The Sun is the Most Prominent Feature in Our Solar System

8/8/2019 The Sun is the Most Prominent Feature in Our Solar System

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The Sun 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 6,000C (11,000F). This layer has a mottled

appearance due to the turbulent eruptions of energy at the surface.

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.

Sun Statistics

Mass (kg)1.989e+30

Mass (Earth = 1)332,830

Equatorial radius (km)695,000

Equatorial radius (Earth = 1)108.97

Mean density (gm/cm^3)1.410

Rotational period (days)25-36*

Escape velocity (km/sec)618.02

Luminosity (ergs/sec)3.827e33

Magnitude (Vo)-26.8

Mean surface temperature6,000C

Age (billion years)4.5

Mercury

Mercury was named by the Romans after the fleet-footed messenger of the gods because it seemed to

move more quickly than any other planet. It is the closest planet to the Sun, and second smallest planet

in the solar system. Its diameter is 40% smaller than Earth and 40% larger than the Moon. It is even

smaller than Jupiter's moon Ganymede and Saturn's moon Titan.


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Mercury could not support water in any form. It has very little atmosphere and is blazing hot during the

day, but in 1991 scientists at Caltech bounced radio waves offMercury and found an unusual bright

return from the north pole. The apparent brightening at the north pole could be explained by ice on or

just under the surface. But is it possible forMercury to have ice? BecauseMercury's rotation is almost

perpendicular to its orbital plain, the north pole always sees the sun just above the horizon. The insides

of craters would never be exposed to the Sun and scientists suspect that they would remain colder than

-161 C. These freezing temperatures could trap water outgassed from the planet, or ices brought to the

planet from cometary impacts. These ice deposits might be covered with a layer of dust and would still

show bright radar returns.

Mercury Statistics

Mass (kg)3.303e+23

Mass (Earth = 1)5.5271e-02

Equatorial radius (km)2,439.7

Equatorial radius (Earth = 1)3.8252e-01


Mean distance from the Sun (km)57,910,000

Mean distance from the Sun (Earth = 1)0.3871

Rotational period (days)58.6462

Orbital period (days)87.969

Mean orbital velocity (km/sec)47.88

Orbital eccentricity0.2056

Tilt of axis (degrees)0.00

Orbital inclination (degrees)7.004

Equatorial surface gravity (m/sec^2)2.78

Equatorial escape velocity (km/sec)4.25

Visual geometric albedo0.10

Magnitude (Vo)-1.9

Mean surface temperature179C


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Maximum surface temperature427C

Minimum surface temperature-173C

Venus

Venus, thejewel of thesky, was once know by ancient astronomers as

the morningstar and eveningstar. Early astronomers once thought Venus to be two separate bodies.

Venus, which is named after the Roman goddess of love and beauty, is veiled by thick swirling cloud

cover. Astronomers refer to Venus as Earth's sister planet. Both are similar in size, mass, density and

volume. Both formed about the same time and condensed out of the same nebula. Venus is scorched

with a surface temperature of about 482 C (900 F). This high temperature is primarily due to a

runaway greenhouse effect caused by the heavy atmosphere of carbon dioxide. Sunlight passes through

the atmosphere to heat the surface of the planet. Heat is radiated out, but is trapped by the dense

atmosphere and not allowed to escape into space. This makes Venus hotter thanMercury.

Venus Statistics

Mass (kg)4.869e+24

Mass (Earth = 1).81476


Equatorial radius (Earth = 1).94886




Rotational period (days)-243.0187







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Magnitude (Vo)-4.4


Atmospheric pressure (bars)92

Earth

Earth is the 3rd planet from the Sun at a distance of about 150

million kilometers (93.2 million miles). It takes 365.256 days for the Earth to travel around the Sun and

23.9345 hours for the Earth rotate a complete revolution. It has a diameter of 12,756 kilometers (7,973

miles), only a few hundred kilometers larger than that of Venus. Our atmosphere is composed of 78

percent nitrogen, 21 percent oxygen and 1 percent other constituents.

Besides affecting Earth's weather, solar activity gives rise to a dramatic

visual phenomenon in our atmosphere. When charged particles from the solar wind become trapped in

Earth's magnetic field, they collide with air molecules above our planet's magnetic poles. These air

molecules then begin to glow and are known as the auroras or the northern and southern lights.

Earth Statistics

Mass (kg)5.976e+24

Mass (Earth = 1)1.0000e+00


Equatorial radius (Earth = 1)1.0000e+00





Rotational period (hours)23.9345



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Atmospheric pressure (bars)1.013

Mars

Mars is the fourth planet from the Sun and is commonly

referred to as the Red Planet. The rocks, soil and sky have a red or pink hue. The distinct red color was

observed by stargazers throughout history. It was given its name by the Romans in honor of their god of

war. Other civilizations have had similar names. The ancient Egyptians named the planet Her Descher

meaning the red one.

Before space exploration, Mars was considered the best candidate for harboring

extraterrestrial life. Astronomers thought they saw straight lines crisscrossing its surface. Thisled to the popular belief that irrigation canals on the planet had been constructed by intelligent

beings. In 1938, when Orson Welles broadcasted a radio drama based on the science fictionclassic War of the Worlds by H.G. Wells, enough people believed in the tale of invading

Martians to cause a near panic.

Another reason for scientists to expect life on Mars had to do with the apparent seasonal color

changes on the planet's surface. This phenomenon led to speculation that conditions mightsupport a bloom of Martian vegetation during the warmer months and cause plant life to become

dormant during colder periods.

Mars Statistics

Mass (kg)6.421e+23

Mass (Earth = 1)1.0745e-01


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Equatorial radius (Earth = 1)5.3264e-01














Magnitude (Vo)-2.01

Minimum surface temperature-140C

Mean surface temperature-63C

Maximum surface temperature20C


Jupiter

Jupiter is the fifth planet from the Sun and is the largest planet in the solar system. If Jupiter were

hollow, more than one thousand Earths could fit inside. It also contains two and a half times the mass of

all the other planets combined. It has a mass of 1.9 x 1027

kg and is 142,800 kilometers (88,736 miles)

across the equator. Jupiter possesses 62 known satellites. The four largest are Callisto, Europa,

Ganymede and Io, and were named after Galileo Galilei who observed them as long ago as 1610. The


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German astronomer SimonMarius claimed to have seen the moons around the same time, but he did

not publish his observations and so Galileo is given the credit for their discovery.

Jupiter has a very faint ring system, but is totally invisible from the Earth. (The

rings were discovered in 1979 by Voyager 1.) The atmosphere is very deep, perhaps comprising the

whole planet, and is somewhat like the Sun. It is composed mainly of hydrogen and helium, with smallamounts of methane, ammonia, water vapor and other compounds. At great depths within Jupiter, the

pressure is so great that the hydrogen atoms are broken up and the electrons are freed so that the

resulting atoms consist of bare protons. This produces a state in which the hydrogen becomes metallic.

Jupiter Statistics

Mass (kg)1.900e+27

Mass (Earth = 1)3.1794e+02















Magnitude (Vo)-2.70

Mean cloud temperature-121C


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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).Much of what is known about the planet is due to the

Voyager explorations in 1980-81. Saturn is visibly flattened at the poles, a result of the very fast rotation

of the planet on its axis. Its day is 10 hours, 39 minutes long, and it takes 29.5 Earth years to revolve

about the Sun. The atmosphere is primarily composed of hydrogen with small amounts of helium and

methane. Saturn is the only planet less dense than water (about 30 percent less). In the unlikely event

that a large enough ocean could be found, Saturn would float in it. Saturn's hazy yellow hue is marked

by broad atmospheric banding similar to, but fainter than, that found on Jupiter.

Saturn Statistics

Mass (kg)5.688e+26

Mass (Earth = 1)9.5181e+01




Mean distance from the Sun (km)1,429,400,000



Orbital period (years)29.458








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Magnitude (Vo)0.67



Uranus

Uranus is the seventh planet from the Sun and is the third largest in the solar system. It

was discovered by William Herschel in 1781. It has an equatorial diameter of 51,800 kilometers (32,190

miles) and orbits the Sun once every 84.01 Earth years. It has a mean distance from the Sun of 2.87

billion kilometers (1.78 billion miles). It rotates about its axis once every 17 hours 14 minutes. Uranus

has at least 22 moons. The two largest moons, Titania and Oberon, were discovered by William Herschel

in 1787.

The atmosphere ofUranus is composed of 83% hydrogen, 15% helium, 2% methane and

small amounts of acetylene and other hydrocarbons.Methane in the upper atmosphere absorbs red

light, giving Uranus its blue-green color.

Uranus Statistics

Discovered byWilliam Herschel

Date of discovery1781

Mass (kg)8.686e+25

Mass (Earth = 1)1.4535e+01






Rotational period (hours)-17.9



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Magnitude (Vo)5.52



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 was discovered on September 23, 1846 by Johann

Gottfried Galle, of the Berlin Observatory, and Louis d'Arrest, an astronomy student, through

mathematical predictions made by Urbain Jean Joseph Le Verrier.

Neptune is a dynamic planet with several large, dark spots reminiscent ofJupiter's

hurricane-like storms. The largest spot, known as the Great Dark Spot, is about the size of the earth and

is similar to the Great Red Spoton Jupiter. Voyager revealed a small, irregularly shaped, eastward-

moving cloud scooting around Neptune every 16 hours or so. This scooteras it has been dubbed could

be a plume rising above a deeper cloud deck.

Neptune Statistics

Discovered byJohann Gotfried Galle

Date of discoverySeptember 23, 1846


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Pluto is usually farther from the Sun than any of the eight planets; however, due to the eccentricity of its

orbit, it is closer than Neptune for 20 years out of its 249 year orbit. Pluto crossed Neptune's orbit

January 21, 1979, made its closest approach September 5, 1989, and remained within the orbit of

Neptune until February 11, 1999. This will not occur again until September 2226.

Pluto Statistics

Discovered byClyde W. Tombaugh

Date of discoveryFebruary 18, 1930

Mass (kg)1.27e+22

Mass (Earth = 1)2.125e-03





Mean distance from the Sun (Earth = 1))39.5294

Rotational period (days)-6.3872









Magnitude (Vo)15.12


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manned missions to date, beginning with the first manned lunar orbiting mission byApollo 8 in 1968, and six manned lunar landings between 1969 and 1972the first being

Apollo 11 in 1969. These missions returned over 380 kg oflunar rocks, which have beenused to develop a detailed geological understanding of the Moon's origins (it is thought to

have formed some 4.5 billion years ago in a giant impact), the formation ofits internal

structure, and its subsequent history.

TheMoon is a differentiated body: it has a geochemically distinct crust, mantle, and core. This

structure is thought to have developed through the fractional crystallization of a global magma ocean

shortly after theMoon's formation 4.5 billion years ago.[23] Crystallization of this magma ocean would

have created a mafic mantle from the precipitation and sinking of the minerals olivine, clinopyroxene,

and orthopyroxene; after about three-quarters of the magma ocean had crystallised, lower-density

plagioclase minerals could form and float into a crust on top.[24]

The final liquids to crystallise would

have been initially sandwiched between the crust and mantle, with a high abundance ofincompatible

and heat-producing elements.[1]

Consistent with this, geochemical mapping from orbit shows the crust is

mostly anorthosite,[5]

and moon rock samples of the flood lavas erupted on the surface from partial

melting in the mantle confirm the mafic mantle composition, which is more iron rich than that of

Earth.[1]

Geophysical techniques suggest that the crust is on average ~50 km thick.[1]

The Sun is the Most Prominent Feature in Our Solar System

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