ORIGINS:
FOURTEEN BILLION YEARS OF COSMIC EVOLUTION,
by Neil deGrasse Tyson and Donald Goldsmith,pp.116-117 (W.W. Norton &
Co., NY, London:2004)
“The
most deeply resonant of all the galaxy images that we may ever see, a
view of the entire Milky Way taken from outside it, will stir our
hearts and minds, just as soon as we manage to send a camera several
hundred thousand light-years above or below the central plane of our
galaxy. Today, when our most far-flung space probes have traveled a
billionth of that distance, this goal may seem unattainable, and
indeed even a probe that could reach nearly the speed of light would
require a long wait—far longer than the current span of recorded
history—to yield the desired result. For the time being,
astronomers must continue to map the Milky Way from inside, sketching
the galactic forest by delineating its stellar and nebular trees.
These efforts reveal that our galaxy closely resembles our closest
large neighbor, the great spiral galaxy in Andromeda. Conveniently
located about 2.4 million light-years away, the Andromeda galaxy has
provided a wealth of information about the basic structural patterns
of spiral galaxies, as well as about different types of stars and
their evolution...On a clear night far from city lights, a keen-eyed
observer who knows where to look can spot the fuzzy outline of the
Andromeda galaxy—the most distant object visible to the unaided
eye, shining with light that left on its journey while our ancestors
roamed the gorges of Africa in search of roots and berries.”
