John N's Software - Planetarium

COMPUTER

PLANETARIUM

Our solar system exists of the sun with a number of planets, who are rotating around the sun in circular orbits. Around some of these planets there are also moons rotating in circular orbits. The force of gravity is the cause of these circular orbits. Because the sun has by far more mass than all other planets together, all these planets are rotating around the sun. The sun is centre of rotation. That is why the sun is the centre of our solar system. A planet has also by far more mass than the moons, who are rotating around this planet. That is why this planet is the centre of rotation of her moons.
Close to the sun we find a number of smaller planets, so as mercury, venus, earth with moon, the planetoids and mars. Farther away from the sun we see the larger planets, so as jupiter, saturn, uranus and neptune. The planetoids consists of many little planets, who are rotating between mars and jupiter in the same orbit around the sun. It seems as if the planetoids are the fragments of an exploded planet. Pluto, who is the most distant planet of the sun, is also a small planet. Pluto is an outsider and is also not rotating in a circular orbit, but in a strong elliptical orbit. The sun also is now not exact in centre of the orbit. Properly speaking, all other planets are also rotating in elliptical orbits in stead of circular orbits around the sun, but the deviation of the circular orbit is there so small that you scarcely can see this.

The sun is the nearest star and is representative for the majority of the numerous other stars. Our star exists for 80% out of hydrogen and 20% helium. In the centre of this huge sphere of gas with a diameter 100x larger than the earth, nuclear reactions take place. The nuclear energy reaches in the form of heat and light the surface of the sun. The temperature of the sun decreases from 10 million degrees celsius in the centre until 6000 degrees celsius at the surface, the temperature of a withe-yellow flame, hence the colour of the sun. In the atmosphere of the sun appear by differences in temperature whirls of electrical and magnetic nature, where sunspots, solar flares and flames make their appearance. With regularity there are during these storms outbursts of energy, what causes that matter is throwing away from the sun.
Also there is, on a more friendly manner, a constant blowing away of matter from the sun to outer space, known to us as the solar wind.

MERCURY.

Mercury and our moon are practical of the same size and are alike in many aspects. The surface is covered by craters, mountains and valleys. There is no water and air present. The temperatures vary from - 200 degrees celsius on the night-side until + 400 degrees on the day-side of the planet. The variations in temperature are strengthened by the strong elliptical orbit of mercury, what causes that the planet in the a month lasting summer is much closer to the sun than in the also a month lasting winter. The planet turns three times around his axe in two orbital loops around the sun, what causes moreover, that in the summer always the same areas are facing the sun, namely alternating the meridian of 0- and 180 degrees. Amidst these areas lay on both sides of the planet the so called poles of heat with very extreme temperatures.

Venus and the earth are about the same size and are alike as to the structure at the surface. By the fact that water is totally missing, the continents rises up as vast highlands. The atmosphere is hundred times denser than the atmosphere of the earth and contains mainly the gas carbondioxide, while the until 70 km altitude reaching opaque layer of clouds consist of sulphuric acid. The sight at the surface of the planet is three km and the illumination of the landscape looks like a very cloudy day on earth.
The temperature is by day and by night about the same and near 500 degrees celsius, the temperature of the melting point of lead. The day and night last almost just long as the summer and winter, together a venus-year of eight earth months. The streams in the dense atmosphere go around the planet in every four days, what is the cause that differences in temperature are neutralised.

The earth should be covered with a layer of water with a thickness of three km, when she did not know the variations in altitude and depth. These large mass of water has a moderating effect on the temperature, who is varying from - 80 degrees celsius at the poles until + 60 degrees celsius on the main land at the equator. Because of the constant volcanic activity in the crust of the earth and the constant erosion of sand, wind and rain at the surface, we see little of the many craters, caused by the strikes of the meteorites, as we see on the most other celestial bodies. The atmosphere consists of 80 per cent nitrogen and 20 per cent oxygen. The layer of clouds consists of raindrops, flakes of snow and particles of ice. The tilted axe of the earth causes the seasons. The axe of the earth keeps in the annual orbit around the sun namely always in the same state with respect to the stars. Because of that the upper and lower half of the earth are alternating more illuminated by the sun.

On the moon air and water are missing. By daylight it is there constantly dry, sunny and very hot with maximum temperatures until 120 degrees celsius. The night is cold and clear with minimum temperatures until 150 degrees beneath zero. On the moon we see many structures, such as plains, craters, mountains and valleys. A thick layer of moondust consisting of numerous glassy particles cover large parts of the surface. The numerous huge plains of many hundreds of km in diameter are the largest structures on the moon. They consist of basins filled with then liquid and now solid dark coloured lava. The moon is covered with many craters. These craters are of volcanic origin or formed by the strike of meteors. The diameters of the craters varies from scarcely visible until many kilometres. The large craters and plains are surrounded by chains of steep mountains. Thousands low hills and dome-formed elevations are present on the moon. The origin of these is denominated to the action of liquid lava and escaping gases.

Although mars is 2x smaller than the earth and 2x larger than the moon, mars is the planet who is most alike the earth, which respect to climate and landscape. Alas there is no liquid water present, why the planet looks like a red desert of sand broken trough chains of high mountains, hugh volcanoes and rifts. The temperature goes from -150 degrees at the poles until +15 degrees celsius at the equator. The day lasts here even long as on earth and the changing seasons 2x so long, because of the two years lasting orbital time. Also the tilted axe of rotation of the planet is alike the tilted axe of the earth, what causes that the differences of the seasons are comparable for both planets. The atmosphere of mars is 100x thinner than the atmosphere of the earth. She consists mainly of carbondioxide and is by the winds, who are connected with the seasons, often filled with the red sand of the desert. These trade winds withdraw the bottom of mars sometimes during months from the eye of the terrestrial observer. Where the red sand is blowing away there originate the dark coloured 'oases' and where it is deposited there we see the more bright and red coloured landscapes of the desert. The both polar caps become with the winter and summer smaller and larger, because of the snow of carbondioxide who falls down or evaporates. More over the whole supply of the water of mars lays down here probably as ice of water and as permafrost in the bottom. Old dry beds of rivers give evidence of the frequent presence of liquid water in the warmer areas at the equator in a far past time.

These two little moons of mars are both a few tens of kilometres in diameter. Their surfaces are covered with craters caused by the strikes of meteorites during milliards of years. Because of that the surface consists of a thick layer glassy particles of smashed rock with a thickness of many tens of metres. The craters of diverse format from a few metre until tens of kilometre in diameter lay in and over each other. The moons are more ellipsoidal than spherical and fairly irregular with respect to their form. They have a speaking likeness with the planetoids (= asteroids) and are supposed to be of the same origin.
An inhabitant of mars should see phobos three times smaller than our moon positioned at the sky and deimos fifteen times smaller. Because mars rotates faster around his axe than phobos around the planet he should see this moon rising in the west and setting in the east. Deimos needs more time than a mars-day for his orbital time and this is why he normally rises in the east and sets in the west. Phobos en deimos are rotating in the same direction as the planet rotates, so that an inhabitant of mars should see a longer orbital time which respect to him than we see from the earth with respect to the fixed stars. For deimos is this orbital time for an inhabitant even more as 5 days in stead of 1 day for the terrestrial observer.

The asteroids or planetoids consist of many tens of thousands blocks of rock of diverse size and vary in diameter of a few m until many km. There are totally 25 asteroids with diameters of 120 km or larger. The largest asteroid ceres has a diameter of thousand km. One expects that the picture of an asteroid looks like the structures at the surfaces of the both moons of mars. These are covered with craters that are caused by the strikes of meteorites. Moreover they have a thick layer on the bottom of smashed rocks, caused by the many strikes. The most of the asteroids are turning their orbits in circles between mars and jupiter, while there exists also a group with more elliptical orbits, who are wandering through the whole solar system and sometimes are crossing the orbit of the earth therewith transforming in a comet.

Jupiter is by far the largest planet of our solar system and is more like the sun than like a planet. Only no nuclear reactions appear in the centre of the planet so as in the centre of the sun. The composition of the planet is the same as the sun, mainly hydrogen and helium. Also other elements are present in smaller quantities, like water, ammoniac and methane. In the outer layers of the planet, who is spinning very fast around his own axe, wild scenes are seen. There we find atmospheric streams in the form of belts, who encircle the planet, storms and hurricanes, as the red eye, larger then the earth. The temperatures in the upper layers of clouds go from -120 degrees until 0 degrees celsius in the lower layers. The splendid colours of jupiter are caused by all sorts of chemical compositions in the layers of clouds originated by the diverse temperatures.

The system of rings seems to lay in a huge plate alike a plate of a gramophone-record placed in the plane of the equator of the planet and with the planet as centre of rotation. The rings have a width of a few tens to many hundreds of kilometres with a thickness of only a few kilometres. Moreover each ring shows privately seen also a substructure of rings. The rings are formed by numerous very small dust and ice-particles and owe their colours to diverse chemical compositions.
Probably the rings originate by strikes of large meteors in the atmosphere of the planet, herewith hugh quantities of matter are lanced into outer space. After that the particles, of which this material consists, encircle the planet as natural satellites. Because of the centripetal forces, who originate by the fast rotation of the planet, the orbits are pulled to the plane of the equator of the planet.

The large outer planets jupiter, saturn, uranus and neptune are giants compared with the other smaller planets. They distinguish their self also from these small planets through chemical composition, mainly hydrogen and in lower quantity helium. The nearest of these planets and by far the largest is jupiter, who also is a model for the other gasgiants.
The surface of saturn shows practical the same picture as jupiter with his belts and spots around and in the atmosphere. There where jupiter dominates with the splendid colours and structures in his atmosphere, it is saturn with the colours and largeness of his system of rings. Although one has recently discovered that all other gasgiants have a system of rings, there is no one who excel saturn with his seven rings, who encircle the planet as belts of emerald.

Besides the earth and pluto with each a large moon, alone the gasgiants possess large moons. All these moons of hundreds or thousands of km diameter are alike our moon with his many craters or are alike the icy moon of pluto. The icy moons are totally or partly covered with ice. A single moon possesses a atmosphere so as titan and only a few show volcanic activity. The moons of mars don't have, just as all lately discovered small moons around the gasgiants, the form of a sphere like the large moons. They are irregularly shaped blocks of rock or ice which a size of usually only a few tens of km in diameter. These moons have common which each other that the long side of the planet always is pointing to the planet around which they are rotating. The cause of this fact is the action of the force of gravity, comparably with the action of ebb and flow on earth.

Pluto is a rocky planet, like mercury, venus, earth and mars. From all these planets pluto is the smallest and has the largest distance from the sun. The sunlight that reaches the planet as light from a brilliant star, brings the temperature not higher than -200 degrees celsius at the equator of the planet. The bright poles consist of methanoic ice from the rarefied methanoic atmosphere.

Pluto has a huge greyish companion, the moon charon. Charon and pluto are in fact twin planets, like the earth and her moon. Charon is also a rocky planet and probably without atmosphere, so that the bright methanoic ice is missing. Pluto and charon circle around a common point of gravity, that is situated somewhere between the planets.

The comets form a group of celestial bodies comparable with the asteroids as to their composition and form. The only difference is that their orbits are strongly elliptical, so that they are moving across the solar system from very far until very close to the sun. When a comet comes close to the sun then the normal frozen liquids and gases evaporate on and in the comet. Around the head of the comet, which is a few km in diameter, forms an envelope of gas, damp and dust, which is a few tens of km diameter. This envelope gives light by the warming up by the sun. Because of the strong solar wind dust and gas are blown away from the comet downward from the sun. So a tail of the comet is building up some times millions km in length. The tail can accept dependent on the chemical composition different colours and forms. The comet bears the name star with a tail because of that.

Meteors or falling stars are fragments of matter, who are making their entry in the atmosphere of the earth from outer space. Because of their high velocity they evaporate by the heat of the friction with the surrounding air. The earth encounters in his orbit around the sun regularly debris of comets and these are debit to the annual rains of meteorites. During such a rain all meteors seem to come from the same point (radiant) of the sky. The swarm of meteors is mostly named according to the constellation of stars, in or near which the radiant is being find. When the point of observation is in front of the earth in his orbit around the sun, this is in the morning, the most of the meteors are seen.

The most fragments, coming from outer space, are very small, in the order of centimetres, and evaporate completely leaving a luminous trail behind. When the fragments are larger, in the order of decimetres, then they survive the journey through the atmosphere as meteor. The found remnants are called meteorites. A meteoroid (fragment from outer space) transforms in a meteor (phenomenon of light in the atmosphere) and is found as meteorite (kind of stone). The meteoroids exist of fragments of stone (which much carbon and iron) or ice (frozen water or frozen gases).

When the meteors are in the order of a metre then they cause during the burning in the atmosphere a tens of metres large envelope of evaporating and lighting gases, what we see as a large sphere of light, called bolide, with colours depending on the chemical composition. Herewith we hear sometimes bangs in an environment of hundreds of km. When the meteoroids are still larger, what is of uncommon excellence, then they can cause explosions comparable with one or more nuclear bombs (as like the Toengoeska catastrophe in Siberia in the year 1908).

Stars are suns on large distance. Our sun is the closest star. Our sun is one of the billion stars, who form together our system of stars (the milky way). From these systems, who each alone exists of billion stars, there are in our unmeasurable universe also many billions present.
The most stars are alike our sun, as to mass, diameter, temperature and colour. Our sun is normal star. Is a star much larger than our sun then it is a giant. Is the star much smaller, then one says it is a dwarf. A star with a higher temperature than our sun is bluer as to colour and a star with a lower temperature is redder. So we know for example red and blue giants, white and brown dwarfs and the numerous white-yellow normal stars alike our sun.

People makes of old the distinction between stars and planets based on their motions. The real stars (suns) we see motionless, apart from their daily rotation around the polar star, while the planets are moving between the fixed stars, because the annual turning of the earth around the sun in combination with their own turning around the sun. We see the planets wandering throughout the constellations of the stars.

Although not all are real stars, people knows the denominations wandering stars for planets, fixed stars for real stars, stars with tails for comets and falling stars for meteors. You can find in the diverse texts over our solar system, the characterises of all these sorts of celestial bodies.

		Solar distance	Diameter	Revolution	Rotation time
		(Earth=1)	(Earth=1)	(In years)	(In days)
1	SUN	--	109		25
2	MERCURY	0.4	0.4	0.2	58
3	VENUS	0.7	0.9	0.6	234
4	EARTH	1.0	1.0	1.0	1
5	MARS	1.5	0.5	1.9	1
6	PLANETOIDS	3	--	5	--
7	JUPITER	5.2	11	12	0.4
8	SATURN	9.5	9	29	0.5
9	URANUS	19	4	84	0.7
10	NEPTUNE	30	4	165	0.7
11	PLUTO	39	0.2	248	6
12	COMETS	--	--	--	--

The planetoids or asteroids are small planets and vary in diameter from several meters to several hundreds of kilometers. They revolve in a circular belt around the sun between Mars and Jupiter. The comets are also small planets with oval orbits, which traverse our solar system from near to the sun to far away. When the earth traverses a orbit of a comet, we see mostly a great meteor shower.

The computer planetarium exists if several simulations and texts over our solar system. The programme is made for a modern MS DOS-computer with a color monitor and works also in Windows XP, 98, 95 and 3x.. The computer planetarium is a product from Drs. Jan Nentjes, The Netherlands.

The programme belongs to the Dutch book 'De klas als ruimtevaartcentrum' by P.Conijn, J.Nentjes, ISBN 90-74043-22-4, appeared in the series 'DE KUNST VAN HET LEERLANDSCHAP' provided for BASTEC-NEDERLAND.
In this book you can read how to transform a classroom in a real space centre with a construction-hall, a observatorium, a computercentre, a library, a travel agency and ... a bar.

For remarks over the programme and the texts or wishes for a next version you can turn to the author by E-mail. This programme is no shareware and may on no way be distributed without written permission of the maker.

For free downloading of the programme go to the Out Basket of our Virtual Office. See, if needed, also instructions for downloading and installing.

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