It is the smallest planet and has one moon. Its temperature is extremely cold, and its surface is frozen and dark because it is so far from the sun. Prior to the lesson, the teacher will set up the investigation area outside. Each planet will be marked on the ground in proportion to the planets' location in space.
Mercury 0. A ball, which is proportional to the planet's actual size, will also be placed at each of the planet's locations. The class will be divided into two groups. Each group will be divided into the nine planets and the sun.
Therefore, the class will consist of two solar systems. The teacher will explain the activity that they will participate in and each person's role.
They will discuss the following rules: when participating in the second activity, everyone should have their own personal space. Each person should be careful to not hit anyone with his orbitor and only perform the activities when instructed to do so by the teacher.
The class will go outside to the designated area. The teacher will show the students the balls and which planet each one represents. They will be asked to observe the difference in size and make comparisons.
Then, the first group will walk to their planetary spots. They will walk towards the sun and observe which planets reach the sun first and which ones take the longest to reach the sun. They will also observe which planets are closer to each other than other planets. The planets will then return to their places. This time, they will walk the orbits of the planets. The students will observe which planets completed their orbit first, and which planets completed their orbit last. If time permits, the next activity will be performed.
Students will find their own personal space about a 3ft. The orbit strings will be distributed. Each student will hold the cup in one hand, and the excess string in the other hand. He will swing the string while holding the cup. As he swings, he will pull the excess string towards the ground. The average orbital data for the planets are summarized in Table 1. Ceres is the largest of the asteroids, now considered a dwarf planet. At the opposite extreme, Neptune has a period of years and an average orbital speed of just 5 kilometers per second.
All the planets have orbits of rather low eccentricity. The most eccentric orbit is that of Mercury 0. It is fortunate that among the rest, Mars has an eccentricity greater than that of many of the other planets.
Otherwise the pre-telescopic observations of Brahe would not have been sufficient for Kepler to deduce that its orbit had the shape of an ellipse rather than a circle. In addition to the eight planets, there are many smaller objects in the solar system. Some of these are moons natural satellites that orbit all the planets except Mercury and Venus. In addition, there are two classes of smaller objects in heliocentric orbits: asteroids and comets. The planets don't remain exactly on the ecliptic, but they stay pretty close to it at all times.
Unlike the Sun, however, the planets don't always move in the same direction along the ecliptic. They usually move in the same direction as the Sun, but from time to time they seem to slow down, stop, and reverse direction! This retrograde motion was a great puzzle to ancient astronomers. Copernicus gave the correct explanation: all planets move around the Sun in the same direction, and retrograde motion is an illusion created when we observe the other planets from our moving point of view, the planet Earth.
It's easiest to understand the retrograde motion of Mercury and Venus. These inner planets are closer to the Sun than we are, and they orbit the Sun faster than we do. From our point of view, the Sun moves slowly along the ecliptic due, of course, to our orbital motion , while Mercury and Venus run rings around the Sun. So at some times we see them moving in the same direction as the Sun, while at other times we see them moving in the opposite direction.
These outer planets are further from the Sun than we are, and they orbit the Sun more slowly than we do. When the Earth passes between one of these planets and the Sun, we see it going backwards because we're moving faster than it is.
When the Earth passes between one of the outer planets and the Sun, we see the Sun and the planet in opposite parts of the sky; the planet will rise about the time the Sun sets, remain visible all night, and set about the time the Sun rises.
The closer a planet is to the Sun, the less time it takes for it to go around the Sun. It takes less time because the length of the orbit is shorter a smaller orbit , but it also moves faster in its orbit. Thanks to gravity, it has to move faster in its orbit to stay in orbit! Below are the distances of the terrestrial planets from the Sun and the length of their years. Obliquity is simply a term for the tilt of the rotation axis of a planet, moon, etc.
So, it applies to all objects as they all spin on an axis. It is an angle measured in degrees relative to the plane of its orbit around the Sun for a planet or asteroid or a planet for a moon. Some values: Mercury: 0. There is less volume in the inner solar system compared to the outer solar system, so there was less material present in the protoplanetary disk to form planets much larger than the terrestrial planets.
Some computer simulations show terrestrial planets a couple to a few times more massive than Earth, but not much beyond that if they formed in the inner part of the disk. Farther from the Sun, in the protoplanetary disk, the temperature was low enough that solid ices could form from the gas it was too hot in the inner part of the disk for ices.
Thus, at the distance where Jupiter is and beyond there was both more solid rocky material and more solid icy material for planets to form out of. This may have allowed the planets to grow much larger and eventually reach a mass that was so large that their gravity could begin capturing hydrogen and helium gas from the disk. This may be how the giant planets formed, although there is still a fair amount of debate.
Each planet, thanks to size, is different. On Earth, magma is brought to the surface by volcanic activity heat generated in the interior being brought to the surface , these rocks cool to form igneous rocks. These rocks can react with the atmosphere weathering and erosion and form sedimentary rocks.
All of these rocks can get reburied and create metamorphic rocks. Much of the volcanic activity and processes that lead to reburying rocks are the result of plate tectonics. We only see this on Earth. On Venus, which is about the same size as the Earth, we do not see evidence for plate tectonics, but we do see evidence for volcanism.
The atmosphere likely reacts with the rocks, but there probably isnt any mechanism to create metamorphic rocks and there is no water to create that kind of erosion or sedimentation though other things could rain out, like sulfuric acid. Mars does not have plate tectonics, but does have past volcanism. It has a thin atmosphere, so there can be erosion and transport by wind great dust storms. There is evidence that the atmosphere used to be thicker, thick enough to have liquid water on the surface that would then lead to erosion and sedimentation, but not metamorphism.
We are still learning about Mercury. It is a relatively dead object but does show evidence of past volcanism. Because it is much smaller than the Earth or Venus, it cooled off and formed a fairly thick crust long ago.
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