Stars come in varying sizes, temperatures, and ages and are basically giant balls of exploding hydrogen and helium. Our Sun is an averaged sized, middled aged yellow Dwarf Star.

 

A star's surface temperatures usually ranges between 2,500 and 40,000°C. We are able to discover the temperature and age of many distant stars merely by observing their colour with the naked eye. The cooler, older stars appear red whereas the hotter, younger stars look blue.

 

A star's colour ranges from red to orange, yellow, white, bluish-white, and blue the hottest. However, other stars such as Protostars and brown dwarfs, may emit energy beyond the visible spectrum in the form of infrared radiation.

 

 

 

 

Betelgeuse in Orion is a fine example of a red supergiant star. Arcturus in Boötes appears orange, Capella in Auriga is a yellow star,  Sirius B in Canis Major is white, and Rigel in Orion is a an extremely hot blue supergiant about 100 times bigger than our sun.

 

 

 The Solar System

 

Our Solar system consists of 8 planets orbiting a yellow star or to give it its Roman name 'Sol."

Planet      Size  Colour     Moons  Temp  (oC)    Atmosphere Earth Day  Earth Year Mercury    8th    orange       0         465 to - 184    hydrogen, helium 59 days   88 days Venus       7th    yellow        0         449                CO2, nitrogen 243 days 225 days  Earth        5th    blue           1         7.2                 nitrogen, oxygen 24 hours 365 days Mars         6th    red            2         36 to -123       CO2, nitrogen 24:39hrs 687 days Jupiter     1st    orange       50       -153                hydrogen, helium 9:55hrs 12 years Saturn      2nd   yellow        61       -184                hydrogen, helium 10:40hrs 29.5 years Uranus     3rd    blue           27       -184                hydrogen, helium 17:24hrs 84 years Neptune   4th    blue          13        -223                hydrogen, helium 16hrs 165 years