Astronomy Packet:  3
Assignment # 2

What else do Venus, Earth and Mars have in common?

Size:

The Earth and Venus are often called sisters because they are so similar in size.  Venus is only 5% smaller than the Earth.  Where Earth and Venus are similar, Mars is very different.  Mars is much smaller, only about half as big as the Earth and Venus.

Temperature:

The Earth and Mars have a similar temperature.  The hottest it gets on Mars is about 98°F (36°C), while the hottest it gets on Earth is about 120°F (49°C).  This time, however, where the Earth and Mars are similar, Venus is different.  Venus is much, much hotter.  The average temperature on Venus is about 850°F (454°C).

Length of Day:

A day on Earth lasts about 23 hours and 56 minutes.  On Mars, the length of a day is quite similar, 24 hours and 37 minutes.  A difference of only 41 minutes.  On Venus, a day lasts more than 344 Earth days.

Materials:

All three planets are made up of similar materials, or elements.  All three have an iron core with crusts made out of lighter rocks called silicates.

Life:

Earth is the only planet that we are completely sure has life.  Venus does not have life because it is much too hot.  Mars might, but we are not sure yet.  If there is life on Mars it would have to live underground because that is the only place on Mars where there might be liquid water.

Assignment # 2:

In your own words state three ways that Earth, Venus and Mars are similar, and three ways they are different.