How stars die

Tests: 3 of 12 right · Exam: 2 of 4 right · Kind: ★★★ · Understood: 10 of 16 · Run: 2026-10-18, commit f3c23ea72

Lesson 19 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.

Every question of this lesson and each of its options parsed by Mova, with trees and pragmatics: the lesson's questions in the corpora.

Test 1 · ★★★ · wrong ✗

Jack says Betelgeuse is gonna blow up tonight, he saw it on TikTok. what's true?

1. It is sure to explode tonight — no support
2. It will never explode — no support
3. It exploded last year — ← Mova's choice · score 3
4. It will explode sometime within about 100,000 years; nobody knows when — ✓ the right answer · score 3

Why: It took the question to ask which statement is true. It chose option 3 with score 3, tied with another option at 3 (the first shown, or the one claiming less beyond what it knows, wins). Its support: lesson 19, line 16: «Betelgeuse, Orion's red shoulder, is a dying red supergiant that will explode as a supernova sometime within about the next 100,000 years; nobody can say exact…», reached through the same lesson line as the sentence the question matched. What matched: the same action «explode» (+2); the same property (+1). The right option, 4, scored 3. · the question and its options parsed, with trees and pragmatics

Test 2 · ★★★ · wrong ✗

Will the Sun end in a supernova?

1. No, it will turn into a planet — ← Mova's choice · score 7
2. Yes, all stars explode at the end, whatever size they are — no support
3. No, it is not heavy enough; it will become a white dwarf — ✓ the right answer · score 6
4. Yes, in about 1,000 years — no support

Why: It took the question to ask which statement is true. It chose option 1 with score 7, against 6 for the next best. Its support: lesson 19, line 7: «In about 5 billion years the Sun will become a red giant, swallowing Mercury and Venus and possibly the Earth.», reached through the option's own match among the sentences about the question's things. What matched: the same doer «sun» (+4); the same action «become» (+3). The right option, 3, scored 6. · the question and its options parsed, with trees and pragmatics

Test 3 · ★★★ · wrong ✗

A pulsar's beam sweeps past the Earth 30 times a second. What does that tell you?

1. Aliens are sending 30 messages a second to the Earth — ← Mova's choice · no support
2. The star is 30 km wide and lights up once for each kilometre — no support
3. The star is 30 years old and flashes once for every year — no support
4. The neutron star spins 30 times a second — ✓ 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

Test 4 · ★★★ · wrong ✗

Two dead stars are compared: one is the size of the Earth, the other only 20 km across but heavier. Which is which?

1. Both are red giants — ← Mova's choice · no support
2. Both are white dwarfs — no support
3. The first is a neutron star, the second a white dwarf — no support
4. The first is a white dwarf, the second a neutron star — ✓ 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

Test 5 · ★★★ · wrong ✗

In 1054 people saw a star by day where there had been none. Why did they call it a guest star?

1. It came from another galaxy to visit our sky for a while — ← Mova's choice · score 5
2. A guest at a feast saw it first — score 3
3. It was the Sun's partner star — score 5
4. It appeared, stayed a while and faded, like a visitor — ✓ the right answer · no support

Why: It took the question to ask why something happens (its cause). It chose option 1 with score 5, tied with another option at 5 (the first shown, or the one claiming less beyond what it knows, wins). Its support: lesson 17, line 14: «Many stars are not alone but come in pairs or groups orbiting each other, and Sirius has a tiny white dwarf partner.», reached through the option's own match among the sentences about the question's things. What matched: the same doer «many stars» (+3); the same action «come» (+2). The right option, 4, found no support in what it remembers. · the question and its options parsed, with trees and pragmatics

Test 6 · ★★★ · right ✓

bloody hell, my gold ring was made by crashing stars??

1. No, gold is made by the Sun every day and falls to the Earth as dust — no support
2. No, all gold is made slowly in the Earth's rocks by heat and pressure — no support
3. Yes, but only the gold that is found on the Moon, not on the Earth — no support
4. Much gold is thought to come from neutron stars crashing together — ← Mova's choice · ✓ the right answer · score 9

Why: It took the question to ask which statement is true. It chose option 4 with score 9, the only option with support. Its support: lesson 19, line 15: «Much of the gold in the universe is thought to be made when two neutron stars crash together, an event first observed in 2017.», reached through the option's own match among the sentences about the question's things. What matched: the same doer «two neutron stars» (+4); the same action «crash» (+3); the same property (+2). · the question and its options parsed, with trees and pragmatics

Test 7 · ★★★ · right ✓

If the Sun became a red giant tomorrow (it won't), what would happen to Mercury?

1. It would be swallowed up — ← Mova's choice · ✓ the right answer · score 6
2. It would turn into a comet — score 4
3. It would become a moon of the Earth — score 4
4. It would be pushed out past Pluto — no support

Why: It took the question to ask what happens next. It chose option 1 with score 6, against 4 for the next best. Its support: lesson 19, line 7: «In about 5 billion years the Sun will become a red giant, swallowing Mercury and Venus and possibly the Earth.», reached through what followed the sentence the question matched. What matched: the same action «swallow» (+4); the same doer «sun» (+4). Against it: a different thing acted on (counts against) (-2). · the question and its options parsed, with trees and pragmatics

Test 8 · ★★★ · wrong ✗

A cartoon shows a planetary nebula with planets inside it. what's wrong

1. Nothing, it is a nest where baby planets grow inside the gas cloud — ← Mova's choice · score 7
2. It is a glowing shell of gas from a dying star, with no planets — ✓ the right answer · score 3
3. It should be a single giant planet — no support
4. It should show the Earth's clouds — no support

Why: It took the question to ask which statement is true. It chose option 1 with score 7, against 3 for the next best. Its support: lesson 2, line 11: «Close to the Sun only rock and metal could stay solid, but beyond the frost line, around where the asteroid belt is now, ice could form too, so the outer plane…», reached through the option's own match among the sentences about the question's things. What matched: the same doer «outer planets» (+4); the same action «grow» (+3). The right option, 2, scored 3. · the question and its options parsed, with trees and pragmatics

Test 9 · ★★★ · wrong ✗

Why could people in Britain not see the 1987 supernova with their own eyes?

1. It happened only in the daytime — ← Mova's choice · no support
2. It was in the Large Magellanic Cloud, seen from the southern hemisphere — ✓ the right answer · no support
3. It was hidden behind Jupiter — no support
4. It was too faint for anyone's eyes — 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

Test 10 · ★★★ · right ✓

Which star would end as a neutron star or worse rather than a white dwarf?

1. A small red dwarf — score 8
2. One 15 times heavier than the Sun — ← Mova's choice · ✓ the right answer · score 12
3. One half as heavy as the Sun — score 12
4. The Sun — score 9

Why: It took the question to ask who or what does it. It chose option 2 with score 12, tied with another option at 12 (the first shown, or the one claiming less beyond what it knows, wins). Its support: lesson 19, line 10: «Stars more than about 8 times as heavy as the Sun end in a supernova, an explosion that for weeks can outshine a whole galaxy.», reached through the remembered sentence the question matched. What matched: the same circumstance (+6); the same action «end» (+4); the same property (+3). Against it: a different doer (counts against) (-1). · the question and its options parsed, with trees and pragmatics

Test 11 · ★★★ · wrong ✗

who found pulsars, some old professor?

1. Yes, Isaac Newton found them in 1687 with his telescope — ← Mova's choice · score 7
2. Yes, Galileo in 1610 — score 7
3. No, a student, Jocelyn Bell Burnell, in 1967 — ✓ the right answer · score 6
4. No, a space probe in 2017 — score 1

Why: It took the question to ask who or what does it. It chose option 1 with score 7, tied with another option at 7 (the first shown, or the one claiming less beyond what it knows, wins). Its support: lesson 19, line 14: «In 1967 Jocelyn Bell Burnell, a student from Northern Ireland, discovered pulsars, spinning neutron stars that sweep beams of radio waves past the Earth like a…», reached through the remembered sentence the question matched. What matched: the same action «discover» (+4); the same thing acted on «pulsars» (+4). Against it: a different doer (counts against) (-1). The right option, 3, scored 6. · the question and its options parsed, with trees and pragmatics

Test 12 · ★★★ · wrong ✗

A white dwarf weighs about half as much as the Sun but is only as big as the Earth. What follows?

1. It must be cold and made of ice — ← Mova's choice · score 8
2. It must be hollow inside — score 6
3. Its matter is packed incredibly tightly — ✓ the right answer · score 4
4. It is made of light gas like a balloon — no support

Why: It took the question to ask who or what does it. It chose option 1 with score 8, against 6 for the next best. Its support: lesson 7, line 4: «The Moon's gravity also tugs the oceans into bulges, so the sea goes in and out twice a day, and at new and full Moon the Sun helps pull to make the biggest sp…», reached through the remembered sentence the question matched. What matched: the same action «make» (+4); it fills the role the question asks for (+3); the same doer «sun» (+1). The right option, 3, scored 4. · the question and its options parsed, with trees and pragmatics

Exam question 1 · formal language · wrong ✗

Identify the final remnant of a star of a mass comparable to that of the Sun.

1. A protostar — ← Mova's choice · no support
2. A supernova — no support
3. A white dwarf — ✓ the right answer · no support
4. A neutron star — 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

Exam question 2 · formal language · right ✓

Select the response that is consistent with the established facts concerning stars exceeding approximately eight solar masses.

1. They terminate their existence in a supernova — ← Mova's choice · ✓ the right answer · score 10
2. They endure for trillions of years — score 9
3. They are transformed into planets — score 4
4. They become planetary nebulae and nothing further — score 6

Why: It took the question to ask which statement is true. It chose option 1 with score 10, against 9 for the next best. Its support: lesson 19, line 10: «Stars more than about 8 times as heavy as the Sun end in a supernova, an explosion that for weeks can outshine a whole galaxy.», reached through the remembered sentence the question matched. What matched: the same doer «stars» (+4); the same action «end» (+3); the same place «supernova» (+3). · the question and its options parsed, with trees and pragmatics

Exam question 3 · formal language · wrong ✗

State the name of the person credited with the discovery of pulsars in the year nineteen hundred and sixty-seven.

1. Galileo Galilei — ← Mova's choice · no support
2. William Herschel — no support
3. Jocelyn Bell Burnell — ✓ the right answer · no support
4. Clyde Tombaugh — 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

Exam question 4 · formal language · right ✓

Ascertain the remnant of the stellar explosion recorded by Chinese astronomers in the year one thousand and fifty-four.

1. The Crab Nebula — ← Mova's choice · ✓ the right answer · no support
2. The Eagle Nebula — no support
3. The Pleiades — no support
4. The Large Magellanic Cloud — 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

This page in Markdown → https://md.mova.elamur.ai/free/en/school-run/space/19-how-stars-die/