How a star's mass decides its life
Grade 9 Science Worksheet - Challenge Me
Circle the best answer.
White dwarf below about 8 Suns; neutron star about 8 to 20; black hole about 20 or more (sources vary). A newly found main-sequence star is blue, with about 25 Sun masses. Which life story fits it, by Esme's reading?
- A short life, a supernova, then probably a black hole
- A long life ending in a supernova
- A long life of billions of years ending as a white dwarf
- A short life ending as a white dwarf
A red main-sequence star has about 0.2 Sun mass. Which life story fits it, by Jun's reading (NASA)?
- A short life ending in a supernova
- A very long life with no explosion
- A few million years, then a black hole
- It ends as a neutron star
Luz's friend says black holes roam space pulling in everything like vacuum cleaners. Which response is best (NASA)?
- Disagree: black holes have no gravity
- Disagree: from far away its gravity acts like any object of the same mass
- Agree: nothing nearby can stay in orbit
- Agree: they pull in whole galaxies quickly
Star card with two branching paths split at about 8 Sun masses. Milo's cousin says every star ends in a supernova. Which response is best?
- Agree: that is how stars finish fusing
- Disagree: only stars above about 8 Sun masses do
- Disagree: stars do not explode
- Agree: the Sun will end that way too, in a supernova
Fusion ladder from hydrogen to iron, with a stop sign at iron. Noah's friend says a massive star could keep going by fusing its iron. Which response is best (NASA)?
- Agree: iron is the richest fuel
- Disagree: massive stars stop at carbon
- Agree: iron fusion releases the most energy of any fuel in the core
- Disagree: iron fusion takes in energy, so the core collapses
Drawing of an expanding shell of glowing gas. NASA studies the remnant of a supernova seen in 1572, about 13,000 light-years away. What does a supernova spread into space, by Pia's reading?
- Light, but no matter
- Nothing; its matter falls into a black hole
- Elements that enrich future clouds and stars
- Pure hydrogen, just as it was after the Big Bang
In a star cluster that formed all at once, every star above 5 Sun masses has left the main sequence. What does this show, by Ren's reading?
- It is older than the life of a 5-Sun star
- Low-mass stars left first
- Its heavy stars kept fusing iron and still shine
- It is younger than any star's life
Which leftover is denser, by Zee's reading (NASA)?
- They are equally dense
- A white dwarf, since it is bigger
- A neutron star: more than the Sun's mass in a city-sized ball
- A red giant
About 8 to 20 Suns, neutron star; about 20 or more, black hole. Why do neutron stars and black holes come from stars of different masses, by Ari's reading (NASA)?
- Black holes come from the lightest stars
- Above about 20 Suns, the core is too massive to stop as a neutron star
- Neutron stars come from stars that do not explode
- Black holes form when stars pull in their planets
Supernova threshold 7 to 10 Sun masses; star mass 2 Suns. Sources put the supernova threshold anywhere from 7 to 10 Sun masses. Which statement about a 2-Sun-mass star holds for every source, by Bo's reading?
- It ends in a supernova
- It becomes a neutron star
- It ends as a white dwarf
- It becomes a black hole