Compare the planets, and where liquid water could exist
Grade 9 Science Worksheet - Challenge Me
Circle the best answer.
A rocky planet orbits inside its star's habitable zone. What should Esme conclude?
- It must look just like Earth, with blue oceans and white clouds
- Liquid water could exist, so it is a good target to study
- Life is known to be there
- Its star is like the Sun
Habitable-zone distance grows as √brightness; star 9 times as bright; planet at 1 AU. A planet sits at 1 AU from a star 9 times as bright as the Sun. Is it at that star's habitable-zone distance, by Jun's math?
- Yes: 1 AU works for any star
- No: the zone is near 3 AU, so 1 AU is too hot
- Yes: brighter stars have closer zones
- No: the zone is near 9 AU
Dip = (planet diameter ÷ star diameter)²; dip 1%; star 1.4 times the Sun's width. A star 1.4 times as wide as the Sun shows a transit dip of 1%. About how wide is the planet, compared with Jupiter (about 0.10 of the Sun's width), by Kira's math?
- Exactly Jupiter's width
- About 14 times Jupiter's width
- About 1% of Jupiter's width
- About 1.4 times Jupiter's width
Luz's friend says any planet in a habitable zone must have life. Which response is best (NASA)?
- Disagree: habitable zones have no water
- Disagree: it means liquid water could exist, not that life does
- Agree: NASA has already found living things on planets in such zones
- Agree: water brings life
Read this first
Planets (NASA Planetary Fact Sheet)
Planet Distance (million km) Mean temperature (°C) Density (kg/m³) Mercury 57.9 167 5,429 Venus 108.2 464 5,243 Earth 149.6 15 5,514 Mars 228.0 −65 3,934 Jupiter 778.5 −110 1,326 Saturn 1,432.0 −140 687 Milo's cousin says the closest planet to a star is always the hottest. Which response is best (NASA)?
- Disagree: Venus is hotter than Mercury because its air traps heat
- Agree: Mercury, nearest the Sun, must be the hottest planet there is
- Agree: distance alone sets temperature
- Disagree: the farthest planets are hottest
NASA says planets in a red dwarf's habitable zone get X-ray and ultraviolet light far stronger than Earth receives. Why does that matter, by Pia's reading?
- It shows those planets have life
- It means the zone is far from the star
- The zone alone does not settle whether conditions stay suitable
- It makes those planets gas giants
Dip = (planet diameter ÷ star diameter)²; dips 1% and 4%. Two stars show transit dips of 1% and 4%, and both stars are the same size. How do the planets' diameters compare, by Tala's math?
- The second is 16 times as wide
- The second is 4 times as wide
- The second is twice as wide
- They are the same width
Planets (NASA Planetary Fact Sheet)
Planet Distance (million km) Mean temperature (°C) Density (kg/m³) Mercury 57.9 167 5,429 Venus 108.2 464 5,243 Earth 149.6 15 5,514 Mars 228.0 −65 3,934 Jupiter 778.5 −110 1,326 Saturn 1,432.0 −140 687 Mars (−65 °C, thin air) and Earth (15 °C) both lie near the Sun's habitable zone. What best explains Mars's cold surface, by Zee's reading?
- It is farther out, and its thin air traps little heat
- It is closer to the Sun than Earth, so its air is colder
- It is in a different star's zone
- It is a gas giant
More than 6,000 exoplanets are confirmed (NASA). Why are Earth-sized planets in wide orbits around Sun-like stars still rare in the list, by Ari's reading?
- Transits of small planets are the deepest
- Sun-like stars have no habitable zone
- They are much harder to detect
- They do not exist
Four data cards, labeled A to D. Which data would help Bo judge whether a planet could hold liquid water?
- Just its distance, since distance alone sets temperature
- Whether life has been seen
- Just the planet's color
- Its distance, its star's brightness and its atmosphere