Aussie Space Portal



    What Is Astronomy?

    How Far Is It? What's Out There?

    What's Close? What's Far Out?

    The Sun - Too Hot To Handle

    A Guide To The Inner Planets

    A Guide To The Outer Planets

    Stars, Clusters, Galaxies and Dust

    What Is Astronomy?

      *Astronomy is the Science that study's objects in the sky. the Babylonians, Greeks and Romans used to watch how the stars moved across the sky each night and the changes over the year. They gave the patterns the stars made names and made stories about them. They also named the visible planets that moved across the stars. It was not until modern times that Astronomers started to find out more about what the stars and the planets are and what they were.

      *Telescopes made these discoveries much easier to make because they could magnify far off objects and show the detail in them.

      *You can use your eyes. With your eyes you can see a great number of objects in the night sky. Nearly all the bright stars such Sirius, Procyon, Altiar and Betelgeuse can be seen in the sky at some time during the year.

      *The Constellations, that is the pattern the Stars make in the sky, make it easy and fun to find stars and other objects at night. Some interesting Constellations are Orion, Scorpius, Taurus, Crux (The Southern Cross) and Centaurus. As the Earth moves around the Sun some constellations will disappear into the setting sun but a few months later can be seen in the early morning sky.

      *With Binoculars a greater amount of objects can be seen, these are star clusters, Nebulas and some galaxies. These objects are very faint and need a dark sky to be seen.

      *Telescopes make it possible to see very faint and distant objects. The bigger the telescope the more detail can be seen in the object. some will be able to show double Stars (Binary), surface features of the Planets, and the fainter Nebulae and Galaxies.

      You can travel far out into the country or out to the back yard. The sky can be a very busy place and out in the back yard of your house it can be very difficult to find some objects. The best way to see any thing from the back yard is to stand in the dark for a while with none of the garden lights on. This will help your eyes adapt to the dark and make it possible to see fainter things. Make sure the street lights or neighbourís lights are not coming over the fence either.

      However, the best place to see the stars, the milky Way, galaxies or other faint objects, is to be far out in the country. That is away from Cities, Towns, Street and Highway lighting, car head lights and house lighting. It is then you will see how crowded the sky really is and with your eyes, binoculars or telescopes will make many more objects easily seen.

    How far Is It? Whatís Out There?

      Most things in the sky are very far away and because of this the planets need to be seen through a telescope to see any detail. The Stars also because of the vast distances will always be seen as small dots of very bright light. The moon is the closest object we can see in space. it is easy to see the craters and the mountains with a small Telescope. However it is still a long way to the moon.

      From the Earth to the Moon is 384,400 Kmís. To make it easier for every one to try to understand the distance's astronomers donít use Miles or Kilometres much at all. They use measurement like Astronomical Units, Light Years and Parsecís.

      An Astronomical Unit is used to measure the distance of the planets. It is 149,597,870 Km's. It is also the mean distance of the Earth to the Sun as the earth compared to the outer planets is very close to the Sun.

      A Light Year is used to measure the distance of the Stars. It is the distance light travel in one year. 299,792,458 Kmís a Second by 60 Seconds by 60 Minutes by 24 hours by 365 days = 9,465,254,955,488,000 Kmís.

    Whatís Close? Whatís Far Out?

    • Alpha Centaurus is- 4.2 l,yís away from Earth, This is the nearest Star system.

    • Sirius (Canis Major) is- 8.7 l,y from Earth., The brightest star in our Sky.

    • Acrux (Southern Cross)- 360 l,y away from Earth., Most seen star to us.

    • The Orion Nebula- 1,300 l.y away from Earth., An easily seen Nebular.

    • The Pleiades (Taurus)- 4,151l,y away from Earth., The Seven Sisters.

    • Centre of Milky Way - 18,000 l,y away from Earth., Our Galaxy.

    • The large Magellanic cloud - 230,000 l,y from Earth., A near by Galaxy.

    • The Andromeda Galaxy (M30) is - 2,200,000 l,y away, Nearest large Galaxy to the milky way galaxy.

    • Quasarís are - 15,000,000,000 l,y away, Furthest objects to be seen.

    The Sun - To Hot To Handle

      The Sun is the centre of the Earthís orbit and every other planet in our solar system. It heats and provides energy to our World and the other Planets. It makes the Weather and gives us day light, keeps us healthy and helps plants to grow. We can also tell the time by where the sun is in the sky and we can tell what month it is by what constellations set with and rise with it.

    Some Facts.

    • The mean distance from the Sun to the Earth is 149,597,870 Kmís.

    • Solar Radius 696.000 Kmís, 109 times larger than the Earth.

    • Luminosity of the Sun is 3.83 x 1026 Watts.

    • Surface Temperature is 5,800 K.

    A Guide To The Inner Planets

    • Mercury, The inner most planet, hot & cold, .39 AU from sun., 4878 Kmís wide.

    • Venus, Like the Earth except hot and Smelly, .72 AU, 12,100 Km,s wide.

    • Earth, Our own world, Mostly harmless, 1 AU, 12,756 Kmís wide.

    • Moon, A Grey, lonely place, 1738 Kmís wide 384,402 Mean Kmís away.

    • Mars, Smaller than Earth, cold, hard getting a drink or a breath, 1.52 AU, 6,762 Km,s wide.

    • Phoebes & Demos, The Moon s of Mars, 9000-23,000 above Mars, 5-13.5 Kmís wide.

    A Guide To The Outer Planets

    • Jupiter. Big , hungry and red eyed, 5.2 AU from Sun, 142,000 Km,s wide.

    • Saturn, Elise gave him a ring, 9.54 AU from Sun, 120,800 Km,s wide.

    • Uranus, Very cool ,very windy, 19.18 AU from Sun., 51,800 Km,s wide.

    • Neptune, A deferent angle, 30.06 AU from Sun, 49,400 Km,s wide.

    • Pluto & Charon, Two far out cool dudes, 39.4 AU from Sun., 3,500 Km,s wide.

    • Asteroids, Rock and role, 2.2-13.7 AU from Sun, 30M to 300Km,s wide.

    • Comets, Small bodies Big show-offís, .3 AU to 1 l,y, 1-50 Km,s wide.

    A Guide To Stars, Clusters, Galaxies, and Dust

    • Binary Stars. Two Stars that orbit a point around each other.

    • Giant Blue Stars, Live fast, Die Young, Will turn in to a super nova.

    • Medium Yellow Stars. Small and common type of star, Our Sun.

    • Giant Red Stars. Old star on the way out, Can get very large.

    • White Dwarf Stars. Very old star left after Red giant.

    • Neutron stars & Pulsars, Very Small Stars left after Super Novaís.

    • Novas & Super Novas, Extremely large Explosions of heavy or dying Stars.

    • Nebulas and clouds, Dust left over after Super Novaís or turning into stars.

    • Globule and Open Clusters, Groups of stars orbiting the Galaxy.

    • Spiral and Elliptical Galaxies, Types of Galaxies in that shape.

    • Celestial poles and Equator, Earth features extended into space.

    • Radio Galaxies, A galaxy that puts out large amounts of radio noise.

    • Quasars, The Furthest things, Puts out a lot of all types of energy.

    • Ecliptic, A strip of the sky the planets move through.

    • Twilight, Light on the upper atmosphere after sun set, it can last an hour.

    • The Universe, Every thing that is Known of.

    Presented by Jim Dale


    History Of Astromony

    A Light Outing

    Astronomy Links

    Mars June Calender

    Have You A Question on Astronomy - 
Ask Jim, Our Star Man