hen the National Space Centre opens in Leicester on June 30, a valuable resource for studying the furthest reaches of space will be on our doorstep. The centre has been offering simulated space travel to older children for some time and, from September, will extend this to include educational activities for all ages. Space travel fascinates children, and introducing it to pupils at an early age can help with concepts of distance, big numbers, science and technology, not forgetting art, literacy and just plain fun. You don't have to travel for millions of light years before you can talk about outer space - you can start in your own playground.
Too far away to touch "This football represents the Sun," said the teacher, "and this marble represents the Earth. So how far apart should they be?" When it had been established that the model Earth would orbit the model Sun somewhere round the perimeter of the playground, the question arose of how far it would be (on this scale) from the Sun to the nearest neighbouring star. As far as the corner shop? The market town? The next county? The answer, when all the calculations had been done, turned out to be the coast of Canada.
The first star beyond our own Sun, Alpha Centauri, is only one of 100,000,000,000 stars in our galaxy; and our galaxy is one of about 100,000,000, 000 galaxies estimated to be in the universe. Each of those galaxies could be as big as, or bigger than, our own. And each of those distant stars could have its own solar system.
Numbers and distances in space are truly astronomical. The number of planets that might exist in our galaxy can be crudely represented by a bucket of sand. Even if you toss out those where life would be impossible - too hot, too cold, too many poisonous gases, no atmosphere - you will still be left with a lot of planets where life might be possible. It could be that the universe is teeming with life. We just don't know.
In our own Solar System, it has been claimed that conditions that might support life, such as an atmosphere containing oxygen and the presence of water, exist on other planets. William Herschel, the astronomer who, with his sister Caroline, discovered and named the planet Uranus, thought he could see forests on the Moon through his telescope. It was also long thought that there were canals on Mars. But our neighbouring planets are mostly too hot or too cold for water to be present in liquid form.
Titan, a giant satellite of Saturn, has a thick gaseous atmosphere very similar to that which it is believed once surrounded Earth. Arthur C. Clarke's novel 2001 focuses on Europa, one of Jupiter's four large moons, believed to have an icy crust floating on a deep, warm ocean.
Mars is the most popular candidate for the presence of life-sustaining conditions. There is water on Mars. At the surface it is frozen but, at a kilometre below, there may be water in the porous rocks, and this may conceivably support life. On the surface, there are twisting networks of channels that could have been cut by water in warmer conditions in the distant past. Perhaps there was life there - one day, we may find fossils to prove it.
A meteorite from Mars, investigated in 1996, contained worm-like structures, a thousand times thinner than a hair. Are these the remains of life-forms - perhaps kinds of bacteria? At present it seems not - Jthey are more likely to be patterns in the rock.
Beyond the Solar System
Many planets are gas giants - huge, fluid, and unable to support life. We have not yet found planets similar in size or nature to Earth. But that does not mean that planets that could support life don't exist. There may be life-forms - just as there are on Earth - that live in environments like volcanic vents at the bottom of the sea, and do not need light or oxygen. However, the presence of oxygen in a planet's atmosphere is our biggest clue to the possibility of life.
If there is life out there, why can't we communicate with it? Distance is against us. A radio message sent from the 300m telescope-dish at Arecibo in Puerto Rico in 1974 towards M13 - a cluster of stars where life might be found - will take 30,000 years to reach its destination. The transmission can be translated into simple pictures illustrating life on Earth, including the molecular structure of human DNA.
Two Pioneer spacecraft are carrying an engraving of two naked Earth people beyond the planets. The engraving also shows the "address" of Earth in pictures. Two Voyager probes carry 100 photographs, greetings in 56 languages and gold-plated records of Beethoven's music, with a stylus to facilitate an interplanetary disco. Voyager 2 flew past Uranus in January 1986, heading towards the margins of our Solar System.
Since 1959, astronomers have been searching for radio and optical communication signals that might have been sent from other parts of the universe. Our own domestic radio and television signals are travelling from Earth into space all the time.
In his novel First Contact, the American astronomer Carl Sagan described a scene in which pictures of the Nuremberg rallies - among the first to be broadcast - reached another inhabited planet.
The search for extraterrestrial intelligence (SETI) has not yet found evidence of life on other planets.(To set your computer to be used in the analysis of SETI signals, go to http: setiathome.ssl.berkeley.edu). If, as the decades pass, there is no response from our closest neighbours, we may have to conclude that, at least in this small part of the universe, the Earth alone is home to intelligent life.
From September, the National Space Centre's Challenger Learning Centre will be offering an educational programme for children of all ages.
For the youngest children, an exciting interactive show in the hi-tech planetarium, in which Mr Sunshine will engage with groups of children - without plunging them into darkness - for half - an-hour.
For infant children, the Night and Day experience will present the evidence, in a lively and interactive way, for the movement of the Earth around the Sun.
For juniors and above, children have the chance to find out if they have what it takes to be an astronaut.
All the events include pre- and post-mission activities for the classroom.
For details, call the National Space Centre (0116 258 2111) or visit www.spacecentre.co.uk, which, from the summer, will be providing educational resources for teaching about the Earth in space.
* For details about the Royal Astronomical Society, write to The RAS, Burlington House, Piccadilly, W1V 0NL, or visit www.ras.org.uk.
* The Huygens probe will land on Titan, one of Saturn's moons, in 2004. To find out more, visit: http:sci.esa.int homehuygensindex.cfm.
* For details of the William Herschel Museum in Bath, tel 01225 446865 or visit http:www.comp.glam.ac. ukpagesstaffbfjonesmuseum.
THINGS TO DO
* What are the conditions needed for life as we know it? What is there on Earth that doesn't exist on other planets? Younger children could record the reasons why they can live on Earth; older children could compare conditions on Earth - temperature, atmosphere, the presence of water - with those on other planets.
* How big are the distances and sizes in the Solar System? Younger children could make scale models of the Sun, Earth and Moon using different sizes of balls or fruit. Older children could extend the model into the Solar System, using seeds and small fruits as the planets.
* What would a first encounter with an extraterrestrial life-form be like? Younger children could imagine the experience and describe what happens. Older children could trawl books, films and stories , and compare how fictional images of extraterrestrial beings have changed from the aggressive aliens of War of the Worlds to friendly life-forms such as ET.
* What might extraterrestrial life-forms look like? All children can imagine this. Older children could design life-forms suited to different conditions, such as soft, marshy ground, extreme temperatures and dim light (for example, large feet, a thick fur coat and large eyes).