Pluto is no longer classified as a planet.

A type B9 star is hotter than a type A0 star.

For a moon the same density as its planet, the Roche limit lies at ________ times the radius of its planet.

White dwarfs lie on the lower left portion of the H-R diagram.

Compared to a type A0 star, a type A9 star is

What is the event horizon of a black hole?

Most stars are single stars like our own.

A loop of gas following the magnetic field lines between sunspots’ poles is

The outward pressure of hot gas in the Sun

A parsec is about 3.3 light-years.