Overview
The average distance between the moon and the earth is 384,4 kilometers.
In p>1969, Neil Armstrong/Armstrong/Neil Armstrong and Buzz Aldrin became the first humans to land on the moon.
orbital data-some data are from [[1]]
average orbital radius of 384,4 km
orbital eccentricity of .549
perigee distance of 363,3 km
apogee distance of 45, 5 km
the average period of revolution is 27 days, 7 hours, 43 minutes and 11.559 seconds
the average revolution speed is 1.23 km/s
the orbital inclination varies between 28.58 and 18.28
(the intersection angle with the ecliptic plane is 5.145).
the right ascension node is 125.8
the perigee angle is 318.15
physical characteristics
the equatorial diameter is 3,476.2km
the polar diameter is 3, 472. km
oblateness .12
surface area 3.976×17 km2
oblateness .12
volume 2.199×11 cubic km
mass 7.349×122 kg
3.35 times of average density water
equator. 6
escape speed is 2.38km/s
rotation period is 27 days, 7 hours, 43 minutes and 11.559 seconds
(synchronous rotation)
rotation speed is 16.655m/s (at the equator)
self-axial inclination changes between 3.6 and 6.69
(the intersection angle with the ecliptic is.
the albedo is .12
the apparent magnitude at full moon is -12.74
the surface temperature (t) -233~123℃ (average -23℃)
the atmosphere
the atmospheric pressure is 1.3×1-1 kPa
both sides of the moon
the moon is one. Therefore, the front of the moon always faces the earth. On the other hand, most of the back of the moon cannot be seen from the earth except in the area near the edge of the moon, which is occasionally visible due to Libra movement. In the era without detectors, the back of the moon has always been an unknown world.
One of the characteristics of the back of the moon is that it has almost no dark lunar surface feature, such as the moon sea. When the probe runs to the back of the moon, it will not be able to communicate directly with the earth.
the moon's periodic name Value (d) Define
Stellar Moon 27.321 661 relative to background star
Shuowang Moon 29.53 588 relative to the sun (moon phase)
Equinox Moon 27.321 582 relative to vernal equinox
Perigee Moon 27.554 55 relative to perigee
Nodal Moon 27.212 22 relative to ascending node
. (d) define
repeat phase/day. 19 years
the average distance between the moon and the earth is ~ 384,4 kilometers
the perigee distance is ~ 364,397 kilometers
the apogee distance is ~ 46,731 kilometers
the average eccentricity of the orbit is .5493
the retrogression period of the intersection point is 18.61 years
the perigee movement period is 8.85 years
the eclipse year is 3 years. Epe at eclipses) on October 11th, 18th year
The average inclination of orbit and ecliptic is 5 9'
The average inclination of the equator and ecliptic is 1 32'
The origin of the moon
The origin of the moon is very old, and it is also a controversial topic in the scientific community.
the earliest hypothesis can be called "homology theory", which holds that the moon and the earth have the same origin, but now it is generally believed that the inclination of the moon's orbit indicates that it is unlikely to form at the same time as the earth or be captured in the later period. Another early speculation is that in the early days of the formation of the solar system, the earth was in a molten state. Because of the rapid rotation of the earth, the moon was separated by the centrifugal force of the earth's rotation. Some people even think that the Pacific Ocean is the scar after this separation. But to satisfy this statement, the initial rotation speed of the earth must be very large. Others think that the moon formed elsewhere and was later captured by the earth.
other theories include * * * birth theory or condensation theory, which means that the earth and the moon formed from accretion disks at the same time. This theory can't explain why the moon lacks iron. There are also some theories that the moon is formed by a lot of debris around the earth (due to collisions between asteroids or planets). Harla
At present, the accepted theory is called the big impact theory, which holds that the moon is formed by the debris of the collision between the semi-molten earth and a Mars-sized celestial body (some people call it Theia).
the geological age of the moon is defined by several major impact events.
tidal force turned the early molten moon into an ellipsoid with its long axis pointing to the earth.
composition
4.5 billion years ago, the surface of the moon was still a sea of liquid magma. Scientists believe that KREEP, the mineral that makes up the moon, shows the chemical clues left by the magma ocean. KREEP is actually a composition of what scientists call "incompatible elements"-substances that cannot enter the crystal structure are left behind and float to the surface of magma. For researchers, KREEP is a convenient clue to understand the volcanic movement history of the lunar shell and to infer the frequency and time of the impact of comets or other celestial bodies.
The lunar shell is composed of many main elements, including uranium, thorium, potassium, oxygen, silicon, magnesium, iron, titanium, calcium, aluminum and hydrogen. When bombarded by cosmic rays, each element emits specific gamma radiation. Some elements, such as uranium, thorium and potassium, are already radioactive, so they can emit gamma rays by themselves. However, no matter what the cause is, the gamma rays emitted by each element are different, and each element has unique spectral line characteristics, and can be measured by spectrometer.
until now, human beings have not made a comprehensive measurement of the abundance of moon elements. At present, the measurement of spacecraft is limited to a part of the moon. For example, in 1992, Galileo measured the abundance of elements while flying over the moon. [2]
Surface Geography
There are tens of thousands of craters with a diameter of more than 1 km on the surface of the moon. Most of them have a history of hundreds of millions of years. The lack of large-scale forests and meteorological activities and recent geological activities ensure that most of them remain intact permanently.
[ The largest crater on the moon, which is also the largest known in the solar system, forms the South Pole-Aitken basin. This crater is located on the back of the moon, near the South Pole, with a diameter of about 2,24 kilometers and a depth of 13 kilometers.
Those dark and less characteristic moon plains are called "Moon Sea" because ancient astronomers thought it was an ocean. In fact, the Moon Sea was formed by basalt magma that flowed out of the moon mantle and covered the surface after the impact of a huge meteorite. The lighter highland is called "Moon Land". Almost only the moon facing the earth has a moon sea, and there are few on the back of the moon. Astronomers believe that this is because the center of mass of the moon is closer to the earth than the centroid (see Moon Sea for details).
On the lunar shell is a layer of rock with a dusty surface, called lunar soil, which is not soil. The distribution of lunar shell and lunar soil on the lunar surface is not uniform. The thickness of the lunar shell ranges from 6km (the front of the moon) to 1km (the back of the moon), while the lunar soil ranges from about 5m (the sea of the moon) to more than 1m (the land of the moon).
in 24, a team led by Dr. Ben Bussey of Johns Hopkins University took photos from the Clementine mission, and found that four areas along the Peary crater edge of the North Pole of the Moon were often exposed to sunlight (but no similar areas were found in the South Pole). These year-round sunshine areas are produced because the axial inclination of the moon is very small. Similarly, there are many craters at the poles that often have no light.
the existence of water
Since ancient times, comets and meteorites have been hitting the moon. Most of these objects contain water. Energy from sunlight breaks down most of this water back to its constituent elements, hydrogen and oxygen. Both usually fly away from the moon immediately. However, some scientists have put forward the hypothesis that there is still a considerable amount of water on the moon, such as on the surface or deep in the lunar shell. The Clementine mission in the United States showed that some tiny water ice cubes (fragments after the impact of water-containing comets) may be hidden in the lunar shell in a permanently sunless area and not melted. Although these ice cubes are very small, the total amount of water may be considerable (about 1 cubic kilometer) < P > And some water molecules may also fall into the crater and hide in it during the lunar bounce. Because the moon's axis of rotation is slightly inclined at 1.5 degrees relative to the normal of the ecliptic plane, the bottom of the crater in some polar regions has never been exposed to sunlight and is in a permanent shadow. The Clementine mission has measured these craters at the South Pole of the Moon ([3]) and mapped them ([4]). Scientists hope that water ice can be found in such craters, and solar energy, electricity or nuclear energy can be exploited and used to electrolyze into hydrogen and oxygen. The amount of water available on the moon greatly affects the cost of living on the moon, because it is impractical to transport water (or hydrogen and oxygen) from the earth.
The rocks collected by Apollo astronauts near the equator of the moon do not contain any water. Neither Lunar Explorer nor other recent studies (such as Smithsonian Institution) found direct evidence of liquid water, ice or water vapor. However, the results of Lunar Explorer indicate that there is hydrogen in the permanently sunless area, and it may exist in the form of water ice.
magnetic field
compared with the earth, the magnetic field of the moon is very weak. It is believed that the magnetic field in some areas comes from the moon itself (for example, the moon shell on the moon stream in Sirsalis), but the collision with other celestial bodies may also change its magnetic field. Whether celestial bodies without atmosphere can obtain magnetic field through the impact of comets and asteroids is a long-standing and often new problem in planetary science. Measuring the lunar magnetic field can provide data such as the size and conductivity of the lunar nucleus, which is very helpful for scientists to understand the origin of the moon. If the lunar core contains more magnetic substances (such as iron) than the earth, the theory of the origin of the moon's impact is less credible (although scientists have explained why the lunar core contains less iron from other angles)
Atmosphere
The moon has only a negligible and thin atmosphere. One of the sources of these atmospheres is degassing, such as the release of radon gas on the surface of the moon, which was originally hidden deep inside the moon. Sometimes, the solar wind is also captured by the moon's gravity. .
1. Poems of the Han and Wei Dynasties
1. Bright moon shines at night
The bright moon shines at night, which promotes the weaving of the East Wall.
Yu Heng refers to Meng Dong, and the stars are vivid.
when the Millennium is stained with weeds, the season suddenly changes.
among the trees in Qiu Chan, the mysterious birds died peacefully.
once upon a time, I was a friend of the same family, holding high and inspiring six purlins.
if you don't want to join hands, you will abandon me like a relic.
there is a bucket in the north of the south basket, and the morning glory does not bear the yoke.
what's the benefit of a good reputation without a solid foundation?
2. Listening to the poems of the moon
Listening to the head of the moon building is too clear, and listening to the moon by the building is the most distinct.
The skyscraper creaks and the ice turns, and the medicine clinks and the jade pestle rings.
the music is wide and cold, and the axe is ding-ding.
Occasionally, a gust of incense blew away the laughter of Chang 'e.
3. How bright is the moon?
How bright is the moon? Take care of my bed.
I can't sleep because I'm sad, and I wander around with my clothes on.
it's better to return home early, although the guest is having fun.
who should I sue if I'm wandering alone when I leave home?
lead him back into the room, with his dress in tears.
4. Complaining songs
Newly cracked and fresh as frost and snow.
cut it into acacia fans, and it looks like a bright moon.
Go in and out of your arms and shake the breeze.
I'm always afraid that autumn will come, and the coolness will rob me of the heat.
if you give up your donation, you will get rid of your kindness.
ii. Poems of Tang and Song Dynasties
Looking at the Moon at Fifteen Nights (Wang Jian)
In the atrium, there is a crow in Bai Shu, and there is a silent and wet osmanthus in Coody Leng.
I wonder whose house Qiu Si will fall into tonight.
Guan Shanyue (Li Bai)
the bright moon lifts from the Mountain of Heaven, in an infinite haze of cloud and sea.
and the wind, that has come a thousand miles, beats at the Jade Pass battlements.
china marches its men down Baideng Road, while Tartar troops peer across blue waters of the bay.
and since not one battle famous in history sent all its fighters back again.
Garrison the border town, and think of home, with wistful eyes.
and of those tonight in the upper chambers, who toss and sigh and cannot rest.
drinking Alone with the Moon (Li Bai)
from a pot of wine among the flowers, I drank alone. There was no one with me.
till, raising my cup, I asked the bright moon, to bring me my shadow and make us three.
alas, the moon was unable to drink, and my shadow tagged me vacantly;.
but still for a while I had these friends, to cheer me through the end of spring.
I sang. The moon encouraged me, I danced. My shadow tumbled after.
have sex when you wake up, and then I was drunk, and we lost one another.
shall goodwill ever be secure?, I watch the long road of the River of Stars.
night thoughts (Li Bai)
so bright a gleam on the foot of my bed, could there have been a frost already?.
lifting myself to look, I found that it was moonlight, sinking back again, I thought suddenly of home.
moonlit night (Liu Fangping)
It's half a house in the deeper moonlight, and the Beidou is dry and inclined to the south.
tonight, I know it's warm in spring, and the sound of insects is fresh through the green window screen.
Chang 'e (Li Shangyin)
The shadow of the mica screen candle is deep, and the long river is gradually sinking.
Chang 'e should regret stealing the elixir.
On August 15th, jathyapple (Du Fu of Tang Dynasty)
On the full moon, he flew to the mirror and returned to his heart to fold his sword.
turn the tent and travel far away, and climb the laurel to the sky.
frost and snow are suspected in the waterway, and feathers are seen in the forest.
at this time, I look at the white rabbit, eager to count the autumn cents.
remembering my brothers on a moonlight night (Du Fu)
In a wanderer hears drums portending battle, geese are singing in autumn.
he knows that the dews tonight will be frost, how much brighter the moonlight is at home!.
o my brothers, lost and scattered, what is life to me without you?.
yet if missives in time of peace go wrong, what can I hope for during war?.
looking at the moon and thinking of one far away (Zhang Jiuling)
the moon, grown full now over the sea, Tianya * * * at this time.
brings to separated hearts, the long thoughtfulness of night!
it is no darker though I blow out my candle, it is no warmer though I put on my coat.
so I leave my message with the moon, and turn to my bed, hoping for dreams.
Shuang Yue (Li Shangyin)
When I first heard of the wild goose, there was no cicada.
A hundred feet of high water reached the sky.
Su E, a young woman, is cold-tolerant, and
she fights in the frost in the middle of the month.
There is a bosom under the autumn night and the moon (Meng Haoran)
There is a bright moon hanging in the autumn sky, and its luster is wet.
I was surprised that the magpie was undecided, and the flying fireflies rolled in.
the cold shadows of the courtyards are sparse, and the sound of the neighboring pestle is urgent at night.
what a long time! Look at the sky and stand.
playing with the moon in Taoyuan on the 15th night of August (Tang Liu Yuxi)
Seeing the moon in the dust is also idle, and the situation is between the immortals in the clear autumn.
the condensation is long and cold, and it stands on the highest mountain at this time.
blue nothingness