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The Planets/ Solar System |
What is it?
The ancients thought the planets were wandering stars, but they are of course cold bodies within our solar system.
Whilst there are countless numbers of solar systems, we don’t have a name for our own system, but we do have names for other stars like Alpha Centauri. The planets in out solar system are believed to
have condensed out of the the interstellar dust as our sun was forming around 4.5 billion years ago. Several planets are visible with naked eye, but all can be seen
much better with a telescope (and some with binoculars)
The Science
Our sun is a second generation star made from a mixture of the primeval hydrogen and helium (that was created at the start of
the Universe in the Big Bang - according the prevailing theory of cosmology), and heavier elements up to iron that were created in the stellar furnaces of the first generation stars, plus even heavier
elements that are created when stars go supernova. The massive outermost gas planets like Jupiter help to herd the remaining heavier dust into rocky planets like the earth, and a whole bunch of bits
were left without forming a planet - between the earth and mars - forming the asteroid belt.
Water ice and carbon based dust coalesced into bodies that form comets. These bodies are small and insignificant
until their orbits become highly elliptical causing them to come close to the sun - then they get interesting as the sun’s radiation (heat) boils off vapour which
forms a tail - pointing away from the sun, following the solar wind.
Comet tails and pieces of asteroids give us meteor showers or meteorites if the bits are big enough and survive to hit the earth’s surface
Basic Data Sheet for the Solar System
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Member
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Diamete r
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Mass
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Temperatu re
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Sun
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1.392 x 106 km
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1.989 x 1030 kg
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5,700o K
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Mercury
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4,878 km
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0.0553 x earth
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100 - 800o K
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Venus
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12,104 km
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0.8149 x earth
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750o K
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Earth
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12,756 km
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5.976 x 1024 kg
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290o K
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Asteroid s
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< 1,000 km
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Mars
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6,760 km
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6.42 x 1023 kg
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220o K
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Jupiter
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139,000 km
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1.90 x 1027 kg
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125o K
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Saturn
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113,000 km
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5.69 x 1026 kg
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95o K
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Uranus
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50,000 km
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14.53 x earth
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55o K
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Neptune
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49,000 km
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17.14 x earth
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55o K
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Pluto
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2,300 km
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0.0021 x earth
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45o K
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