planetary system is a noun.  There is 1 definition.

Definition 1 is:  A planet and its satellite or satellites as the Earth and its Moon, or Saturn and its 21 satellites and flat luminous encircling rings.

This link will be to the Spanish:  _____.  This link will be to the French:  _____.  This link will be to the German:  _____.

Associations with planetary system, Definition 1, are:

Pluto is a noun.  Definition 3 of 3 in Astronomy is:  A planet of the solar system.  Its mean distance from the sun is 3.674 billion miles; period of revolution, 248.53 years; diameter, 2,100 miles.  It has one known satellite, Charon, discovered in 1978.

Charon is large for a moon, at half the size of its parent planet.  Because of the small difference in their sizes, Pluto and Charon are sometimes considered to be a double-planet system.

Within the hierarchical structure, this down link is to Pluto's planetary atmosphere and this up link is to star.

Proteus orbits Neptune at 73,100 miles. Its diameter is 259 miles.

Triton is the largest Neptunian moon, with a diameter of 1,681 miles, and the coldest object in the Solar System, with a temperature of minus 591 degrees Fahrenheit  Unlike most moons in the Solar System, Triton orbits its mother planet in the opposite direction to the planet's rotation.  Triton is getting nearer to Neptune and is expected to approach and collide with the planet or, more likely, to disintegrate at a close approach and form a ring system.  Triton's average distance from Neptune is 22,500 miles.

Uranus is a noun.  Definition 2 of 2 in Astronomy is:  A planet of the solar system.  Its mean distance from the sun is 1,781 millions of miles, its sidereal period about 84 years and its diameter about 34,800 miles.  It has 15 satellites.

Uranus has eleven identified rings:  Epsilon ring, which is sharply defined; Ring 1986 U1R; Delta ring; Gamma ring; Eta ring; Beta ring; Alpha ring; Rings 4 and 5; Ring 6; and Ring 1986 U2R.  The rings consist of rocks interspersed with dust lanes.  The rings contain some of the darkest matter in the Solar System.  They are extremely narrow, making them difficult to detect:  nine of them are less than six miles wide, whereas most of Saturn's rings are thousands of miles in width.  There are 15 known Uranian moons, all of which are icy and most of which are farther out than the rings.  The 10 inner moons are small and dark, with diameters of less than 100 miles, and the five outer moons are between 290 and 1,000 miles in diameter.  The outer moons have a wide variety of surface features.

Oberon, with a diameter of 946 miles, circles Uranus at an altitude of 362,000 miles.

Titania, with a diameter of 981 miles, circles Uranus at an altitude of 270,900 miles.

Umbriel, with a diameter of 726 miles, circles Uranus at an altitude of 165,500 miles.

Ariel, with a diameter of 720 miles, circles Uranus at an altitude of 118,800 miles.

Miranda, with a diameter of 295 miles, has the most varied surface, with cratered areas broken up by huge ridges and cliffs 12 miles high.  It circles Uranus at an altitude of  80,700 miles.

There are icy clouds of frozen methane, which represents 3 per cent of Uranus' atmosphere, blown by winds of up to 185 miles per hour.  The other components are:  hydrogen, 85 per cent; and helium, 12 per cent.  The cloud-top temperature is about minus 350 degrees Fahrenheit.

Saturn is a noun.  Definition 1 of 3 in Astronomy is:  The planet next beyond Jupiter and next to Jupiter in size, distant from the sun about 886,000,000 miles; remarkable for its 21 known satellites and its flat luminous encircling rings.  Its diameter is 75,000 miles at the equator; its revolutionary period, 29 1/2 years.

Saturn has an extremely thin but wide system of rings that is less than one mile thick but extends outward to about 260,000 miles from the planet's surface.  The main rings comprise thousands of narrow renglets, each made of icy lumps that range in size from tiny particles to chunks several yards across.  The D, E, and G rings are very faint, the F ring is brighter, and the A, B, and C rings are bright enough to be seen from Earth with binoculars.  From the outermost to the innermost, the rings, and sometimes the space between or within the rings, have names:  F ring; A ring, a broad ring comprising many ringlets, with the Encke Division, a gap where the mooon Pan orbits, included; Cassini Division, an apparent gap containing at least 100 ringlets; B ring, a broad ring comprising many ringlets; C ring, (crepe ring), also a broad ring comprising many ringlets; and D ring. Some of the known moons orbit inside the rings and are thought to exert a gravitional influence on the shapes of the rings.

Unusually, seven of the moons are co-orbital -- they share an orbit with another moon.  Astronomers believe that such co-orbital moons may have originated from a single satellite that broke up.

Dione, with a diameter of 695 miles, circles Saturn at an altitude of 234,000 miles.

Tethys, with a diameter of 652 miles, circles Saturn at an altitude of 183,000 miles.

Enceladus, with a diameter of 309 miles, circles Saturn at an altitude of 148,000 miles.

Mimas, with a diameter of 247 miles, circles Saturn at an altitude of 115,600 miles.

Jupiter is a noun.  Definition 2 of 3 in Astronomy is:  The fifth planet from the sun; its diameter is about 86,500 miles, and it revolves around the sun in about 11 7/8 years at a mean distance of 483,000,000 miles.  It has 16 moons.

The four largest moons (called the Galileans) are Ganymede, Callisto, Lo, and Europa.  Ganymede and Callisto are cratered and probably icy.  Europa is smooth and icy and may contain water.  Lo is covered in bright red, orange, and yellow splotches.  This coloring is caused by sulfurous material from active volcanoes that shoot plumes of lava hundreds of miles above the surface.

Callisto, with a diameter of 2,983 miles, circles Jupiter at an altitude of 1,168,200 miles.

Ganymede, with a diameter of 3,270 miles, circles Jupiter at an altitude of 664,900 miles.

Europa, with a diameter of 1,950 miles, circles Jupiter at an altitude of 416,900 miles

Lo, with a diameter of 262,100 miles, circles Jupiter at an altitude of 262,100 miles

Jupiter has one thin, faint, main ring, inside of which is a holo ring of tiny particles extending toward the planet.

Mars is a noun.  Definition 2 of 2 in Astronomy is:  The fourth planet in order of distance from the sun, from which its mean distance is 141,500,000 miles, its least distance from the earth being 35,000,000 miles, as in the years 1909 and 1924.  Mars has a diameter of about 4,230 miles, a diurnal rotation of 24 hours, 37 minutes, 22.67 seconds, and a year of 686.9 days.  The light of Mars is of a pronounced red color.  It has two moons.  (Their small, irregularly shaped size indicates that they may be asteroids that have been captured by the gravity of Mars.)

Deimos, with an average diameter of 8 miles, circles Mars at an average altitude of 14,600 miles.

Phobos, with an average diameter of 14 miles, circles Mars at an average altitude of 5,800 miles.

Earth is a noun.  Definition 1 of 11 in Astronomy is:  The globe on which we dwell, considered as a whole; distinguished (1) from other heavenly bodies and (2) from the abode of departed spirits.  Its area is 196,940,000 square miles; its mean diameter is 7,917.5; mean distance from the sun, 93,000,000 miles.  It has one natural satellite, the Moon..

The Moon is large enough for both bodies to be considered a double-planet system.

The Moon, with a diameter of 2,160 miles, circles the Earth at a mean altitude of about 238,857 miles.  It travels in an elliptical orbit around the earth that sometimes places it as close as 221,800 miles, its perigee or closest point to earth, and sometimes as far out as 252,700 miles, its apogee or farthest point from earth.

tide.  Generally there are two high tides and two low tides daily, with high tide and low tide about six hours apart.  This is due to the 24 hour rotation of the earth as it exposes its oceans to the moon's pull.

spring tides.  High tides.

neap tides  The the lowest of the high tides.

gravitation

penumbra

umbra

eclipse

total eclipse of the moon can last as long as four hours, and at least half the world may see it at the same time.

lunar eclipses do not occur at regular intervals.  This is because the earth-moon plane is different from the earth-sun plane.  The moon's orgit around the earth is tilted five degrees to the earth-sun plane.  And thus the moon often moves slightly above the earth's shadow or slightly below it.  In some years there may be no lunar eclipses at all.  In other years, however, there may be as many as three.

solar eclipses, eclipses of the sun by the moon, occur at least twice a year and sometimes as often as five times a year.

partial eclipse

Baily's beads.  During a solar eclipse, the last sunlight sparkling through the mountains and valleys on the edges of the moon.

corona

The plural of planetary system is:  planetary systems.  The possessive of planetary system is:  planetary system's.

This link will be to planetary system synonyms, antonyms and etymology.

Within the hierarchical structure, this down link is to planetary atmosphere and this up link is to star.

This link is to a Word Search.

Last update of this page:

2000 MAR 02  Pronunciation added.

1999 JUL 20