22.15: The Solar System- Challenge 3

1. The outer planets are ___.

Jupiter, Saturn, Uranus, and Neptune

2. The inner planets are ___.

Mercury, Venus, Earth, and Mars

3. Compared to Earth, Mercury has ___ years and ___ days.

short; long

4. Mercury's large core is mostly liquid ___.

iron

5. Mercury is ___ because it has such a large core.

dense

6. Venus is sometimes referred to as the ___.

Morning Star

7. Surface temperatures on Venus reach up to ___.

465 degrees Celsius

8. The atmospheric pressure on Venus is ___ times greater than the atmospheric pressure on Earth.

90

9. The dark areas of the Moon are called ___.

maria

10. The footprints of astronauts on the Moon cannot be erased by weathering and erosion, but a ___ could destroy them.

meteorite impact

11. Maria cover about ___ percent of the Moon's surface.

16

12. Mars is nicknamed the Red Planet because of the ___ in its soil.

iron oxide

13. Water cannot stay in liquid form for long on Mars because ___.

the atmospheric pressure is too low

14. Mars has ___ moons, named ___ and ___.

two; Phobos; Deimos