--- title: Pluto, the Kuiper belt, the Oort cloud and comets — how Mova does on the tests · Space description: Lesson 15 of the space course of Mova's primary school: 5 of 12 tests right, exam 3 of 4, every question with the options, the student's choice, the right answer and why it chose. --- [Mova](https://md.mova.elamur.ai/free/en/) · [this page in HTML](https://mova.elamur.ai/free/en/school-run/space/15-pluto-the-kuiper-belt-the-oort-cloud-and-comets/) [home](https://md.mova.elamur.ai/free/en/) / [at school](https://md.mova.elamur.ai/free/en/school-run/) / [Space](https://md.mova.elamur.ai/free/en/school-run/space/) / 15 # Pluto, the Kuiper belt, the Oort cloud and comets **Tests:** 5 of 12 right · **Exam:** 3 of 4 right · **Kind:** ★★ · **Understood:** 7 of 16 · **Run:** 2026-10-18, commit `f3c23ea72` Lesson 15 of the space course of Mova's primary school, as Mova's small model took its tests: it had read this lesson and the ones before it and learned from their exercises. Each test shows the options in the order the student saw them, its choice, the right answer, the score of every option and why it chose. The lesson itself, sentence by sentence with trees and pragmatics: [the lesson in the corpora](https://md.mova.elamur.ai/free/en/corpora/school/space/15-pluto-the-kuiper-belt-the-oort-cloud-and-comets/). Every question of this lesson and each of its options parsed by Mova, with trees and pragmatics: [the lesson's questions in the corpora](https://md.mova.elamur.ai/free/en/corpora/questions/space/15-pluto-the-kuiper-belt-the-oort-cloud-and-comets/). ### Test 1 · ★★ · right ✓ {#t1} A comet is racing away from the Sun. Which way does its tail point? - **1.** Ahead of it, still away from the Sun — **← Mova's choice** · **✓ the right answer** · no support - **2.** Down towards the Earth — no support - **3.** Behind it, back towards the Sun it left — no support - **4.** Straight up, whatever the direction — no support **Why:** No option found support in what it remembers, so it guessed: it took the first option shown. · [the question and its options parsed, with trees and pragmatics](https://md.mova.elamur.ai/free/en/corpora/questions/space/15-pluto-the-kuiper-belt-the-oort-cloud-and-comets/t1/) ### Test 2 · ★★ · wrong ✗ {#t2} my grandad saw Halley's Comet in 1986. if I'm 10 now (2026), how old will I be next time it's bright? - **1.** 10 — **← Mova's choice** · no support - **2.** 76 — no support - **3.** 45 — **✓ the right answer** · no support - **4.** 86 — no support **Why:** No option found support in what it remembers, so it guessed: it took the first option shown. · [the question and its options parsed, with trees and pragmatics](https://md.mova.elamur.ai/free/en/corpora/questions/space/15-pluto-the-kuiper-belt-the-oort-cloud-and-comets/t2/) ### Test 3 · ★★ · wrong ✗ {#t3} In a cartoon a comet is drawn as a ball of fire burning through space. What is wrong? - **1.** Comets are made of burning coal — **← Mova's choice** · no support - **2.** Comets are tiny stars that explode — no support - **3.** A comet is icy and its head glows only when the Sun warms it — **✓ the right answer** · no support - **4.** Nothing, comets are made of fire — no support **Why:** No option found support in what it remembers, so it guessed: it took the first option shown. · [the question and its options parsed, with trees and pragmatics](https://md.mova.elamur.ai/free/en/corpora/questions/space/15-pluto-the-kuiper-belt-the-oort-cloud-and-comets/t3/) ### Test 4 · ★★ · right ✓ {#t4} Ella says Pluto got kicked out because it's too small to have a moon. what's wrong? - **1.** It has a big moon; it was renamed because it shares its orbit with similar objects — **← Mova's choice** · **✓ the right answer** · score 7 - **2.** Pluto was too big, not too small — no support - **3.** Pluto stopped orbiting the Sun in 2006 — no support - **4.** Pluto has no moons at all — no support **Why:** It took the question to ask which statement is true. It chose option 1 with score 7, the only option with support. Its support: lesson 13, line 7: «Titan is Saturn's biggest moon, larger than the planet Mercury.», reached through the remembered sentence the question matched. What matched: the same doer «titan» (+4); the same thing acted on «biggest moon» (+3). · [the question and its options parsed, with trees and pragmatics](https://md.mova.elamur.ai/free/en/corpora/questions/space/15-pluto-the-kuiper-belt-the-oort-cloud-and-comets/t4/) ### Test 5 · ★★ · wrong ✗ {#t5} Why did it take until 2019 to see Arrokoth up close? - **1.** It was hidden behind Saturn until telescopes got bigger in 2018 — **← Mova's choice** · no support - **2.** It only formed in 2018 — no support - **3.** It is so far that New Horizons needed years to get there — **✓ the right answer** · no support - **4.** Nobody wanted to look at it — no support **Why:** No option found support in what it remembers, so it guessed: it took the first option shown. · [the question and its options parsed, with trees and pragmatics](https://md.mova.elamur.ai/free/en/corpora/questions/space/15-pluto-the-kuiper-belt-the-oort-cloud-and-comets/t5/) ### Test 6 · ★★ · wrong ✗ {#t6} If the Earth did not cross a comet's dust trail in August, what would happen to the Perseids? - **1.** They would happen in winter instead — **← Mova's choice** · score 2 - **2.** We would not see that shower — **✓ the right answer** · score 2 - **3.** They would be brighter than ever — no support - **4.** The comet would fall onto the Earth — no support **Why:** It took the question to ask what happens next. It chose option 1 with score 2, tied with another option at 2 (the first shown, or the one claiming less beyond what it knows, wins). Its support: lesson 15, line 17: «Meteor showers happen when the Earth passes through trails of dust left by comets, such as the Perseids every August.», reached through what followed the sentence the question matched. What matched: the same action «pass» (+4). Against it: a different doer (counts against) (-2). The right option, 2, scored 2. · [the question and its options parsed, with trees and pragmatics](https://md.mova.elamur.ai/free/en/corpora/questions/space/15-pluto-the-kuiper-belt-the-oort-cloud-and-comets/t6/) ### Test 7 · ★★ · wrong ✗ {#t7} Which is the most distant object ever explored up close? - **1.** Pluto — **← Mova's choice** · no support - **2.** Arrokoth — **✓ the right answer** · no support - **3.** Comet 67P — no support - **4.** Neptune — no support **Why:** No option found support in what it remembers, so it guessed: it took the first option shown. · [the question and its options parsed, with trees and pragmatics](https://md.mova.elamur.ai/free/en/corpora/questions/space/15-pluto-the-kuiper-belt-the-oort-cloud-and-comets/t7/) ### Test 8 · ★★ · right ✓ {#t8} Pluto's heart is made of what? - **1.** Red sand — no support - **2.** Frozen lava — no support - **3.** Nitrogen ice — **← Mova's choice** · **✓ the right answer** · score 12 - **4.** Liquid water — no support **Why:** It took the question to ask a circumstance (with what, when, how). It chose option 3 with score 12, the only option with support. Its support: lesson 12, line 9: «Saturn's rings are made of countless chunks of water ice, from tiny grains to pieces as big as a house, and the ice makes them shine brightly, as fresh snow do…», reached through the remembered sentence the question matched. What matched: the same action «make» (+5); it fills the role the question asks for (+5); the same circumstance (+3). Against it: a different thing acted on (counts against) (-1). · [the question and its options parsed, with trees and pragmatics](https://md.mova.elamur.ai/free/en/corpora/questions/space/15-pluto-the-kuiper-belt-the-oort-cloud-and-comets/t8/) ### Test 9 · ★★ · right ✓ {#t9} honestly why do they reckon the Oort cloud's real if nobody's seen it - **1.** It is just a story with no reason — no support - **2.** It glows in the night sky — no support - **3.** Comets keep falling in from that far away — **← Mova's choice** · **✓ the right answer** · score 4 - **4.** Someone photographed it with a big telescope in 1930 — no support **Why:** It took the question to ask which statement is true. It chose option 3 with score 4, the only option with support. Its support: lesson 15, line 12: «The Oort cloud is a vast shell of icy bodies thought to surround the Solar System, reaching perhaps a quarter of the way to the nearest star; it has never been…», reached through the same lesson line as the sentence the question matched. What matched: the same action «keep» (+2); the same doer «comets» (+2). · [the question and its options parsed, with trees and pragmatics](https://md.mova.elamur.ai/free/en/corpora/questions/space/15-pluto-the-kuiper-belt-the-oort-cloud-and-comets/t9/) ### Test 10 · ★★ · wrong ✗ {#t10} Which is true? - **1.** Comets are bigger than the Earth — **← Mova's choice** · no support - **2.** Comets are a few kilometres across but their tails can be huge — **✓ the right answer** · no support - **3.** Comets have no tails until they hit the Earth — no support - **4.** Comets come from inside the Sun — no support **Why:** Nothing it remembers matched the question, so it guessed: it took the first option shown. · [the question and its options parsed, with trees and pragmatics](https://md.mova.elamur.ai/free/en/corpora/questions/space/15-pluto-the-kuiper-belt-the-oort-cloud-and-comets/t10/) ### Test 11 · ★★ · right ✓ {#t11} Why does a comet grow a glowing head only near the Sun? - **1.** It only exists near the Sun — no support - **2.** The Sun's heat turns its ice into gas and frees dust — **← Mova's choice** · **✓ the right answer** · score 8 - **3.** The Sun paints it with light — score 4 - **4.** The Sun's heat lights a fire on its surface, like a match — no support **Why:** It took the question to ask why something happens (its cause). It chose option 2 with score 8, against 4 for the next best. Its support: lesson 15, line 13: «Comets are dirty snowballs of ice, dust and rock a few kilometres across, which grow a glowing head and tails, often millions of kilometres long, when they com…», reached through the same lesson line as the sentence the question matched. What matched: the same thing acted on «ice» (+3); the same action «turn» (+2); the same place «gas» (+2); the same doer «heat» (+1). · [the question and its options parsed, with trees and pragmatics](https://md.mova.elamur.ai/free/en/corpora/questions/space/15-pluto-the-kuiper-belt-the-oort-cloud-and-comets/t11/) ### Test 12 · ★★ · wrong ✗ {#t12} lol Rosetta landed on a comet? no way. what did it really do - **1.** Scooped up a comet and brought it back to the Earth whole — **← Mova's choice** · no support - **2.** Crashed into Halley's Comet on purpose to see inside it — no support - **3.** Flew past Pluto taking photos of its heart-shaped plain — no support - **4.** Orbited Comet 67P and dropped the Philae lander on it — **✓ the right answer** · no support **Why:** No option found support in what it remembers, so it guessed: it took the first option shown. · [the question and its options parsed, with trees and pragmatics](https://md.mova.elamur.ai/free/en/corpora/questions/space/15-pluto-the-kuiper-belt-the-oort-cloud-and-comets/t12/) ### Exam question 1 · formal language · right ✓ {#e1} Identify the principal reason for which Pluto was reclassified as a dwarf planet in the year two thousand and six. - **1.** It ceased to orbit the Sun — no support - **2.** Its diameter was found to have diminished — no support - **3.** It was found to be a satellite of Neptune — no support - **4.** It has not cleared its orbit of comparable bodies — **← Mova's choice** · **✓ the right answer** · score 3 **Why:** It took the question to ask which statement is true. It chose option 4 with score 3, the only option with support. Its support: lesson 15, line 7: «In 2006 astronomers reclassified Pluto as a dwarf planet because it has not cleared its orbit of other similar objects.», reached through a sentence linked to the one the question matched. What matched: the same action «clear» (+2); the same thing acted on «orbit» (+2). Against it: a different doer (counts against) (-1). · [the question and its options parsed, with trees and pragmatics](https://md.mova.elamur.ai/free/en/corpora/questions/space/15-pluto-the-kuiper-belt-the-oort-cloud-and-comets/e1/) ### Exam question 2 · formal language · wrong ✗ {#e2} Select the response that is consistent with the established facts concerning the orientation of cometary tails. - **1.** They are invariably directed towards the Earth — **← Mova's choice** · no support - **2.** They trail behind the comet in all positions — no support - **3.** Both tails are directed towards the Sun — no support - **4.** Both tails are directed away from the Sun — **✓ the right answer** · no support **Why:** Nothing it remembers matched the question, so it guessed: it took the first option shown. · [the question and its options parsed, with trees and pragmatics](https://md.mova.elamur.ai/free/en/corpora/questions/space/15-pluto-the-kuiper-belt-the-oort-cloud-and-comets/e2/) ### Exam question 3 · formal language · right ✓ {#e3} State the interval at which Halley's Comet returns to the vicinity of the Sun. - **1.** Approximately seventy-six years — **← Mova's choice** · **✓ the right answer** · no support - **2.** Approximately one thousand years — no support - **3.** Approximately one year — no support - **4.** Approximately seven days — no support **Why:** No option found support in what it remembers, so it guessed: it took the first option shown. · [the question and its options parsed, with trees and pragmatics](https://md.mova.elamur.ai/free/en/corpora/questions/space/15-pluto-the-kuiper-belt-the-oort-cloud-and-comets/e3/) ### Exam question 4 · formal language · right ✓ {#e4} Ascertain the origin of the meteor shower designated the Perseids. - **1.** The eruption of terrestrial volcanoes during the month of August — no support - **2.** The collapse of distant stars within the constellation Perseus — no support - **3.** The gradual fragmentation of the Moon under terrestrial tides — no support - **4.** The passage of the Earth through dust shed by a comet — **← Mova's choice** · **✓ the right answer** · score 3 **Why:** It took the question to ask which statement is true. It chose option 4 with score 3, the only option with support. Its support: lesson 15, line 5: «Comets leave dust along their path, and when the Earth runs through that dust every year we see a meteor shower, such as the Perseids in August.», reached through the same lesson line as the sentence the question matched. What matched: the same doer «earth» (+2); the same place «dust» (+2). Against it: a different action (counts against) (-1). · [the question and its options parsed, with trees and pragmatics](https://md.mova.elamur.ai/free/en/corpora/questions/space/15-pluto-the-kuiper-belt-the-oort-cloud-and-comets/e4/) - ← previous: [14. Uranus and Neptune](https://md.mova.elamur.ai/free/en/school-run/space/14-uranus-and-neptune/) - next →: [16. Meteors, meteorites and shooting stars](https://md.mova.elamur.ai/free/en/school-run/space/16-meteors-meteorites-and-shooting-stars/) - ↑ back to [Space](https://md.mova.elamur.ai/free/en/school-run/space/)