22.26: The Solar System- Challenge 5

1. ___ extrasolar planets have been discovered so far.: More than 1500

2. Scientists started discovering exoplanets in ___.: 1990s

3. A planet is considered to be in a star's habitable zone when ___.: it has the right temperature to have liquid water

4. Scientists are interested in asteroids because ___.: many are representatives of the earliest solar system

5. ___ near-Earth asteroids cross Earth's orbit.: More than 4,500

6. Long-period comets come from the ___.: Oort Cloud

7. In the early solar system, comets that struck Earth may have brought ___.: water

8. Before reaching Earth's atmosphere, meteors are known as ___.: meteoroids

9. A meteor shower occurs when ___.: Earth passes through a comet's tail

10. ___ are meteors that make it to Earth's surface.: Meteorites

11. Eris has ___ known moon(s).: 1

12. ___ is the largest known dwarf planet in the solar system.: Eris

13. ___ is the third-largest and second-brightest dwarf planet discovered so far.: Makemake