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Are we alone?

earthriseDesign your own planet

This is your opportunity to design your own planet!! There's lots to think about:

  • What kind of star will your planet orbit? One star or two? A small, dying star or a young bright star?
  • What colour will your star be? Generally, larger, bluer stars are hotter than smaller, redder ones. So if you have a large, blue star your planet will need to be further away from its star.
  • Will your planet have a moon like Earth? Or will it have lots of moons, like Jupiter and Saturn, or no moon at all?
  • How big will it be - small like Mercury, huge like Jupiter, ...?
  • What will the gravity be like? Remember - the bigger the planet, the stronger the gravity. Low gravity means you can move easily, but your atmosphere is likely to escape into space; high gravity will hold onto your atmosphere, but it will be hard to move.
  • How circular will the orbit be - orbits which are circular or almost circular (like that of Earth) mean that the temperature does not vary too much as the planet orbits its star; very eccentric orbits (like that of Pluto) mean greater temperature variations.
  • How hot will the planet be? - the surface of Venus (the hottest planet) is over 450 degrees C, the surfaces of Uranus, Neptune and Pluto are all around -200 degrees C or less. An atmosphere will keep the planet warmer than a planet without an atmosphere.
  • What kind of planet will it be - rocky like Mercury, Venus, Earth, Mars and Pluto, or will it be a gas giant like Jupiter, Saturn, Uranus and Neptune?
  • Will your planet's surface have oceans - will they be made of water, or petrol, or acid, ...?
  • What kind of atmosphere will it have - nitrogen/oxygen as on Earth, poisonous acid clouds as on Venus, hydrogen/helium as on Jupiter, ...?
  • What life forms will the planet support - people, little green aliens, plants, bacteria, ...?
  • How will they move - or will they be unable to move at all?
  • How will they communicate - will they talk to each other, what will their language be like? Or will they communicate directly from one mind to another? Perhaps they might use maths to communicate - maths is a universal language, after all.
  • What will they eat - will they eat other beings on the planet, will they be vegetarian or eat minerals or rocks ...?
  • Where will they live - underground, under the oceans, in the oceans, in houses, in trees, in the clouds, ...?

You can probably think of many more things to decide about your planet. Let your imaginations run riot - but make sure that the science works out. It's no good having a small planet, then saying it has an atmosphere. It's no good having life forms which drink water if the temperature is over 100 degrees C - unless they live underground or in air-conditioned units of some kind.

You might be interested in this website: In 2003, NASA had a "Design a Martian" competition for schools. This link is to the archive created from that competition. The BBC website also has pages which may be helpful, particularly for thinking about life forms.