Q 01/05

A neutron star is the gravitationally collapsed core of what kind of object?

A) A low-mass red dwarf

B) A Sun-like yellow dwarf

C) A massive supergiant

D) A brown dwarf

Answer · why

C) A massive supergiant

A massive supergiant has a core heavy enough to collapse when its fuel runs out, whereas a star like the Sun simply fades into a white dwarf and never...

Q 02/05

A typical neutron star packs more mass than the Sun into a ball about as wide as what?

A) A city

B) The Moon

C) The Earth

D) Jupiter

Answer · why

A) A city

A city is the usual comparison: the star is only about 20 kilometres across, and its gravity is strong enough to bend light from its far side into vie...

Q 03/05

Which class of objects is the only one denser than neutron stars?

A) Black holes

B) Quasars

C) White dwarfs

D) Brown dwarfs

Answer · why

A) Black holes

Black holes are what a collapsing core becomes when it is too heavy even for packed neutrons to hold up, which leaves a neutron star as the densest ob...

Q 04/05

Collisions between neutron stars are thought to forge much of the universe's supply of which element?

A) Gold

B) Iron

C) Carbon

D) Oxygen

Answer · why

A) Gold

Gold and platinum were among the freshly made heavy elements reported in the glow of the first neutron-star collision ever observed, while carbon, oxy...

Q 05/05

About how many neutron stars are thought to exist in the Milky Way?

A) Around ten thousand

B) Around one million

C) Around one billion

D) Around one trillion

Answer · why

C) Around one billion

Around one billion is the usual estimate, worked out from how many stars have exploded over the galaxy's history, and most of them have long since coo...