Comparing Earth with other planets and with moons helps us to work out if we could send astronauts, explorers or even settlers to these places one day. It also helps us to explore the possibility of finding useful natural resources in other parts of our universe.
Activity Fig. 1 shows an artist’s impression of the planets of our solar system. They are not drawn to scale and their relative distances from the sun are not correct. Can you identify Earth in the picture? How many other planets can you identify? How did you identify them? Does this picture allow you to compare Earth with the other planets?
Scientists compare space objects in many
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different ways, including: Mass Size
Composition (what it is made from) Gravity
36.1 Comparing mass
Fig. 1 An artist’s impression of the planets of our solar system.
Fig. 1 allows us to make some comparisons between Earth and other planets. However, scientists need to make more precise comparisons. They often use mathematical calculations to make these comparisons. For example, a mathematical calculation shows that the mass of Mars is about one-ninth the mass of Earth. This is calculated by dividing the mass of Mars by the mass of Earth, giving the relative mass of Mars compared to Earth. This calculation of relative mass is one way to compare the two planets.
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Compare To give an account of the similarities and/or differences between two or more items.
LO 3 Earth and Space strand LO 4 Nature of Science strand
