The Range of Stellar Lifetimes
The tables in the adjacent frame indicate that there is an enormous range of lifetimes on the main
sequence for stars of different masses. On the one hand, the most massive stars spend only a million years,
there, hardly the
twinkling of an eye on the cosmic timescale. On the other, the lower mass stars have
lifetimes on the main sequence that are older than the present age of the Universe (thus, none of those stars
have yet had time to leave the main sequence).