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Grandpa Pencil
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Solar System


The Solar System

Our solar system consists of one star, the Sun, eight major planets, their moons and thousands of smaller bodies including asteroids, comets and meteors.
Until 2006 there were assumed to be nine planets though in that year Pluto was excluded because it shares Neptune's orbit for a part of the time.
A planet must have a unique orbit according to the scientific community. though I don't think the Plutonians will be too impressed with the decision.
The Sun is the only body in our solar system that has any light of its own with the rest simply reflecting its rays.

The Sun

 

The Sun is one of the smaller known stars and is made up of a mass of hot gasses.

More than a million times larger than Earth, the Sun is nearly 300 000 times as heavy.

Light from the Sun takes around eight and a half minutes to reach Earth where rays from our next nearest star, Proxima Centauri, takes more than 4 years.

The Sun's surface is estimated to be 10 800 F and is called the photosphere and is surrounded by a crimson gas called chromosphere.

The Sun provides us with the light and heat that is essential to our existence as well as providing us with a gravitational anchor that helps us retain those essentials.

Mercury
Distance
from Sun
(million km)
Diameter
at equator
(km)
Gravity
(Earth = 1)
58
4 991
0.27

Mercury is the smallest of the known planets of our Solar System and is less than half the size of Earth.
It is the nearest planet to the Sun and travels in an elongated orbit around the Sun taking 88 Earth days.

It was considered at one time that one side of Mercury always faces the Sun and its surface reaches temperatures of up to 380 C whilst the other side is intensely cold. This is incorrect.

In its early days Mercury's gravity was unable to hold onto its gasses and they boiled off. The planet, then, has no real atmosphere except for a few traces of carbon dioxide.

Mercury has no moons.

Venus
Distance
from Sun
(million km)
Diameter
at equator
(km)
Gravity
(Earth = 1)
108
12 397
0.86

The second planet from the Sun is Venus which is much the same size as the Earth.

After sunset Venus is known as the Evening Star and just before sunrise as the Morning Star.

Scientists cannot determine the actual length of a Venus day because the planet is constantly covered by dense cloud though it is estimated to be around 30 Earth days.

Venus is the bright white 'star' that is the first to appear after sunset, long before any other star is visible.

Venus has no moons.

Earth
Distance
from Sun
(million km)
Diameter
at equator
(km)
Gravity
(Earth = 1)
150
12 761
1

As beautiful as it is, Earth is not the 'centre of the universe'. It is simply one of the smaller planets in our Solar System.

Although it does maintain intelligent life I believe it would be most unintelligent of us to just assume that it is the only such body in the vastness of the Universe.

Earth is the third planet from the Sun and over two thirds of its surface is covered with water. Its atmosphere, composed mainly of oxygen and nitrogen, results in the relatively moderate temperature range over much of the planet.

Earth has one moon.

Mars
Distance
from Sun
(million km)
Diameter
at equator
(km)
Gravity
(Earth = 1)
228
6 762
0.37

The forth planet from the sun is Mars which is just over one tenth the size of Earth.

Mars takes 687 Earth days to circle the Sun and it revolves on its axis each 24 1/2 hours. It has seasons just as on Earth, though they are around twice as long as ours.

At its equator the planet's temperatures reach almost 27C with its nights being extremely cold.

Mars is considered the planet, apart from Earth, most likely to support life as we know it.

The planet's atmosphere is made up of a small amount of oxygen with most of the rest being nitrogen.

Mars has two moons: Phobos and Deimos.

Jupiter
Distance
from Sun
(million km)
Diameter
at equator
(km)
Gravity
(Earth = 1)
778
142 807
2.64

Jupiter is the fifth planet out from the Sun and is the giant of the solar system.

Jupiter's atmosphere is made up mainly of hydrogen, methane, and ammonia with an average temperature of minus 130 C and is divided into several broad bands each moving at different speeds.

The bands are constantly changing colour but their number always remains the same.

Although the surface can not be examined by telescope, because of the dense cloud cover, scientists claim that the surface is covered by a layer of ice that is possibly 27 000 Km thick.

Jupiter has 12 moons including Amalthea, Lo, Europa, Ganymede and Callisto with the rest unnamed.

Saturn
Distance
from Sun
(million km)
Diameter
at equator
(km)
Gravity
(Earth = 1)
1 427
120 900
1.17

Saturn is the sixth planet out from the sun and is the one with the rings around it.

Although Saturn is some 750 times bigger than Earth its gravitational force is only marginally greater (1.17 times) as it is not packed as tightly as Earth.

The atmosphere is similar to that of Jupiter made up mainly of hydrogen, methane and ammonia below which is a deep layer of ice.

Saturn's three rings measure over 273 000 Km edge to edge and between 16 and 64 Km deep and are believed to consist of small pieces of ice encrusted rock.

Saturn has nine moons including Mimas, Enceladus, Tethys, Dione, Rhea, Titan, Hyperion,Iapetus and Phoebe. Titan, a massive 5 630 Km in diameter, is believed to be the only moon to possess its own gravity.

Uranus
Distance
from Sun
(million km)
Diameter
at equator
(km)
Gravity
(Earth = 1)
2 870
47 173
0.92

Seventh out from the Sun is Uranus which, although it can just be seen with the naked eye, was only discovered in 1781 Seen through a telescope Uranus is a pale green disk without distinct surface markings.

The axis of Jupiter is deeply tilted and where Earth is tilted by twenty three and a half degrees, Jupiter is ninety eight degrees.

One result of this tilting is that the planet is often seen end on with its north pole toward us and its moons appear to act strangely.

Uranus has an extremely poisonous methane atmosphere and surface temperatures of minus 190 C.

The planet's five moons are Miranda, Ariel, Umbriel, Titania and Oberon.

Neptune
Distance
from Sun
(million km)
Diameter
at equator
(km)
Gravity
(Earth = 1)
4 503
44 597
1.44

Eighth out from the Sun, Neptune is another of the giant planets and was discovered in 1846.

Scientists were attempting to explain the irregular movements of Uranus that could only be explained by the existence of another planet.

Neptune takes some 165 years to orbit the Sun and has an atmosphere of mainly methane with clouds of ammonia crystals. Neptune has two moons called Triton and Nereid.

Pluto
(No longer considered to be a planet)
Distance
from Sun
(million km)
Diameter
at equator
(km)
Gravity
(Earth = 1)
5 909
5 796
?

Predicted by the astronomer, Lowell, in 1905 it was not until 1930 that Pluto was actually observed by Clyde Tombaugh.

Pluto takes around 250 years to orbit the Sun and as a result of its highly elliptical orbit is occasionally closer to the Sun than Neptune leading some astronomers to presume that it is not a planet but a breakaway, rogue moon of Neptune.

Little is known of Pluto though it is believed to be extremely cold and have no moons.



     

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