in 2005, astronomer Warren Brown of the Harvard-
Smithsonian Center for Astrophysics discovered a
star that was moving at a speed of 1.5 million miles
per hour; a speed making it the fastest known star
in our galaxy

further, this speed was twice as great as that need-
ed to escape the gravitational filed of the Milky Way;
and therefore it was on its way to intergalactic space

Dr. Brown called this object "the outcast star"; and
since its discovery, seven more have been found -

they have become known as hypervelocity stars

in the video below, Brown discusses the mystery
posed by speed of the outcast star and the deduc-
tive reasoning that allowed him to solve the case -

in hindsight it was elementary: a pair of orbiting
stars pass close to a supermassive black hole -

one of the two stars is captured by the black hole,
the other is flung out at colossal speed



the soundtrack of the above video is an excerpt
from a New Scientist podcast which can be heard
at Brown's website