest away from earth, it is 252,088 miles away.

Planet Jupiter
Planetary Science
The Moon

What is the closest planet near Earth's moon?

Well, it is obviously Earth. But if you meant the nearest planet (excluding Earth), it varies from time to time; at their closest approaches Venus is around 45,000,000 km away to the Earth and Mars is around 80,000,000 km away from the Earth. But they aren't always or even usually at their closest approach to Earth. Whether Earth and the Moon are closer to Venus or to Mars depends on the three planets' relative positions in their orbits. When Mars is at opposition it is only about 80 million km from Earth and the Moon (60 million km if the opposition occurs at Mars' perihelion), and when Venus Is at superior conjunction it is 225 million km away.

The Moon

How long exactly is one lunar month?

A lunar month is the amount of time it takes for the Moon to pass through each of its phases (new moon, half, full moon), and then return back to its original position. It takes 29 days, 12 hours, 44 minutes and 3 seconds for the Moon to complete one lunar month. You might have heard that the Moon only takes 27.3 days to complete one orbit around the Earth. So why is a lunar month more than 2 days longer than the orbit of the Moon? A lunar month is the amount of time it takes for the Moon to get from a specific phase, like a new moon, back to the same phase. In other words, the Moon has to get back to the point in its orbit where the Sun is in the same position from our point of view. Since the Moon is going around the Sun with the Earth as part of its orbit, the Moon has to catch up a little bit on each orbit. It takes 2.2 additional days each orbit of the Moon to catch up.

Planetary Science
The Moon
Sailor Moon

How was the moon created?

Theories of the Origin of the Moon

After years of research, studying gamma rays and rock samples from the Earth and the Moon, it is generally accepted that the ages of the Earth and the Moon are the same. There are several theories on its formation.

  • IMPACT : One theory is that it was formed from the Earth's crust, following the impact of a large (Mars-sized) asteroid. A long string of rocky fragments were blown out from the Earth in the form of a trail, which coalesced into the Moon. Supporting this, the Earth has a large iron core but the Moon does not : the Earth's iron would have already sunken into the core by the time the giant impact happened.
  • COACCRETION : Another theory, advocated by Edward Roche, is known as coaccretion. It proposes the concurrent information of both the Earth and the Moon from clouds of space material. As a result the new Moon gets spun by the Earth's gravity field and starts to circle the Earth. The fact is that all smaller solar bodies appear to be irregularly shaped, but larger ones are nearly spherical.
  • FISSION : The fission theory states that the Moon long ago split off from a fast-rotating Earth, like mud flung from a spinning bicycle wheel. The present Pacific Ocean basin is the most popular site for the part of the Earth from which the Moon may have come. This is not supported by evidence of higher rotational speed in the past.
  • CAPTURE : If the Moon formed separately, it could have come close enough to the Earth's gravitational field to be trapped. The angle of orbital approach would have to be within narrow parameters in relationship to the moving centre of the orbiting Earth. The chance of this occurrence is very low without some other gravitational interaction.

The prevailing theory at present is some form of early impact, possibly by a co-orbiting object that fused with the Earth after the collision, but that blasted loose the material which later formed the Moon.

Most widely accepted scientific explanation

It is believed that the moon formed around 4.5 billion years ago and only a few hundred million years after the Earth.

Today, based on the evidence, the most widely accepted scientific explanation for the formation of the Moon is called the Giant Impact Hypothesis. According to this model, the Moon formed from debris that was the result of a huge collision. Not long after Earth formed, a proto-planet about the size of Mars (often called Theia) smashed into it at a low angle and relatively low speed. The cataclysmic impact rendered the entire Earth molten, and caused significant amounts of its mantle and crust to be blown into space. The metallic core of the impactor sunk through the Earth's mantle to fuse with Earth's core, thereby depleting the Moon of metallic material and explaining its unusual composition. The force of the collision is also believed to have been responsible for tilting the Earth at angle of 23.5 degrees, allowing for seasons.

The debris from the collision began orbiting the Earth and gathered together through gravity to form a sphere: the Moon. The Moon formed surprisingly quickly, possibly in less than a month but no more than a century. It started out closer to the Earth than it is today, and must have caused massive tides. Slowly, due to conservation fo angular momentum, it moved further and further out until it got to the familiar orbit it is now. Even today, the Moon is receding from Earth by an inch and a half every year, but it will take billions of years for the Moon to escape from Earth's gravity altogether.

There are still some problems with the Giant Impact hypothesis that need to be overcome. For example, the ratios of the Moon's volatile elements (such as water) are not explained by this model. Also, the moon's oxygen isotopic ratios are essentially identical to Earth's when they should be different. Regardless, the Giant Impact model is currently the best explanation scientists have based on the evidence that has been gathered, and holds more weight than the other theories for the Moon's formation.

  • The Fission Theory: This theory proposes that the Moon was once part of the Earth and somehow separated from the Earth early in the history of the solar system. The present Pacific Ocean basin is the most popular site for the part of the Earth from which the Moon came. This theory was thought possible since the Moon's composition resembles that of the Earth's mantle and a rapidly spinning Earth could have cast off the Moon from its outer layers. However, the present-day Earth-Moon system should contain "fossil evidence" of this rapid spin and it does not. Also, this hypothesis does not have a natural explanation for the extra baking the lunar material has received.
  • The Capture Theory: This theory proposes that the Moon was formed somewhere else in the solar system, and was later captured by the gravitational field of the Earth. The Moon's different chemical composition could be explained if it formed elsewhere in the solar system, however, capture into the Moon's present orbit is very improbable. Something would have to slow it down by just the right amount at just the right time, and scientists are reluctant to believe in such "fine tuning". Also, this hypothesis does not have a natural explanation for the extra baking the lunar material has received.
  • The Condensation Theory: This theory proposes that the Moon and the Earth condensed individually from the nebula that formed the solar system, with the Moon formed in orbit around the Earth. However, if the Moon formed in the vicinity of the Earth it should have nearly the same composition. Specifically, it should possess a significant iron core, and it does not. Also, this hypothesis does not have a natural explanation for the extra baking the lunar material has received.
Apollo Moon Missions
Neil Armstrong
The Moon

How many men have walked on the moon?

Twelve men have walked on the Moon, all US astronauts of the Apollo program.

They were :

Apollo 11

(July 20, 1969)- Neil Armstrong and Edwin "Buzz" Aldrin (the first men to walk on the Moon)

Apollo 12 - Charles Conrad, Jr. and Alan Bean

Apollo 14 - Alan Shepard Jr. and Edgar Mitchell (Shepard was also the first US 'man in space' in 1961).

Apollo 15 - David Scott and James Irwin

Apollo 16 - John Young and Charles Duke, Jr.

Apollo 17 - Eugene Cernan and Dr. Harrison Schmitt

(Cernan was the last man to walk on the moon on December 14, 1972)

--see the related question below

Planetary Science
The Moon

What is the circle of light around the sun called?

The circle of light around the sun is called a Corona. The corona can usually only be seen during a total solar eclipse. When this happens it can be seen as an irregularly shaped glow surrounding the moon.

The Moon
Planet Earth

The earth spins on its axis yes or no?


Rock Music
The Moon
Moons and Natural Satellites

How cold is nighttime on the Moon?


The temperature of the Moon's night is -173.3 degrees C. (-280 degrees Fahrenheit).

The Moon

Why is life not possible on moon?

"Life as we know it" is not possible on the Moon because the Moon has no atmosphere. When people go to live on the Moon, we will need to provide pressurized habitats in which we can live without a pressure suit. We will probably also have to live underground, since the lack of atmosphere also means that there is no protection from the damaging UV radiation from the Sun.

The Moon also lacks a strong magnetosphere to protect life from bombardment by charged particles.


The Lunar inhabitants are likely to refer to themselves as living "IN the Moon" rather than "ON the Moon" because the habitations are likely to be underground rather than on the surface.

Planet Jupiter
The Moon

Why is Io more volcanically active than your Moon?

Io is close to the massive Jupiter. As a result " tidal forces" cause large amounts of "flexing" inside Io. This means that Io is volcanically active.

The situation with Earth's moon is not really comparable.

Neil Armstrong
The Moon

Who was second person go to moon first time?

Edwin Aldrin was the second man on the moon.

Planetary Science
The Moon

Why does the moon look orange when it rises?

The Moon appears orange-ish when it rises for the same reason the Sun looks redder at sunset -- the Earth's atmosphere scatters the shorter, bluer wavelengths of light and more of the reddish light makes it to your eye. At moonrise, you are seeing the moon through more of the Earth's atmosphere than when the moon is overhead, and more of the light at red wavelengths makes it through the atmosphere to your eye.

Neil Armstrong
Apollo Moon Missions
The Moon

Who was the ninth man on the moon?

It was John Young, commander of Apollo 16.

The Moon

How is the Moon different from the Sun?

The moon is a solid ball of rock. The sun is a star, a roiling mass of gases undergoing nuclear fusion reactions.

Planetary Science
The Moon

What it the distance from the earth to the Sun?

Average distance is about 150 million kilometers. Keep in mind, though, earth is continuously moving around the sun so this measurement in sure to change at any point in time. Earth has and oval- shaped orbit around the sun- not a perfect circle so there could be a point that the earth is at its minimal distance from the sun or at its maximum. No one knows exactly.

The Moon
Science Experiments

How is the gibbous moon and gibbous monkey alike?

That's a misspelling; gibbous is a phase of the moon (more than half but not full), and Gibbons are a species of ape.

The Moon

What is the meaning of waxing gibbous moon?

it means its almost a full moon but not there yet.

and nobody improve this answer i hate it when ppl do that!!

Planetary Science
The Moon

What is the moons lunar temperature?

The mean surface temperature during the day is 107° C (226.6° F)

At night that temperature is negative and drops to -153° C (-243.4 F)

The maximum surface temperature is 123° C (253.4° F)

The minimum surface temperature is -233° C (-387.4 F)

Planetary Science
The Moon

What did people think of solar eclipse in ancient times?

It depends on the ancient culture you're referring to.

Ancient China:

It was believed that a dragon was eating the Sun to symbolise that famine and disease was coming. The Ancient Chinese who believed this would form defences around their land to ward off the dragon, preventing famine and disease from affecting them.

They were also used to forecast predictions for the Chinese Emperors. Which was a very risky thing to do, because if you got the Emperor's forecast wrong, you were executed.

Ancient Japan:


And sometimes, earthquakes do actually occur after an eclipse. Although nowadays there is a scientific explanation, related to enhanced gravitational pull during the eclipse, resulting in an earthquake.

Superstitious Ancient Japanese would fire arrows at the eclipse to battle it. Later they even fired Tetsuho's at the eclipse.

(Tetsuho's were the first Japanese gunpowder-firearms, a heavy and extremely inaccurate hand-held cannon).

Ancient India:

Bad luck for pregnant women.

After an eclipse, pregnant women who were pregnant at the time of the event would be protected from doing household work such as weaving, cutting food, sewing and so on. This was to protect their unborn child from deformities and scars from the result of an eclipse-influenced accident.

There were many rituals performed on pregnant women, such as various bathing techniques, to ward off the "unlucky curse".

Ancient Arabia:

Message: It's time to seek forgiveness.

In Islam, the Sun and Moon are both connected to Allah's reverence.

When an eclipse occurs, it was believed that Allah was expressing his desire for the sinful to seek forgiveness and bestow greatness upon him.

Ancient Holy Roman Empire:

It was believed that an eclipse symbolised the wrath of God, casting his anger over man.

It was also seen as a threat from God to Mankind, "I am angry, appease me or Judgement Day will come".

Some Christians still believe this despite scientific evidence explaining the real reasons for the eclipse.

Ancient Babylon:

The Ancient Babylonians were one of the only ancient civilisations to get the facts about eclipses correct.

They were the first civilisation to discover that eclipses were a celestial event, not something caused by Gods or omens.

Ancient Babylonian astronomers were able to successfully forecast solar and lunar eclipses.

Ancient Egypt.

Nobody really knows.

Most of our knowledge of Ancient Egypt comes from tomb paintings and temple inscriptions. There are various theories about what Ancient Egyptians knew or thought about solar eclipses, but none of them have solid proof.

The evidence of most Egyptian knowledge, including what they knew about astronomy, mathematics and medicine, was lost in the fire of the Great Library of Alexandria.

The Moon
Ocean Tides

Does the Moon's pull effect lakes and rivers like it effects the oceans?

Technically, yes. However, the tidal effects of moderate-sized bodies of water such as medium-sized lakes is vanishingly small. The Great Lakes have very small tidal effects, but rivers are far more influenced by the flow of the river.

This is because there isn't much water to displace to create a noticeable effect.

Oddly enough, the moon's tides also effect solid ground. The earths crust flexes through a range of about 1 foot over the course of a day.

2nd response:

Great Answer!! Actually, the moon and Earth pull on each other, so since Earth is much bigger, there is a lot of tidal force applied to the moon . . . enough so that over billions of years, the moon has slowed its spin rate to where just one 'side' of the moon faces Earth all the time.

Apollo Moon Missions
The Moon

Who were the first ten astronauts to land in moon?

There have been 12 men to land and walk on the moon.

In order:

1: Neil Armstrong

2: Buzz Aldrin

3: Pete Conrad

4: Alan Bean

5: Alan Shepard

6: Edgar Mitchell

7: Dave Scott

8: Jim Irwin

9: John Young

10: Charlie Duke

11: Gene Cernan

12: Harrison Schmitt

Armstrong and Aldrin were from Apollo 11, Conrad and Bean from Apollo 12, Shepard and Mitchell from Apollo 14, Scott and Irwin from Apollo 15, Young and Duke were on Apollo 16 and Cernan and Schmitt were Apollo 17.

So to answer your question, the first 10 on the list were the first 10 people to land on the moon.

Space Travel and Exploration
The Moon

Who does the moon belong to?

Jenaro Gajardo Vera (*November 18, 1919 in Traiguén, Malleco Province - †May 3, 1998 in Santo Domingo, San Antonio Province) was an eccentric lawyer, painter and Chilean poet. He became famous from September 25 of 1953 until his death, as the legitimate owner of the Moon.

The United Nations 1967 publication "Outer Space Treaty" states space is the "province of all mankind", and is not subject to claims on sovereignty by States. As treaties apply to States and place obligations on States, and since the Space Treaties were drafted at a time when, realistically, the only "people" going into space were States, none of the space treaties make reference to private parties. The Outer Space Treaty of 1967 has currently been ratified by 98 states, including all the major space-faring nations.

The international Moon Treaty, finalised in 1979 and entering into force in 1984, forbids private ownership of extraterrestrial real estate. However, as of January 1, 2008 only 13 states have ratified the agreement, and none of these are major space-faring nations. Kazakhstan has ratified the treaty and is host to the Baikonur Cosmodrome. However, the facility is operated through a leasing agreement by Russia.

The Moon

Why isn't the moon always full?

The reflection of sunlight off of the moon's surface can only be seen when the earth is in the path of the reflected light. Essentially when the moon is not full, you see part of the moon that is in shadow. This is the same as looking at a part of the earth where it is night time, from space.

Planetary Science
The Moon

When is the next total eclipse in Melbourne?

I'm afraid you will be waiting a long time. The next Total Solar Eclipse is not until April 4th 2220.

But there will be one in Sydney on July 22 2028, and one in northern Victoria, about a 3 hour drive from Melbourne (near Kerang / Shepparton / Wangaratta on December 26 (Boxing Day) 2038.

The Moon

Does the moon rotate on its axis?

The moon does rotate about its own axis, once every 27.32 days. "Day and night" on the Moon are each 13.66 Earth days long.

....but don't think of it this way just yet. This will create confusion until you understand truly what I'm saying.

If you take a basketball and spin it on your finger, the basketball is spinning on its own axis. If this was exactly how the moon rotated, we could see all sides of it, just like the basketball. But the way that it works is different...the far side of the moon can never be seen from Earth by looking into the sky (unless you use mirrors!).

Take a basketball (Earth) and a ping pong ball (moon) and mark an 'X' on the ping pong ball. Make the ping pong balls 'X' face the 'Earth.' Now rotate the 'moon' around the 'Earth' so that the 'X' is always facing the Earth.

If you watch from above (bird's-eye view), you will notice that the ping pong ball actually has completed one full rotation about its own axis, as well as one revolution about the 'Earth' axis (one orbit around the Earth). And yet, no matter where on Earth you are you wouldn't be able to see the far side because it is always facing away from you!

This is due to a phenomenon called tidal locking. The moon is tidally locked with the earth, which means its rotation is the same as its orbit, causing the same portion of the moon to always be visible from earth, which is why we only ever see one side of the moon.

You can tell that the moon actually does rotate by its phases; the bright portion of the moon is sunlight reflecting off its surface and it is daytime on the portion of the moon that is lit by the Sun.


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