SOLAR SYSTEM

Our solar system consists of an average star we call the Sun, the planets Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto. It includes: the satellites of the planets; numerous comets, asteroids, and meteoroids; and the interplanetary medium.

A. Origin of the Solar System

History:

The solar system formed around 4.5 billion years ago from a huge swirling cloud of dust. We know this because advances in technology, such as the Hubble telescope, have allowed us to look deep into space to observe the birth of stars similar to our sun.

A huge cloud of dust

Throughout the Milky Way, and other galaxies like it, are gigantic swirling clouds of dust and gas known as nebula. It is within nebula that stars are born. Our star, the sun, was created in one such nebula.

Something, perhaps the shock wave from an exploding supernova (dying star) triggered dust particles to be drawn together to form a dense spherical cloud. The accumulation of dust set off a chain reaction. As the core of the cloud attracted more dust, its gravitational pull increased. More and more dust was sucked in and the cloud collapsed in on itself. As this happened, the rotation of the cloud increased in speed, as happens when spinning ice skaters pull in their arms. The rotational forces at the equator of the cloud prevented dust along this plane being drawn in, causing the cloud to flatten into a disc spinning around a dense core.

A pillar of dust and gas in the Orion Nebula.

A star is born

As more and more mass accumulated at the centre of the disc, the temperature increased dramatically. Eventually there was enough energy to set off nuclear reactions. Hydrogen atoms fused to form helium, releasing enormous amounts of energy in vigorous bursts. This marked the birth of the sun, although it would take between one and 10 million more years for it to settle into the main sequence star recognisable today.

The formation of the planets

The planets, and other extraterrestrial objects such as asteroids, formed in the flat plane of the spinning disc of dust. Electrostatic forces or sticky carbon coatings made dust particles stick together to form clusters, which in turn stuck together to form rocks. Mutual gravity caused these rocks to come together, eventually to form planets. This 'coming together' of material is a process known as accretion.

A star forming region in the Orion Nebula.

Disproving the Seven Theories:

1. Nebular Hypothesis

It is the most widely accepted model explaining the formation and evolution of the Solar System. There is evidence that it was first proposed in 1734 by Emanuel Swedenborg.

About 4.5 billion years ago it is believed that the Solar System consisted of a large cloud of gas and dust, called a nebula. This cloud started rotating, and the dust particles combined to form planetesimals. As the cloud rotated faster, it flattened, and the planetesimals combined to form, first of all, the Sun at the center, and secondly, the planets in orbit around the Sun. This model explains qualitatively many features of the Solar System, including the fact that the planets essentially all revolve around the Sun in the same plane.

2. Fission TheoryThe "fission theory" says that our sun burst one day, and all our planets came from it. Then the

moons shot out from each planet, stopped, turned sideways and began circling the planets they came out of. Our moon is said to have emerged from an explosion in the Pacific Ocean.

3. Capture Theory

The "capture theory" says that our planets and moons were wandering around in space and the planets were captured by the gravity of our sun, and the moons were captured by the planets.

4. Accretion theory

The "accretion, condensation, nebular contraction," or "dust cloud" theory says that small chunks of material separately formed themselves into our earth and the moon."According to this idea, a dust cloud began to rotate. . When the mass had swept up most of the material in an eddy, a planet was formed."—*M. Bishop, *B. Sutherland, and *P. Lewis, Focus on Earth Science (1981),

A pile of space dust and rock chunks pushed together into our planet, and another pile pushed itself into our moon. Then the moon got close enough and began encircling the earth.

5. Planetary Collision Theory

Our world collided with a small planet, and the explosion threw off rocks which became the moon, and then it began orbiting us.

6. Stellar Collision Theory

Our planets, moons, and suns spun off from the collision between stars.

7. Gas Cloud Theory

Gas clouds were captured by our sun and began to whirl and push themselves into planets and moons.

Cosmological theories:

● Big bang Theory

- All of the matter and energy in the universe was concentrated in a very dense state, from which it “exploded.”

- The relative abundance of hydrogen and helium is used as a test of the theory.- Optical and radio astronomy believed that the energy reaching us now from some of these

objects was emitted not long after the creation of the universe.

● Steady State Theory

- A model developed in 1948 by Fred Hoyle, Thomas Gold, Hermann Bondi - The theory implies that the universe has always expanded, with no beginning or end; at a

uniform rate and that it will always expand and maintain a constant density

● Pulsating Theory

- It is possible that at a certain time, the expansion of the universe may be stopped by the gravitational pull and they may contract again.

B. Planets

A planet (from Ancient Greek (astēr planētēs), meaning "wandering star") is a celestial body orbiting a star or stellar remnant that is massive enough to be rounded by its own gravity, is not massive enough to cause thermonuclear fusion, and has cleared its neighbouring region of planetesimals.

Inner Planets: Mercury, Venus. Earth & Mars

MERCURY

Mercury, the planet closest to the Sun, has almost no atmosphere, and its dusty surface of craters resembles the Moon. The planet was named for the Roman god Mercury, a winged messenger, and it travels around the Sun faster than any other planet. Mercury is difficult to see from Earth—in fact, the famous astronomer Nicolaus Copernicus, for all his years of research and observation, never once was able to see Mercury.

Size: Two-fifths the size of Earth in diameter; second smallest in the solar system Diameter: 3,032.4 miles (4,880 km) Surface: Covered by a dusty layer of minerals (silicates), the surface is made up of plains, cliffs,

and craters Atmosphere: A thin mixture of helium (95%) and hydrogen Temperature: Mercury alternately bakes and freezes, depending on what side is lit by the Sun.

The sunlit side can reach up to 950° F (510° C) and the dark side can drop as low as –346° F (–210° C)

Rotation of its axis: 59 Earth days Rotation around the Sun: 88 Earth days Your weight: If you weigh 100 pounds on Earth, you would weigh 38 pounds on Mercury. Satellites: 0 Rings: 0 Neat Fact: Closest planet to the Sun.

A photo of a section of Mercury's Shakespeare Quadrangle showing remarkably Moon-like craters. Pictures were taken by the Mariner 10 mission, the only spacecraft to visit Mercury so far. The MESSENGER mission, launched in 2004, will reach it in 2011.

VENUS

Venus is often called Earth's twin because the two planets are close in size, but that's the only similarity. The thick clouds that cover Venus create a greenhouse effect that keeps it sizzling at 864°F. Venus, named after the Roman goddess of love and beauty, is also known as the “morning star” and “evening star” since it is visible at these times to the unaided eye. Venus appears as a bright, white disk from Earth.

Size: About 650 miles smaller in diameter than Earth Diameter: 7,519 miles (12,100 km) Surface: A rocky, dusty, waterless expanse of mountains, canyons,

and plains, with a 200-mile river of hardened lava Atmosphere: Carbon dioxide (95%), nitrogen, sulfuric acid, and

traces of other elements Temperature: Ranges from 55°F (13°C) to 396°F (202°C) at the

surface Rotation of its axis: 243 Earth days

Rotation around the Sun: 225 Earth days Your weight: If you weigh 100 pounds on Earth, you would weigh 88 pounds on Venus. Distance from Earth: At its closest, Venus is 26 million miles (41,840,000 km) away Mean Distance from Sun: 67.24 million miles (108.2 million km) Satellites: 0 Rings: 0 Neat Fact: Rotates in the opposite direction from the other planets.

This is an image of Venus passing in front of

the Sun. Photo courtesy of NASA

EARTH

Earth is not perfectly round; it bulges at the equator and is flatter at the poles. From space the planet looks blue with white swirls, created by water and clouds.

Size: Four planets in our solar system are larger and four are smaller than Earth

Diameter: 7,926.2 miles (12,756 km) Surface: Earth is made up of water (70%), air, and solid ground.

It appears to be the only planet with water Atmosphere: Nitrogen (78%), oxygen (21%), other gases Rotation of its axis: 23 hours, 56 minutes, 4 seconds Rotation around the Sun: 365.2 days Satellites: 1 Mean Distance from Sun: 92.9 million miles (149.6 million km) Rings: 0 Neat Fact: Travels around the Sun at a speed of >66,000 miles per hour.

MARS

Because of its blood-red color (which comes from iron-rich dust), this planet was named for Mars, the Roman god of war. Mars is the fourth planet from the Sun, situated between Earth and Jupiter. Three-quarters red, Mars also has dark blotches on it and white areas at the poles—these are white polar ice caps.

Size: About one-half the size of Earth in diameter Surface: Canyons, dunes, volcanoes, and polar caps of water ice and carbon dioxide ice Diameter: 4,194 miles (6,794 km) Atmosphere: carbon dioxide (95%) Temperature: as low as –305°F (–187°C)

Rotation of its axis: 24 Earth hours, 37 minutes, 23 seconds Rotation around the Sun: 687 Earth days

Your weight: If you weigh 100 pounds on Earth, you would weigh 38 pounds on Mars.

Distance from Earth: 35 million miles (56 million km) at the closest point in its orbit

Mean Distance from Sun:141.71 million miles (227.9 million km)

Satellites: 2 Rings: 0 Neat Fact: The largest volcano in the Solar System is on Mars. It is called Olympus Mons.

Outer Planets: Jupiter, Uranus, Saturn & Neptune

JUPITER

A belt of asteroids (fragments of rock and iron) between Mars and Jupiter separate the four inner planets from the five outer planets.

Jupiter is the fifth planet from the Sun and is the largest planet in the solar system. It is the largest planet in our solar system, was named for the most important Roman god because of its size. About 1,300 Earths would fit into it. Viewed through a large telescope, Jupiter is stunningly colorful—it is a disk covered with bands of blue, brown, pink, red, orange, and yellow. Its most distinguishing feature is “the Great Red Spot,” an intense windstorm larger in size than Earth, which has continued for centuries without any signs of dying down.

Size: 11 times the diameter of Earth Diameter: 88,736 miles (142,800 km) Surface: A hot ball of gas and liquid Atmosphere: Whirling clouds of colored dust, hydrogen,

helium, methane, water, and ammonia. The Great Red Spot is an intense windstorm larger than Earth.

Temperature: –234°F (–148°C) average Rotation of its axis: 9 hours and 55 minutes Rotation around the Sun: 12 Earth years Your weight: If you weigh 100 pounds on Earth, you would

weigh 265 pounds on Jupiter. Distance from Earth: At its closest, 370 million miles (591 million km) Mean Distance from Sun: 483.88 million miles (778.3 million km) Satellites: 63 Rings: 4 Neat Fact: The four largest moons were found by Galileo in 1601; the others were discovered in

2003.

URANUS

Uranus is the seventh planet from the Sun and is the third largest in the solar system. Uranus is a greenish-blue planet, twice as far from the Sun as its neighbor Saturn. Uranus wasn't discovered until 1781. Its discoveror, William Herschel, named it Georgium Sidus (the Georgian star) after the English king, George III. Later its name was changed to Uranus, after an ancient Greek sky god, since all the other planets had been named after Roman and Greek gods.

Size: 4 times larger than Earth in diameter Diameter: 32,193 miles (51,810 km) Surface: Little is known Atmosphere: Hydrogen, helium, and methane Temperature: uniform temperature of –353°F (–214°C) Rotation of its axis: 17 hours Rotation around the Sun: 30,685 days or 84 Earth years Your weight: Not known Distance from Earth: At the closest point, 1,607,000,000 miles Mean Distance from Sun: 1,783.98 million miles (2,870 million

km) Satellites: 27 Rings: 11 Neat Fact: Its north pole stays dark for 42 years at a time.

SATURN

Saturn is the sixth planet from the Sun and is the second largest in the solar system with an equatorial diameter of 119,300 kilometers (74,130 miles). It has majestic rings surrounding it. Named for the Roman god of farming, Saturn was the farthest planet known by the ancients. Saturn's seven rings are flat and lie inside one another. They are made of billions of ice particles. Saturn is known to be the only planet which has visible rings around it.

Size: About 10 times larger than Earth in diameter Diameter: 74,978 miles (120,660 km) Surface: Liquid and gas Atmosphere: Hydrogen and helium Temperature: –288°F (–178°C) Rotation of its axis: 10 hours, 40 min, 24 sec Rotation around the Sun: 291/2 Earth years Your weight: If you weigh 100 pounds on Earth, you

would weigh 107 pounds on Saturn. Distance from Earth: 744 million miles at the closest

point Mean Distance from Sun: 887.14 million miles (1,427 million km) Satellites: 31

Neat Fact: Galileo discovered the rings around Saturn with a simple early telescope.

NEPTUNE

Neptune is the outermost planet of the gas giants. It has an equatorial diameter of 49,500 kilometers (30,760 miles). If Neptune were hollow, it could contain nearly 60 Earths. Neptune orbits the Sun every 165 years. It has eight moons, six of which were found by Voyager. A day on Neptune is 16 hours and 6.7 minutes. Neptune, named for an ancient Roman sea god, is a stormy blue planet about 30 times farther from the Sun than Earth. Neptune was discovered when astronomers realized that something was exerting a gravitational pull on Uranus, and that it was possible that an unknown planet might be responsible. Through mathematical calculations, astronomers determined there was indeed an undiscovered planet out in space—a year before it was actually seen for the first time through a telescope (in 1846).

Size: Almost 4 times the size of Earth in diameter Diameter: 30,775 miles (49,528 km) Surface: A liquid layer covered with thick clouds and with

constant, raging storms Atmosphere: Hydrogen, helium, methane, and ammonia Temperature: –353°F (–214°C) Rotation of its axis: 16 hours and 7 minutes Rotation around the Sun: 165 Earth years Your weight: Not known Distance from Earth: 2,680,000,000 miles at closest point Mean Distance from Sun: 2,796.46 million miles (4,497 million km) Satellites: 13 Rings: 4 Neat Fact: Neptune can have winds up to 2400 miles per second.

More Planet Facts:

Largest Planet: Jupiter Smallest Planet: Pluto Fasting Orbiting Planet: Mercury Slowest Orbiting Planet: Pluto Hottest Planet: Venus Coldest Planet: Pluto Shortest Day: Jupiter Longest Day: Mercury

Dwarf Planets:

A dwarf planet, as defined by the International Astronomical Union (IAU), is a celestial body in direct orbit of the Sun that is massive enough that its shape is controlled by gravitational forces rather than mechanical forces (and thus an ellipsoid in shape), but has not cleared its neighboring region of other objects. It is so cold on these dwarf planets that even the "air" freezes. The ice on the surface isn't just normal ice made of water. There are currently five official dwarf planets: Pluto, Ceres, Eris, Makemake & Haumea.

PLUTO

Pluto is the second largest known dwarf planet and tenth largest orbiting the Sun. From its time of discovery in 1930 to 2006 it was considered to be the ninth planet in the solar system, but because additional objects have been discovered including Eris which is 27% more massive, the IAU reclassified Pluto and the other objects as dwarf planets. Pluto, named after the Roman and Greek god of the underworld, is the coldest, smallest, and outermost planet in our solar system. Pluto and its moon, Charon, are called “double planets” because Charon is so large it seems less of a moon than another planet. Pluto was predicted to exist in 1905 and discovered in 1930. It is the only planet that has not yet been studied closely by a space probe.

During each revolution around the sun, Pluto passes inside Neptune's orbit for 20 years, making Neptune the outermost planet for that time. Pluto passed inside Neptune's orbit in 1979 and remained there until 1999.

CERES

It is the only dwarf planet in the inner Solar System, and the largest asteroid in the main asteroid belt between Mars and Jupiter. It is a rock–ice body some 950 km (590 mi) in diameter, and though the smallest identified dwarf planet, it constitutes a third of the mass of the asteroid belt. Discovered on 1 January 1801 by Giuseppe Piazzi, it was the first asteroid to be identified, though it was classified as a planet at the time. It is named after Ceres, the Roman goddess of growing plants, the harvest, and motherly love.

ERIS

Eris, is the most massive known dwarf planet in the Solar System and the ninth most massive body known to orbit the Sun directly. It is estimated to be 2326 (±12) km in diameter and 27% more massive than Pluto, or about 0.27% of the Earth's mass. Eris is a dwarf planet that lies at the outer reaches of our solar system. It was discovered in 2005 by professional astronomers who were examining images taken at California's Palomar Observatory two years previously.

MAKEMAKE (pronounced MAH-keh MAH-keh)

Makemake is one of the largest objects known in the outer Solar System and is just slightly smaller and dimmer than Pluto, its fellow plutoid. The dwarf planet is reddish in colour and astronomers believe the surface is covered by a layer of frozen methane.

Like other plutoids, Makemake is located in a region beyond Neptune that is populated with small Solar System bodies. The object was discovered in 2005 by a team from the California Institute of Technology led by Mike Brown and was previously known as 2005 FY9 (or unofficially "Easterbunny").

HAUMEA

The fifth dwarf planet of the solar system, Haumea, and at least one of its two satellites, are covered in crystalline water-ice due to the tidal forces between them and the heat of radiogenic elements. This is the finding of an international research study using observations from the VLT telescope at the European Southern Observatory in Chile.

C. THE SUN

The Sun is the star at the center of the Solar System. It is the most prominent feature in our solar system. It is the largest object and contains approximately 98% of the total solar system mass. One hundred and nine Earths would be required to fit across the Sun's disk, and its interior could hold over 1.3 million Earths. The Sun's outer visible layer is called the photosphere and has a temperature of 6,000°C (11,000°F). This layer has a mottled appearance due to the turbulent eruptions of energy at the surface. Solar energy is created deep within the core of the Sun. It is here that the temperature (15,000,000° C; 27,000,000° F) and pressure (340 billion times Earth's air pressure at sea level) is so intense that nuclear reactions take place.

The chromosphere is above the photosphere. Solar energy passes through this region on its way out from the center of the Sun. Faculae and flares arise in the chromosphere. Faculae are bright luminous hydrogen clouds which form above regions where sunspots are about to form. Flares are bright filaments of hot gas emerging from sunspot regions. Sunspots are dark depressions on the photosphere with a typical temperature of 4,000°C (7,000°F).

The corona is the outer part of the Sun's atmosphere. It is in this region that prominences appears. Prominences are immense clouds of glowing gas that erupt from the upper chromosphere. The outer region of the corona stretches far into space and consists of particles traveling slowly away from the Sun. The corona can only be seen during total solar eclipses.

The Sun appears to have been active for 4.6 billion years and has enough fuel to go on for another five billion years or so. At the end of its life, the Sun will start to fuse helium into heavier elements and begin to swell up, ultimately growing so large that it will swallow the Earth. After a billion years as a red giant, it will suddenly collapse into a white dwarf -- the final end product of a star like ours. It may take a trillion years to cool off completely.

D. MOON

Name & Etymology

The English proper name for Earth's natural satellite is "the Moon". The noun moon derives from moone (around 1380), which developed from mone (1135), which derives from Old English mōna (dating from before 725), which, like all Germanic language cognates, ultimately stems from Proto-Germanic.

The principal modern English adjective pertaining to the Moon is lunar, derived from the Latin Luna. Another less common adjective is selenic, derived from the Ancient Greek Selene from which the prefix "seleno-" (as in selenography) is derived.

Physical characteristics

Internal structure:

The Moon is a differentiated body: it has a geochemically distinct crust, mantle, and core. The Moon has a solid iron-rich inner core and a fluid outer core primarily made of liquid iron. Around the core is a partially molten boundary layer. his structure is thought to have developed through the fractional crystallization of a global magma ocean shortly after the Moon's formation 4.5 billion years ago. The Moon is the second densest satellite after Io, a satellite of Jupiter.

The Moon is the only natural satellite of the Earth, and the fifth largest satellite in the Solar System. It is the largest natural satellite of a planet in the Solar System relative to the size of its primary, having a quarter the diameter of Earth but only 1⁄81 it’s mass. The Moon is the only celestial body other than Earth on which humans have set foot.The Moon travels around Earth in an oval orbit at 36,800 kilometers per hour. The Moon does not have an atmosphere, so temperatures range from -184 degrees Celsius during its night to 214 degrees Celsius during its day except at the poles where the temperature is a constant -96 degrees Celsius.

The Moon is actually a little lopsided due to the lunar crust being thicker on one side than the other. When you look at the Moon, you will see dark and light areas. The dark areas are young plains called maria and are composed of basalt. The basalt flowed in and flooded the area created by a huge impact with an asteroid or comet. The light areas are the highlands, which are mountains that were uplifted as a result of impacts. The lunar surface is covered by a fine-grained soil called “regolith” which results from the constant bombardment of the lunar rocks by small meteorites.

Scientists theorize that the Moon was the result of a collision between Earth and an object the size of Mars. One theory states that the debris from the impact was hurtled into space where, due to gravity, it combined. This resulted in the formation of the Moon.

The gravitational pull of the Moon on the Earth affects the ocean tides on Earth. The closer the Moon is to Earth, the greater the effect. The time between high tides is about 12 hours and 25 minutes.

Moon’s Phases

Although this cycle is a continuous process, there are eight distinct, traditionally recognized stages, called phases. The phases designate both the degree to which the Moon is illuminated and the geometric appearance of the illuminated part. These phases of the Moon, in the sequence of their occurrence (starting from New Moon), are listed below

(1) New Moon - When the Moon is roughly in the same direction as the Sun, its illuminated half is facing away from the Earth, and therefore the part that faces us is all dark: we have the new moon. When in this phase, the Moon and the Sun rise and set at about the same time.

(2) Waxing Crescent Moon - As the Moon moves around the Earth, we get to see more and more of the illuminated half, and we say the Moon is waxing. At first we get a sliver of it, which grows as days go by. This phase is called the crescent moon.

(3) Quarter Moon - A week after the new moon, when the Moon has completed about a quarter of its turn around the Earth, we can see half of the illuminated part; that is, a quarter of the Moon. This is the first quarter phase.

(4) Waxing Gibbous Moon - During the next week, we keep seeing more and more of the illuminated part of the Moon, and it is now called waxing gibbous (gibbous means "humped").

(5) Full Moon - Two weeks after the new moon, the moon is now halfway through its revolution, and now the illuminated half coincides with the one facing the Earth, so that we can see a full disk: we have a full moon. As mentioned above, at this time the Moon rises at the time the Sun sets, and it sets when the Sun rises. If the Moon happens to align exactly with the Earth and Sun, then we get a lunar eclipse.

(6) Waning Gibbous Moon - From now on, until it becomes new again, the illuminated part of the Moon that we can see decreases, and we say it's waning. The first week after full, it is called waning gibbous.

(7) Last Quarter Moon - Three weeks after new, we again can see half of the illuminated part. This is usually called last quarter.

(8) Waning Crescent Moon - Finally, during the fourth week, the Moon is reduced to a thin sliver from us, sometimes called waning crescent.

E. TIDES

The rise and fall of sea levels caused by the combined effects of the gravitational forces exerted by the Moon and the Sun and the rotation of the Earth. (Regular rising and falling of the ocean's surface)

Kinds of Tides

Tidal Variations

The moon's gravity affects each object on and in the Earth. When gravitational forces act on the Earth, objects distort, including water and the Earth itself. Oceans distort in the form of two tidal bulges. Oceans on the side of the Earth closest to the moon exhibit a large tidal bulge. Oceans on the opposite side of the planet also exhibit a smaller tidal bulge, as the moon's gravitational pull moves the Earth toward the moon and away from the water. As the Earth rotates under these two bulges, any coastline on the planet's surface generally experiences two high tides and two low tides during each full rotation. Of course, there are exceptions to this simplistic model.

Spring Tides

One complicating factor that creates different types of tides is the sun's gravitational pull. When the moon is in its new and full phases, the Earth, moon and sun are aligned in a formation that adds the sun's gravitational pull to the moon's gravitational pull. This phenomenon, known as spring tide, results in higher-than-normal high tides and lower-than-normal low tides.

Neap Tides

When the moon is in its first and third quarters, the sun and moon are aligned at right angles to the Earth. Because the sun's gravitational pull works against the moon's pull in this alignment,

both high tides and low tides are weaker. This phenomenon is known as neap tide. Spring tides and neap tides alternate at 1-week intervals.

Perigean Tides

Like other heavenly bodies, the moon's orbit around the Earth is elliptical. Once each month, the moon passes by the Earth at perigee, which is about 30,000 miles closer than at apogee, or the furthest point in orbit. When spring tides and perigee align, the moon's extra-strong pull results in unusually high tides, known as perigean tides. Perigean tides take place at intervals that are slightly longer than six months, according to the Woods Hole Oceanographic Institution.

Semi-diurnal tide (Semidaily Tides)

Have a single high tide and a single low tide per day. When two high and two low tides of the same height take place in a lunar day, it's called a

semi-diurnal tide. Semi-diurnal tidal periods are 12 hour and 25 minutes long. Most coastlines experience semi-diurnal tides.

Mixed tide

When heights of two successive high tides or low tides are markedly different.

Higher high water tide (HHW), lower high water tide (LHW), higher low water ide (HLW), & lower low water tide (LLW)

Mixed tides consist of two high tides and two low tides of varied heights during a lunar day. Most open coastlines, such as the west coast of the U.S., experience mixed tides.

Diurnal tide (Daily Tides)

Have two high tides and two low tides of approximately equal height each tidal day.

May have daily inequity, where successive high tides have different heights. Easy to predict because high (or low) tides occur a consistent length of time after the moon has

passed overhead. If one high tide and one low tide take place in a lunar day, it's known as a diurnal tide. Diurnal

tides create 24-hour, 50-minute tidal periods. Oceans in partially enclosed basins, such as the Caribbean and the Gulf Coast of the U.S. often experience diurnal tides.

Characteristics

Tide changes proceed via the following stages:

Sea level rises over several hours, covering the intertidal zone; flood tide. The water rises to its highest level, reaching high tide. Sea level falls over several hours, revealing the intertidal zone; ebb tide. The water stops falling, reaching low tide.

Tidal streams

Oscillating currents produce by tides.

Slack water or slack tide

The moment that the tidal current ceases. Occurs near high water and low water.

Tidal constituents

Tidal changes

Are the net result of multiple influences that act over varying periods. These influences are called tidal constituents.

NOTE: Variations with periods of less than half a day are called harmonic constituents. Conversely, cycles of days, months, or years are referred to as long period constituents.

Principal lunar semi-diurnal constituent

Largest constituent Also known as the M2 (or M2) tidal constituent Lasted 12 hours and 25.2 minutes, exactly half a tidal lunar day

NOTE:

1. Lunar day is longer than the Earth day because the Moon orbits in the same direction the Earth spins. This is analogous to the minute hand on a watch crossing the hour hand at 12:00 and then again at about 1:05½ (not at 1:00).

2. When there are two high tides each day with different heights (and two low tides also of different heights), the pattern is called a mixed semi-diurnal tide.

Range variation: springs and neaps

The Sun, Moon and Earth form a line (a condition known as syzygy) the tidal force due to the sun reinforces that due to the Moon. The tide's range is then at its maximum: this is called the spring tide, or just springs. It is not named after the season but, like that word, derives from the meaning "jump, burst forth, rise", as in a natural spring.

Lunar altitude

The changing distance separating the Moon and Earth also affects tide heights. When the Moon is closest, at perigee, the range increases, and when it is at apogee, the range shrinks. Every 7½ lunations (the full cycles from full moon to new to full), perigee coincides with either a new or full moon causing perigean spring tides with the largest tidal range. Even at its most powerful this force is still weak[9] causing tidal differences of inches at most

Bathymetry

The shape of the shoreline and the ocean floor changes the way that tides propagate, so there is no simple, general rule that predicts the time of high water from the Moon's position in the sky.

Other constituents

These include solar gravitational effects, the obliquity (tilt) of the Earth's equator and rotational axis, the inclination of the plane of the lunar orbit and the elliptical shape of the Earth's orbit of the sun.

A compound tide (or over tide) results from the shallow-water interaction of its two parent waves.

PROJECT IN

PHYSICAL SCIENCE

(PLANET)

Submitted by: Calma, Liahona Jaen I.Dimaano, Jorgie AnnDuyog, NeliaLuna, Zaira ShaneSuico, Gabrielle

Submitted to: Ms. Miriam Rañola