EDM 212 The Exploration of Science II
Assessment C: The Earth and Beyond
The Solar System
Astronomy is often considered the oldest of all sciences, records have been discovered dating back to 4th century BC with the ancient Greeks, Romans, Chinese, Babylonians and Arabians all documenting sightings of what was considered phenomena back then but are now called comets, planets, eclipses and supernovae.
As with other science disciplines new discoveries are always being made in astronomy such as the recent discovery of what is being claimed by some experts as a new planet in the solar system, 2003 VB16 otherwise known as Sedna (the inuit goddess of the sea.) This planet/object was found 14 November 2003 when NASA funded researchers noticed a dim object moving, slightly, across the starry field. It has been estimated that this planet/object is 84 billion miles from the sun and due to the distance from the sun it has an estimated temperature which never reaches above 240 degrees Celsius. (Kutner 2003)
The above picture shows an artists rendition to show the Sedna in relation to other bodies in the Solar System, including Earth and its Moon; Pluto; and Quaoar, a planetoid beyond Pluto that was until now the largest known object beyond Pluto. The diameter of Sedna is slightly smaller than Pluto's but likely somewhat larger than Quaoar.
The first stumbling block with the teaching of the subject of Astronomy is at key stage 2 the pupils are required to know the very basics regarding the solar system. At this stage it is mostly considered that a basic knowledge and an understanding of shape of the planets and their movements around the sun causing the changes in seasons is important as without this knowledge it would make the further studies and in depth analysis of further key stages impossible.
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One of the important features of the key stage 2 astronomy is making it apparent that the students probably knew more than they believed they did, as with regards to the teaching of how the position of the sun during the day will change the shape of shadows. A large amount of focus is placed on the sun and earths’ relationship so that the students can fully understand such things as the earth being on an axis and how day and night are related to this.
At key stage 2 very little information is given with regards to the solar system, a little focus on the earth and its relationship with the sun and moon, but, with regards to the planets of the solar system they are listed but with only the order of them being taught.
At key stage 3 the advancement in information taught to the student is very apparent as more complex ideas are tackled such as the behaviour of light, this makes the information taught in astronomy much easier. At this time students are also taught the relative movements of the earth with regards to the other planets in the solar system, and, how this causes the apparent daily and annual movement of the sun and other stars.
At this level the student is taught the history of planetary discovery, and how before the invention of telescopes only five planets were known (apart from earth) as they were firstly believed to be stars in the sky but it was later realised that in fact they were different as week by week they moved slowly whilst the actual stars were in a fixed position. For this reason the ancient Greeks named them planets which means “wanderer”. (Kutner 2003)
The means by which telescopes adapt and intensify light is discussed at this key stage so that the student can fully understand how they made it possible to discover the remaining 3 planets (or 4 if you include Sedna). At this level space probes and space telescopes would be discussed so as to make them aware that the advancements in knowledge are leaping so far ahead to what was previously thought possible, and for the students there has never been a better time to learn as with slides and presentations it is possible to show the pupils actual photographic evidence of the surface of a planet or even a different galaxy. (Karttunen 2003)
It is also this time when an in depth look at the many exploratory probes which have and are currently attempting to gather more and more information with regards to the
Solar system we are in. This is also the ideal time to discuss the possibility of terra-forming and humans living on other planets.
Key stage 3 is also the time when students will begin to notice how some of their subjects will begin to merge and this is very apparent when considering the subject matter as most of it involves either physics or mathematics.
Newton’s laws of motion which was devised in the 17th century is covered in great detail in physics, this is also of great use when trying to understand movement in space as his first law states that an object will stay at rest or will continue to move with a constant velocity, unless they are subjected to an unbalanced force. This can be directly related with space travel as when launched into space a rocket will continue to move without a constant need for a motor to push it.
The second law is with regards to rate of change of velocity in that it is directly proportional to the mass in that the larger the mass, the slower the rate of change of velocity, but, the change of rate is directly proportional to an increase in force. In space terms this would mean that a larger rocket would need more thrust in order to leave the earths gravity.
The third law states that when an object forces another there is automatically an equal and opposite reaction force on the first object. The obvious way this can be related to space is in the initial launch as the rocket ejects a stream of hot gas downwards and it is this that causes the rocket to be lifted off the ground.
As can be seen the obvious link between physics and astronomy is very apparent, and, when trying to work out any of the actual forces required that is when knowledge of mathematics would be required as even the most basic formula requires knowledge of algebra. (Karttunen 2003)
At key stage 4 the student is expected to have a firm base of knowledge from which to further add the more complex ideas. As an understanding of the positioning of the planets it is also the ideal time to make the students aware of just how incredulous numbers involved when computing the size of planets and the distance between them.
It is at this point when generally the immenseness of the solar system becomes obvious to the pupil and usually an attempt at a scale model is attempted but unfortunately it can only be a general representation as due to the massive differences in size the sun is always an incorrect size. A way to try and comprehend the size of the sun is to say that it contains more than 99.8% of the total mass of the solar system another way to put this is to say that it is equivalent to 332,830 earths. (Kutner 2003)
This representation above gives an idea of the size of the planets with the fuzzy shape to the left being part of the edge of the sun.
When considering the distances between the planets the numbers become even more mind-boggling for students as although the universe is mostly empty space, even a crowded region like the solar system has distances between the planets which are very hard to imagine. When trying to consider the distances which would need to be travelled to get to the far reaches of this solar system, at the speed of today’s fastest spacecraft (20km/second), it would take almost ten years to travel the distance and even at the speed of light it would take 5 ½ hours. (Kutner 2003)
One of the final considerations which needs to be passed over to the pupils is that the solar system does not just contain planets in that although they are of the greatest physical mass, there are many other objects and that although it is called space, it is actually filled with many objects which vary from dust to comets to black holes (possibly) and each of which combine to make the solar system as we know it.
Kutner, M.L. (2003) Astronomy: Physical Perspective. Melbourne: Cambridge University Press
Karttunen, H (2003) Fundamental Astronomy. New York: Springer-Verlag Publications