|
|
| Line 1: |
Line 1: |
| − | {{Planet|image=Moon2.jpg | + | {{Planet |
| − | |caption=The Moon one week after [[full moon]] | + | | image=Jumpsas.jpg |
| − | |primary=Earth | + | | caption=This processed color image of Jupiter was produced in 1990 by the U.S. Geological Survey from a Voyager image captured in 1979 |
| − | |periapsis=363,300 km | + | |symbol=Jupiter symbol.svg |
| − | |apoapsis=405,500 km | + | |discname=Known to ancients |
| − | |semimajor=384,400 km | + | |origname=Roman king of gods |
| − | |orbitradius=378,000 km | + | |order=6 |
| − | |eccentricity=0.0549 | + | |primary=Sun |
| − | |sidereal=27.3217 da | + | |periapsis=4.95 AU |
| − | |synodic=29.530588 da | + | |apoapsis=5.46 AU |
| − | |orbitspeed=1.023 km/s | + | |semimajor=5.203 AU |
| − | |inclination=18.28° | + | |bode=5.2 AU |
| − | |siderealday=27.3217 da | + | |circumference=32.675 AU |
| − | |solarday=29.530588 da | + | |eccentricity=0.048 |
| − | |mass=7.35 * 10<sup>22</sup> (1.23% earth) | + | |sidereal=11.862 a |
| − | |density=3350 kg/m³ | + | |synodic=398.88 da (1.092 a) |
| − | |surfacegrav=1.62 m/s² (0.165 ''g'') | + | |orbitspeed=13.07 km/s |
| − | |escapespeed=2.38 km/s | + | |inclination=1.305° |
| − | |meanradius=1737.1 km
| + | |reference=the ecliptic |
| − | |equatorradius =1738.1 km | + | |siderealday=9.925 h (0.414 da) |
| − | |polarradius =1736.0 km
| + | |axialtilt=3.13° |
| − | |surfacearea=37,919,000 km² (7.434% earth) | + | |mass=1.8986 * 10<sup>27</sup> kg (317.705 * earth) |
| − | |mintemp=100 K | + | |density=1,326 kg/m³ |
| − | |meantemp=250 K | + | |surfacegrav=22.88 m/s² (2.333 ''g'') |
| − | |maxtemp=400 K | + | |escapespeed=59.56 km/s |
| − | }}[[image:Moon2.jpg|right|thumb|350px|The Moon one week after [[full moon]]]] | + | |equatorradius =71,492 km |
| − | The '''Moon''' is a natural [[satellite]] orbiting the [[Earth]] at an average distance of about 238,000 miles (380,000 km).
| + | |surfacearea=61,400,000,000 km² (120.375 * earth) |
| | + | |meantemp=152 K |
| | + | |moons=28 |
| | + | |composition=90% hydrogen and 10% helium |
| | + | |color=Colored latitudinal bands |
| | + | |albedo=0.52 |
| | + | }} |
| | + | '''Jupiter''' is the fifth [[planet]] from the [[sun]] and the largest planet in our Solar System. (It is, however, the sixth body from the sun of a size large enough to shape itself into a sphere or spheroid from its own gravity, hence its order designation of 6 instead of 5 in the table.) It is named for the highest deity in the Roman pantheon of gods. |
| | | | |
| − | Unlike most planets in the [[solar system]], [[Earth]] has only one moon.
| + | Jupiter is conspicuous and easy to recognize when you know what to look for, and is easily visible through binoculars. It is not so bright as to instantly draw attention, but it is a good deal brighter than the brightest star. It is in fact the fourth brightest object in the sky (the others being the [[sun]], the [[moon]], and the planet [[Venus]]). Jupiter is not only brighter than any star, it also shines more steadily. Jupiter is visible in the sky about half the time, and is often high up and clear of surrounding houses and trees. |
| | | | |
| − | ==The Moon as God's creation==
| + | As of February, 2007, Jupiter is visible in the eastern sky before sunrise, and even in the early stages of dawn. |
| | | | |
| − | The Earth's moon has several striking characteristics. To many, these characteristics appear as "clues" or "hints" left by God for men to discover. [http://www.math.nus.edu.sg/aslaksen/gem-projects/hm/0102-1-phase/CALENDARS.htm]
| + | Through any pair of "real" binoculars (any binoculars that an adult uses for birding or hunting will do; they should be at least 7 power; a "spotting scope" is even better), you can see that Jupiter is not a star, but shows as a tiny round circle; astronomers say it has a visible "disc." Jupiter through binoculars looks about 1/5 the size as the Moon looks ''without'' binoculars. You can't see any of the dramatic markings that you see in photographs made by astronomers, but you can see that it is a round dot. |
| | | | |
| − | ===Size of its disc===
| + | The exciting thing about Jupiter is that usually you will see two, three, or four little "stars" near it that are all lined up in a straight line, with each other, and with Jupiter. If you watch it night after night, these "stars" will change their position relative to Jupiter, but you almost always will see several of them and they will always be lined up. These are four of the satellites (moons) of Jupiter. |
| | | | |
| − | The Moon appears to have the same size as the [[Sun]] when viewed from Earth. This creates a unique symmetry and phenomenal solar eclipses. The odds of this occurring by chance are nearly zero.
| + | Jupiter was visited by several [[NASA]] spacecraft including Pioneer 10 in 1973 and Pioneer 11 in 1974. Larger craft, both Voyager 1, Voyager 2 passed by Jupiter in 1979. The spacecraft Galileo orbited Jupiter specifically for eight years. Many other craft have visited Jupiter, using it's gravity field to "boost" their speed on the way to their ultimate destination. |
| | | | |
| − | ===Rotation and revolution===
| + | {{Solarsystem}} |
| − | | |
| − | The Moon presents the same side to [[Earth]] at all times. That means that the rotation of the Earth offsets the separate effects of the revolution of the Moon. Physical explanations rely on [[tidal locking]], asserting that tidal forces on Earth caused a bulge on the Moon, thereby creating a drag on the rotation of the Moon until its same face always presents to the Earth.<ref> The same theory suggested that the planet [[Mercury]] had a similar locked rotation due to gravitational forces from the sun, such that the same side of Mercury always faces the sun. In fact, that is false. [[Mercury]]'s tidal locking is incomplete and it does not always present the same face to the sun.</ref> In fact, current tidal forces exerted by the [[Earth]] on the Moon cannot account fully for its bulge or egg shape.<ref>http://physics.fortlewis.edu/Astronomy/astronomy%20today/CHAISSON/AT308/HTML/AT30803.HTM</ref>
| |
| − | | |
| − | ===Origin theories===
| |
| − | | |
| − | [[Atheistic]] theories of the [[origin of the Moon]], widely taught for decades despite lacking the falsifiability requirement of science (see [[Philosophy of science]]), have been proven false.<ref>Planetary Science Institute: [http://www.psi.edu/projects/moon/moon.html The Origin of the Moon]</ref> Lacking any other [[atheistic]] alternatives, some scientists assert that the Moon originated from a collision early in Earth's history which created an orbiting ring of debris from the [[iron]]-poor surface of the planet which eventually coalesced into the moon.<ref>http://www.astronomy.com/asy/default.aspx?c=a&id=2198</ref> This theory, however, is contrary to key observations of the Moon, such as the relatively low levels of [[iron]] in the Moon's crust. Additional tests fail to support the [[atheistic]] theory.<ref>J. H. Jones: [http://www.lpi.usra.edu/meetings/origin98/pdf/4045.pdf Tests of the Giant Impact Hypothesis]</ref><br />Biblical history records the Moon being created on the fourth day of [[Creation Week|creation week]], along with the Sun.
| |
| − | | |
| − | ===Rate of recession===
| |
| − | | |
| − | The Moon currently recedes from the Earth at a rate of 1.5 inches (3.8 cm) per year<ref>NASA [http://sunearth.gsfc.nasa.gov/eclipse/SEhelp/ApolloLaser.html Measuring the Moon's Distance], LPI Bulletin, No. 72, August, 1994.</ref>, and is believed by mainstream scientists to be 4.6 billion years old <ref>NASA, [http://history.nasa.gov/SP-350/ch-15-2.html Apollo Expeditions to the Moon], Chapter 15.2.</ref>.<br />The Moon could never have been closer than about 11,000 miles or it would have been broken up by tidal forces.<ref name="js">Sarfati, Jonathan, [http://www.creationontheweb.com/content/view/764/ The moon: the light that rules the night], ''Creation'' 20(4):36–39, September 1998.</ref><br />If the rate of recession stayed constant at 3.8 cm per year, it would take 9.6 billion years for the lunar distance to migrate from 11,000 miles to the present distance of about 240,000 miles.<br />However, the rate of recession would not have been constant, but would have been greater in the past, so that extrapolating backwards in time results in the moon being in contact with the earth 1.37 billion years ago,<ref name="js" /> seemingly (if the assumptions stated above are correct) contradicting the view of an [[Old Earth]] promoted by [[atheists]].
| |
| − | | |
| − | ==Tides==
| |
| − | | |
| − | The gravitational force of the Moon causes the ocean [[tides]]; these tidal forces have other effects as well. These tidal forces have the effect of creating resistance which slows down the rotation of both objects. In the case of the Earth, the result is that the Earth's rotation slows on the order of one millisecond per century. The Moon's rotation is locked in to its period of revolution, and the same side of the Moon always faces the Earth.
| |
| − | | |
| − | ==The "dark" or far side==
| |
| − | | |
| − | The phrase "the ''dark'' side of the Moon" is inaccurate because the Moon does rotate relative to the Sun, with the same period as its period of revolution, once every 29 days. Our view of the Moon from the Earth always shows the same side of the Moon, with the same markings and features. When the Moon is full, the entire side that faces us is experiencing lunar "day" and is lit by the Sun. Two weeks later, when the Moon is new, the side that faces us is experiencing solar "night" and is unlit (and virtually invisible).
| |
| − | | |
| − | Due to a slight "wobble" in the lunar motion called ''libration,'' we actually see a little bit more than half of the Moon's surface; sometimes it is turned a bit one way and sometimes the other. However, nobody had any idea of what the far side of the Moon looked like until 1959, when a Soviet satellite photographed it and relayed pictures back.
| |
| − | | |
| − | [[image:oldmooninnew.jpg|200px|right|thumb|The "old Moon in the new Moon's arms"]]
| |
| − | In the old Scottish ballad ''Sir Patrick Spens''<ref>Child, Francis James (1860), ''The English and Scottish Popular Ballads,'' [http://www.sacred-texts.com/neu/eng/child/ch058.htm No. 58]; the ballad is thought to refer to an actual event of the year A.D. 1290.</ref>, a sailor cautions:
| |
| − | | |
| − | :"I saw the new moon late yestreen
| |
| − | ::With the old moon in her arm;
| |
| − | :And if we go to sea, master,
| |
| − | ::I fear we'll come to harm."
| |
| − | | |
| − | ==Earthshine==
| |
| − | | |
| − | The effect known as "the old Moon in the new Moon's arms" can often be seen when the Moon is a narrow [[crescent]]. Within the intensely bright crescent, a dim and mysterious view of the entire circular moon is seen. The effect is also known as ''earthshine'' because it is light from the Sun reflected off the Earth to the Moon and back that lights up the darker portion of the Moon. The bright crescent is lit by the Sun and is in full daylight. The rest of the Moon is not lit by the Sun; but an [[astronaut]] standing in this area would see a "full Earth" dominating the nighttime sky, lighting it up by its earthshine. The brightness of Earthshine, and hence the visibility of the old Moon in the new Moon's arms, varies. When the Earth is covered with clouds, or when there is a lot of snow-pack on the side of the Earth facing the Moon, the Earth is a white and bright and the Earthshine is intense. When the Earth looks like a "big, blue marble," it is less intense.
| |
| − | | |
| − | ==Lunar calendars==
| |
| − | | |
| − | Throughout history, many calendar systems have been based on the phases of the moon.
| |
| − | | |
| − | The months of the [[Islam|Muslim]] [[calendar]] are determined by observations of the [[hilal]], the moment at which the thin crescent moon first becomes visible. This marks the start of a month. Traditionally, and today in [[Pakistan]] and [[Jordan]], hilal is determined by actual observation and can be affected by weather and other factors. When following the traditional method, it is not actually possible to be certain precisely when future months will begin. In most Muslim countries, actual observation has been replaced by [[astronomy|astronomical]] rules.
| |
| − | | |
| − | ==The moon in culture==
| |
| − | | |
| − | "The Old Moon in the New Moon's Arms" is the title of a poem by [[Ella Wheeler Wilcox]], in which she interprets the effect as the New Moon wishing that her lost love, the Old Moon, be in her arms one last time; Venus grants the wish, and:
| |
| − | | |
| − | :Swift thro' the vapors and the golden mist—<br>
| |
| − | ::The Full Moon's shadowy shape shone on the night,<br>
| |
| − | :The New Moon reached out clasping arms and kissed<br>
| |
| − | ::Her phantom lover in the whole world's sight.<br>
| |
| − | | |
| − | == Trivia==
| |
| − | | |
| − | Although the Moon is often described as revolving around the Earth, this is slightly inaccurate: the Earth and the Moon ''both'' revolve around their ''barycenter'', their common [[centroid|center of mass]]. This point is 1,700 below the earth's surface, which is about 1/4 of the earth's [[radius]].<ref> The radius of the Earth is 6,378 kilometers, so that means that the barycenter is located INSIDE the Earth about 1707 kilometers below its surface. [http://www.astronomycafe.net/qadir/q665.html] </ref>
| |
| − | | |
| − | The combined motion is like an athlete performing an [[Olympics| Olympic]] hammer throw: one object swings in a large circle, the other almost pivots around a fixed point but actually performs a small opposing circle of its own. <ref>The Earth and the Moon orbit each other around a gravitational midpoint called the ''barycenter.'' This point is, however, actually inside the Earth, about 3/4 of its radius from its center. It is not the Earth, but the barycenter of the Earth-Moon system, that orbits the [[Sun]] in a near-perfect ellipse. Relative to this ellipse, Earth is 3,000 miles closer to the Sun at full moon and 3,000 miles further from the Sun at new moon.</ref>
| |
| − | | |
| − | When speaking of things having to do with the moon, the adjective ''lunar'' is used. The Greek-derived prefixed root ''selen-'' followed by the morpheme ''-o-'' is used as well; for example, the [[science]] of mapping the moon is called ''[[selenography]]'' (morphemes: ''selen-o-graph-y''). (Note, however, that the apsides of the orbits of the [[Project Apollo]] spacecraft were always called ''pericynthion'' and ''apocynthion'', not "periselene" and "aposelene.")
| |
| − | | |
| − | == See also ==
| |
| − | *[[Origin of the Moon]]
| |
| − | | |
| − | == Notes and References ==
| |
| − | | |
| − | <references/>
| |
| − | | |
| − | [[Category:Astronomy]]
| |
Jupiter is the fifth planet from the sun and the largest planet in our Solar System. (It is, however, the sixth body from the sun of a size large enough to shape itself into a sphere or spheroid from its own gravity, hence its order designation of 6 instead of 5 in the table.) It is named for the highest deity in the Roman pantheon of gods.
Jupiter is conspicuous and easy to recognize when you know what to look for, and is easily visible through binoculars. It is not so bright as to instantly draw attention, but it is a good deal brighter than the brightest star. It is in fact the fourth brightest object in the sky (the others being the sun, the moon, and the planet Venus). Jupiter is not only brighter than any star, it also shines more steadily. Jupiter is visible in the sky about half the time, and is often high up and clear of surrounding houses and trees.
As of February, 2007, Jupiter is visible in the eastern sky before sunrise, and even in the early stages of dawn.
Through any pair of "real" binoculars (any binoculars that an adult uses for birding or hunting will do; they should be at least 7 power; a "spotting scope" is even better), you can see that Jupiter is not a star, but shows as a tiny round circle; astronomers say it has a visible "disc." Jupiter through binoculars looks about 1/5 the size as the Moon looks without binoculars. You can't see any of the dramatic markings that you see in photographs made by astronomers, but you can see that it is a round dot.
The exciting thing about Jupiter is that usually you will see two, three, or four little "stars" near it that are all lined up in a straight line, with each other, and with Jupiter. If you watch it night after night, these "stars" will change their position relative to Jupiter, but you almost always will see several of them and they will always be lined up. These are four of the satellites (moons) of Jupiter.
Jupiter was visited by several NASA spacecraft including Pioneer 10 in 1973 and Pioneer 11 in 1974. Larger craft, both Voyager 1, Voyager 2 passed by Jupiter in 1979. The spacecraft Galileo orbited Jupiter specifically for eight years. Many other craft have visited Jupiter, using it's gravity field to "boost" their speed on the way to their ultimate destination.
