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Every star you see is in our Milky Way, the time
to look is nigh |
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September 29, 2017 |
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Every visible star is within Milky Way
By Deborah Byrd
EarthSky.org
What could be better than a beautiful night
under the Milky Way? But did you know that every
night of your life is a night under the Milky
Way? By that we mean … every individual star you
can see with the unaided eye, in all parts of
the sky, lies within the confines of our Milky
Way galaxy. And the best night of the year to
see it is approaching.
Our galaxy is estimated to be some 100,000
light-years wide and only about 1,000
light-years thick. That’s why the starlit band
of the Milky Way, which is visible in the
evening this month, appears so well defined in
our sky. Gazing into it, we’re really looking
edgewise into the thin plane of our own galaxy.
The image above gives you an idea of the awesome
beauty of our Milky Way galaxy in the night sky.
It’s mosaic of multiple shots on large-format
film. It comprises all 360 degrees of the galaxy
from our vantage point. Photography was done in
Ft. Davis, Texas for the northern hemisphere
shots and from Broken Hill, New South Wales,
Australia, for the southern portions.
Note the dust lanes, which obscure our view of
some features beyond them. Note that the galaxy
is brightest at its center, where most of the
stars – and a possible hidden giant black hole –
reside. This image shows stars down to 11th
magnitude – fainter than the eye alone can see.
Still, if you’re standing under a clear, dark
night sky, you’ll see the Milky Way clearly as a
band of stars stretched across the sky on late
summer evenings.
The band of the Milky Way is tough to see unless
you’re far from the artificial lights of the
city and you’re looking on a night when the moon
is down.
At present, the waxing gibbous moon is washing
the fainter stars of the Milky Way from the
night sky After today – September 29 – the
waxing moon will stay out longer each night,
until the full Harvest Moon arrives on October
5.
By October 10 or thereabouts, the waning moon
will provide moon-free skies for an evening view
of the Milky Way.
If you do look in a dark country sky, you’ll
easily spot the Milky Way. And, assuming you’re
looking from the Northern Hemisphere, you’ll
notice that it gets broader and richer in the
southern part of the sky, in the direction of
the constellations Scorpius and Sagittarius.
This is the direction toward the galaxy’s
center. If you’re in the Southern Hemisphere,
the galactic center is still in the direction of
Sagittarius. |
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