ES3

In the table above, data for some of the largest objects in our system, including the sun, the planets, some dwarf planets and some moons. In each case, the mass, radius, and surface gravities of the object are shown relative to those of the Earth. For example, the sun's relative radius of 109 means that its radius is 109 times the radius of the earth.

1. Other than the sun, which of the celestial bodies is the largest? Justify your answer.

Jupiter, as it has the greatest relative radius of all the celestial bodies listed.

2. Do you think that the objects in the table are listed in order of mass, in order of radius or in order of gravity?

The objects are placed in order of decreasing relative radius. The objects with the greatest relative radius are listed on top. As you go down the column, the relative radius decreases.

3. Do you think the planet with the greatest density will be made of gas, like Jupiter, or made of solid rock, like Earth? Explain your answer

Rock. Rock is solid. Therefore, it has a much greater density than a gas

4. Do you think that a person has the same mass on Mars as on Earth? Explain your answer

Yes they have the same mass. Mass is a measure of the amount of a substance present. This does not change by changing location.

5. Do you think that a person has the same weight on Mars as on Earth? Explain your answer.

No they have a different weight. Weight is a measure of the force of gravity on a body. The relative gravity of Mars is much less than the relative gravity of Earth. Therefore, the weight on Mars is less than that on Earth.

6. Compare Jupiter with Earth under the following headings: Mass, gravity, Size

Mass: Jupiter has a mass 318 times greater than the Earth.

Gravity: The gravity on the surface of Jupiter is 2.53 times the gravity on the surface of the Earth.

Size: The radius of Jupiter is 11 times greater than the Earth.

In the table above, data for some planets is given.

1. Are the data in each column listed above in order of mass, in order of distance from the sun, in order of dimeter or in order of density?

The data are listed in order of increasing distance from the Sun.

2. List the order of the planets in order of increasing distance from the Sun, starting with the one closest to the Sun.

Mercury, Venus, Earth, Mars and Jupiter

3. One of the planets is mostly made of gas. Using the table above, predict which one of the planets this is likely yo be. Justify your answer.

Since Jupiter has the lest density of all the planets, it is most likely to be made of gas. Gases have lower density than solids or liquids.

4. A certain comet has been observed from Earth in the years 1835, 1910 and 1985. Estimate when it is likely to be seen from Earth again.

The time from 1835 to 1910 is 75 years. The time from 1910 to 1985 is also 75 years. I would expect to see it again 75 years after the last sighting in 1985. This would be in the year 2060.

In the table above, data for some celestial bodies that are in orbit around our Sun. The values given are relative to the Earth. For example, Saturn is 9.58 times further from the Sun that the Earth)

1. Is the table in order of relative density, relative diameter or relative distance from the Sun?

The table is in order of increasing relative diameter.

2. Which of the celestial bodies is the largest? Justify your answer

Saturn is the largest body as it has the largest relative diameter.

3. Which of the celestial bodies is closest to the Sun?

Mercury is closest to the sun since it has the smallest relative distance from the Sun.

4. Which of the celestial bodies is in orbit around the sun and has an orbit that is greater that that of Saturn?

Neptune has a greater relative distance from the Sun than Saturn. Neptune's orbit must be outside the orbit of Saturn.

5. Which of the planets Mercury or Saturn is most likely yo be made of gas?

Saturn has a lower relative density than Mercury and is therefore more likely to be made up of gas.

6.Which of the celestial bodies is likely yo be the coldest?

Neptune is most likely to be the coldest as it is farthest from the Sun.

7. Each of the celestial bodies has at least one moon. What is a moon?

A moon is a natural satellite of a planet.

In the table above, data for some planets in our Solar system is given. The data on mass, diameter and distance from the Sun is relative to the Earth. For example, Neptune is 30 times further from the Sun than the Earth.

1. Name the largest planet by size, and the smallest planet listed on the table

The largest planet by size is Jupiter and the smallest is Mercury. This is obtained from the data on relative diameter

2. Are planets in the table listed in order of relative mass, in order or relative distance from the Sun or in order of relative diameter?

The objects are ordered by relative distance from the Sun. The distance from the Sun increases as you go across the table

3. Compare the planet Neptune with planet Earth for size, distance from the Sun, mean temperature, mass.

Neptune is larger than Earth, it has a greater relative diameter

Neptune is further from the Sun than the Earth, it has greater relative distance from the Sun

Neptune is much colder average temperature than Earth, it has a lower mean temperature

Neptune is of a greater mass than Earth, it has a greater relative mass

4. Is there a relationship between distance from the Sun and the surface temperature of a planet? What is this relationship?

Yes. The table shows that planets closer to the Sun have a high mean temperature. Planets further away from the Sun have a low mean temperature. As the distance from the Sun increases, the mean temperature decreases.

5. If water existed on the surface of Jupiter, predict if you would expect to find it as a solid, liquid or gas?

If water existed on Jupiter it would exist as ice, since the mean surface temperature of Jupiter is much lower than 0°C

6. The NASA Voyager space programme uses space probes that travel at very high speeds to research the outer solar system. When designing the Voyager space probes, scientists favoured the use of a small nuclear reactor, especially when the probes moved further from the Sun. Why would this be the case?

As you move further from the Sun, the amount of energy from the Sun falling on the solar panels gets less and less. The power output of the panels decreases with distance from the Sun and may not be sufficent to power the probes equipment. A nuclear reactor would be a more reliable source of energy. Also, the large area of solar panels could be damaged by the collision with small objects as it moves at great speeds through the solar system.